Predictors of survival in human immunodeficiency virus-infected patients with pulmonary tuberculosis. The Makerere University-Case Western Reserve University Research Collaboration

Activities of Daily Living, Hypoxemia, and Lymphocytes Score for Predicting Mortality Risk in Patients With Pulmonary TB

BACKGROUND

A clinically applicable mortality risk prediction system for pulmonary TB may improve treatment outcomes, but no easy-to-calculate and accurate score has yet been reported. The aim of this study was to construct a simple and objective disease severity score for patients with pulmonary TB.

RESEARCH QUESTION

Does a clinical score consisting of simple objective factors predict the mortality risk of patients with pulmonary TB?

STUDY DESIGN AND METHODS

The data set from our previous prospective study that recruited patients newly diagnosed with pulmonary TB was used for the development cohort. Patients for the validation cohort were prospectively recruited between March 2021 and September 2022. The primary end point was all-cause in-hospital mortality. Using Cox proportional hazards regression, a mortality risk prediction model was optimized in the development cohort. The disease severity score was developed by assigning integral points to each variate.

RESULTS

The data from 252 patients in the development cohort and 165 patients in the validation cohort were analyzed, of whom 39 (15.5%) and 17 (10.3%), respectively, died in the hospital. The disease severity score (named the AHL score) included three clinical parameters: activities of daily living (semi-dependent, 1 point; totally dependent, 2 points); hypoxemia (1 point), and lymphocytes (< 720/μL, 1 point). This score showed good discrimination with a C statistic of 0.902 in the development cohort and 0.842 in the validation cohort. We stratified the score into three groups (scores of 0, 1-2, and 3-4), which clearly corresponded to low (0% and 1.3%), intermediate (13.5% and 8.9%), and high (55.8% and 39.3%) mortality risk in the development and validation cohorts.

INTERPRETATION

The easy-to-calculate AHL disease severity score for patients with pulmonary TB was able to categorize patients into three mortality risk groups with great accuracy.

CLINICAL TRIAL REGISTRATION

University Hospital Medical Information Network Center; No. UMIN000012727 and No. UMIN000043849; URL: www.umin.ac.jp.

Use of amplified Mycobacterium tuberculosis direct test in respiratory samples from HIV-infected patients in Brazil

OBJECTIVE:

To compare the accuracy of the amplified Mycobacterium tuberculosis direct (AMTD) test with reference methods for the laboratory diagnosis of tuberculosis in HIV-infected patients.

METHODS:

This was a study of diagnostic accuracy comparing AMTD test results with those obtained by culture on Löwenstein-Jensen (LJ) medium and by the BACTEC Mycobacteria Growth Indicator Tube 960 (BACTEC MGIT 960) system in respiratory samples analyzed at the Bioassay and Bacteriology Laboratory of the Oswaldo Cruz Foundation Evandro Chagas Clinical Research Institute in the city of Rio de Janeiro, Brazil.

RESULTS:

We analyzed respiratory samples collected from 118 patients, of whom 88 (74.4%) were male. The mean age was 36.6 ± 10.6 years. Using the AMTD test, the BACTEC MGIT 960 system, and LJ culture, we identified M. tuberculosis complex in 31.0%, 29.7%, and 27.1% of the samples, respectively. In comparison with LJ culture, the AMTD test had a sensitivity, specificity, positive predictive value, and negative predictive value of 87.5%, 89.4%, 75.7%, and 95.0%, respectively, for LJ culture, whereas, in comparison with the BACTEC MGIT 960 system, it showed values of 88.6%, 92.4%, 83.8%, and 94.8%, respectively.

CONCLUSIONS:

The AMTD test showed good sensitivity and specificity in the population studied, enabling the laboratory detection of M. tuberculosis complex in paucibacillary respiratory specimens.

Early versus delayed initiation of antiretroviral therapy for Indian HIV-Infected individuals with tuberculosis on antituberculosis treatment

Background

For antiretroviral therapy (ART) naive human immunodeficiency virus (HIV) infected adults suffering from tuberculosis (TB), there is uncertainty about the optimal time to initiate highly active antiretroviral therapy (HAART) after starting antituberculosis treatment (ATT), in order to minimize mortality, HIV disease progression, and adverse events.

Methods

In a randomized, open label trial at All India Institute of Medical Sciences, New Delhi, India, eligible HIV positive individuals with a diagnosis of TB were randomly assigned to receive HAART after 2-4 or 8-12 weeks of starting ATT, and were followed for 12 months after HAART initiation. Participants received directly observed therapy short course (DOTS) for TB, and an antiretroviral regimen comprising stavudine or zidovudine, lamivudine, and efavirenz. Primary end points were death from any cause, and progression of HIV disease marked by failure of ART.

Findings

A total of 150 patients with HIV and TB were initiated on HAART: 88 received it after 2-4 weeks (early ART) and 62 after 8-12 weeks (delayed ART) of starting ATT. There was no significant difference in mortality between the groups after the introduction of HAART. However, incidence of ART failure was 31% in delayed versus 16% in early ART arm (p = 0.045). Kaplan Meier disease progression free survival at 12 months was 79% for early versus 64% for the delayed ART arm (p = 0.05). Rates of adverse events were similar.

Interpretation

Early initiation of HAART for patients with HIV and TB significantly decreases incidence of HIV disease progression and has good tolerability.

