The clinical burden of tuberculosis among human immunodeficiency virus-infected children in Western Kenya and the impact of combination antiretroviral treatment.

CONTEXT: The burden of tuberculosis (TB) disease in children, particularly in HIV-infected children, is poorly described because of a lack of effective diagnostic tests and the emphasis of public health programs on transmissible TB.

OBJECTIVES

The objectives of this study were to describe the observed incidence of and risk factors for TB diagnosis among HIV-infected children enrolled in a large network of HIV clinics in western Kenya.

DESIGN

Retrospective observational study.

SETTING

The USAID-Academic Model Providing Access to Healthcare (AMPATH) Partnership is Kenya's largest HIV/AIDS care system. Since 2001, the program has enrolled over 70,000 HIV-infected patients in 18 clinics throughout Western Kenya.

PATIENTS: This analysis included all HIV-infected children aged 0 to 13 years attending an AMPATH clinic.

MAIN OUTCOME MEASURE: The primary outcome was a diagnosis of any TB, defined either by a recorded diagnosis or by the initiation of anti-TB treatment. Diagnosis of TB is based on a modified Kenneth Jones scoring system and is consistent with WHO case definitions.

RESULTS

There were 6535 HIV-infected children aged 0 to 13 years, eligible for analysis, 50.1% were female. Of these, 234 (3.6%) were diagnosed with TB at enrollment. There were subsequently 765 new TB diagnoses in 4368.0 child-years of follow-up for an incidence rate of 17.5 diagnoses (16.3-18.8) per 100 child-years. The majority of these occurred in the first 6 months after enrollment (IR: 106.8 per 100 CY, 98.4-115.8). In multivariable analysis, being severely immune-suppressed at enrollment (Adjusted Hazard Ratio [AHR]: 4.44, 95% CI: 3.62-5.44), having ever attended school AHR: 2.65, 95% CI: 2.15-3.25), being an orphan (AHR: 1.57, 95% CI: 1.28-1.92), being severely low weight-for-height at enrollment (AHR: 1.46, 95% CI: 1.32-1.62), and attending an urban clinic (AHR: 1.39, 95% CI: 1.16-1.67) were all independent risk factors for having an incident TB diagnosis. Children receiving combination antiretroviral treatment were dramatically less likely to be diagnosed with incident TB (AHR: 0.15, 95% CI: 0.12-0.20).

CONCLUSIONS

These data suggest a high rate of TB diagnosis among HIV-infected children, with severe immune suppression, school attendance, orphan status, very low weight-for-height, and attending an urban clinic being key risk factors. The use of combination antiretroviral treatment reduced the probability of an HIV-infected child being diagnosed with incident TB by 85%.