Feasibility and cost-effectiveness of standardised second-line drugtreatment for chronic tuberculosis patients: a national cohortstudy in Peru
Pedro G Suárez, Katherine Floyd, Jaime Portocarrero, Edith Alarcón, Elisabetta Rapiti, Gilbert Ramos, Cesar Bonilla, Ivan Sabogal, Isabel Aranda, Christopher Dye, Mario Raviglione, Marcos A Espinal
IntroductionMultidrug-resistant (MDR) tuberculosis—ie, resistance to
Background There are no data on the feasibility and cost-
at least rifampicin and isoniazid—is a threat to
effectiveness of using second-line drugs to treat patients with
tuberculosis control efforts in some countries.1,2 Patients
chronic tuberculosis, many of whom are infected with
with MDR tuberculosis often do not respond to short-
multidrug resistant (MDR) strains of Mycobacterium
course chemotherapy with first-line drugs.3
tuberculosis, in low or middle-income countries.
treatment with second-line drugs may be needed to curethese individuals and to curtail transmission of such
Methods A national programme to treat chronic tuberculosis
strains of Mycobacterium tuberculosis. However, data from
patients with a directly observed standardised 18-month daily
low-income or middle-income countries on the
regimen, consisting of kanamycin (3 months only),
management of MDR tuberculosis with second-line drugs
ciprofloxacin, ethionamide, pyrazinamide, and ethambutol,
under programme conditions are not available. As a
was established in Peru in 1997. Compliance and treatment
result, international public-health institutions, including
outcomes were analysed for the cohort started on treatment
the WHO, do not have definitive policy recommendations
between October, 1997, and March, 1999. Total and average
in place; guidelines exist only for specialised centres where
costs were assessed. Cost-effectiveness was estimated as
resources that permit treatment are available.4 Treatment
of MDR tuberculosis is, however, available in more-developed countries.5,6
Findings 466 patients were enrolled; 344 were tested for
After results of a survey of drug-resistant tuberculosis
drug susceptibility and 298 (87%) had MDR tuberculosis.
showed an MDR prevalence of 16% among previously
225 patients (48%) were cured, 57 (12%) died, 131 (28%) did
not respond to treatment, and 53 (11%) defaulted. Of the
Programme introduced a standardised treatment regimen,
413 (89%) patients who complied with treatment, 225 (55%)
including second-line drugs, for patients who had failed to
were cured. Among MDR patients, resistance to five or more
respond to standard treatment with first-line drugs. Our
drugs was significantly associated with an unfavourable
aim was to assess the feasibility, effectiveness,
outcome (death, non-response to treatment, or default; odds
affordability, and cost-effectiveness of implementing such
ratio 3·37, 95% CI 1·32–8·60; p=0·01). The programme cost
US$0·6 million per year, 8% of the National TuberculosisProgramme budget, and US$2381 per patient for those who
completed treatment. The mean cost per DALY gained was
$211 ($165 at drug prices projected for 2002).
Peru is a middle-income country that had a per capitaGross National Income of US$2390 in 1999.7 The DOTS
Interpretation Treating chronic tuberculosis patients with high
strategy was introduced in 1991 and is now implemented
levels of MDR with second-line drugs can be feasible and
in all health facilities.8,9 WHO targets for tuberculosis
cost-effective in middle-income countries, provided a strong
control (70% case detection and 85% cure rate among
tuberculosis control programme is in place.
new smear-positive pulmonary cases) have been achievedand sustained, as a result of which the incidence rate is
Lancet 2002; 359: 1980–89. Published online May 14, 2002.
http://image.thelancet.com/extras/01art7269web.pdf
Before 1997, the treatment policy in Peru was limited to
short-course chemotherapy with first-line drugs. All newly-diagnosed tuberculosis cases are administered a treatmentregimen consisting of an intensive phase of isoniazid,rifampicin, ethambutol, and pyrazinamide for 2 months,followed by a continuation phase with rifampicin andisoniazid for 4 months. Patients who do not respond to thetreatment regimen or default with this regimen, or who arecured but later relapse, are given a re-treatment regimen,which involves five drugs in the 3-month intensive phase of
National Tuberculosis Control Programme, Ministry of Health,
treatment (isoniazid, rifampicin, ethambutol, and pyrazi-
Lima, Peru (J Portocarrero MD, G Ramos MD, C Bonilla MD,
namide for 3 months; streptomycin for first 2 months
I Sabogal MD, I Aranda RN, P G Suárez MD, E Alarcón RN); and
only), and a continuation phase with rifampicin, isoniazid,
WHO, Geneva, Switzerland (K Floyd PhD, E Rapiti MPH, C Dye Dphil,
and ethambutol for 5 months. In both regimens, treatment
is administered daily in the intensive phase and twice a
Correspondence to: Dr Marcos Espinal, WHO, Stop TB Department,
week during the continuation phase. In each instance,
treatment is directly observed by health workers, and is
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method in the network of 1168 laboratories available in
Two categories of patient were eligible for the second-line
Peru at the time of the study. Quality control for smear
drug treatment programme introduced in October, 1997.