Trial registration

CTRI/2011/12/002260

A randomized trial of punctuated antiretroviral therapy in Ugandan HIV-seropositive adults with pulmonary tuberculosis and CD4⁺ T-cell counts of ≥ 350 cells/μL

BACKGROUND

Optimal treatment of human immunodeficiency virus (HIV)-associated tuberculosis in patients with high CD4⁺ T-cell counts is unknown. Suppression of viral replication during therapy for tuberculosis may block effects of immune activation on T cells and slow HIV disease progression.

METHODS

We conducted a randomized trial in 214 HIV-infected patients with active tuberculosis and CD4⁺ T-cell counts of ≥ 350 cells/μL to determine whether 6 months of antiretroviral therapy given during tuberculosis treatment would improve clinical outcomes. Subjects were randomized to receive 6 months of abacavir-lamivudine-zidovudine concurrent with tuberculosis therapy or delayed antiretroviral therapy. Endpoints were CD4⁺ T-cell counts of < 250 cells/μL, AIDS, or death.

RESULTS

Intervention and comparison arms had similar median CD4⁺ counts (517 and 534 cells/μL, respectively) and HIV RNA levels (4.6 and 4.7 log₁₀ copies/μL, respectively). Viral suppression was achieved in 86% of patients allocated to intervention. Seventeen subjects (15.6%) in the intervention arm developed study outcome compared to 25 subjects (22.8%) in the comparison arm (P = .17). Grade 3 or 4 adverse events were less frequent in the intervention arm. By 2 months, 90% of subjects in both arms were culture-negative for tuberculosis.

CONCLUSIONS

Short-term antiretroviral therapy during tuberculosis treatment in patients with CD4⁺T-cell counts of >350 cells/μL was safe and associated with clinical benefits.

[Treatment outcome and laboratory confirmation of tuberculosis diagnosis in patients with HIV/AIDS in Recife, Brazil]

OBJECTIVE

To compare the frequency of unfavorable outcome (death or default and treatment failure) between tuberculosis (TB)/HIV co-infected patients treated for TB after laboratory confirmation of the diagnosis and TB/HIV co-infected patients who were so treated without diagnostic confirmation.

METHODS

A retrospective cohort of TB/HIV co-infected patients who started TB treatment between July of 2002 and June of 2004 at an HIV/AIDS referral center in Recife, Brazil. The main exposure variable, laboratory confirmation of TB, was adjusted for three different sets of variables: sociodemographic variables; HIV/AIDS-related variables; and TB-related variables. In order to evaluate the statistical significance of the results, we calculated odds ratios, with 95% confidence intervals, and p values (from chi-square tests and likelihood ratio tests).

RESULTS

A total of 262 patients were studied. No association was found between laboratory confirmation of the diagnosis of TB at treatment outset and unfavorable outcome, even after adjustment for confounders. In the final multiple logistic regression model, the following variables remained: the presence of other opportunistic diseases; CD4 lymphocyte count below 50 cells/mm(3); viral load between 10,000 and 100,000 copies/mL; dyspnea; the disseminated form of TB; and change in the TB treatment regimen due to adverse reactions or intolerance.

CONCLUSIONS

Our results suggest that TB treatment in TB/HIV co-infected patients without etiologic confirmation of TB, at the discretion of experienced physicians in referral centers, did not increase the risk of unfavorable outcomes. In addition, it allowed the identification of groups that should be closely monitored due to a greater risk of unfavorable outcomes.

Mortality, TB/HIV co-infection, and treatment dropout: predictors of tuberculosis prognosis in Recife, Pernambuco State, Brazil

This non-concurrent cohort study aims to identify predictors of tuberculosis mortality in a large population database in Brazil. Tuberculosis, death, and TB/HIV cases were validated respectively from the tuberculosis surveillance (SINAN/TB), mortality (SIM), and SINAN/AIDS databases for a five-year period. Analysis included proportional hazard models with relative risk estimates. Out of 5,451 individuals reported with tuberculosis, 320 (5.9%) died (incidence and mortality rates of 98.6 and 12.2/100 thousand inhabitants, respectively). After adjustment, relative risk of dying from tuberculosis was 9.8 for individuals>50 years of age; 9.0 for TB/HIV co-infection; 3.0 for mixed TB clinical presentation; and 2.0 for treatment dropout. In the multivariate model, using cases with HIV/AIDS, all adjusted predictors lost significance except mixed clinical presentation (RR 1.9; 1.1-3.1). TB/HIV co-infection is an important predictor of TB mortality. However, among individuals without HIV/AIDS, mortality is still highly associated with older age, mixed clinical forms, and treatment dropout.

Response to M. tuberculosis selected RD1 peptides in Ugandan HIV-infected patients with smear positive pulmonary tuberculosis: a pilot study

Background

Tuberculosis (TB) is the most frequent co-infection in HIV-infected individuals still presenting diagnostic difficulties particularly in developing countries. Recently an assay based on IFN-gamma response to M. tuberculosis RD1 peptides selected by computational analysis was developed whose presence is detected during active TB disease. Objective of this study was to investigate the response to selected RD1 peptides in HIV-1-infected subjects with or without active TB in a country endemic for TB and to evaluate the change of this response over time.

