Lisa J. Nelson

HIV Infection and Multidrug-Resistant Tuberculosis—The Perfect Storm

BACKGROUND Multidrug-resistant (MDR) tuberculosis (TB) has emerged as a global epidemic, with ~425,000 new cases estimated to occur annually. The global human immunodeficiency virus (HIV) infection epidemic has caused explosive increases in TB incidence and may be contributing to increases in MDR-TB prevalence. METHODS We reviewed published studies and available surveillance data evaluating links between HIV infection and MDR-TB to quantify convergence of these 2 epidemics, evaluate the consequences, and determine essential steps to address these epidemics. RESULTS Institutional outbreaks of MDR-TB have primarily affected HIV-infected persons. Delayed diagnosis, inadequate initial treatment, and prolonged infectiousness led to extraordinary attack rates and case-fatality rates among HIV-infected persons. Whether this sequence occurs in communities is less clear. MDR-TB appears not to cause infection or disease more readily than drug-susceptible TB in HIV-infected persons. HIV infection may lead to malabsorption of anti-TB drugs and acquired rifamycin resistance. HIV-infected patients with MDR-TB have unacceptably high mortality; both antiretroviral and antimycobacterial treatment are necessary. Simultaneous treatment requires 6-10 different drugs. In HIV-prevalent countries, TB programs struggle with increased caseloads, which increase the risk of acquired MDR-TB. Surveillance data suggest that HIV infection and MDR-TB may converge in several countries. CONCLUSIONS Institutional outbreaks, overwhelmed public health programs, and complex clinical management issues may contribute to the convergence of the MDR-TB and HIV infection epidemics. To forestall disastrous consequences, infection control, rapid case detection, effective treatment, and expanded program capacity are needed urgently.

Four-Year Treatment Outcomes of Adult Patients Enrolled in Mozambique's Rapidly Expanding Antiretroviral Therapy Program

Background In Mozambique during 2004–2007 numbers of adult patients (≥15 years old) enrolled on antiretroviral therapy (ART) increased about 16-fold, from <5,000 to 79,500. All ART patients were eligible for co-trimoxazole. ART program outcomes, and determinants of outcomes, have not yet been reported. Methodology/Principal Findings In a retrospective cohort study, we investigated rates of mortality, attrition (death, loss to follow-up, or treatment cessation), immunologic treatment failure, and regimen-switch, as well as determinants of selected outcomes, among a nationally representative sample of 2,596 adults initiating ART during 2004–2007. At ART initiation, median age of patients was 34 and 62% were female. Malnutrition and advanced disease were common; 18% of patients weighed <45 kilograms, and 15% were WHO stage IV. Median baseline CD4+ T-cell count was 153/µL and was lower for males than females (139/µL vs. 159/µL, p<0.01). Stavudine, lamivudine, and nevirapine or efavirenz were prescribed to 88% of patients; only 31% were prescribed co-trimoxazole. Mortality and attrition rates were 3.4 deaths and 19.8 attritions per 100 patient-years overall, and 12.9 deaths and 57.2 attritions per 100 patient-years in the first 90 days. Predictors of attrition included male sex [adjusted hazard ratio (AHR) 1.5; 95% confidence interval (CI), 1.3–1.8], weight <45 kg (AHR 2.1; 95% CI, 1.6–2.9, reference group >60 kg), WHO stage IV (AHR 1.7; 95% CI, 1.3–2.4, reference group WHO stage I/II), lack of co-trimoxazole prescription (AHR 1.4; 95% CI, 1.0–1.8), and later calendar year of ART initiation (AHR 1.5; 95% CI, 1.2–1.8). Rates of immunologic treatment failure and regimen-switch were 14.0 and 0.6 events per 100-patient years, respectively. Conclusions ART initiation at earlier disease stages and scale-up of co-trimoxazole among ART patients could improve outcomes. Research to determine reasons for low regimen-switch rates and increasing rates of attrition during program expansion is needed.

Intensified tuberculosis case finding among HIV-Infected persons from a voluntary counseling and testing center in Addis Ababa, Ethiopia.

Objective:To evaluate commonly available screening tests for pulmonary tuberculosis (TB), using sputum bacteriology as a gold standard, in HIV-infected persons attending an urban voluntary counseling and testing clinic in Addis Ababa, Ethiopia. Design:Prospective enrollment of HIV-infected persons, all of whom underwent TB screening, regardless of symptoms, with: (1) symptom screening and physical examination, (2) 3 sputum specimens for smear microscopy, and (3) chest radiograph. One sputum was also sent for concentrated smear microscopy and mycobacterial culture. Chest radiographs were reviewed by 2 independent radiologists. A confirmed TB diagnosis was defined as 1 positive sputum smear and/or 1 positive sputum culture. Results:We enrolled 438 HIV-infected persons: 265 (61%) females, median age 34 years (range: 18-65), median CD4 cell count 181 cells per cubic millimeter (range: 2-1185). Overall, 32 (7%) persons were diagnosed with TB, of whom 5 (16%) were asymptomatic but culture-confirmed TB cases. Screening for cough >2 weeks would have detected only 12 (38%) confirmed TB cases; screening for cough or fever, of any duration, would have detected 24 (75%) cases, with specificity of 64%. Negative predictive value of screening for these 2 symptoms was 97%. Simulation of the current Ethiopian national guidelines had a sensitivity of 63% and specificity of 83% for diagnosing TB disease among study patients. Conclusions:Traditional symptom screening is insufficient for detecting TB disease among HIV-infected persons but may serve to exclude TB disease. More sensitive, rapid, and low-cost diagnostic tests are needed to meet the demand of resource-limited settings.

