Factors associated with screening failure and study withdrawal in multidrug-resistant TB

SETTING: Multidrug-resistant TB (MDR-TB) clinical trial in Lima, Peru and Cape Town, South Africa.OBJECTIVE: To identify baseline factors associated with screening failure and study withdrawal in an MDR-TB clinical trial.DESIGN: We screened patients for a randomized, blinded, Phase II trial which assessed culture conversion over the first 6 months of treatment with varying doses of levofloxacin plus an optimized background regimen (ClinicalTrials.gov: NCT01918397). We identified factors for screening failure and study withdrawal using Poisson regression to calculate prevalence ratios and Cox proportional hazard regression to calculate hazard ratios. We adjusted for factors with P < 0.2.RESULTS: Of the 255 patients screened, 144 (56.5%) failed screening. The most common reason for screening failure was an unsuitable resistance profile on sputum-based molecular susceptibility testing (n = 105, 72.9%). No significant baseline predictors of screening failure were identified in the multivariable model. Of the 111 who were enrolled, 33 (30%) failed to complete treatment, mostly for non-adherence and consent withdrawal. No baseline factors predicted study withdrawal in the multivariable model.CONCLUSION: No baseline factors were independently associated with either screening failure or study withdrawal in this secondary analysis of a MDR-TB clinical trial.

Prevalence and clinical characteristics of pulmonary TB among pregnant and post-partum women

SETTING: Antenatal care (ANC) and postpartum care (PPC) clinic in Manhiça District, Mozambique.OBJECTIVE: To estimate the prevalence of TB among pregnant and post-partum women and describe the clinical characteristics of the disease in a rural area of Southern Mozambique.METHODS: We conducted a cross-sectional TB prevalence study among pregnant and post-partum women recruited from September 2016 to March 2018 at the Manhiça Health Care Center (MHC). We recruited two independent cohorts of women consecutively presenting for routine pregnancy or post-partum follow-up visits.RESULTS: A total of 1,980 women from the ANC clinic and 1,010 from the PPC clinic were enrolled. We found a TB prevalence of 505/100,000 (95% CI: 242-926) among pregnant women and 297/100,000 (95% CI: 61-865) among post-partum women. Among HIV-positive pregnant women, TB prevalence was 1,626/100,000 (95% CI: 782-2,970) and among postpartum HIV-positive women, TB prevalence was 984/100,000 (95% CI: 203-2,848).CONCLUSIONS: The burden of TB was not higher in postpartum women than in pregnant women. Most TB cases were detected in HIV-positive women. TB screening and diagnostic testing among pregnant and postpartum women attending ANC and PPC clinics in Manhiça District is acceptable and feasible.

OUP accepted manuscript

Current methods for tuberculosis treatment monitoring are suboptimal. We evaluated plasma matrix metalloproteinase (MMP) and procollagen III N-terminal propeptide concentrations before and during tuberculosis treatment as biomarkers. Plasma MMP-1, MMP-8, and MMP-10 concentrations significantly decreased during treatment. Plasma MMP-8 was increased in sputum Mycobacterium tuberculosis culture–positive relative to culture-negative participants, before (median, 4993 pg/mL [interquartile range, 2542–9188] vs 698 [218–4060] pg/mL, respectively; P = .004) and after (3650 [1214–3888] vs 720 [551–1321] pg/mL; P = .008) 6 months of tuberculosis treatment. Consequently, plasma MMP-8 is a potential biomarker to enhance tuberculosis treatment monitoring and screen for possible culture positivity.

HIV-related tuberculosis: mortality risk in persons without vs. with culture-confirmed disease

BACKGROUND

Tuberculosis (TB) diagnosis in human immunodeficiency virus (HIV) positive persons is difficult, particularly in resource-limited settings. The relationship between TB culture status and mortality in HIV-positive persons treated for TB is unclear.

METHODS

We evaluated HIV-positive adults treated for TB at or after their first HIV clinic visit in Argentina, Brazil, Chile, Honduras, Mexico or Peru from 2000 to 2015. Anti-tuberculosis treatment included 2 months of isoniazid, rifampicin (RMP)/rifabutin (RBT), pyrazinamide ± ethambutol, followed by continuation phase treatment with isoniazid + RMP/RBT.

RESULTS

Of 759 TB-HIV patients, 238 (31%) were culture-negative, 228 (30%) had unknown culture status or did not undergo culture and 293 (39%) were culture-positive. The median CD4 at TB diagnosis was 96 (interquartile range 40-228); 636 (84%) received concurrent antiretroviral therapy (ART) and anti-tuberculosis treatment. There were 123 (16%) deaths: 90/466 (19%) with TB culture-negative, unknown or not performed vs. 33/293 (11%) who were TB culture-positive (P = 0.005). In Kaplan-Meier analysis, mortality in TB patients without culture-confirmed disease was higher (P = 0.002). In a Cox model adjusted for age, sex, CD4, ART timing, disease site and stratified by study site, mortality in persons without culture-confirmed TB was not significantly increased compared to those with culture-positive TB (hazard ratio 1.39, 95%CI 0.89-2.16, P = 0.15).

CONCLUSION

Most HIV-positive patients treated for TB did not have culture-confirmed TB, and mortality tended to be higher in patients without culture-confirmed disease, although the association was not statistically different after adjusting for other variables. Accurate TB diagnosis in HIV-positive persons is crucial.

Older age at first tuberculosis diagnosis is associated with tuberculosis recurrence in HIV-negative persons

SETTING

Tuberculosis (TB) clinic in Durban, South Africa.

OBJECTIVE

To assess the factors associated with TB recurrence among human immunodeficiency virus (HIV) negative adults and children.

DESIGN

We conducted a retrospective longitudinal study from January 2000 to December 2012. We defined recurrence as a TB episode occurring within the study period after treatment completion or cure of a previous episode. We used a multivariable Poisson regression model to assess the factors associated with the number of recurrences among HIV-negative patients.

RESULTS

Among 17 941 patients with known HIV status, 3653 (20%) were HIV-negative; of these, 235 (6%) had one recurrence, 21 (1%) had two recurrences and 4 (0.1%) had three recurrences. The median follow-up time from the end of treatment for the first episode was 3.0 years (interquartile range 1.9-4.2). Age at the first TB episode was significantly associated with the number of TB recurrences: younger patients had the lowest rate of recurrence, with a steady increase in rates until age 40 years, after which rates stabilized.

CONCLUSIONS

TB recurrence rates among HIV-negative patients were higher at increased age at the first TB episode. Further translational studies are needed to clarify the factors that drive multiple TB recurrences in older age, including impaired immunity, the results of which have implications for TB vaccine development.