Methods

30 HIV-infected individuals were prospectively enrolled, 20 with active TB and 10 without. Among those with TB, 12 were followed over time. IFN-gamma response to selected RD1 peptides was evaluated by enzyme-linked immunospot (ELISPOT) assay. As control, response to RD1 proteins was included. Results were correlated with immune, microbiological and virological data.

Results

Among patients with active TB, 2/20 were excluded from the analysis, one due to cell artifacts and the other to unresponsiveness to M. tuberculosis antigens. Among those analyzable, response to selected RD1 peptides evaluated as spot-forming cells was significantly higher in subjects with active TB compared to those without (p = 0.02). Among the 12 TB patients studied over time a significant decrease (p =< 0.007) of IFN-gamma response was found at completion of therapy when all the sputum cultures for M. tuberculosis were negative. A ratio of RD1 peptides ELISPOT counts over CD4⁺ T-cell counts greater than 0.21 yielded 100% sensitivity and 80% specificity for active TB. Conversely, response to RD1 intact proteins was not statistically different between subjects with or without TB at the time of recruitment; however a ratio of RD1 proteins ELISPOT counts over CD4⁺ T-cell counts greater than 0.22 yielded 89% sensitivity and 70% specificity for active TB.

Conclusion

In this pilot study the response to selected RD1 peptides is associated with TB disease in HIV-infected individuals in a high TB endemic country. This response decreases after successful therapy. The potential of the novel approach of relating ELISPOT spot-forming cell number and CD4⁺ T-cell count may improve the possibility of diagnosing active TB and deserves further evaluation.

Capacity building for the clinical investigation of AIDS malignancy in East Africa

PURPOSE

To build capacity in the resource-poor setting to support the clinical investigation and treatment of AIDS-related malignancies in a region of the world hardest hit by the AIDS pandemic.

METHODS

An initial MEDLINE database search for international collaborative partnerships dedicated to AIDS malignancies in developing countries failed to identify any leads. This search prompted us to report progress on our collaboration in this aspect of the epidemic. Building on the formal Uganda-Case Western Reserve University (Case) Research Collaboration dating back to 1987, established NIH-supported centers of research excellence at Case, and expanding activities in Kenya, scientific and training initiatives, research capital amongst our institutions are emerging to sustain a international research enterprise focused on AIDS and other viral-related malignancies.

RESULTS

A platform of clinical research trials with pragmatic design has been developed to further enhance clinical care and sustain training initiatives with partners in East Africa and the United States. An oral chemotherapy feasibility trial in AIDS lymphoma is near completion; a second lymphoma trial of byrostatin and vincristine is anticipated and a feasibility trial of indinavir for endemic Kaposi's sarcoma is planned.

CONCLUSIONS

In the absence of published reports of evolving international partnerships dedicated to AIDS malignancy in resource constrained settings, we feel it important for such progress on similar or related international collaborative pursuits to be published. The success of this effort is realized by the long-term international commitment of the collaborating investigators and institutions to sustain this effort in keeping with ethical and NIH standards for the conduct of research; the provision of formal training of investigators and research personnel on clinical problems our East African partners are faced with in practice and the development of pragmatic clinical trials and therapeutic intervention to facilitate technology transfer and enhance clinical practice.

Tuberculosis, a re-emergent disease

Tuberculosis (TB) remains a major cause of morbidity and mortality worldwide. In Western Europe, regions with a high incidence of TB usually also have a high incidence of HIV infection; TB and HIV co-infection have increased over the past decade and among HIV infected patients, nearly half also develop TB. In settings where HIV is prevalent, TB drug resistance has also increased and several reports of TB and multi-drug resistant TB outbreaks, especially in health care settings, raise serious concerns about nosocomial transmission. Further research and new developments into more rapid diagnostic methods and sensitivity testing as well as the development of new anti-TB drugs are important to fight the disease. In addition, public health infrastructures have to be strengthened in order to increase adherence to TB treatment, where directly observed treatment strategy is the cornerstone for a successful outcome.

Immunoadjuvant prednisolone therapy for HIV-associated tuberculosis: a phase 2 clinical trial in Uganda

Background. Human immunodeficiency virus (HIV)-infected patients with tuberculosis (TB) respond to effective antituberculous therapy, but their prognosis remains poor. Mounting evidence from clinical studies supports the concept of copathogenesis in which immune activation that is triggered by TB and mediated by cytokines stimulates viral replication and worsens HIV infection, especially when immune function is preserved.Methods. We performed a phase 2, randomized, double-blind, placebo-controlled clinical trial in Kampala, Uganda, to determine whether immunoadjuvant prednisolone therapy in HIV-infected patients with TB who have CD4(+) T cell counts >/=200 cells/ mu L is safe and effective at increasing CD4(+) T cell counts.Results. Short-term prednisolone therapy reduced levels of immune activation and tended to produce higher CD4(+) T cell counts. Although prednisolone therapy was associated with a more rapid clearance of Mycobacterium tuberculosis from the sputum, it was also associated with a transient increase in HIV RNA levels, which receded when prednisolone therapy was discontinued. The intervention worsened underlying hypertension and caused fluid retention and hyperglycemia.Conclusion. The benefits of prednisolone therapy on immune activation and CD4(+) T cell counts do not outweigh the risks of adverse events in HIV-infected patients with TB and preserved immune function.

