Scientists with large clinics in the United States and Canada conducted an analysis of changes in weight among 14,000 HIV-positive people who initiated HIV treatment (ART) between 1998 and 2010. They found that the proportion of people with obesity prior to ART initiation doubled from 9% in 1998 to 18% in 2010.

On average, three years after initiation of ART, 22% of people who entered the study with a normal weight had become overweight and 18% of people who were overweight at the start of the study had become obese.

Study details

North America’s premier HIV observational database, NA-ACCORD, has published many important analyses related to the health and wellbeing of HIV-positive people. One NA-ACCORD study that has often been overlooked focused on weight gain before and after the initiation of ART. In this study, clinics in Southern Alberta and Montreal contributed data.

A note about BMI

Body mass index (BMI) is obtained by dividing a person’s weight (in kilos) by their height (in metres) squared. BMI is a crude assessment of a person’s relative fatness or thinness. A high BMI tends to occur in people who are overweight or obese. However, people who are very muscular can also have a high BMI and it can give a misleading impression of their fatness. What is considered a normal BMI can vary from one continent and one ethno-racial group to another. Still, BMI is a cheap and simple way to find broad trends in data and is often used in studies.

The average profile of participants upon entering the study was as follows:

• 83% men, 17% women
• age – 40 years
• major ethno-racial groups: white – 43%; black – 38%; Hispanic – 15%
• CD4+ count – 241 cells/mm³
• viral load – 50,000 copies/mL
• commonly used regimens were based on protease inhibitors or non-nukes

On average, participants were monitored for three years.

Results

Scientists found that the proportion of people who were obese at the time they initiated ART increased significantly over the course of the study from 9% at the beginning to 18% by the end of the study.

Weight gain

Scientists also found that people who were underweight or of normal weight at the time they entered the study were significantly more likely to gain weight than people who entered the study being overweight or obese. Other points related to weight gain included the following:

• Most (80%) of the increase in weight occurred during the first year of using ART.
• Regardless of their race/ethnicity, men experienced what the scientists called “a sharp early rise in weight while women showed a more uniform rise over three years.”
• In general, scientists found that people who had lower pre-ART CD4+ cell counts and higher viral loads were more likely to subsequently gain weight after ART initiation.

Trends in time

According to the scientists, in the early years of the study (1998 to 2002) participants “tended to gain weight during the first year [which] then reached a plateau or fell in the subsequent two years.” In the latter years of the study, scientists found that “weight gain continued over the full three years.”

Trends in weight categories

After one year of using ART, scientists found that “20% of participants who had entered the study with a normal BMI had become overweight, and 15% of those overweight at baseline had become obese.”

They also found that three years after initiating ART, “22% of participants with a normal BMI at ART initiation had become overweight, and 18% of those overweight at baseline had become obese.”

The scientists noted that a shift after three years of ART “from normal BMI to overweight was most common among white males (23%), while a shift from overweight to obese was more common among [women of colour—21%].”

Bear in mind

The NA-ACCORD analysis is derived from a large well-designed study. It has confirmed broad trends seen in other analyses and in society. Even before ART is initiated, the proportions of HIV-positive people who are overweight and obese have been on the rise in North America.

Other points:

• Women of colour seem to be particularly affected by increased weight after ART initiation; this has been seen in randomized clinical trials.
• The greater the degree of immune deficiency (indicated by low CD4+ cell counts combined with higher viral loads), the greater the subsequent increase in weight. This suggests that there may be something caused by HIV infection itself that contributes to subsequent weight gain after ART initiation.
• Integrase inhibitors were not widely used to initiate ART in the present study. The vast majority of people in the NA-ACCORD analysis used regimens anchored by protease inhibitors or non-nukes. This shows that older regimens are associated with weight gain.

—Sean R. Hosein

REFERENCE:

Koethe JR, Jenkins CA, Lau B, et al. Rising obesity prevalence and weight gain among adults starting antiretroviral therapy in the United States and Canada. AIDS Research and Human Retroviruses. 2016 Jan;32(1):50-58.