Isoniazid-monoresistant tuberculosis is associated with poor treatment outcomes in Durban, South Africa

SETTING

A large tuberculosis (TB) clinic in Durban, South Africa.

OBJECTIVE

To determine the association between isoniazid (INH) monoresistant TB and treatment outcomes.

DESIGN

We performed a retrospective longitudinal study of patients seen from 2000 to 2012 to compare episodes of INH-monoresistant TB with those of drug-susceptible TB using logistic regression with robust standard errors. INH-monoresistant TB was treated with modified regimens.

RESULTS

Among 18 058 TB patients, there were 19 979 TB episodes for which drug susceptibility testing was performed. Of these, 557 were INH-monoresistant and 16 311 were drug-susceptible. Loss to follow-up, transfer, and human immunodeficiency virus (HIV) co-infection (41% had known HIV status) were similar between groups. INH-monoresistant episodes were more likely to result in treatment failure (4.1% vs. 0.6%, P < 0.001) and death (3.2% vs. 1.8%, P = 0.01) than drug-susceptible episodes. After adjustment for age, sex, race, retreatment status, and disease site, INH-monoresistant episodes were more likely to have resulted in treatment failure (OR 6.84, 95%CI 4.29-10.89, P < 0.001) and death (OR 1.81, 95%CI 1.11-2.95, P = 0.02).

CONCLUSION

INH monoresistance was associated with worse clinical outcomes than drug-susceptible TB. Our findings support the need for rapid diagnostic tests for INH resistance and improved treatment regimens for INH-monoresistant TB.

CD4:CD8 Ratio and CD8 Count as Prognostic Markers for Mortality in Human Immunodeficiency Virus-Infected Patients on Antiretroviral Therapy: The Antiretroviral Therapy Cohort Collaboration (ART-CC)

Background

We investigated whether CD4:CD8 ratio and CD8 count were prognostic for all-cause, AIDS, and non-AIDS mortality in virologically suppressed patients with high CD4 count.

Methods

We used data from 13 European and North American cohorts of human immunodeficiency virus–infected, antiretroviral therapy (ART)–naive adults who started ART during 1996–2010, who were followed from the date they had CD4 count ≥350 cells/μL and were virologically suppressed (baseline). We used stratified Cox models to estimate unadjusted and adjusted (for sex, people who inject drugs, ART initiation year, and baseline age, CD4 count, AIDS, duration of ART) all-cause and cause-specific mortality hazard ratios for tertiles of CD4:CD8 ratio (0–0.40, 0.41–0.64 [reference], >0.64) and CD8 count (0–760, 761–1138 [reference], >1138 cells/μL) and examined the shape of associations using cubic splines.

Results

During 276526 person-years, 1834 of 49865 patients died (249 AIDS-related; 1076 non-AIDS-defining; 509 unknown/unclassifiable deaths). There was little evidence that CD4:CD8 ratio was prognostic for all-cause mortality after adjustment for other factors: the adjusted hazard ratio (aHR) for lower vs middle tertile was 1.11 (95% confidence interval [CI], 1.00–1.25). The association of CD8 count with all-cause mortality was U-shaped: aHR for higher vs middle tertile was 1.13 (95% CI, 1.01–1.26). AIDS-related mortality declined with increasing CD4:CD8 ratio and decreasing CD8 count. There was little evidence that CD4:CD8 ratio or CD8 count was prognostic for non-AIDS mortality.

Conclusions

In this large cohort collaboration, the magnitude of adjusted associations of CD4:CD8 ratio or CD8 count with mortality was too small for them to be useful as independent prognostic markers in virally suppressed patients on ART.

Fluoroquinolones for the treatment and prevention of multidrug-resistant tuberculosis

Although fluoroquinolones (FQs) play an important role in the treatment of multidrug-resistant tuberculosis (MDR-TB), there are several issues that need to be addressed to optimize their effectiveness and minimize toxicity. This includes identification of the optimal dose of FQs such as levofloxacin (LVX) and moxifloxacin, and the optimal role of FQs in combination with other anti-tuberculosis drugs, particularly those with overlapping toxicity, such as QT prolongation. While the ability of FQs to penetrate into cavities and granulomas is likely beneficial, suboptimal sensitivity of genotypic tests to detect FQ resistance could negatively affect treatment outcomes of FQ-containing regimens. Several trials are underway to evaluate the safety and effectiveness of FQs as part of combination MDR-TB therapy; there are also two planned studies of LVX to prevent tuberculosis among close contacts of MDR-TB.

Outcomes of HIV-positive patients with cryptococcal meningitis in the Americas

BACKGROUND

Cryptococcal meningitis (CM) is associated with substantial mortality in HIV-infected patients. Optimal timing of antiretroviral therapy (ART) in persons with CM represents a clinical challenge, and the burden of CM in Latin America has not been well described. Studies suggest that early ART initiation is associated with higher mortality, but data from the Americas are scarce.

METHODS

HIV-infected adults in care between 1985-2014 at participating sites in the Latin America (the Caribbean, Central and South America network (CCASAnet)) and the Vanderbilt Comprehensive Care Clinic (VCCC) and who had CM were included. Survival probabilities were estimated. Risk of death when initiating ART within the first 2 weeks after CM diagnosis versus initiating between 2-8 weeks was assessed using dynamic marginal structural models adjusting for site, age, sex, year of CM, CD4 count, and route of HIV transmission.

FINDINGS

340 patients were included (Argentina 58, Brazil 138, Chile 28, Honduras 27, Mexico 34, VCCC 55) and 142 (42%) died during the observation period. Among 151 patients with CM prior to ART 56 (37%) patients died compared to 86 (45%) of 189 with CM after ART initiation (p=0.14). Patients diagnosed with CM after ART had a higher risk of death (p=0.03, log-rank test). The probability of survival was not statistically different between patients who started ART within 2 weeks of CM (7/24, 29%) vs. those initiating between 2-8 weeks (14/53, 26%) (p=0.96), potentially due to lack of power.

INTERPRETATION

In this large Latin-American cohort, patients with CM had very high mortality rates, especially those diagnosed after ART initiation. This study reflects the overwhelming burden of CM in HIV-infected patients in Latin America.