Tuberculosis and HIV disease: two decades of a dual epidemic

The HIV epidemic is currently in its third decade without any sign of abating. Tuberculosis (TB) is responsible for a third of all AIDS deaths, 99% of which occur in developing countries. The two epidemics fuel each other, together making up the leading infectious causes of mortality worldwide. Tuberculosis-HIV coinfection presents special diagnostic and therapeutic challenges and constitutes an immense burden on the health care systems of heavily infected countries. Despite major gains that have been made in the past two decades, important questions still remain. To cope with the challenge of TB-HIV coinfection, further research in the design of diagnostic tests for tuberculosis, detection of drug resistant Mycobacterium tuberculosis strains in HIV-positive people, as well as development of more effective therapeutic agents and vaccines are urgently needed. It has become evident that this dual epidemic will persist unless comprehensive measures are instituted through the provision of sufficient funding in addition to expanding and strengthening current control strategies adopted by governments and international organizations.

Improved outcomes of HIV-1-infected adults with tuberculosis in the era of highly active antiretroviral therapy

OBJECTIVES

To compare the survival and treatment responses to antiretroviral therapy between HIV-1-infected patients with active TB (TB patients) and without (non-TB patients) in the era of highly active antiretroviral therapy (HAART).

DESIGN

8-year prospective observational study at a university hospital.

METHODS

A total of 125 (17.5%) TB patients (median CD4 cell count at TB diagnosis, 37 x 10(6) cells/l) and 591 non-TB patients (CD4 cell count at enrolment, 79 x 10(6) cells/l) were prospectively observed between June 1994 and October 2002. Virologic and immunologic responses were assessed in 230 antiretroviral-naive non-TB patients and 46 TB patients who concurrently initiated antituberculous therapy and HAART. The clinical outcome was evaluated by comparing incidence of new AIDS-associated opportunistic illnesses (OIs) and survival of all TB and non-TB patients. RESULTS Among antiretroviral-naive patients, CD4 cell count increase (71 versus 64 x 10(6) cells/l, P = 0.70) and proportions of patients achieving undetectable plasma viral load [20 of 46 versus 107 of 230, relative risk (RR), 0.93; 95% confidence interval (95% CI), 0.65-1.34; P = 0.71] at week 4 of HAART were similar between the 46 TB and 230 non-TB patients, as was the virologic failure during HAART (RR, 1.49; 95% CI, 0.92-2.41; P = 0.14). The risk for HIV progression to new OIs was also similar between the two groups (adjusted RR, 1.16; 95% CI, 0.764-1.77). The adjusted hazard ratio for death of TB patients compared with non-TB patients was 1.18 (95% CI, 0.65-2.32) before HAART era and 0.89 (95% CI, 0.57-1.69) in HAART era.

CONCLUSIONS

Our data indicated that virologic, immunologic, and clinical responses to HAART and prognosis of HIV-1-infected TB patients who were concurrently treated with antituberculous therapy and HAART were similar to those of non-TB patients.

Clinical presentation and survival of smear-positive pulmonary tuberculosis patients of a university general hospital in a developing country

From January 1995 to August 1997 we evaluated prospectively the clinical presentation, laboratory findings and short-term survival of smear-positive pulmonary tuberculosis (TB) patients who sought care at our hospital. After providing informed, written consent, the patients were interviewed and laboratory tests were performed. Information about survivorship and death was collected through September 1998. Eighty-six smear-positive pulmonary TB patients were enrolled; 26.7% were HIV-seropositive. Seventeen HIV-seronegative pulmonary TB patients (19.8%) presented chronic diseases in addition to TB. In the multiple logistic regression analysis a CD4+ cell count <= 200 cell/mm was independently associated with HIV seropositivity. In the Cox regression model, fitted to all patients, HIV seropositivity and age > or = 50 years were independently associated with decreased survival. Among HIV-seronegative persons, the presence of an additional disease increased the risk of death of almost six-fold. Use of antiretroviral drugs was associated with a lower risk of death among HIV-seropositive smear-positive pulmonary TB patients (RH = 0.32, 95% CI 0.10-0.92). In our study smear-positive pulmonary TB patients had a low short-term survival rate that was strongly associated with HIV infection, age and co-morbidities. Therapy with antiretroviral drugs reduced the short-term risk of death among HIV-seropositive patients after TB diagnosis.

Survival of patients with pulmonary tuberculosis: clinical and molecular epidemiologic factors

Using restriction fragment-length polymorphism data, we conducted a retrospective cohort study of 139 adult patients with pulmonary tuberculosis to investigate the clinical impact of Mycobacterium tuberculosis infection with a clustered isolate. The cumulative all-cause mortality rate during treatment was 21%. Patients with clustered DNA fingerprint patterns had a reduced risk of death, compared with patients with unique patterns (hazard ratio [HR], 0.5; 95% confidence interval [CI], 0.2-1.1), but this finding was confounded by age (adjusted HR, 0.8; 95% CI, 0.4-1.8). After adjustment for age, the strongest predictors of death were such underlying illnesses as diabetes mellitus, renal failure, chronic obstructive pulmonary disease, and human immunodeficiency virus infection. We conclude that comorbidity and immunosuppression are important predictors of survival for patients with pulmonary tuberculosis in an inner-city cohort. Recently transmitted infection, as determined by use of DNA fingerprinting to classify patients' isolates as being either clustered or unique, was not independently associated with death.