microscopy, culture, and drug susceptibility testing is
The first consisted of patients who remained sputum-
done routinely in Peru.11 In 1999, proficiency testing by
smear positive after completing a fully supervised re-
the WHO Supranational Reference Laboratory in
treatment regimen. These patients are defined as chronic
Argentina showed 100% agreement between the two
laboratories for identification of susceptibility to
subcategories. The first subcategory comprised patients
rifampicin, isoniazid, ethambutol, and streptomycin.
who had consecutively failed to respond to the standard
Cure was defined as two negative sputum smear
treatment and re-treatment regimens with first-line drugs
microscopy results or two negative culture results, or
under direct observation by a health worker. The second
both, at the end of treatment. Patients who did not
subcategory included patients who had been declared
respond to treatment were those who remained
cured in response to the standard treatment regimen with
bacteriologically positive at the end of treatment.
first-line drugs, but who later relapsed and failed to
Defaulters were patients who did not attend to take their
respond to the standard re-treatment regimen. The
drugs for 1 month or more at any time after registration.
second category consisted of patients defined asexceptions—for example, those whose previous treatment
Data management and statistical analysis
had not been administered under direct observation, or
At enrolment, we obtained data on demographic
involved regimens not recommended by the National
variables, clinical history, previous treatments for
tuberculosis, history of diseases other than tuberculosis,
We obtained written informed consent before giving
previous imprisonment, and previous hospital admission.
eligible patients a standardised 18-month daily regimen,
During treatment, staff recorded each dose of the drugs
consisting of kanamycin (1 g injectable), ciprofloxacin
administered, any adverse effects and how they were
(1 g orally), ethionamide (750 mg orally), pyrazinamide
managed, and radiological and bacteriological results.
(1500 mg orally), and ethambutol (1200 mg orally).
Data were collected in pretested standardised forms.
Kanamycin was administered only for the first 3 months.
Before analysis, electronic data were compared with
Treatment was provided on an ambulatory basis under
200 patient charts to verify their accuracy.
direct observation at a local health clinic.
Data were analysed with SPSS (version 7.5.2).
Univariate analysis included the 2 test for the
comparison of categorical variables. Crude and adjusted
Patients were enrolled between October, 1997, and
odds ratios and 95% CIs were calculated by logistic
March, 1999, in any of the 6435 health facilities that
regression to test for the relation between an unfavourable
provided tuberculosis services in Peru. An MDR
outcome—ie, death, non-response to treatment, or
tuberculosis unit was established as part of the National
default—and predictor variables. To adjust for possible
Tuberculosis Programme in Lima, to manage the
confounding effects, all variables were entered into
implementation of the treatment programme. This unit
multiple logistic regression models. Variables were
was staffed by a coordinator, two physicians, a nurse, and
selected for removal according to their biological
a data manager, and was in regular contact with the
importance and by backward elimination with the
tuberculosis coordinators of the 34 health regions of Peru.
A training programme, consisting of two nationalworkshops and several regional workshops, was
Cost-effectiveness was assessed from the perspective of
An expert committee of 12 lung specialists, public-
the public sector in year 2000 prices (in US$) with
health specialists, and laboratory specialists was
established in Lima to approve or reject requests from
programme described above was compared with two
the general health facilities to enrol patients. Requests
other strategies using second-line drugs. The first was
for enrolment followed a standardised approach, which
identical to the standardised treatment programme,
included submission of the patients’ medical history,
except that patients who do not respond to treatment on
previous treatments received and outcomes, and the
this programme are given the additional option of
latest smear microscopy, culture, and drug susceptibility
treatment with an individualised regimen, tailored to their
test results. Decisions of the committee to approve or
drug susceptibility pattern. The second was a new
reject access to drugs were by consensus.
strategy proposed for national implementation in 2001.
Patients were seen daily by nurses for administration
This approach also includes provision of individualised
of drugs and monitoring of any adverse effects
treatment to patients not responding to the standardised
associated with treatment, and monthly by doctors for a
second-line drug treatment programme. However, in
medical check-up. To discourage defaulting from
addition, patients who do not respond to the first-line
treatment, the guidelines of Peru’s National
treatment regimen are tested for MDR. Those identified
Tuberculosis Programme were followed: patients were
with MDR tuberculosis are enrolled in the standardised
provided, for example, with an appointment card and a
second-line drug treatment programme, instead of the
weekly food parcel. Baseline and monthly follow-up
first-line re-treatment regimen. For each of the three
cultures of sputum samples from which to isolate
alternative strategies, cost-effectiveness was calculated
according to a strategy’s total incremental costs and
75 laboratories that were doing cultures in Peru between
effects compared with a situation where second-line drugs
1997 and 1999. Cultures were done on a Löwenstein-
are not available and treatment is confined to isoniazid
Jensen medium. Drug susceptibility testing of first-line
monotherapy—ie, the analysis focused on the increase in
drugs was done with the proportion method at the
total costs and effects associated with the use of second-
National Institute of Health laboratory in Lima.