Epidemiology of smear-negative pulmonary tuberculosis in the United States, 1993-2008.

BACKGROUND Smear-negative tuberculosis (TB) is difficult to diagnose and has been associated with poor treatment outcomes and excessive mortality, particularly in high human immunodeficiency virus (HIV) prevalent settings. However, few studies have used mycobacterial culture to rigorously confirm all smear-negative TB cases in a population-based cohort. DESIGN We included all culture-confirmed, pulmonary TB cases reported to the US National TB Surveillance System from 1993 to 2008. We analyzed smear-negative TB risk factors and survival, as compared to smear-positive TB. We calculated prevalence ratios (PRs) and adjusted for confounders (aPR). RESULTS From 1993 to 2008, 159,121 cases of culture-confirmed pulmonary TB were reported in the United States, of which 58,786 (37%) were sputum smear-negative. Smear-negative TB cases were more likely to be foreign-born (aPR 1.10, 95%CI 1.08-1.12), incarcerated (aPR 1.52, 95%CI 1.48-1.56) or HIV-infected (aPR 1.27, 95%CI 1.24-1.30). Hispanics and non-Hispanic Blacks were less likely to have smear-negative TB (respectively aPR 0.87, 95%CI 0.85-0.89 and aPR 0.90, 95%CI 0.89-0.92). Smear-negative TB cases had lower mortality (aRR 0.78, 95%CI 0.74-0.81), independent of HIV status. CONCLUSION Smear-negative TB represents a large proportion of TB cases in the United States, and occurs more often among persons in groups more likely to undergo TB screening. The lower mortality may indicate earlier TB detection, and underscores the need for continued vigilance in screening of high-risk persons.

Incidence and determinants of tuberculosis among adults initiating antiretroviral therapy--Mozambique, 2004-2008.

Background In Mozambique, tuberculosis (TB) is thought to be the most common cause of death among antiretroviral therapy (ART) enrollees. Monitoring proportions of enrollees screened for TB, and incidence and determinants of TB during ART can help clinicians and program managers identify program improvement opportunities. Methodology/Principal Findings We conducted a retrospective cohort study among a nationally representative sample of the 79,500 adults (>14 years old) initiating ART during 2004–2007 to estimate clinician compliance with TB screening guidelines, factors associated with active TB at ART initiation, and incidence and predictors of documented TB during ART follow-up. Of 94 sites enrolling >50 adults on ART, 30 were selected using probability-proportional-to-size sampling; 2,596 medical records at these sites were randomly selected for abstraction and analysis. At ART initiation, median age of patients was 34, 62% were female, median baseline CD4+ T-cell count was 153/µL, and 11% were taking TB treatment. Proportions of records with TB screening documentation before ART initiation improved from 31% to 66% during 2004–2007 (p<0.001). TB screening compliance varied widely by ART clinic [n = 30, 2%–98% (p<0.001)] and supporting non-Governmental Organization (NGO) [n = 7, 27%–83% (p<0.001)]. Receiving TB treatment at ART enrollment was associated with male sex (p<0.001), weight <45 kg (p<0.001) and CD4<50/µL (p = 0.001). Isoniazid preventive therapy (IPT) was prescribed to <1% of ART enrollees not taking TB treatment. TB incidence during ART was 2.32 cases per 100 person-years. Factors associated with TB incidence included adherence to ART <95% (AHR 2.06; 95% CI, 1.32–3.21). Conclusion Variations in TB screening by clinic and NGO may reflect differing investments in TB screening activities. Future scale-up should target under-performing clinics. Scale-up of TB screening at ART initiation, IPT, and ART adherence interventions could significantly reduce incident TB during ART.

New Guidelines About Latent Tuberculosis Infection in Children and Adolescents: A Welcome Advancement

In a supplement to this month’s issue of Pediatrics , comprehensive new guidelines are being published on finding and treating latent tuberculosis infection (LTBI) in children and adolescents.1 The collaborative group responsible for the guidelines is composed of health professionals from US health departments, the National Tuberculosis Model Centers, academic institutions, and the Centers for Disease Control and Prevention. With these guidelines, pediatricians have a single comprehensive reference about preventing tuberculosis (TB) in their patients. The guidelines are founded on a paradigm that is evolving with the TB epidemiology for US children and adolescents. Although TB rates have been declining overall since 1992, infections and cases have become even more concentrated among high-risk groups such as children born outside the United States. Thus, these guidelines recommend that children should be screened for risk factors for TB and LTBI and tested with the tuberculin skin test only if at least 1 risk factor is present. These guidelines discourage the use of administrative or mandated tuberculin skin tests for entry to child care, school, or summer camp, because these they are likely to consume limited resources but yield very little in finding current cases or preventing future ones. For these settings and most others, testing should be undertaken only if (1) preceded by screening for risk factors as described in the guidelines and (2) coupled to systems that start children who have LTBI on treatment and help them to complete it. The authors of … Reprint requests to (L.J.N.) Division of TB Elimination, Centers for Disease Control and Prevention, 1600 Clifton Rd, MS E-10, Atlanta, GA 30333. E-mail: lnelson{at}cdc.gov