Molecular epidemiology study of exogenous reinfection in an area with a low incidence of tuberculosis

In geographical areas with a low incidence of tuberculosis, recurrent tuberculosis is generally due to reactivation of the disease. However, the relative contribution of tuberculosis reinfection increases in parallel with the incidence of disease and is likely to depend on the epidemiological context: factors such as the spread of multidrug resistance, human immunodeficiency virus (HIV) infection, and immigration from developing countries could modify disease transmission in areas at low risk for tuberculosis. A molecular epidemiology study was performed in Lombardy, Northern Italy, where the incidence of tuberculosis is 17.5 cases per 100,000 persons. A total of 2,452 cases of culture-confirmed tuberculosis in 2,127 patients were studied. A group of 32 patients (1.5%), each of whom had two episodes of tuberculosis with cure as the outcome of the first episode and with more than 6 months between the two episodes, were studied by means of restriction fragment length polymorphism DNA fingerprinting analysis. For 5 of the 32 patients (16%), the DNA fingerprinting patterns of Mycobacterium tuberculosis strains responsible for the second episode did not match those of the corresponding isolates of the first episode, indicating exogenous reinfection. Two of these patients developed multidrug-resistant tuberculosis during the second episode, and in three cases the isolates belonged to clusters of M. tuberculosis strains spreading in the community. A fourfold-increased risk for reinfection was observed in immigrant patients compared to Italian subjects. In contrast, a higher risk of relapse rather than reinfection was evidenced in HIV-positive subjects and in patients infected with multidrug-resistant tuberculosis. Episodes of tuberculosis reinfection in areas with a low incidence of tuberculosis are rare compared to those in high-incidence geographical regions. In populations that have immigrated from high-risk areas, reinfection may represent a considerable contributor to the rate of recurrent tuberculosis. This finding emphasizes the importance of containing the spread of epidemic strains in close communities, in order to prevent changes in global tuberculosis trends for developed countries.

Changing clinical presentation and survival in HIV-associated tuberculosis after highly active antiretroviral therapy

OBJECTIVE

To assess changes in clinical presentation and outcome of HIV-associated tuberculosis (TB) before and after widespread implementation of highly active antiretroviral therapy (HAART).

METHODS

We reviewed clinical charts of HIV-infected patients with culture-confirmed pulmonary TB in two referral clinical centers in Rome, Italy. The 67 patients diagnosed in 1995 to 1996 were compared with 51 patients diagnosed in 1997 to 1998. To analyze factors associated with survival we used a Cox model including antiretroviral therapy as a time-dependent covariate.

RESULTS

Patients diagnosed in 1997 to 1998 were more likely to have TB as the first AIDS-defining illness (78% versus 58%, p <.05), to have HIV diagnosed <2 months before TB (33% vs. 7%, p <.005) and to have typical chest radiograph pattern (45% vs. 25%, p <.05), and had a higher CD4(+) count (median 105 vs. 43, p <.005). Survival at 1 year was 80% for patients diagnosed in 1997 to 1998 vs. 65% for those diagnosed in 1995 to 1996 (p by log-rank =.02). After adjusting at multivariate analysis, time period of diagnosis was not confirmed as associated with survival (hazard ratio, 1.05; 95% confidence interval, 0.39--2.81). Age, CD4+ cell count <25/mm(3), and AIDS-defining illnesses before TB diagnosis were all associated with an higher risk of death, whereas a decreased risk of death was observed in patients starting a triple combination antiretroviral therapy after TB diagnosis (hazard ratio, 0.14; 95% confidence interval, 0.03--0.57).

CONCLUSIONS

Cases of HIV-associated TB occurring in patients with advanced immunosuppression and presenting with atypical radiologic appearance tend to be relatively less common in the HAART era. HAART is a major factor in prolonging survival in these patients.

Tuberculosis case fatality rates in high HIV prevalence populations in sub-Saharan Africa

BACKGROUND

Tuberculosis is a leading cause worldwide of morbidity and mortality among HIV-infected people. The HIV era has seen a dramatic increase of the tuberculosis case fatality rate (CFR) in high HIV prevalence populations. Providing care for HIV-infected people must include measures to tackle this high tuberculosis CFR.

AIMS

To analyse the extent of the increased tuberculosis CFR in high HIV prevalence populations in sub-Saharan Africa, the reasons for this increase and the causes of death, in order to identify possible ways of tackling this problem.

METHODS

References were obtained by searching the MEDLINE on 'tuberculosis', 'HIV infection', and 'mortality' (MesH or textword). In addition, available data from National Tuberculosis Programme reports were reviewed.

FINDINGS

Tuberculosis CFR is closely linked to HIV prevalence. Limited autopsy data suggest that death from HIV-related diseases other than tuberculosis is probably the main reason for the increased CFR in HIV-infected tuberculosis patients. Among HIV-infected tuberculosis patients, the higher tuberculosis CFR in sputum smear-negative and extrapulmonary than in sputum smear-positive tuberculosis cases can also be attributed to misdiagnosis of HIV-related diseases as tuberculosis. The adverse effect of the HIV/AIDS epidemic on general health service performance probably accounts for the higher tuberculosis CFR among HIV-negative tuberculosis patients in high prevalence populations than that in low HIV-prevalence populations.