Pediatric multidrug-resistant tuberculosis clinical trials: challenges and opportunities

On June 17, 2016, RESIST-TB, IMPAACT, Vital Strategies, and New Ventures jointly hosted the Pediatric Multidrug Resistant Tuberculosis Clinical Trials Landscape Meeting in Arlington, Virginia, USA. The meeting provided updates on current multidrug-resistant tuberculosis (MDR-TB) trials targeting pediatric populations and adult trials that have included pediatric patients. A series of presentations were given that discussed site capacity needs, community engagement, and additional interventions necessary for clinical trials to improve the treatment of pediatric MDR-TB. This article presents a summary of topics discussed, including the following: current trials ongoing and planned; the global burden of MDR-TB in children; current regimens for MDR-TB treatment in children; pharmacokinetics of second-line anti-tuberculosis medications in children; design, sample size, and statistical considerations for MDR-TB trials in children; selection of study population, design, and treatment arms for a trial of novel pediatric MDR-TB regimens; practical aspects of pediatric MDR-TB treatment trials; and strategies for integrating children into adult tuberculosis trials. These discussions elucidated barriers to pediatric MDR-TB clinical trials and provided insight into necessary next steps for progress in this field. Investigators and funding agencies need to respond to these recommendations so that important studies can be implemented, leading to improved treatment for children with MDR-TB.

Factors associated with non-completion of follow-up: 33-month latent tuberculous infection treatment trial

SETTING

A post-hoc exploratory analysis of a randomized, open-label clinical trial that enrolled 8053 participants from the United States, Canada, Brazil, and Spain.

OBJECTIVE

To assess factors associated with non-completion of study follow-up (NCF) in a 33-month latent tuberculous infection treatment trial, PREVENT TB.

DESIGN

Participants were randomized to receive 3 months of weekly directly observed therapy vs. 9 months of daily self-administered therapy. NCF was defined as failing to be followed for at least 993 days (33 months) from enrollment. Possible factors associated with NCF were analyzed using univariate and multivariate regression via Cox proportional hazard model.

RESULTS

Of 7061 adults selected for analysis, 841 (11.9%) did not complete study follow-up. Homelessness, young age, low education, history of incarceration, smoking, missing an early clinic visit, receiving isoniazid only, and male sex were significantly associated with NCF. Similar results were found in the North American region (United States and Canada) only. In Brazil and Spain, the only significant factor was missing an early clinic visit.

CONCLUSIONS

Study subjects at higher risk for NCF were identified by characteristics known at enrollment or in early follow-up. Evaluation of follow-up in other trials might help determine whether the identified factors consistently correlate with retention.

Three months of weekly rifapentine plus isoniazid is less hepatotoxic than nine months of daily isoniazid for LTBI

SETTING

Nine months of daily isoniazid (9H) and 3 months of once-weekly rifapentine plus isoniazid (3HP) are recommended treatments for latent tuberculous infection (LTBI). The risk profile for 3HP and the contribution of hepatitis C virus (HCV) infection to hepatotoxicity are unclear.

OBJECTIVES

To evaluate the hepatotoxicity risk associated with 3HP compared to 9H, and factors associated with hepatotoxicity.

DESIGN

Hepatotoxicity was defined as aspartate aminotransferase (AST) >3 times the upper limit of normal (ULN) with symptoms (nausea, vomiting, jaundice, or fatigue), or AST >5 x ULN. We analyzed risk factors among adults who took at least 1 dose of their assigned treatment. A nested case-control study assessed the role of HCV.

RESULTS

Of 6862 participants, 77 (1.1%) developed hepatotoxicity; 52 (0.8%) were symptomatic; 1.8% (61/3317) were on 9H and 0.4% (15/3545) were on 3HP (P < 0.0001). Risk factors for hepatotoxicity were age, female sex, white race, non-Hispanic ethnicity, decreased body mass index, elevated baseline AST, and 9H. In the case-control study, HCV infection was associated with hepatotoxicity when controlling for other factors.

CONCLUSION

The risk of hepatotoxicity during LTBI treatment with 3HP was lower than the risk with 9H. HCV and elevated baseline AST were risk factors for hepatotoxicity. For persons with these risk factors, 3HP may be preferred.

Detection and management of drug-resistant tuberculosis in HIV-infected patients in lower-income countries

SETTING

Drug resistance threatens tuberculosis (TB) control, particularly among human immunodeficiency virus (HIV) infected persons.

OBJECTIVE

To describe practices in the prevention and management of drug-resistant TB under antiretroviral therapy (ART) programs in lower-income countries.

DESIGN

We used online questionnaires to collect program-level data on 47 ART programs in Southern Africa (n = 14), East Africa (n = 8), West Africa (n = 7), Central Africa (n = 5), Latin America (n = 7) and the Asia-Pacific (n = 6 programs) in 2012. Patient-level data were collected on 1002 adult TB patients seen at 40 of the participating ART programs.

RESULTS

Phenotypic drug susceptibility testing (DST) was available in 36 (77%) ART programs, but was only used for 22% of all TB patients. Molecular DST was available in 33 (70%) programs and was used in 23% of all TB patients. Twenty ART programs (43%) provided directly observed therapy (DOT) during the entire course of treatment, 16 (34%) during the intensive phase only, and 11 (23%) did not follow DOT. Fourteen (30%) ART programs reported no access to second-line anti-tuberculosis regimens; 18 (38%) reported TB drug shortages.

CONCLUSIONS

Capacity to diagnose and treat drug-resistant TB was limited across ART programs in lower-income countries. DOT was not always implemented and drug supplies were regularly interrupted, which may contribute to the global emergence of drug resistance.

Body mass index and early CD4 T-cell recovery among adults initiating antiretroviral therapy in North America, 1998-2010

OBJECTIVES

Adipose tissue affects several aspects of the cellular immune system, but prior epidemiological studies have differed on whether a higher body mass index (BMI) promotes CD4 T-cell recovery on antiretroviral therapy (ART). The objective of this analysis was to assess the relationship between BMI at ART initiation and early changes in CD4 T-cell count.

METHODS

We used the North American AIDS Cohort Collaboration on Research and Design (NA-ACCORD) data set to analyse the relationship between pre-treatment BMI and 12-month CD4 T-cell recovery among adults who started ART between 1998 and 2010 and maintained HIV-1 RNA levels < 400 copies/mL for at least 6 months. Multivariable regression models were adjusted for age, race, sex, baseline CD4 count and HIV RNA level, year of ART initiation, ART regimen and clinical site.

RESULTS

A total of 8381 participants from 13 cohorts contributed data; 85% were male, 52% were nonwhite, 32% were overweight (BMI 25-29.9 kg/m(2) ) and 15% were obese (BMI > 30 kg/m(2) ). Pretreatment BMI was associated with 12-month CD4 T-cell change (P < 0.001), but the relationship was nonlinear (P < 0.001). Compared with a reference of 22 kg/m(2) , a BMI of 30 kg/m(2) was associated with a 36 cells/μL [95% confidence interval (CI) 14, 59 cells/μL] greater CD4 T-cell count recovery among women and a 19 cells/μL (95% CI 9, 30 cells/μL) greater recovery among men at 12 months. At a BMI > 30 kg/m(2) , the observed benefit was attenuated among men to a greater degree than among women, although this difference was not statistically significant.