line drugs. This was justified on the basis that most low-
Baseline and monthly follow-up sputum smear
income and middle-income countries routinely provide
microscopy analyses were done by the Ziehl-Neelsen
treatment with first-line drugs through government
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Variable value (distribution Referencewhere applicable)*
Cost of individualised treatment Cost of drugs plus other costs per patient treated (US$)
Three scenarios assessed: 4, 18, 19, 201) 2500 2) 5000 3) 10 000
General variables related to effectivenessPrevalence of MDR among patients who do not respond to first-line treatment regimen (%)
Self-cure rate among chronic patients (%)
Treatment outcomes on the re-treatment regimen for patients who do not respond to first treatment regimen
Treatment outcomes on the re-treatment regimen for patients who do not respond to first treatment regimen and do not have MDR
Treatment outcomes for patients who are treated with the standardised second-line drug regimen immediately after failing to respond to the first regimen and being found to have MDR (ie, the re-treatment regimen is not used)
Treatment outcomes for patients treated with individualised treatment regimen after non-response to the standardised second-line drug regimen¶
Long-term death rate from tuberculosis, chronic patients not receiving treatment with
second-line drugs (%)Long-term death rate from tuberculosis among patients who do not respond to treatment
with second-line drugs (%)Long-term relapse rate among those initially cured with regimens that include second-line drugs (%)
Death rate from tuberculosis among patients initially cured with regimens that include second-line
drugs, but who later relapse (%)Death rate among patients who default (%)
for chronic cases with no access to second-line drugs
Average period of survival for patients who die after failing to respond to treatment with first-line drugs,in the absence of treatment with second-line drugs (years)
Discount rate for valuing health gains arising in the future (%)
Average health gain associated with one averted death (DALYs)**
Variables specifically related to effects associated with the impact of treatment on transmissionCase reproduction number for chronic tuberculosis when no treatment with second-line drugs is
available††—ie, average number of secondary cases produced by primary case in the next generation. Case reproduction number for chronic tuberculosis, in the presence of treatment with second-line drugs
infectiousness in presence amount of of treatmentϬaverage transmission
for chronic tuberculosis when no treatment with second-line drugs is available
Total number of secondary cases arising g years in the future, where g=generation time in years
and R is the case reproduction numberTotal number of secondary cases arising in the future, where r is the total number of secondary
cases arising g years in the future and g is the generation time in years, ie, r=Re–0·03ϫg
Average duration of infectiousness, chronic case not treated with second-line drugs (years)
Average duration of infectiousness, chronic case treated with second-line drugs whose outcome is
re-treatment regimen considered in the analysis
Average duration of infectiousness, when final outcome is non-response to treatment (years)
treatment from point of entry into the analysis
Average duration of infectiousness, non-responders to the treatment regimen who are cured on the
re-treatment regimen (years)Average duration of infectiousness, patients who are cured on the standardised second-line drug
re-treatment regimen considered in the analysis
Average duration of infectiousness, patients who are cured on individualised treatment after not
responding to the standardised second-line drug treatment regimen (years)
re-treatment and standardised second-line drug regimen considered in the analysis
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Death rate for secondary cases on first-line treatment regimen (%)
Death rate for secondary cases on first-line treatment regimen among patients who default from
proportion of untreated chronic cases that die
Non-response rate for secondary cases on first-line treatment regimen (%)
Average cost per patient treated on the first-line treatment regimen for drugs plus all other costs (US$) 322
Average cost per patient treated on the re-treatment regimen for drugs plus all other costs (US$)
*Uniform=analysis used values chosen at random between the lower and upper figures specified for the distribution; normal=first number specifies the mean and thesecond number the SD that define the distribution. †Unpublished—details available upon request. ‡Values chosen on the assumption that the cure rate for patientswithout MDR would be higher than the overall cure rate among all patients who do not respond to the first-line treatment regimen. §Values chosen on assumption thatthe cure rate would be slightly higher than for the cohort treated 1997–99, due to earlier use of second-line drugs. ¶Since most data were from industrialised countrysettings, the lower limit for the cure rate was deliberately set as lower than the minimum cure rate reported and approximately equivalent to the cure rate achievedwith the standardised regimen used in Peru 1997–99. The higher rate was set as the proportion of those completing treatment multiplied by 0·8, to reflect the higherlevel of cure among those completing treatment reported in some studies,24 and which seems plausible based on data reported from Lima, Peru.22 ||Assumptionjustified on the basis that patients who default no longer receive treatment, and can therefore be expected to have treatment outcomes similar to those of chronictuberculosis patients with no access to second-line drugs. **Formula for calculating DALYs provided in reference given.28 Use of the formula requires data on theaverage age at onset of disease (30 years), and the average life expectancy at that age (40 years). ††Assumed to be between 0·5 and 1 to be conservative whenassessing cost-effectiveness. A less conservative assumption, which would improve (ie, lower) cost per DALY gained figures, would have been to assume that thecase reproduction number in the absence of treatment with second-line drugs would be equal to 1. ‡‡Value is conservative with respect to effectiveness and cost-effectiveness calculations (ie, value may lead to effectiveness being under-estimated) because the period on treatment is added to the duration of infectiousnessexpected in the absence of treatment. §§Value is conservative with respect to effectiveness and cost-effectiveness calculations (ie, value may lead to effectivenessbeing underestimated) because it is assumed that for those who cure, culture/smear conversion will take the same time as on the standardised second-line regimen,even though an individualised regimen is tailored to a patient’s drug susceptibility pattern.