CONCLUSION

Tackling the problem of the increased tuberculosis CFR in high HIV prevalence populations requires collaboration between tuberculosis control and HIV/AIDS programmes in implementing measures such as improved health services, tuberculosis and HIV control services, preventive treatment for HIV-related diseases and anti-HIV treatment.

Effect of post-treatment isoniazid on prevention of recurrent tuberculosis in HIV-1-infected individuals: a randomised trial

BACKGROUND

Patients with HIV-1 infection respond well to treatment for active tuberculosis, but whether such patients are at increased risk of disease recurrence after complete cure is uncertain. We did a randomised trial in Port au Prince, Haiti, to determine whether recurrent tuberculosis after curative tuberculosis treatment is more common in HIV-1-infected individuals than HIV-1-uninfected individuals, and to determine whether post-treatment isoniazid prophylaxis decreases the risk of recurrent tuberculosis.

METHODS

Patients older than 18 years who were diagnosed with a first episode of tuberculosis at the national HIV testing centre in Haiti, and who successfully completed a 6-month rifampicin-containing regimen for active pulmonary tuberculosis, were randomly assigned 1 year of post-treatment isoniazid prophylaxis or placebo. The primary outcome measure was rate of recurrent tuberculosis after at least 24 months. An intention-to-treat analysis was used.

FINDINGS

Of 354 patients with active pulmonary tuberculosis, 274 successfully completed treatment, and 233 were randomised. Of 142 HIV-1-positive patients, 68 were assigned isoniazid and 74 placebo. Of 91 HIV-1-negative individuals, 51 were assigned isoniazid and 40 placebo. The rate of recurrent tuberculosis was 4.8 per 100 person-years in HIV-1-infected individuals and 0.4 per 100 person-years in uninfected individuals (relative risk 10.7 [95% CI 1.4-81.6]). Among HIV-1-positive patients receiving isoniazid, the tuberculosis recurrence rate was 1.4 per 100 person-years, and among HIV-1-positive patients receiving placebo, it was 7.8 per 100 person-years (0.18 [0.04-0.83]). Among HIV-1-positive individuals, all cases of recurrent tuberculosis occurred in individuals with a history of HIV-1-related symptoms before initial tuberculosis diagnosis.

INTERPRETATION

The rate of recurrent tuberculosis is higher in HIV-1-positive individuals than in HIV-1-negative individuals, and is strongly associated with a history of symptomatic HIV-1 disease before initial tuberculosis diagnosis. Post-treatment isoniazid prophylaxis decreases the risk of recurrence in HIV-1-positive individuals, and should be considered for HIV-1-positive individuals with a history of HIV-1-related symptoms at the time of tuberculosis diagnosis.

Impact of pulmonary tuberculosis on survival of HIV-infected adults: a prospective epidemiologic study in Uganda

BACKGROUND

Retrospective cohort studies of tuberculosis suggest that active tuberculosis accelerates the progression of HIV infection. The validity of these findings has been questioned because of their retrospective design, diverse study populations, variable compliance with anti-tuberculous therapy and use of anti-retroviral medication. To assess the impact of tuberculosis on survival in HIV infection we performed a prospective study among HIV-infected Ugandan adults with and without tuberculosis.

METHODS

In a prospective cohort study, 230 patients with HIV-associated tuberculosis and 442 HIV-infected subjects without tuberculosis were followed for a mean duration of 19 months for survival. To assess changes in viral load over 1 year, 20 pairs of tuberculosis cases and controls were selected and matched according to baseline CD4 lymphocyte count, age, sex and tuberculin skin test status.

RESULTS

During the follow-up period, 63 out of of 230 tuberculosis cases (28%) died compared with 85 out of 442 controls (19%), with a crude risk ratio of 1.4 [95% confidence interval (CI), 1.07-1.87]. Most deaths occurred in patients with CD4 lymphocyte counts < 200 x 10(6) cells/l at baseline (n = 99) and occurred with similar frequency in the tuberculosis cases (46%) and the controls (44%). When the CD4 lymphocyte count was > 200 x 10(6)/l, however, the relative risk of death in HIV-associated tuberculosis was 2.1 (95% CI, 1.27-3.62) compared with subjects without tuberculosis. For subjects with a CD4 lymphocyte count > 200 x 10(6)/l, the 1-year survival proportion was slightly lower in the cases than in the controls (0.91 versus 0.96), but by 2 years the survival proportion was significantly lower in the cases than in the controls (0.84 versus 0.91; P < 0.02; log-rank test). For subjects with a CD4 lymphocyte count of 200 x 10(6) cells/l or fewer, the survival proportion at 1 year for the controls was lower than cases (0.59 versus 0.64), but this difference was not statistically significant (P = 0.53; logrank test). After adjusting for age, sex, tuberculin skin test status, CD4 lymphocyte count, and history of HIV-related infections, the overall relative hazard for death associated with tuberculosis was 1.81 (95% CI, 1.24-2.65). In a nested Cox regression model, the relative hazard for death was 3.0 (95% CI, 1.62-5.63) for subjects with CD4 lymphocyte counts > 200 x 10(6)/l and 1.5 (95% CI, 0.99-2.40) for subjects with a CD4 lymphocyte count of 200 x 10(6)/l or fewer.

CONCLUSION

The findings from this prospective study indicate that active tuberculosis exerts its greatest effect on survival in the early stages of HIV infection, when there is a reserve capacity of the host immune response. These observations provide a theoretical basis for the treatment of latent tuberculous infection in HIV-infected persons.

