An optimal body mass index range associated with improved immune reconstitution among HIV-infected adults initiating antiretroviral therapy

Abstract

Background: Higher body mass index (BMI) was associated with slower human immunodeficiency virus (HIV) disease progression before the availability of effective antiretroviral therapy (ART), but the relationship between pretreatment BMI and CD4(+) lymphocyte recovery on ART is not well described.

Methods: We conducted an observational cohort study of HIV-infected, ART-naive adults starting treatment at a clinic affiliated with Vanderbilt University in Nashville, Tennessee. We assessed the relationship between pretreatment BMI and CD4(+) lymphocyte count change from baseline to 12 months in all subjects, among those with plasma HIV-1 RNA levels <400 copies/mL for ≥ 6 months and those with <10% change in weight during follow-up. Linear regression models were adjusted for age, sex, race, protease inhibitor usage, year of ART initiation, and baseline CD4(+) lymphocyte count and HIV-1 RNA level.

Results: A total of 915 patients met inclusion criteria; 78% were male, and their median age, BMI, and CD4(+) lymphocyte count were 39 years, 24 kg/m², and 171 cells/μL, respectively. The CD4(+) lymphocyte increase at 12 months was greatest among patients with a pretreatment BMI of ~25-30 kg/m² and diminished above and below this range (P = .03). Similar patterns were observed in the subgroup analyses. Among patients with a pretreatment CD4(+) lymphocyte count < 200 cells/μL, a BMI of ~25 kg/m² was associated with the highest odds of reaching a CD4(+) lymphocyte count > 350 cells/μL at 12 months (P = .05).

Conclusions: 12-month immune reconstitution on ART was highest among patients commonly classified as overweight, suggesting there may be an optimal BMI range for immune recovery on ART.

Figure 1.

Baseline body mass index (BMI) and change in CD4⁺ lymphocyte count at 12 months, stratified by sex, for all patients (A), the virologic suppression subgroup (B), and the stable weight subgroup (C). Regression lines are adjusted for age, race, protease inhibitor usage, year of antiretroviral therapy (ART) initiation, and baseline CD4⁺ lymphocyte count and plasma HIV-1 RNA level (log₁₀ transformed); dashed lines represent 95% confidence intervals. Shaded histogram shows the number of patients contributing data (same scale as CD4⁺ lymphocyte count change; each bar represents a 2 kg/m² BMI interval). ^aIncludes patients with ≥6 months cumulative virologic suppression between ART initiation to 12 months. ^bIncludes patients with <10% change in weight between ART initiation and 12 months.

Figure 2.

Baseline body mass index (BMI) and the probability of attaining a 12-month CD4⁺ lymphocyte count >200 or >350 cells/μL. Regression lines are adjusted for age, race, protease inhibitor usage, year of antiretroviral therapy initiation, and baseline CD4⁺ lymphocyte count and plasma HIV-1 RNA level (log₁₀ transformed); dashed lines represent 95% confidence intervals.