Table 1: Variables and variable values used to estimate effectiveness and cost-effectiveness
services, but they do not routinely provide treatment with
reports,11,15,16 patient case notes, and a study of the
second-line drugs. The important question for policy-
economic impact of tuberculosis in Peru.17
making purposes is, therefore, what are the additional
In view of the uncertainty about several measures that
costs and effects associated with implementing second-line
affect effectiveness, and the cost of individualised
treatment in middle-income countries, effectiveness and
Treatment costs in the absence of second-line drugs
cost-effectiveness were estimated as part of a multivariate
were assessed as zero. This was justified in view of the low
uncertainty analysis. This analysis involved three main
price of isoniazid (US$0.01 per 100 mg dose in Peru) and
the possibility that use of health services is infrequent. For
First, a spreadsheet model was developed in Microsoft
the standardised second-line drug treatment programme
Excel (version 7.0), in which treatment paths were defined
implemented between 1997 and 2000, two groups of costs
for each alternative strategy. The earliest starting point for
were considered: the average cost of individual
a treatment path was non-response to the first-line
components of treatment—eg, drugs, a visit for direct
treatment regimen, since this is the earliest point at which
observation of treatment (DOT), training—and the
patients become eligible for treatment with second-line
drugs in the three strategies assessed. However, the
Wherever possible, the costs of individual components
treatment paths for exceptions and relapse patients who
of treatment were calculated with an “ingredients”
did not respond to the first-line re-treatment regimen
approach—ie, the quantity of resources used was
started at a later point, to reflect when they become
combined with unit price data. The exceptions were: non-
eligible for treatment with second-line drugs and because
personnel recurrent inputs, for which there was only
treatment before this time is the same in each strategy.
expenditure data; and laboratory tests and radiographs, for
Second, the number of patients following each treatment
which only prices were available. Overhead tuberculosis
path, together with the associated costs and effects, was
programme costs—eg, supervision and management,
defined according to: the variables, variable values and
monitoring, and surveillance—were allocated equally
distributions, and data sources2–5,9,11,14,18–31 listed in table 1;
across all notified tuberculosis patients in Peru. Since staff
the costs per patient reported in this article; and the
time was judged to broadly indicate overall resource use
treatment outcomes associated with the standardised
for different types of patient in outpatient health facilities,
second-line drug regimen. The high cost scenario for
overhead clinic costs were allocated to tuberculosis
individualised treatment (US$10 000 per patient for drugs
patients in accordance with the fraction of clinic staff time
plus all other costs) was based on drug prices reported for
spent on their care. Vehicle and equipment costs were
low-income and middle-income countries in the absence of
annualised using current replacement prices, the
concessional prices,20 and allowance for other costs besides
assumption of a 5-year life expectancy, and a discount rate
drugs—such as those that applied to the standardised
of 3% (the currently recommended international rate).14
second-line drug treatment programme already
Start-up training costs were annualised over 3 years.
implemented. The intermediate cost scenario for
Building costs per year were based on rental values per
individualised treatment (US$5000 per patient for drugs
month. All local costs were converted into US$ according
plus all other costs) was chosen to reflect the cost per
to the average exchange rate in 2000 (US$1=Peruvian
patient that might apply with both concessional drug
prices20 and with allowance for the costs of other inputs
The average cost per patient treated was calculated as
being higher than those of the standardised second-line
the cost of each treatment component multiplied by the
drug treatment programme. The low-cost scenario for
average number of times this cost was incurred. This
individualised treatment represented an optimistic
calculation was done overall, and for three groups of
situation in which drugs are available at highly concessional
patients: those who completed the full course of
prices, and the costs of inputs besides drugs are similar to
treatment—ie, cures plus non-responders; those who died;
those of the standardised second-line drug treatment
programme. Normal distributions were used when
Sources of data included expenditure records, standard
mean (SD) could be calculated. If only range information
salary scales, a database maintained by the MDR unit in
was available, a uniform distribution across this range was
Lima, interviews with the National Tuberculosis
Programme staff, National Tuberculosis Programme
The third step was to run a Monte Carlo simulation,
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involving 5000 iterations, with @RISK (version 3.5), to
enrolled patients. 11 (2%) of the enrolled patients were
estimate means and lower and upper bounds (5th and 95th
excluded from our analysis; reasons included use of a non-
centiles) for the main outputs of interest. These outputs
standardised treatment regimen, and unfinished treatment.
