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.”