Having low levels of vitamin D when starting treatment is associated with a more than doubled risk of HIV progression, virologic failure and death, according to a recent study published in The Journal of Infectious Diseases.
The study followed 1,571 treatment-naive patients in Brazil, Haiti, India, Malawi, Peru, South Africa, Thailand, the United States and Zimbabwe. The primary endpoint was progression to WHO (World Health Organization) stage 3/4 or death within 96 weeks of starting treatment. The secondary endpoint was virologic failure (defined as two consecutive viral loads above 1,000 copies/mL after 16 weeks of starting treatment).
The researchers compared levels of baseline vitamin D to see if there was an association with increased disease progression. Data on possible vitamin D supplementation was not collected, but the researchers noted that supplementation was not common and was unlikely to have occurred in resource-limited settings.
Almost half (49%) of all participants in the study had low vitamin D concentrations at baseline. Prevalence of low vitamin D varied between countries, ranging from 27% in Brazil to 78% in Thailand and 72% in India. Prevalence was 92% among African-Americans in the US.
After controlling for country and HIV treatment regimen, the factors significantly associated with low vitamin D were race, season of sampling (winter/spring), high or low body mass index (BMI) and lower HIV viral load.
Analysis that took into account history of previous AIDS-defined illness and controlled for season, baseline CD4 count and viral load, BMI and race showed that low vitamin D concentrations at the start of therapy were associated with a twofold increase in the risk of clinical disease progression (HR = 2.13; 95% CI, 1.09-4.18).
Given the results, the researchers concluded that low vitamin D levels are "common in diverse HIV-infected populations and is an independent risk factor for clinical and virologic failure," as well as HIV progression and death. They noted that further studies are needed to examine the potential benefit of vitamin D supplementation among people starting treatment.