were total costs, total and average (per patient treated)
Table 2 shows demographic characteristics according to
effects (cures, deaths averted, years of life gained, and
entry criteria. Susceptibility test results were available for
DALYs gained), and cost-effectiveness ratios (cost per
344 (74%) patients. 335 (97%) individuals were resistant
cure, cost per death averted, cost per year of life gained, and
to one or more drugs, 298 (87%) had MDR tuberculosis,
cost per DALY gained). To facilitate comparison with
and 273 (79%) were resistant to three or more drugs.
other health interventions, the cost-effectiveness results
During treatment, 242 (52%) individuals had adverse
focus on cost per DALY gained figures.
effects (table 3), leading to permanent interruption of oneor more drugs in 24 (5%) patients. An additional 61 (13%)
Sensitivity and threshold analysis
patients underwent drug adjustments during treatment—
A sensitivity analysis was done to assess the effect of
including the extension of kanamycin beyond 3 months and
reductions in the cost of the standardised second-line drug
addition of drugs such as isoniazid, clavulanic acid, and
regimen on total costs and cost-effectiveness ratios.
Projected drug prices were provided by WHO. A thresholdanalysis was done to identify the cost per patient at which
use of individualised regimens for MDR patients who do
Table 4 shows treatment outcomes. Of the 466 patients
not respond to the first-line treatment regimen would be as
analysed, 225 (48%) were cured. The proportion of cured
cost effective as the strategy proposed for national
patients increased to 55% (225 of 413) when patients who
complied with treatment (cured plus died plus non-responders) were evaluated, and to 63% (225 of 356)
when patients who completed chemotherapy (cured plus
The sponsors of the study had no role in study design, data
non-responders) were evaluated. Of the 225 patients
collection, data analysis, data interpretation, or writing of
cured, 210 (93%) and 215 (96%) had converted to
sputum smear negative status after 3 months and 6 months of treatment, respectively. Comparable figures
for culture conversion were 153 (68%) and 193 (86%).
Baseline characteristics and monitoring of participants
Of the 298 proven MDR tuberculosis cases, 136 (46%)
During enrolment, the committee assessed 755 requests to
were cured, 96 (32%) did not respond to treatment,
treat tuberculosis cases with second-line drugs; 477 (63%)
32 (11%) died, and 34 (11%) defaulted. Of the 264 MDR
were accepted. 21 of 34 health departments in Peru
tuberculosis patients who complied with treatment, 52%
Susceptibility test resultsMDR tuberculosis
Data are n (%). *Patients who are sputum positive at the end of a fully supervised re-treatment regimen with first-line drugs.
Table 2: Demographic characteristics and disease-related variables according to enrolment criteria
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Overall programme management, central level
Supervision at department and district levels
*Patients could have two or more side-effects simultaneously.
Side-effects and changed treatment (eg, added
Table 3: Adverse effects in 466 patients who underwent
*Patients treated on the standardised second-line drug regimen who died ontreatment received an average of 57 intensive phase doses and 64
were cured. Patients without susceptibility test results
continuation phase doses, whereas those who defaulted received an average
were less likely to fail treatment than those with MDR
of 59 intensive phase doses and 107 continuation phase doses. Average costs
(20 of 122, 16%, vs 96 of 298, 32%; p=0.001) and other
for patients who died and patients who defaulted were $1026 and $1209,respectively.
patterns of drug resistance (20 of 122, 16%, vs 13 of 37,
Table 5: Average cost per patient treated for patients who
35%; p=0·02). There was a significant increasing trend to
completed the full course of treatment,* standardised second-
fail the second-line drug regimen as the number of drugs
line drug treatment programme implemented in Peru
to which patients were resistant increased (p=0·02).
Of the 57 patients who died, 34 (60%) were
bacteriologically positive at the time of death and 23 (40%) had 3 months or less of treatment. Among
resistance to two drugs or less), and not responding to two
patients who defaulted from treatment, 27 (51%) were
consecutive treatment regimens with first-line drugs (0·61,
bacteriologically negative by the time they defaulted.
0·37–0·99; p=0·04; reference group: relapses of the
The average duration of treatment before default was
treatment regimen who subsequently did not respond to
6 months. Reasons for defaulting included feeling better,
the re-treatment regimen with first-line drugs). When
moving house, finding a new job, and mismanaged
MDR patients were assessed separately, the probability of
an unfavourable outcome in the presence of resistance to
In multivariate analysis, the final model for explaining
five or more drugs increased (3·37, 1·32–8·60; p=0·01).
an unfavourable outcome included sex, the number ofdrugs to which patients were resistant, and entry criteria.
An unfavourable outcome—ie, death, non-response,
The average cost per patient treated on the standardised
default—was significantly associated with two factors:
second-line drug treatment programme, for patients that
resistance to five or more drugs (odds ratio 2·94,
completed the full course of treatment, was US$2381
95%CI 1·26–6·85; p=0·01; reference group: drug
(table 5). Drugs, at US$824 per patient, were the greatest
NA=not available.*The number of smear and culture negative results declined over time due to the increase in the number of patients in the “defaulted” and “died”categories over time; in addition, not all patients maintained the same bacteriological status throughout treatment.
