Incorporating loss to follow-up in estimates of survival among HIV-infected individuals in sub-Saharan Africa enrolled in antiretroviral therapy programs

Measuring the survival of human immunodeficiency virus–infected adult patients enrolled in antiretroviral therapy (ART) programs is complicated by short observation periods and loss to follow-up. We synthesized data from treatment cohorts in sub-Saharan Africa to estimate survival over 5 years after initiation of ART.

We used data on retention, mortality, and loss to follow-up from 34 cohorts, including a total of 102 306 adult patients from 18 sub-Saharan African countries. These data were augmented by data from 13 sub-Saharan African studies tracking death rates among adult patients who were lost to follow-up (LTFU). We used a Poisson regression model to estimate survival over time, incorporating predicted mortality among LTFU patients.

Across studies, the median CD4+ cell count at ART initiation was 104 cells/mm3, 65% of patients were female, and the median age was 37 years. Survival at 1 year and 5 years were estimated to be 0.87 (95% confidence interval [CI], 0.72–0.94) and 0.70 (95% CI, 0.36–0.86), respectively, after adjustment for loss to follow-up. The life-years gained by a patient during the 5-year period after starting ART were estimated at 2.1 (95% CI, 1.6–2.3) in the adjusted model, compared with 1.7 (95% CI, 1.1–2.0) if there was 100% mortality among LTFU patients and with 2.4 (1.7–2.7) if there was 0% mortality among LTFU patients.

Accounting for loss to follow-up produces substantial changes in the estimated life-years gained during the first 5 years of ART receipt.

 

FUNDING

Bill & Melinda Gates Foundation – Disease Control Priorities Network (Investment # OPP51229)