CONCLUSIONS

A BMI of approximately 30 kg/m(2) at ART initiation was associated with greater CD4 T-cell recovery at 12 months compared with higher or lower BMI values, suggesting that body composition may affect peripheral CD4 T-cell recovery.

Body mass index and the risk of incident noncommunicable diseases after starting antiretroviral therapy

OBJECTIVES

Obesity and HIV infection are associated with an increased incidence of noninfectious comorbid medical conditions, but the relationship between body mass index (BMI) and the development of noncommunicable diseases (NCDs) among individuals on antiretroviral therapy (ART) has not been well characterized.

METHODS

A cohort study of adults initiating ART between 1998 and 2010 at an academic centre with systematic laboratory and clinical data collection, including AIDS and NCD diagnoses, was carried out. The relationship between BMI at ART initiation and the risk of incident cardiovascular, hepatic, renal or oncological NCDs was assessed using Cox proportional hazard models. BMI was fitted using restricted cubic splines and models adjusted for age, sex, race, CD4 count, protease inhibitor use, year of initiation, and prior AIDS-defining illness.

RESULTS

Among 1089 patients in the analysis cohort, 54% had normal BMI, 28% were overweight, and 18% were obese. Baseline BMI was associated with developing an incident NCD (P<0.01), but the relationship was nonlinear. Compared with a BMI of 25 kg/m(2) , a BMI of 30 kg/m(2) conferred a lower risk of an incident NCD diagnosis [adjusted hazard ratio (AHR) 0.59; 95% confidence interval (CI) 0.40, 0.87]. This protective effect was attenuated at a BMI of 35 kg/m(2) (AHR 0.78; 95% CI 0.49, 1.23). Results were similar in sensitivity analyses incorporating tobacco, alcohol and illicit drug use, statin and antihypertensive exposure, and virological suppression.

CONCLUSIONS

Overweight individuals starting ART have a lower risk of developing NCDs compared with normal BMI individuals, which may reflect a biological effect of adipose tissue or differences in patient or provider behaviours.

Risk factors for treatment default in close contacts with latent tuberculous infection

OBJECTIVE

1) To characterize risk factors for non-completion of latent tuberculous infection treatment (LTBIT), and 2) to assess the impact of LTBIT regimens on subsequent risk of tuberculosis (TB).

METHODS

Close contacts of adults aged ⩾15 years with pulmonary TB were prospectively enrolled in a multi-center study in the United States and Canada from January 2002 to December 2006. Close contacts of TB patients were screened and cross-matched with TB registries to identify those who developed active TB.

RESULTS

Of 3238 contacts screened, 1714 (53%) were diagnosed with LTBI. Preventive treatment was recommended in 1371 (80%); 1147 (84%) initiated treatment, of whom 723 (63%) completed it. In multivariate analysis, study site, initial interview sites other than a home or health care setting and isoniazid preventive treatment (IPT) were significantly associated with non-completion of LTBIT. Fourteen TB cases were identified in contacts, all of whom initiated IPT: two TB cases among persons who received ⩾6 months of IPT (66 cases/100 000 person-years [py]), and nine among those who received 0-5 months (median 2 months) of IPT (792 cases/100 000 py, P < 0.001); data on duration of IPT were not available for three cases.

CONCLUSION

Only 53% (723/1371) of close contacts for whom IPT was recommended actually completed treatment. Close contacts were significantly less likely to complete LTBIT if they took IPT. Less than 6 months of IPT was associated with increased risk of active TB.

Long-term mortality in HIV-positive individuals virally suppressed for >3 years with incomplete CD4 recovery

BACKGROUND

Some human immunodeficiency virus (HIV)-infected individuals initiating combination antiretroviral therapy (cART) with low CD4 counts achieve viral suppression but not CD4 cell recovery. We aimed to identify (1) risk factors for failure to achieve CD4 count >200 cells/µL after 3 years of sustained viral suppression and (2) the association of the achieved CD4 count with subsequent mortality.

METHODS

We included treated HIV-infected adults from 2 large international HIV cohorts, who had viral suppression (≤500 HIV type 1 RNA copies/mL) for >3 years with CD4 count ≤200 cells/µL at start of the suppressed period. Logistic regression was used to identify risk factors for incomplete CD4 recovery (≤200 cells/µL) and Cox regression to identify associations with mortality.

RESULTS

Of 5550 eligible individuals, 835 (15%) did not reach a CD4 count >200 cells/µL after 3 years of suppression. Increasing age, lower initial CD4 count, male heterosexual and injection drug use transmission, cART initiation after 1998, and longer time from initiation of cART to start of the virally suppressed period were risk factors for not achieving a CD4 count >200 cells/µL. Individuals with CD4 ≤200 cells/µL after 3 years of viral suppression had substantially increased mortality (adjusted hazard ratio, 2.60; 95% confidence interval, 1.86-3.61) compared with those who achieved CD4 count >200 cells/µL. The increased mortality was seen across different patient groups and for all causes of death.

CONCLUSIONS

Virally suppressed HIV-positive individuals on cART who do not achieve a CD4 count >200 cells/µL have substantially increased long-term mortality.

Cost-effectiveness of a 12-dose regimen for treating latent tuberculous infection in the United States

SETTING

A large randomized controlled trial recently showed that for treating latent tuberculous infection (LTBI) in persons at high risk of progression to tuberculosis (TB) disease, a 12-dose regimen of weekly rifapentine plus isoniazid (3HP) administered as directly observed treatment (DOT) can be as effective as 9 months of daily self-administered isoniazid (9H).

OBJECTIVES

To assess the cost-effectiveness of 3HP compared to 9H.

DESIGN

A computational model was designed to simulate individuals with LTBI treated with 9H or 3HP. Costs and health outcomes were estimated to determine the incremental costs per active TB case prevented and per quality-adjusted life year (QALY) gained by 3HP compared to 9H.

RESULTS

Over a 20-year period, treatment of LTBI with 3HP rather than 9H resulted in 5.2 fewer cases of TB and 25 fewer lost QALYs per 1000 individuals treated. From the health system and societal perspectives, 3HP would cost respectively US$21,525 and $4294 more per TB case prevented, and respectively $4565 and $911 more per QALY gained.

CONCLUSIONS

3HP may be a cost-effective alternative to 9H, particularly if the cost of rifapentine decreases, the effectiveness of 3HP can be maintained without DOT, and 3HP treatment is limited to those with a high risk of progression to TB disease.

