Vigilance over early weight loss on HIV treatment needed, Tanzanian study shows

Carole Leach-Lemens
Published: 18 January 2012

Nearly one-third of patients experienced substantial weight loss in the first ten months after starting antiretroviral therapy, research has shown. Leading American and Tanzanian researchers warn that healthcare workers in resource-limited settings need to be on the look out for the ill effects of anaemia, malabsorption and malnutrition in patients starting antiretroviral therapy (ART).

Three months after starting ART, the median weight gain among 19,000 HIV-infected adults in Dar es Salaam, Tanzania, was 2.5 kg (IQR:0.2-5.0). Yet close to 4000 people (21%) lost weight, and 1520 (8%) had a significant weight loss (greater than or equal to 5% of their weight), researchers report in the advance online edition of AIDS.

Those who were underweight at the start of ART were less likely to lose weight than those of normal or above-average weight, and they also gained the most weight after starting treatment (a mean of 10kg in the first year, compared to 3kg for patients who were classified as obese).

Baseline symptoms – including loss of appetite, nausea and/or vomiting, and difficulty breathing – were all independent predictors of weight loss, three months after starting ART in this cross-sectional and longitudinal analysis.

Lower socioeconomic status and being younger or older than those aged 30 to 49 were associated with a higher risk of long-term significant weight loss, while being female had a lower risk.

Before the introduction of ART, wasting and/or weight loss were among the most frequent AIDS-defining conditions and strong predictors of death and disease.

Multiple factors contribute to HIV-related weight loss. The inability to digest and absorb food nutrients (gastrointestinal malabsorption), often indicated by diarrhoea, is a suggested major cause.

The authors cite Nutrition for Healthy Living (NFHL), a longitudinal study from 1995 to 2005 of HIV-infected adults in the greater Boston area of the United States, as showing that – even in the era of effective HIV treatment – malabsorption still contributes to weight loss.

In addition, a decreased intake of calories due to neurological and/or psychiatric problems, or oral symptoms making eating and/or swallowing difficult, contribute to and/or exacerbate malabsorption.

In spite of the positive benefits of ART, weight loss is still an independent predictor of HIV disease progression and death.

The authors note that most published studies have focused on resource-rich settings with small sample sizes; few have looked at predictors of weight change after starting ART with some only looking at factors contributing to weight gain.

So the authors chose to look at those factors predicting significant weight loss after starting ART in a large cohort of HIV-infected adults in a resource-poor setting in the short term (three months) and long term.

From November 2004 to December 2009, 21,987 HIV-infected adults started ART and were followed for at least three months in US PEPFAR-supported HIV care and treatment clinics in Dar es Salaam, Tanzania. After excluding those who had previously been on ART, pregnant women and those without body mass index (BMI) or weight data at the start of ART, the final sample size was 18,956.

BMI categories were defined as follows:

  • below 18.5kg/m2 – underweight

  • between 18.5 and below 25.0 kg/m2 – normal weight

  • between 25.0 kg/m2 and below 30.0 kg/m2 – overweight

  • equal to or over 30.0 kg/m2 – obese.

Possible predictors of weight loss at the start of ART included: age; gender; CD4 cell count; haemoglobin level; WHO clinical HIV stage; district of Dar es Salaam (as a proxy for socioeconomic status); calendar year; and ART regimen. People living in the three districts of Dar es Salaam were categorised as belonging to high (Kinondoni), medium (Ilala) and low (Temeke) socioeconomic status areas.

The median age of the cohort was 36 years (IQR: 31-43), with the majority female (67%).

The proportions of those underweight, normal weight and overweight/obese at the start of ART were 28, 57 and 15%, respectively. In total, 55% had a CD cell count under 200 cells/mm3 and 85% were at WHO clinical stage 3 or 4.

The median weight change among those who were underweight was 4.0 kg (IQR: 1.0-7.0) – significantly higher (p<0.01) than the weight change among those of normal weight and who were overweight/obese.

Close to 50% of underweight patients gained more than 10% of their baseline weight, compared to 19% and 8% among those of normal weight and who were overweight/obese, respectively.

The authors note other studies have reported similar findings in resource-poor settings.

Over a median follow-up period of 10 months (IQR: 4 to 20 months), a total of 5889 people (31%) experienced an initial significant weight loss after starting ART.

The authors note patients of middle-age (30 to 49 years) were less likely to have a significant weight loss, as were those living in the highest SES district – possibly because of better socioeconomic conditions and so better access to nutrition-rich diets.

The authors found low haemoglobin levels (an indicator for anaemia) at the start of ART were linked to a risk for significant weight loss at three months for all except those who were underweight.

They suggest a higher BMI at the start of ART may mean an absence of other illnesses, so making the effect of anaemia on weight loss more pronounced.

Anaemia, they add, has been found to be an independent predicator of weight loss and death in HIV-infected individuals. And, in resource-poor settings, it is associated with tuberculosis and malnutrition, among other conditions.

As in other studies, CD4 cell count was an independent predictor of long-term significant weight loss. When CD4 cell counts were over 350 cells/mm3, the association with weight loss decreased.

One of the study’s strengths is the inclusion of a large, diverse population in a resource-poor setting. Limitations included no data on viral load, food availability or nutrient intake.

The authors conclude that, while body weight increased steadily after the start of ART, close to 10% lost more than or equal to 5% of their body weight at three months. They caution that: “Even in the era of ART, physicians still need to remain vigilant about patients’ weight. Our findings on the effect of socio-demographics, symptoms and diseases, time-varying biomedical indicators in relation to weight loss provide important information that has significant practical implications.”

Reference

Li N et al. Predictors of weight loss after highly-active antiretroviral therapy (HAART) initiation among HIV-infected adults in Tanzania. Advance online edition AIDS 25, doi: 10.1097/QAD.0b013e32834f9851, 2011.

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