Relapse rates after short-course (6-month) treatment of tuberculosis in HIV-infected and uninfected persons

OBJECTIVE

To determine the rate of tuberculosis relapse among HIV-seropositive and -seronegative persons treated for active tuberculosis with short-course (6-month) therapy.

DESIGN

Consecutive cohort study.

SETTING

City of Baltimore tuberculosis clinic.

PATIENTS

Tuberculosis patients treated between 1 January 1993 and 31 December 1996.

INTERVENTION

Patients received 2 months of isoniazid, rifampin, pyrazinamide and ethambutol followed by 4 months of isoniazid and rifampin.

MAIN OUTCOME MEASURE

Passive follow-up for tuberculosis relapse was performed through September 30, 1998.

RESULTS

There were 423 cases of tuberculosis during the study period; 280 patients completed a 6-month course of therapy. Therapy was directly-observed for 94% of patients. Of those who completed therapy, 47 (17%) were HIV-seropositive, 127 (45%) were HIV-seronegative, and 106 (38%) had unknown HIV status. HIV-infected patients required more time to complete therapy (median 225 versus 205 days; P = 0.04) but converted sputum culture to negative within the same time period (median 77 versus 72 days; P = 0.43) as HIV-seronegative or unknown patients. Relapse occurred in three out of 47 (6.4%) HIV-infected patients compared to seven out of 127 (5.5%) HIV-seronegative patients (P = 1.0). Relapse rates also did not differ when HIV-seropositive patients were compared with HIV-seronegative and patients with unknown HIV status (6.4% versus 3.0%; P = 0.38). Of the 10 patients with tuberculosis relapse, restriction fragment length polymorphism data were available for five; all five relapse isolates matched the initial isolate.

CONCLUSIONS

These results support current recommendations to treat tuberculosis in HIV-infected patients with short-course (6-month) therapy.

Consensus statement. Global burden of tuberculosis: estimated incidence, prevalence, and mortality by country. WHO Global Surveillance and Monitoring Project

OBJECTIVE

To estimate the risk and prevalence of Mycobacterium tuberculosis (MTB) infection and tuberculosis (TB) incidence, prevalence, and mortality, including disease attributable to human immunodeficiency virus (HIV), for 212 countries in 1997.

PARTICIPANTS

A panel of 86 TB experts and epidemiologists from more than 40 countries was chosen by the World Health Organization (WHO), with final agreement being reached between country experts and WHO staff.

EVIDENCE

Incidence of TB and mortality in each country was determined by (1) case notification to the WHO, (2) annual risk of infection data from tuberculin surveys, and (3) data on prevalence of smear-positive pulmonary disease from prevalence surveys. Estimates derived from relatively poor data were strongly influenced by panel member opinion. Objective estimates were derived from high-quality data collected recently by approved procedures.

CONSENSUS PROCESS

Agreement was reached by (1) participants reviewing methods and data and making provisional estimates in closed workshops held at WHO's 6 regional offices, (2) principal authors refining estimates using standard methods and all available data, and (3) country experts reviewing and adjusting these estimates and reaching final agreement with WHO staff.

CONCLUSIONS

In 1997, new cases of TB totaled an estimated 7.96 million (range, 6.3 million-11.1 million), including 3.52 million (2.8 million-4.9 million) cases (44%) of infectious pulmonary disease (smear-positive), and there were 16.2 million (12.1 million-22.5 million) existing cases of disease. An estimated 1.87 million (1.4 million-2.8 million) people died of TB and the global case fatality rate was 23% but exceeded 50% in some African countries with high HIV rates. Global prevalence of MTB infection was 32% (1.86 billion people). Eighty percent of all incident TB cases were found in 22 countries, with more than half the cases occurring in 5 Southeast Asian countries. Nine of 10 countries with the highest incidence rates per capita were in Africa. Prevalence of MTB/HIV coinfection worldwide was 0.18% and 640000 incident TB cases (8%) had HIV infection. The global burden of tuberculosis remains enormous, mainly because of poor control in Southeast Asia, sub-Saharan Africa, and eastern Europe, and because of high rates of M tuberculosis and HIV coinfection in some African countries.

HIV and tuberculosis in rural sub-Saharan Africa: a cohort study with two year follow-up

The objective was to examine the effect of HIV seropositivity on outcomes in tuberculosis (TB) patients in a rural African setting, including rates of TB relapse, other morbid events and mortality. The study setting was a district level hospital in Mzuzu, Malawi. Adult TB patients presenting between November 1991 and May 1993 were included in the study. Treatment was given according to national guidelines. Patients with smear-positive TB received 8 months of rifampicin-containing short-course chemotherapy. Patients with smear-negative or extrapulmonary TB received 12 months of 'standard' treatment. Subjects were followed until they died or until the study concluded (December 1994). There were 225 eligible patients; 187 were tested for HIV and enrolled in the study (66.8% HIV seropositive). Ninety-four percent had complete follow-up information. The cure rate in smear-positive patients who survived to the end of treatment was over 90% and not significantly affected by HIV. Disorders of the gastrointestinal, neurological and dermatological systems were significantly more common in HIV-seropositive patients. HIV had a significant effect on the risk of relapse of TB (hazard ratio [HR] = 10.55 [95% CI 1.38, 80.93]) and on all-cause mortality (HR = 2.81 [95% CI 1.63, 4.64]). Despite high HIV prevalence, high rates of TB cure are achievable using the usual treatment protocols. However, excess TB relapse, other illnesses and mortality associated with HIV seropositivity have serious implications for TB control. There is an urgent need to identify effective intervention strategies aimed at prevention, early diagnosis and treatment of these illnesses.

