6-month versus 36-month isoniazid preventive treatment for tuberculosis in adults with HIV infection in Botswana: a randomised, double-blind, placebo-controlled trial.

BACKGROUND: In accordance with WHO guidelines, people with HIV infection in Botswana receive daily isoniazid preventive therapy against tuberculosis without obtaining a tuberculin skin test, but duration of prophylaxis is restricted to 6 months. We aimed to assess effectiveness of extended isoniazid therapy. METHODS: In our randomised, double-blind, placebo-controlled trial we enrolled adults infected with HIV aged 18 years or older at government HIV-care clinics in Botswana. Exclusion criteria included current illness such as cough and an abnormal chest radiograph without antecedent tuberculosis or pneumonia. Eligible individuals were randomly allocated (1:1) to receive 6 months' open-label isoniazid followed by 30 months' masked placebo (control group) or 6 months' open-label isoniazid followed by 30 months' masked isoniazid (continued isoniazid group) on the basis of a computer-generated randomisation list with permuted blocks of ten at each clinic. Antiretroviral therapy was provided if participants had CD4-positive lymphocyte counts of fewer than 200 cells per µL. We used Cox regression analysis and the log-rank test to compare incident tuberculosis in the groups. Cox regression models were used to estimate the effect of antiretroviral therapy. The trial is registered at ClinicalTrials.gov, number NCT00164281. FINDINGS: Between Nov 26, 2004, and July 3, 2009, we recorded 34 (3·4%) cases of incident tuberculosis in 989 participants allocated to the control group and 20 (2·0%) in 1006 allocated to the continued isoniazid group (incidence 1·26% per year vs 0·72%; hazard ratio 0·57, 95% CI 0·33-0·99, p=0·047). Tuberculosis incidence in those individuals receiving placebo escalated approximately 200 days after completion of open-label isoniazid. Participants who were tuberculin skin test positive (ie, ≥5 mm induration) at enrolment received a substantial benefit from continued isoniazid treatment (0·26, 0·09-0·80, p=0·02), whereas participants who were tuberculin skin test-negative received no significant benefit (0·75, 0·38-1·46, p=0·40). By study completion, 946 (47%) of 1995 participants had initiated antiretroviral therapy. Tuberculosis incidence was reduced by 50% in those receiving 360 days of antiretroviral therapy compared with participants receiving no antiretroviral therapy (adjusted hazard ratio 0·50, 95% CI 0·26-0·97). Severe adverse events and death were much the same in the control and continued isoniazid groups. INTERPRETATION: In a tuberculosis-endemic setting, 36 months' isoniazid prophylaxis was more effective for prevention of tuberculosis than was 6-month prophylaxis in individuals with HIV infection, and chiefly benefited those who were tuberculin skin test positive. FUNDING: US Centers for Disease Control and Prevention and US Agency for International Development.

Isoniazid, rifampin, ethambutol, and pyrazinamide pharmacokinetics and treatment outcomes among a predominantly HIV-infected cohort of adults with tuberculosis from Botswana.

BACKGROUND: We explored the association between antituberculosis drug pharmacokinetics and treatment outcomes among patients with pulmonary tuberculosis in Botswana. METHODS: Consenting outpatients with tuberculosis had blood samples collected 1, 2, and 6 h after simultaneous isoniazid, rifampin, ethambutol, and pyrazinamide ingestion. Maximum serum concentrations (C(max)) and areas under the serum concentration time curve were determined. Clinical status was monitored throughout treatment. RESULTS: Of the 225 participants, 36 (16%) experienced poor treatment outcome (treatment failure or death); 155 (69%) were infected with human immunodeficiency virus (HIV). Compared with published standards, low isoniazid C(max) occurred in 84 patients (37%), low rifampin C(max) in 188 (84%), low ethambutol C(max) in 87 (39%), and low pyrazinamide C(max) in 11 (5%). Median rifampin and pyrazinamide levels differed significantly by HIV status and CD4 cell count category. Only pyrazinamide pharmacokinetics were significantly associated with treatment outcome; low pyrazinamide C(max) was associated with a higher risk of documented poor treatment outcome, compared with normal C(max) (50% vs. 16%; P < .01). HIV-infected patients with a CD4 cell count <200 cells/microL had a higher risk of poor treatment outcome (27%) than did HIV-uninfected patients (11%) or HIV-infected patients with a CD4 cell count 200 cells/microL (12%; P = .01). After adjustment for HIV infection and CD4 cell count, patients with low pyrazinamide C(max) were 3 times more likely than patients with normal pyrazinamide C(max) to have poor outcomes (adjusted risk ratio, 3.38; 95% confidence interval, 1.84-6.22). CONCLUSIONS: Lower than expected antituberculosis drug C(max) occurred frequently, and low pyrazinamide C(max) was associated with poor treatment outcome. Exploring the global prevalence and significance of these findings may suggest modifications in treatment regimens that could improve tuberculosis cure rates.

