Vitamin D deficiency in medical patients at a central hospital in Malawi: a comparison with TB patients from a previous study.

Objectives: To determine the prevalence of vitamin D deficiency (VDD) in adult medical, non-tuberculous (non-TB) patients. To investigate associations with VDD. To compare the results with a similar study in TB patients at the same hospital.

Design: Cross-sectional sample.

Setting: Central hospital in Malawi.

Participants: Adult non-TB patients (n = 157), inpatients and outpatients.

Outcome Measures: The primary outcome was the prevalence of VDD. Potentially causal associations sought included nutritional status, in/outpatient status, HIV status, anti-retroviral therapy (ART) and, by comparison with a previous study, a diagnosis of tuberculosis (TB).

Results: Hypovitaminosis D (≤75 nmol/L) occurred in 47.8% (75/157) of patients, 16.6% (26/157) of whom had VDD (≤50 nmol/L). None had severe VDD (≤25 nmol/L). VDD was found in 22.8% (23/101) of in-patients and 5.4% (3/56) of out-patients. In univariable analysis in-patient status, ART use and low dietary vitamin D were significant predictors of VDD. VDD was less prevalent than in previously studied TB patients in the same hospital (68/161 = 42%). In multivariate analysis of the combined data set from both studies, having TB (OR 3.61, 95%CI 2.02-6.43) and being an in-patient (OR 2.70, 95%CI 1.46-5.01) were significant independent predictors of VDD.

Conclusions: About half of adult medical patients without TB have suboptimal vitamin D status, which is more common in in-patients. VDD is much more common in TB patients than non-TB patients, even when other variables are controlled for, suggesting that vitamin D deficiency is associated with TB.