Non-adherence and drug-related interruptions are risk factors for delays in completion of treatment for tuberculosis

SETTING

A key program performance objective established by the Centers for Disease Control and Prevention (CDC) is that ≥93% of tuberculosis (TB) cases complete treatment within 12 months.

OBJECTIVE

To determine the rate of and risk factors for delay in anti-tuberculosis treatment completion.

DESIGN

Nested case-control study among TB cases reported to the Tennessee Department of Health between 1 January 2000 and 31 December 2010. Time to complete treatment was calculated using treatment start and stop dates documented in the Tuberculosis Information Management System (TIMS).

RESULTS

Of 2627 cases, 261 (9.9%) required >12 months to complete treatment. In adjusted conditional logistic regression analyses, cavitary disease and positive cultures after 2 months of therapy (OR 5.85, 95%CI 1.98-17.32, P = 0.001), non-adherence (OR 4.13, 95%CI 1.76-9.72, P < 0.001), and interruptions in treatment due to drug-related issues (OR 6.91, 95%CI 3.76-12.70, P < 0.001) were independently associated with delay in completion of TB treatment.

CONCLUSION

From 2000 to 2010, the proportion of TB cases completing treatment within 12 months increased from 84.6% to 94.9%, and remained above the CDC target during 2009-2010. Efforts to improve patient adherence and reduce interruptions in treatment due to anti-tuberculosis drug-related issues could improve the proportion of TB cases completing treatment within 12 months.

Fluoroquinolone exposure prior to tuberculosis diagnosis is associated with an increased risk of death

SETTING

Fluoroquinolone (FQ) exposure before tuberculosis (TB) diagnosis is common, but its effect on outcomes, including mortality, is unclear.

DESIGN

Among TB patients reported to the Tennessee Department of Health from 2007 to 2009, we assessed FQ exposure within 6 months before TB diagnosis. The primary outcome was the combined endpoint of death at the time of TB diagnosis and during anti-tuberculosis treatment.

RESULTS

Among 609 TB cases, 214 (35%) received FQs within 6 months before TB diagnosis. A total of 71 (12%) persons died; 10 (2%) were dead at TB diagnosis and 61 (10%) died during anti-tuberculosis treatment. In multivariable logistic regression analysis, factors independently associated with death were older age (OR 1.05 per year, 95%CI 1.04-1.07), human immunodeficiency virus infection (OR 8.08, 95%CI 3.83-17.06), US birth (OR 3.03, 95%CI 1.03-9.09), and any FQ exposure before TB diagnosis (OR 1.82, 95%CI 1.05-3.15). Persons with FQ exposure before TB diagnosis were more likely to have culture- and smear-positive disease than unexposed persons.

CONCLUSIONS

Among this patient population, FQ exposure before TB diagnosis was associated with an increased risk of death. These findings underscore the need for cautious use of FQs in persons with possible TB.

Microcolonies in fluoroquinolone agar proportion susceptibility testing of Mycobacterium tuberculosis: an indicator of drug resistance

Microcolony growth of Mycobacterium tuberculosis on agar proportion susceptibility testing is neither well-defined nor previously reported with fluoroquinolone susceptibility testing. We describe here M. tuberculosis microcolony growth with fluoroquinolones, and assess its clinical significance. We screened 797 M. tuberculosis isolates for ofloxacin resistance (2.0 μg/mL) by agar proportion; 19 ofloxacin-resistant and 38 ofloxacin-susceptible isolates were selected for more detailed susceptibility testing with ofloxacin, ciprofloxacin, levofloxacin (all at 2.0 μg/mL) and moxifloxacin (0.5 μg/mL). The 57 isolates were also tested at two concentrations both above and below the critical concentrations. Microcolonies were defined as colonies 0.2-0.4 mm in diameter; confirmed microcolonies were present on repeat testing. Of the 57 isolates tested in detail, 7 grew microcolonies, of which 2 (0.3% of all isolates tested) had confirmed microcolonies on repeat testing (6 tests performed, and microcolonies were present on at least 4). Both M. tuberculosis isolates were ofloxacin-resistant on screening, and had ofloxacin minimum inhibitory concentration (MIC) >8 μg/mL. The five other isolates were ofloxacin-susceptible on screening, but had regular colony growth (i.e., resistance) at the drug concentration that initially resulted in microcolonies (ofloxacin 0.5 or 1.0 μg/mL). Microcolonies were observed infrequently with fluoroquinolone susceptibility testing, but when confirmed, they were associated with drug resistance.

Chronic lung disease and HIV infection are risk factors for recurrent tuberculosis in a low-incidence setting

SETTING

Programmatic data from the United States on tuberculosis (TB) recurrence are limited.

OBJECTIVES

To determine the TB recurrence rate and to determine if chronic lung disease (CLD) and human immunodeficiency virus (HIV) infection are risk factors for recurrence in this population.

DESIGN

Nested case-control study among TB cases reported to the Tennessee Department of Health between 1 January 2000 and 31 December 2006. Time at risk for recurrence was through 31 December 2007. Multiple imputation accounted for missing data.

RESULTS

Of 1431 TB cases, 20 cases recurred (1.4%, 95%CI 0.9-2.1). Median time at risk for recurrence was 4.5 years (interquartile range 2.7-6.1). Initial and recurrent Mycobacterium tuberculosis isolates were available for genotyping for 15 patients; 12 were consistent with relapse (0.8%, 95%CI 0.4-1.5) and three with re-infection (0.2%, 95%CI 0.04-0.6). HIV infection (OR 5.01, P = 0.04) and CLD (OR 5.28, P = 0.03) were independently associated with recurrent TB, after adjusting for a disease risk score. HIV infection was a risk factor for TB re-infection (P < 0.001).

CONCLUSIONS

In this low-incidence US population, the TB recurrence rate was low, but CLD and HIV were independent risk factors for recurrence. HIV infection was also a risk factor for TB re-infection.

Potentially preventable tuberculosis among HIV-infected persons in the era of highly active antiretroviral treatment

OBJECTIVE

To characterize the proportion of tuberculosis (TB) cases that could have been prevented among human immunodeficiency virus (HIV) infected persons receiving care in the era of highly active antiretroviral treatment (HAART).

DESIGN

We conducted an observational cohort study among HIV-infected patients with >or=2 out-patient visits at the Comprehensive Care Center, Nashville, Tennessee, USA, between 1 January 1998 and 31 December 2005.

METHODS

A potentially preventable TB case was defined as a case in which the patient received no screening tuberculin skin test (TST) prior to TB diagnosis or a case in which a patient with a positive screening TST did not complete treatment for latent infection.