Serum concentrations of antimycobacterial drugs in patients with pulmonary tuberculosis in Botswana.

BACKGROUND: We conducted a pharmacokinetic study of antimycobacterial drugs involving a cohort of patients with pulmonary tuberculosis (TB) in Gaborone, Botswana, to assess the prevalence of and risk factors for low drug concentrations in serum. METHODS: Adults participated if they had a history of cough > or =2 weeks, had abnormal chest radiograph findings, consented to testing for human immunodeficiency virus (HIV), had sputum cultures positive for Mycobacterium tuberculosis, and were receiving antituberculous therapy for >7 days. Observed maximum serum concentrations were compared with published normal ranges. RESULTS. Of 91 patients enrolled, 89 (98%) were outpatients, and 59 (68%) of 87 patients tested had HIV infection. The following numbers of patients had low serum concentrations of the following drugs: isoniazid, 27 (30%) of 90; rifampin, 71 (78%) of 91; ethambutol, 37 (41%) of 91; and pyrazinamide, 1 (1%) of 91. Low serum concentrations of both isoniazid and rifampin occurred in 23 (26%) of 90 patients. Low serum concentrations of rifampin were found in both HIV-infected and non-HIV-infected patients, and such patients were less likely to have >4 weeks of symptoms, more likely to have lymphadenopathy, and more likely to have low serum albumin levels (P<.05 for all). The associations with noncavitary pulmonary disease (P=.12) and HIV infection (P=.07) did not reach statistical significance. Delayed absorption was most common with ethambutol, followed by rifampin. CONCLUSIONS: These data, predominantly from HIV-infected patients with TB, suggest that low isoniazid, rifampin, and ethambutol concentrations are common in Botswana. In contrast, pyrazinamide usually is well absorbed.

Tuberculosis serodiagnosis in a predominantly HIV-infected population of hospitalized patients with cough, Botswana, 2002.

A sensitive and accurate tuberculosis (TB) serodiagnostic test would aid in the control of TB, but results of current tests are relatively unreliable for persons infected with human immunodeficiency virus (HIV). We evaluated a new prototype immunochromatographic strip test and 5 commercially available serodiagnostic TB tests in a prospective study comprised of 465 consecutively enrolled patients with suspected TB from 2 hospitals in Botswana. Consenting adults underwent HIV testing, >/=2 sputum smears and cultures, and mycobacterial blood culture. Patients were defined as having TB on the basis of any positive smear or culture. Between January and September 2002, 465 of 498 consecutive patients consented to enrollment. A total of 384 patients (83%) were infected with HIV, and 175 (38%) had TB; the mycobacterial blood culture was the sole source of diagnosis for 26 patients (15%) with TB. Among the tests evaluated, the sensitivity was 0%-63%, the specificity was 39%-99%, the positive predictive value was 0%-39%, and the negative predictive value was 63%-65%. We conclude that the serodiagnostic tests evaluated in this study lacked sufficient sensitivity as sole tests for TB in this population.

HIV risk factors among patients with tuberculosis--Botswana 1999.

To identify factors associated with HIV in Botswana, a standardized questionnaire was administered to 135 tuberculosis patients with known HIV status. HIV-positive patients were more likely than HIV-negative patients to: be female (45% vs 26% (adjusted prevalence odds ratio (aPOR)=3.8, 95% confidence interval (CI)=1.1-12.7)); be 26-35 years old (50% vs 19% (aPOR=2.7, CI=0.7-10.7)); be unmarried (91% vs 71% (aPOR=13.3, CI=2.5-72.7)); have higher income (24% vs 10% (aPOR=8.2, CI=1.6-42.9)); report separation from spouse/partner for work (63% vs 52% (aPOR=1.8, CI=0.5-6.2)); have 2 sex partners other than their regular partner (82% vs 67% (aPOR=1.8, CI=0.5-7.5)); and state that they or their partner drank alcohol before sex (77% vs 55% (aPOR=6.8, CI=1.9-24.1)). Only 22% of respondents used condoms during all of their past 10 sexual encounters. These data provide information for HIV prevention strategies.