In this study, 34.1% of HIV-negative and 38.0% of HIV-positive women lost at least 10% of their body weight between 6 weeks and 24 months postpartum. Yet despite this high background rate of weight loss, HIV-positive postpartum breastfeeding women who lost ≥10% of their body weight during any of the 10 time intervals between 6 weeks and 24 months postpartum were at substantially higher risk of death compared with similar women who did not experience this weight loss during the same time interval. Significant independent predictors of experiencing a ≥10% weight loss in HIV-positive women were BMI, CD4, and household income. Compared to women with a 6 week BMI 18.5–24.9, women with BMI ≥25 had a 26% higher risk of weight loss and women with BMI <18.5 had a 45% lower risk of a ≥10% weight loss. To investigate whether there was detection bias of weight loss in those with BMI <18.5 because they were too sick to have weight measured, sensitivity analysis was conducted by excluding women who died but results remained similar (data not shown). It has been reported that larger gestational weight gain is associated with more postpartum weight loss25
and this result might be reflecting this phenomenon. Women whose household income was in the higher quartile were protected from weight loss. It might have been that poorer women had economic difficulties obtaining food that could fulfill the increased caloric demand of breastfeeding. Also, higher income women may have had more medical attention and access to drugs to control opportunistic infections that lead to weight loss, and/or more sedentary life styles with lower caloric requirements. The relationship between CD4 and weight loss is most likely mediated by the characteristics of advanced HIV infection such as higher risk of opportunistic infections,7–9
and abnormal metabolism,11
which all contribute to weight loss.
The observation that weight loss is associated with poor survival is in accordance with previous studies, which were all conducted in developed countries. First, in a group of mainly but not restricted to gay white men, ≥10% weight loss over a period of 4 months in HIV-positive individuals was associated with a 2.54 time higher risk of death when compared to those without this magnitude of weight loss.3
Similarly, in another study, body weight of <90% of self-reported usual weight was associated with a 8.3 (95% CI 2.3–34.1) times higher risk of death.1
Third, 10% weight loss from near the time of first AIDS diagnosis was associated with a 6.7 (95% CI 5.2–8.6) times higher mortality.5
Finally, a weight loss of ≥4.5
kg between 3 and 9 months before development of AIDS was associated with a significantly shorter survival (median 1.06 vs. 1.45 years) compared to those without this magnitude of weight loss in gay men.2
Since weight loss is a simple measure that does not necessitate sophisticated diagnostic facilities or trained personnel, it may be a useful adjunct to CD4 or viral load estimations in assessing HAART eligibility in resource-limited settings. Although weight loss was a significant predictor of mortality in our study, it has been pointed out that weight loss alone may be too sensitive for HAART eligibility13
and its utility as a HAART eligibility criterion must be assessed. The predictive value of weight loss on risk of disease progression or death must be compared to other conditions of HAART eligibility that can easily be identified in resource-limited settings. Furthermore, the inclusion of other conditions such as anemia, low BMI, presence of fever, diarrhea, or oral candidiasis with weight loss may further improve detection of those who are truly in need of HAART and this requires further investigation. Also, the WHO definition of 10% weight loss does not specify the timeframe in which weight loss occurs.12
In our study, the highest hazard rate of death was observed in those who had weight loss over a short period of time (between 6 weeks and 3 months), but we could not detect a distinct pattern in the relationship between death and weight loss of an acute and chronic nature.
In this study, the peak weight loss was at 15 months (–2.0
kg) and 21 months (–1.5
kg) for HIV-positive and HIV-negative women, respectively. Two studies in Africa have reported postpartum weight change among lactating women. The first one from South Africa reported a 1.4
kg weight loss in HIV-positive women and a 0.4
kg weight gain in HIV-negative women between 8 and 24 weeks26
and another study from Zambia reported a 1.1
kg weight gain between 4 and 24 months among HIV-positive women who breastfed for a median of 16 months.19
Our results showed a median weight loss of 0.5
kg (HIV-positive women) and 0.2
kg (HIV-negative women) between 6 weeks and 6 months and no weight gain between 3 and 24 months among HIV-positive women. The reason why the weight change pattern between previous studies and ours differs is unclear, but the study from South Africa had a small sample size and thus this may be attributable to random variation.
We had three major limitations. First, the longest interval for weight measurement in our study was between 6 weeks and 12 months, so we were limited to weight loss that occurred within less than a year in our analyses. Future studies would be necessary to determine whether there is a difference in risk of death associated with acute and chronic weight loss with a longer follow-up period. Second, we did not have CD4 counts at follow-up. It would be important to investigate the correlation of weight loss with CD4 count (the gold standard for initiation of HAART) at the time of identification of a ≥10% weight loss. This is particularly important because nevirapine-based HAART, which is the most common regimen in developing countries, may be more likely to induce hepatotoxicity in those with high CD4 counts,27
and thus evaluating the range of CD4 counts when a ≥10% weight loss is observed would be important. Finally, we did not have weight measurement before and during pregnancy. Since larger gestational weight gain has been reported to be associated with more postpartum weight loss,25
the magnitude of the residual confounding effect of this factor remains unknown.
In conclusion, 10% weight loss after 6 weeks postpartum was predictive of death up to 24 months in HIV-positive women in a prolonged breastfeeding setting. Our findings support the WHO recommendation that HIV-positive people who experience a ≥10% weight loss should be initiated on HAART, and provide evidence that this recommendation is specifically applicable for HIV-positive lactating women in developing countries.