RESULTS

Of 3601 HIV-infected persons in care (13 905 person-years [p-y] of follow-up), 29 developed TB (230/100,000 p-y). Of the 29, 20 (69%) had not had TST performed as part of routine screening. Of the nine patients screened, four had a positive test, three of whom completed treatment for latent TB infection. Of 29 TB cases, 21 (72%) were therefore potentially preventable.

CONCLUSIONS

Most TB cases in this cohort were potentially preventable had the patients undergone a screening TST followed by treatment of latent infection if they had a positive TST.

Normal chest radiography in pulmonary tuberculosis: implications for obtaining respiratory specimen cultures

SETTING

Urban tuberculosis (TB) clinic, Nashville, Tennessee, USA.

OBJECTIVE

Chest radiographs (CXRs) help in the diagnosis of pulmonary TB, but may be normal. Mycobacterium tuberculosis in culture is diagnostic of TB, but cultures are not routinely obtained in resource-poor settings. We examined rates and risk factors for pulmonary TB associated with normal CXR.

DESIGN

An observational cohort study was performed among all respiratory culture-positive TB cases referred to the Nashville Health Department from October 1992 to July 2003. Clinical factors, demographics and underlying medical conditions were assessed.

RESULTS

Of 601 study patients, 53 (9%) had normal CXRs: 31/138 (22%) were human immunodeficiency virus (HIV) infected and 22/463 (5%) were non-HIV-infected/unknown (P<0.001). Among HIV-infected patients, normal CXR was more likely in persons with renal failure (13% vs. 3%, P=0.048). Among non-HIV-infected/unknown patients, normal CXR was more likely in those who were asymptomatic at presentation (32% vs. 13%, P=0.022). In multivariable logistic regression analysis, HIV infection was associated with an increased risk of normal CXR (odds ratio [OR] 6.61, P<0.0001); factors associated with reduced risk were dyspnea (OR 0.24, P=0.026), positive sputum smear (OR 0.45, P=0.028) and cough (OR 0.48, P=0.038).

CONCLUSIONS

The rate of normal CXR among persons with culture-confirmed pulmonary TB was high. Respiratory specimen cultures should be obtained in TB suspects with a normal CXR, particularly HIV-infected persons.

Resistance to amphotericin B: emerging clinical and microbiological patterns

There has been an increasing number of reports of clinically significant amphotericin B (AmB) resistance in fungal pathogens, including Candida albicans. Concomitantly, advances in antifungal susceptibility testing have led to an improved correlation between microbiologic and clinical failure. Reports of AmB resistance, correlation of results and in vitro/in vivo correlations, mechanisms of resistance, and the transmission of resistant isolates within confined environments are reviewed. Recommendations are given regarding the clinical settings in which AmB susceptibility testing should be considered.

Mortality in a large tuberculosis treatment trial: modifiable and non-modifiable risk factors

SETTING

North America.

OBJECTIVES

Tuberculosis (TB) patients in North America often have characteristics that may increase overall mortality. Identifying modifiable risk factors would allow for improvements in outcome.

DESIGN

We evaluated mortality in a large TB treatment trial conducted in the United States and Canada. Persons with culture-positive pulmonary TB were enrolled after 2 months of treatment, treated for 4 more months under direct observation, and followed for 2 years (total observation: 28 months). Cause of death was determined by death certificate, autopsy, and/or clinical observation.

RESULTS

Of 1075 participants, 71 (6.6%) died: 15/71 (21.1%) HIV-infected persons, and 56/1004 (5.6%) non-HIV-infected persons (P < 0.001). Only one death was attributed to TB. Cox multivariate regression analysis identified four independent risk factors for death after controlling for age: malignancy (hazard ratio [HR] 5.28, P < 0.0001), HIV (HR 3.89, P < 0.0001), daily alcohol (HR 2.94, P < 0.0001), and being unemployed (HR 1.99, P = 0.01). The risk of death increased with the number of independent risk factors present (P < 0.0001). Extent of disease and treatment failure/relapse were not associated with an increased risk of death.

CONCLUSIONS

Death due to TB was rare. Interventions to treat malignancy, HIV, and alcohol use in TB patients are needed to reduce mortality in this patient population.

Impact of empiric antibiotics and chest radiograph on delays in the diagnosis of tuberculosis

SETTING

Maryland Department of Health and Mental Hygiene, Division of Tuberculosis (TB) Control.

OBJECTIVES

To assess the implications of antibiotic treatment of presumed community-acquired pneumonia (CAP) on delays in the diagnosis of TB, and to assess the frequency with which chest radiographs (CXRs) were utilized before a diagnosis of pneumonia or pulmonary TB was made.

DESIGN

A nested case-control study within a prospective study conducted to assess factors associated with delays in the diagnosis of TB.

RESULTS

Cases (n = 85; 54%) were patients who received antibiotics for non-TB diagnoses/indications prior to TB diagnosis, and controls (n = 73; 46%) were patients who had initially received TB therapy. Median health care delay for cases was 39 days vs. 15 days (P < 0.01) for controls. Median antibiotic delay was similar among all antibiotic classes. Of 54 patients who did not have a CXR at their first health care visit, 41 (79%) received empiric antibiotics, compared to 44/105 (42%) who had a CXR (P < 0.01). Only 31/54 (57%) patients initially diagnosed with CAP had a CXR at the time of diagnosis.

CONCLUSION

More widespread use of CXR when diagnosing CAP should reduce delays in diagnosing TB, and the unnecessary use of antibiotics.

The WHO/IUATLD diagnostic algorithm for tuberculosis and empiric fluoroquinolone use: potential pitfalls

According to the current WHO/IUATLD diagnostic algorithm for tuberculosis, to establish the diagnosis of smear-negative pulmonary disease, patients should first demonstrate no clinical response to a course of broad-spectrum antibiotics. The fluoroquinolones have broad-spectrum activity against respiratory pathogens and are generally considered first-line therapy for the treatment of community-acquired pneumonia; they also have bactericidal activity against Mycobacterium tuberculosis. Of note, empiric fluoroquinolone monotherapy has been associated with delays in the initiation of appropriate anti-tuberculosis therapy, and also resistance in M. tuberculosis. Delays in the diagnosis and treatment of tuberculosis are associated with increased morbidity and mortality. Resistance to fluoroquinolones in M. tuberculosis could limit the use of this potentially first-line class of anti-tuberculosis agents. The WHO/IUATLD diagnostic criteria for smear-negative tuberculosis should be revised to ensure that fluoroquinolones are not used inappropriately and that the detrimental effects of empiric fluoroquinolone monotherapy in tuberculosis patients are avoided.

Evaluation of an extensive tuberculosis contact investigation in an urban community and jail

SETTING

Urban community and jail.