Table 4: Follow-up and treatment outcome in patients who underwent re-treatment with second-line drugs
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Standardised second-line Standardised second-line Standardised plus individualiseddrug treatment
individualised treatment 2001†for patients not responding to treatmentwith standardised second-line drug regimen
Cost indicatorsTotal annual cost in US$ millions
Affordability indicators‡Total annual cost as % National Tuberculosis
Programme budgetTotal annual cost as % total cost of tuberculosis
control in PeruTotal annual cost as % total Ministry of Health budget
Effectiveness indicatorsLong-term cure rate, all patients included in the analysis (%)§
Long-term cure rate, patients treated with second-line drugs (%)
Total deaths averted, excluding transmission benefits
Total deaths averted, including transmission benefits
Deaths averted per patient treated on second-line drugs,
excluding transmission benefits¶Deaths averted per patient treated on second-line drugs,
Cost-effectiveness indicators||Cost per DALY gained, excluding transmission benefits
Cost per DALY gained, including transmission benefits
*Year 2000 US$ prices for standardised second-line drug regimen and US$10 000 per patient for individualised treatment; †ie, as for strategy implemented1997–2000, with two modifications: (a) individualised treatment for patients who do not respond to the standardised second-line drug treatment regimen and (b) standardised second-line drug regimen for patients who do not respond to the treatment regimen with first-line drugs and who are diagnosed with MDR. ‡Affordability in relation to National Tuberculosis Programme (NTP) annual budget (approximately US$4 million) based on costs paid for from this budget;estimated annual cost of tuberculosis control US$23·8 million,17 Ministry of Health annual budget US$497 million. §n=500 (ie, treatment non-responders plusrelapses and exceptions); total number treated on second line drugs estimated as 295 per year for the programme implemented 1997–2000, 295 for the strategythat adds individualised treatment for patients not responding to standardised second-line drug treatment regimen, and 404 for the new strategy proposed fornational implementation in 2001. ¶Average figure for proposed strategy is lower because although more deaths are averted in total, more patients are also treatedon second-line drugs. ||Figures are not simply total annual costs divided by total effects, because they also incorporate the costs of treating the secondary casesthat are associated with each strategy. These costs amounted to about US$30 000–125 000, dependent on the strategy; incremental cost-effectiveness ratioswere calculated but are not shown; details available from the authors.
Table 6: Mean cost, affordability, effectiveness, and cost-effectiveness indicators for alternative strategies, highest costscenarios assessed* (5th and 95th centiles)
single cost item. Food parcels, DOT visits, consultations
depending on whether or not transmission was included in
with doctors, and the MDR tuberculosis unit in Lima also
the analysis, of increasing the total number of deaths
represented large costs. The total annual cost of the
averted by 17–42% (table 6). In the highest cost scenario,
programme was about US$0·6 million, with costs funded
the cost per DALY gained with these two strategies ranged
by the National Tuberculosis Programme equivalent to
from about US$200 to US$700, with means of US$368
8% of their budget (table 6). An average of 0·49 deaths
and US$484 (table 6). However, if the price of the
were averted per patient treated when benefits arising from
standardised second-line drug regimen fell to levels
prevented transmission were included; the figure was 0·36
projected for 2002, and the cost per patient treated with
when only deaths averted among treated patients were
individualised regimen was less than US$5000, the mean
considered. The mean cost per DALY gained, including
cost per DALY gained for both strategies would be
transmission benefits, was US$211 (range 126–339). At
drug prices projected for 2002, the mean cost per DALY
The threshold cost at which use of individualised
gained fell to US$165 (table 7), and the cost of the
regimens for MDR patients who do not respond to the
standardised regimen would be reduced even if
first-line treatment regimen would be as cost effective as
capreomycin was used instead of kanamycin, and ofloxacin
the strategy proposed for national implementation in 2001
was used instead of ciprofloxacin (drug cost US$753 vs
was US$1500–6000 per patient (figure).
US$824 for patients completing treatment).
The total costs of the two alternative strategies with
second-line drugs varied considerably. In the highest cost
These data from Peru provide evidence with respect to the
scenario, in which individualised treatment was assumed
feasibility and cost-effectiveness of providing standardised
to cost US$10 000 per patient, total annual costs were
second-line drug treatment for chronic tuberculosis
between US$1·3 million and US$2·0 million, and around
patients among whom MDR prevalence is high, under
one quarter to one third of the National Tuberculosis
programme conditions and on a national basis, in a
Programme budget (table 6). At lower estimates of the cost
middle-income country. They show that Peru’s National
of individualised treatment, and with projected reductions
Tuberculosis Programme was able to achieve a
in the cost of the standardised second-line drug regimen,
compliance rate of nearly 90%, a cure rate of almost 50%
total costs fell to around 10–20% of the National
among all patients enrolled, and a cure rate of 63% among
Tuberculosis Programme budget (table 7).
those who completed the full course of treatment. The
Compared with the standardised programme, both
total programme cost was affordable in the context of the
strategies that included individualised treatment were
National Tuberculosis Programme’s budget, and the
estimated to be capable of raising cure rates and,
mean cost per DALY gained was around US$150-200.