Human immunodeficiency virus and the outcome of treatment for new and recurrent pulmonary tuberculosis in African patients

The purpose of this study was to evaluate the impact of human immunodeficiency virus (HIV) infection on treatment for tuberculosis (TB). The study population comprised 28,522 black Southern African gold miners. Patients with sputum culture-positive new or recurrent pulmonary TB diagnosed in 1995 were prospectively enrolled in the cohort. Directly observed therapy (DOT) was practiced and outcomes were assessed at 6 mo after treatment was begun. There were 376 cases of TB (incidence 1,318 per 100,000), of which 190 (50%) were HIV positive and 82 (22%) had recurrent TB. There was no association between HIV status and history of previous TB or drug resistance. Neither the treatment interruption rate (2%) nor the rate at which patients transferred out of the treatment program (1.6%) were associated with HIV status. Excluding deaths, cure rates were similar for HIV-positive and HIV-negative patients (89% versus 88%), but significantly lower in those with recurrent than in those with new TB (77% versus 92%). Mortality was 0.5% in HIV-negative patients versus 13.7% in HIV-positive patients, and in the latter group was associated with CD4(+) lymphocyte depletion. Autopsy examination showed that in HIV-positive patients, early mortality was due to TB whereas late deaths were most commonly due to cryptococcal pneumonia. The study showed that a well-run TB control program can result in acceptable cure rates even in a population with a very high incidence of TB and HIV infection. Particular vigilance is needed for concurrent infections, which may contribute significantly to mortality during treatment of TB in HIV-positive patients.

A trial of three regimens to prevent tuberculosis in Ugandan adults infected with the human immunodeficiency virus. Uganda-Case Western Reserve University Research Collaboration

BACKGROUND

Infection with the human immunodeficiency virus (HIV) greatly increases the risk of reactivation tuberculosis. We evaluated the safety and efficacy of three preventive-therapy regimens in a setting where exposure to tuberculosis is common.

METHODS

We performed a randomized, placebo-controlled trial in 2736 HIV-infected adults recruited in Kampala, Uganda. Subjects with positive tuberculin skin tests (induration, > or =5 mm) with purified protein derivative (PPD) were randomly assigned to one of four regimens: placebo (464 subjects), isoniazid daily for six months (536), isoniazid and rifampin daily for three months (556), or isoniazid, rifampin, and pyrazinamide daily for three months (462). Subjects with anergy (0 mm induration in reaction to PPD and candida antigens) were randomly assigned to receive either placebo (323 subjects) or six months of isoniazid (395). The medications were dispensed monthly and were self-administered.

RESULTS

Among the PPD-positive subjects, the incidence of tuberculosis in the three groups that received preventive therapy was lower than the rate in the placebo group (P=0.002 by the log-rank test). The relative risk of tuberculosis with isoniazid alone, as compared with placebo, was 0.33 (95 percent confidence interval, 0.14 to 0.77); with isoniazid and rifampin, 0.40 (0.18 to 0.86); and with isoniazid, rifampin, and pyrazinamide, 0.51 (0.24 to 1.08). Among the subjects with anergy, the relative risk of tuberculosis was 0.83 (95 percent confidence interval, 0.34 to 2.04) with isoniazid as compared with placebo. Side effects were more common with the multidrug regimens, and particularly with the regimen containing pyrazinamide. Survival did not differ among the groups, but the subjects with anergy had a higher mortality rate than the PPD-positive subjects.

CONCLUSIONS

A six-month course of isoniazid confers short-term protection against tuberculosis among PPD-positive, HIV-infected adults. Multidrug regimens with isoniazid and rifampin taken for three months also reduce the risk of tuberculosis.

Costs and benefits of improving tuberculosis control: the case of Thailand

The study evaluates the economic costs and benefits of improving tuberculosis control interventions in Thailand. Provider costs are determined on the basis of marginal treatment costs for varying case numbers and estimates of the cost of required infrastructure changes. Indirect costs are calculated as income lost due to morbidity and premature mortality. An epidemiological model is used to calculate case numbers and mortality under current control conditions and a scenario of improved control. An improved control strategy initially leads to a higher number of detected cases. For longer projection periods, the epidemiological impact of curing a higher proportion of infectious sources results in lower case numbers than those expected without programme improvement. Model simulations show a reduction of total annual case numbers through improved control measures by an average 45% after a simulation period of 20 years. The corresponding societal savings in form of reduced indirect costs from the disease are U.S.$2.4 billion. Reductions in direct provider costs can be expected as a result of decreased numbers of detected cases for longer evaluation periods, as well as a lower proportion of multi-drug-resistant cases. The mean value of predicted savings is U.S.$8.3 million. Since this value is likely to be higher than the required investment in improved infrastructure, net savings can be expected. The result of an uncertainty analysis shows a wide range of potential additional costs or net savings with respect to direct provider costs. Indirect cost calculations show net savings for all parameter values.