OBJECTIVES/DESIGN

Evaluate outcome and process of an extensive tuberculosis contact investigation, including completion of treatment of latent TB infection (TLTBI).

RESULTS

Between April 2000 and September 2001, 18 epidemiologically-linked tuberculosis cases were identified; 15 were culture-confirmed, all with a matching 14-band DNA fingerprint pattern. The source case had cavitary pulmonary disease and had been incarcerated 4 months prior to diagnosis. Sixty-six of 67 (99%) community contacts and 221/344 (64%) jail contacts were evaluated. The presumed new infection rate was 56% for community contacts (11 cases, 25 tuberculin skin test [TST] positive) and 20% for jail contacts (6 cases, 32 TST converters). Screening results for 113 (33%) jail contacts were obtained in the jail TST registry upon rearrest. All identified cases completed treatment. Of 22 community contacts initiating TLTBI, 11 completed (44% of infected, 50% of initiators). Of 32 infected jail contacts, 12 initiated TLTBI (all who remained incarcerated), and 10 completed (31% of infected, 83% of initiators). None of 20 additional in-fected jail contacts, all of whose TST conversions were identified with re-arrest data, were subsequently located. Two additional related cases have been identified as of October 2003.

CONCLUSIONS

Close health department/corrections collaboration facilitated this extensive contact investigation, which identified high Mycobacterium tuberculosis transmission rates and controlled the outbreak. Numerous contacts were identified and screened, but rates of treatment completion for infected contacts were low. Novel strategies are needed to maximize the number of infected contacts who are not only identified and evaluated, but completely treated.

A high tuberculosis case-fatality rate in a setting of effective tuberculosis control: implications for acceptable treatment success rates

Worldwide, the case-fatality rate of smear-positive pulmonary tuberculosis among persons on treatment is 3.8%. We assessed the case-fatality rate among such patients in Baltimore between January 1993 and June 1998. Tuberculosis incidence was < 17/100 000 population, and 99% of patients received directly observed therapy. Of 174 patients, 42 (24%) died on treatment. Patients who died were older (mean age 62 vs. 47 years; P < 0.001) and were more likely to have underlying medical conditions. In multivariate analyses, older age, diabetes mellitus, and renal failure were independently associated with an increased risk of death. With effective control, tuberculosis may become concentrated in older persons with chronic diseases and be associated with high case-fatality rates. In such settings, acceptable treatment success rates may need to be revised.

HIV-1 RNA, CD4 T-lymphocytes, and clinical response to highly active antiretroviral therapy

OBJECTIVE

To determine if HIV-1 RNA and CD4 lymphocyte thresholds for the initiation of highly active antiretroviral therapy (HAART) are associated with clinical response to therapy.

DESIGN

Observational cohort study.

SETTING

Johns Hopkins Hospital HIV Clinic.

PATIENTS

HIV-infected adults.

INTERVENTION

Patients initiating HAART (n = 530) were compared with concurrent patients who did not receive HAART (n = 484).

MAIN OUTCOME MEASURE

Progression to a new AIDS-defining illness or death.

RESULTS

The average duration of follow-up for the cohort was 22 months. HAART resulted in decreased disease progression among persons with fewer than, but not more than, 200 x 10(6) CD4 lymphocytes/l prior to treatment. Among persons receiving HAART, plasma HIV-1 RNA level prior to therapy was not associated with HIV disease progression within CD4 T-lymphocyte count strata. In a Cox multivariate proportional hazards model that adjusted for age, sex, race, prior opportunistic infection, and CD4 T lymphocytes, < or = 200 x 10(6) CD4 lymphocytes/l was the strongest predictor of disease progression. HIV-1 RNA level prior to starting HAART of < 5000 copies/ml, 5001-55 000 copies/ml, or > 55 000 copies/ml was not associated with disease progression on therapy, particularly among persons with > 200 x 10(6) CD4 lymphocytes/l. There was no sex difference in disease progression on treatment.

CONCLUSIONS

Our data suggest that current guidelines for initiating HAART should place greater emphasis on CD4 lymphocyte than HIV-1 RNA level for both men and women. Further longitudinal follow-up will be needed to better ascertain whether HAART initiated at > 200 x 10(6) CD4 lymphocytes/l is effective in slowing disease progression.

Transmission of Mycobacterium tuberculosis through casual contact with an infectious case

BACKGROUND

An ongoing restriction fragment length polymorphism study of Mycobacterium tuberculosis isolates from tuberculosis cases showed an identical 12-band IS6110 pattern unique to 3 unrelated patients (Patients A-C) diagnosed as having tuberculosis within a 9-month period.

METHODS

In an attempt to identify epidemiologic links between the 3 patients, we performed site visits to the retail business work site of patient A and conducted detailed interviews with all 3 patients and their contacts.

RESULTS

Patient B had visited patient A's work site 3 times during patient A's infectious period, spending no more than 15 minutes each time. Patient C visited patient A's work site on 6 to 10 occasions during this period for no more than 45 minutes at any one time. There were no other epidemiologic links between these 3 cases other than the contact at the store. Contact investigation identified 4 tuberculin skin test conversions among 8 (50%) of patient A's coworkers, 6 positive tests among 15 household contacts (40%), and 8 positive tests among 16 identified customers who were casual contacts (50%). Patient B and patient C were most likely infected by patient A during one of their brief visits to patient A's work site.

CONCLUSIONS

These data demonstrate that some tuberculosis is spread through casual contact not normally pursued in traditional contact investigations and that, in certain situations, M tuberculosis can be transmitted despite minimal duration of exposure. In addition, this outbreak emphasizes the importance of DNA fingerprinting data for identifying unusual transmission in unexpected settings.

Human immunodeficiency virus-seronegative adults with extrapulmonary tuberculosis have abnormal innate immune responses

Extrapulmonary tuberculosis is presumably a marker of underlying immunodeficiency, but cytokine response pathways in these patients have not been well studied. Cytokine responses of peripheral blood mononuclear cells from human immunodeficiency virus-seronegative adults with prior culture-confirmed extrapulmonary tuberculosis were compared with those of persons with latent Mycobacterium tuberculosis infection. Mitogen-stimulated interferon (IFN)-gamma production, interleukin (IL)-12 production, and IFN-gamma receptor- and IL-12 receptor-mediated cytokine production did not differ between case patients and control patients. However, median resting IL-8 production was significantly lower in case patients than control patients (8051 vs. 19,290 pg/mL; P=.009). In addition, the median tumor necrosis factor (TNF)-alpha response was lower in case patients than control patients after stimulation with lipopolysaccharide (833 vs. 1149 pg/mL; P=.06) and lipopolysaccharide plus IFN-gamma (3301 vs. 4411 pg/mL; P=.04). These abnormalities in resting IL-8 and lipopolysaccharide-induced TNF-alpha production were not associated with IFN-gamma or IL-12 abnormalities and were detected up to several years after cure of disease, suggesting an abnormality in innate immunity.