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Mean total annual cost in US$ millions (costs funded by NTP
Cost per DALY gained (5th and 95th centiles)*
Standardised regimen Standardised regimen Standardised regimen Standardised regimen Standardised regimen Standardised regimenat projected prices for at projected prices for at projected prices for at projected prices for at projected prices for at projected prices for 2002, individualised
line drug treatment programme imple-mented 1997–2000
line drug treatment programme plus individualised treatment for patients not responding to treatment withstandardised second-line drug regimen
individualisedtreatment strategyproposed forimplementationin 2001†
NTP=National Tuberculosis Programme. *Includes costs and effects associated with transmission. †ie, as for strategy implemented 1997–2000, with twomodifications: (a) individualised treatment for patients who do not respond to the standardised second-line drug treatment regimen and (b) standardised second-line drug regimen for patients who do not respond to the treatment regimen with first-line drugs and who are diagnosed with MDR.
Table 7: Cost and cost-effectiveness indicators for alternative strategies under different cost assumptions
We believe that the feasibility of using second-line
tuberculosis unit operating within the overall framework
drugs nationwide relied on three key factors. First, the
of the National Tuberculosis Programme, facilitating co-
new service was built on a tuberculosis control
programme that had already achieved WHO’s global
Our results are consistent with previous observations
tuberculosis control targets with first-line drugs.8,9
that cure rates for patients with chronic disease who
Second, there was a special committee to filter requests
complete treatment range from around 60% to 80% when
for access to second-line drugs, which allowed the
second-line drugs are used,24 and with a study of
National Tuberculosis Programme to benefit from the
treatment outcomes for patients with MDR-tuberculosis
best expertise available in the country, and to screen out
in the USA.5 They are poorer than figures reported for
candidates for whom treatment with first-line drugs was a
patients with MDR tuberculosis in the Netherlands and
more appropriate option. Third, there was an MDR
Canada, but in these studies a large proportion of patients
Standardised second-line drug regimen at 2002 projected prices, individualised treatment US$10 000 per patient, including transmission
Standardised second-line drug regimen at 2002 projected prices, individualised treatment US$10 000 per patient, excluding transmission
Standardised second-line drug regimen at 2002 projected prices,
individualised treatment US$5 000 per patient, including transmission
Standardised second-line drug regimen at 2002 projected prices,
individualised treatment US$5 000 per patient, excluding transmission
Standardised second-line drug regimen at 2002 projected prices, individualised treatment US$2 500 per patient, including transmission
Standardised second-line drug regimen at 2002 projected prices, individualised treatment US$2 500 per patient, excluding transmission
Threshold cost per patient treated (US$) 1000
Threshold costs for individualised treatment of patients with MDR who do not respond to the first-line treatment regimen and arediagnosed with MDR when compared with strategy proposed for national implementation in 2001
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had no history of previous treatment.18,23 Cure rates are
our assumptions were conservative, and the exclusion of
never likely to be as high as those for new drug susceptible
costs borne by patients is consistent with the cost, budget,
cases—patients have already failed treatment with first-
and cost-effectiveness figures with which we compared
line drugs, and second-line drugs are less effective and
It is noteworthy that 83% of enrolled patients were
The data suggest that cure rates with second-line drugs
from Lima. There is evidence to suggest that Lima has
can be improved in Peru. Half the patients who defaulted
high rates of MDR tuberculosis,38 but these data could
were bacteriologically negative at the time of default.
indicate selection bias, resulting from the special
Individuals who abandoned therapy could be traced by
committee’s location in Lima. Moreover, some of the
health workers for adjustment of the time and location of
patients enrolled in this programme as exceptions had a
treatment. Improved training for health workers with
history of only one previous treatment, suggesting that
respect to management of adverse effects, and
they did not meet the inclusion criteria.
strengthening the standardised treatment regimen, might
The data have important programmatic policy
also help. Substitution of capreomycin for kanamycin,
implications, and Peru’s National Tuberculosis
and ofloxacin for ciprofloxacin could soon be possible
Programme adopted three new policies in 2001. First, a
with no increase in cost to the National Tuberculosis
patient will be declared as not responding to treatment if
Programme, and use of cycloserine could be considered
they are culture positive after 6 months of treatment (or
in the presence of MDR and ethambutol resistance.
150 doses) with a standardised second-line drug regimen.