Paradoxical worsening of tuberculosis in HIV-infected persons

OBJECTIVE

To determine the incidence of paradoxical worsening of tuberculosis (TB) in HIV-infected persons.

DESIGN

Observational cohort study.

SETTING

Public, urban TB clinic.

PATIENTS

HIV-infected persons treated for TB between January 1, 1996, and December 31, 1999, and followed through June 30, 2000.

INTERVENTION

Patients received standard anti-TB therapy. Antiretroviral therapy was provided by primary medical providers. Patients receiving antiretroviral therapy were given nucleoside reverse transcriptase inhibitors alone or highly active antiretroviral therapy (HAART; nucleoside reverse transcriptase inhibitors in combination with a protease inhibitor or a nonnucleoside reverse transcriptase inhibitor).

MAIN OUTCOME MEASURE

Paradoxical worsening of TB.

RESULTS

There were 82 TB cases in 76 patients. Paradoxical worsening was identified in 6 of 82 cases (7%; 95% confidence interval, 3 to 15%). Paradoxical worsening occurred in 3 of 28 cases (11%) in patients receiving HAART and in 3 of 44 cases (7%) in patients not receiving antiretroviral therapy (p = 0.67). Cases complicated by paradoxical worsening were more likely to have both pulmonary and extrapulmonary disease at initial diagnosis than cases without paradoxical worsening (83% vs 24%; p = 0.006). TB relapse occurred in 2 of 6 cases (33%) in patients with paradoxical worsening and in 4 of 76 cases (5%) in patients without paradoxical worsening (p = 0.06).

CONCLUSIONS

Paradoxical worsening of TB occurred less frequently than in previous reports and was not associated with HAART. Paradoxical worsening also appeared to be associated with an increased risk of TB relapse. Further studies are warranted to better characterize the risk factors for paradoxical worsening and the appropriate duration of anti-TB therapy in patients in whom it occurs.

Initial plasma HIV-1 RNA levels and progression to AIDS in women and men

BACKGROUND

It is unclear whether there are differences between men and women with human immunodeficiency virus type 1 (HIV-1) infection in the plasma level of viral RNA (the viral load). In men, the initial viral load after seroconversion predicts the likelihood of progression to the acquired immunodeficiency syndrome (AIDS), but the relation between the two has not been assessed in women. Currently, the guidelines for initiating antiretroviral therapy are applied uniformly to women and men.

METHODS

From 1988 through 1998, the viral load and the CD4+ lymphocyte count were measured approximately every six months in 156 male and 46 female injection-drug users who were followed prospectively after HIV-1 seroconversion.

RESULTS

The median initial viral load was 50,766 copies of HIV-1 RNA per milliliter in the men but only 15,103 copies per milliliter in the women (P<0.001). The median initial CD4+ count did not differ significantly according to sex (659 and 672 cells per cubic millimeter, respectively). HIV-1 infection progressed to AIDS in 29 men and 15 women, and the risk of progression did not differ significantly according to sex. For each increase of 1 log in the viral load (on a base 10 scale), the hazard ratio for progression to AIDS was 1.55 (95 percent confidence interval, 0.97 to 2.47) among the men and 1.43 (95 percent confidence interval, 0.76 to 2.69) among the women. The median initial viral load was 77,822 HIV-1 RNA copies per milliliter in the men in whom AIDS developed and 40,634 copies per milliliter in the men in whom it did not; the corresponding values in the women were 17,149 and 12,043 copies per milliliter. Given the recommendation that treatment should be initiated when the viral load reaches 20,000 copies per milliliter, 74 percent of the men but only 37 percent of the women in our study would have been eligible for therapy at the first visit after seroconversion (P<0.001).

CONCLUSIONS

Although the initial level of HIV-1 RNA was lower in women than in men, the rates of progression to AIDS were similar. Treatment guidelines that are based on the viral load, rather than the CD4+ lymphocyte count, will lead to differences in eligibility for antiretroviral treatment according to sex.

A multi-state outbreak of tuberculosis among members of a highly mobile social network: implications for tuberculosis elimination

SETTING

Baltimore, Maryland.

OBJECTIVE

To describe a tuberculosis (TB) outbreak among a highly mobile population and the efforts required to control it.

DESIGN

Epidemiologic outbreak investigation.

RESULTS

Between June 1998 and January 2000, 20 TB outbreak cases were identified, of which 18 were culture-confirmed. Seventeen isolates of Mycobacterium tuberculosis had an identical 11-band DNA fingerprint; another isolate had one additional band and was considered a match. Two cases were diagnosed in New York City; another patient lived primarily in Atlanta, but was diagnosed in Baltimore. Persons in the outbreak were predominantly young (median age 24 years), black, male, infected with the human immunodeficiency virus (HIV), and gay, transvestite or transsexual. Activities common among many TB cases included attending two nightclubs, membership in one of three social 'Houses', attending balls or pageants in East Coast cities, marijuana use, and prostitution. Community outreach, extended contact tracing, DNA fingerprinting, directly-observed therapy, and expanded use of preventive therapy were utilized to assess and control the outbreak. During the outbreak period the Baltimore City TB rate declined by 10%. However, additional public health personnel were required to control the outbreak, resulting in a 17% increase in TB clinic staff.

CONCLUSION

As TB rates decline, remaining cases are likely to occur in difficult-to-reach populations. Increased resources per case of TB treated will be required to eliminate TB.

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.

Sex differences in longitudinal human immunodeficiency virus type 1 RNA levels among seroconverters

Cross-sectional studies have demonstrated lower plasma human immunodeficiency virus type 1 (HIV-1) RNA virus levels (VLs) in women than in men, but it is unknown whether this sex difference is present at the time of seroconversion and throughout the course of infection. A nested case-control study was performed among HIV-1 seroconverters within a cohort of injection drug users. Plasma VL was determined longitudinally among both rapid progressors to AIDS (24 patients) and nonprogressors (47 controls). The initial median VL among female patients (n=10) was 14,918 copies/mL, compared with 148,354 copies/mL among male patients (n=14; P=.001); median plasma VL also tended to be lower among female (n=10) than among male controls (n=37; 11,917 vs. 61,311 copies/mL; P=.08). VL increased more rapidly over time in women than in men and subsequently converged in patients and controls, respectively. Understanding the mechanisms responsible for the sex difference in VL may provide insight into HIV-1 pathogenesis.