Further options for increasing cure rates include use of
Second, patients who do not respond to the standardised
individualised treatment for some patients, and earlier use
second-line drug regimen will have access to a second-
of second-line drugs. A promising experience with
line drug regimen tailored to their drug susceptibility
individualised treatment in Northern Lima is already
pattern. This regimen will be provided through an
underway;33 what remains to be proven is feasibility and
international partnership collaboration that will include
upgrading the capabilities of the national reference
Choice among strategies should also be informed by
laboratory to enable testing for susceptibility to second-
economic considerations. Cost was a major factor when
line drugs. Third, patients who do not respond to the
the standardised programme was first implemented in
first-line treatment regimen will be treated with the
1997, with the regimen chosen being the most affordable
standardised second-line drug regimen if they are
in the context of the National Tuberculosis Programme’s
diagnosed with MDR—ie, the first-line re-treatment
budget. Other options remain more expensive, but are
regimen will not be used for these patients.39 To enhance
becoming increasingly realistic with substantial
access to second-line drugs outside Lima, special
reductions in drug prices.20 Treatment of patients with
subcommittees to approve or reject requests for access to
chronic disease with second-line drugs is, on average, less
standardised second-line drug treatment have been
cost-effective than the basic DOTS programme, which
established in each of the country’s 34 health
relies on first-line drugs. The DOTS programme is much
more effective in terms of the cure rate8,9 and previous
Our findings are probably applicable to middle-income
estimates of averted deaths per patient treated,26 and is
countries where high cure and compliance rates with first-
substantially less expensive. Nevertheless, the cost-
line drugs are achieved, prevalence of HIV-1 is low, and
effectiveness figures for all the strategies that we assessed
ambulatory care is used. Tuberculosis programmes that
are much lower than per capita Gross National Income,
are not able to manage first-line drugs properly are
which is a more general benchmark for assessing whether
unlikely to be successful with second-line drugs.
or not an intervention is cost-effective,34,35 and around or
Effectiveness in terms of DALYs gained would be lower if
below the US$548–822 per DALY gained (converted to
rates of HIV-1 infection among tuberculosis patients are
year 2000 US$ prices) that was estimated for the “limited
high, due to a smaller number of years of life being gained
care” component of an essential health package for
per death averted. If admission to hospital is relied on,
middle-income countries by the World Bank in 1993.36
costs would be higher in both low-income and middle-
The figures for the standardised programme implemented
1997–2000 are similar to the US$176 (converted to year
Our findings indicate that use of second-line drugs to
2000 US$ prices) per DALY gained that was suggested as
treat chronic tuberculosis patients with high levels of
a threshold for defining an “attractive” investment in low-
MDR can be feasible and cost-effective in middle-income
income countries in 1995.37 The threshold should be
countries with strong tuberculosis control programmes.
higher in Peru, in view of its middle-income status.
Widespread use of second-line drugs in other countries
Our study has several limitations. The treatment
will depend on efforts to reduce costs and increase access
outcome data are not the result of a trial, so we were not
under tightly controlled approaches,20 and on success in
able to assess efficacy. Although patients are being
building strong tuberculosis control programmes.
followed up for 2 or more years to assess the relapse rate,long-term follow up data are not yet available. There were
no data with respect to susceptibility to second-line drugs,
M Espinal and K Floyd wrote the report; P Suárez, E Alarcón, J Portocarrero, I Sabogal, and M Espinal designed and planned the study;
since the necessary infrastructure and logistics had not
J Portocarrero was the study coordinator; C Bonilla and G Ramos
been developed in Peru during the period of enrolment
coordinated doctors at the MDR tuberculosis unit; I Aranda was the head
and follow-up. A quarter of the patients enrolled for
nurse coordinating patient follow-up and data management; E Rapiti and
treatment did not have susceptibility results for first-line
M Espinal were responsible for data analysis with respect to feasibilityand treatment outcomes; K Floyd was responsible for cost and cost-
drugs. In the cost-effectiveness analysis, we had no data
effectiveness analysis; P Suárez and E Alarcón assisted with the collection
on the long-term outcomes and costs associated with
of cost data; C Dye assisted with the transmission component of the cost-
isoniazid monotherapy, or comprehensive and detailed
effectiveness analysis; M Raviglione assisted with analysis of treatment
cost data for individualised treatment in a low-income or
outcomes; and all investigators contributed to the interpretation of thedata and revisions to the report.
middle-income setting. Several assumptions wererequired to estimate effectiveness, and costs from the
perspective of patients were not assessed. Nonetheless,
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21 Lew W. The fate of intractable multidrug resistant tuberculosis cases
We thank Antonio Pio, Fabio Luelmo, Thomas Frieden, and
under national tuberculosis programme in Korea. Masters thesis,
Rajesh Gupta for helpful comments, and the health workers of Peru for
London: London School of Hygiene and Tropical Medicine
their commitment to the implementation of this project. The work was
supported in part by a grant given from the US Agency for International
22 Bayona J, Furin JJ, Palacios E, et al. DOTS-plus in the northern cone of
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EMC on the Internet (No. 26, Final) Traceability Whenever I hear news about a new find of some ancient ruins, the thing I am most interested in is what period the ruins date from. One particular method for dating ruins is to apply the tree-ring dating method by counting the tree rings of excavated wood material that still has bark attached. An annual tree ring is highly sensitive to en
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