Efficacy of Vitamin D Supplementation for the Prevention of Pulmonary Tuberculosis and Mortality in HIV: a Randomised, Double-blind, Placebo-controlled Trial

Background: Observational data suggest that low vitamin D status is associated with an increased incidence of pulmonary tuberculosis and mortality among people living with HIV. The primary aims of this study were to assess the effect of vitamin D supplementation on the risk of mortality and incidence of pulmonary tuberculosis among adults initiating antiretroviral therapy (ART).

Methods: This was a randomised, double-blind, placebo-controlled trial of vitamin D supplementation among adults living with HIV who initiated ART and had serum 25-hydroxyvitamin D concentrations of less than 30 ng/mL at four large HIV care and treatment centres in Dar es Salaam, Tanzania. Patients were excluded if they were younger than 18 years, pregnant at the time of randomisation, or were enrolled in any other clinical trial. Patients were randomly assigned 1:1 to receive either weekly oral 50 000 IU vitamin D supplements (cholecalciferol) for the first month of ART followed by daily 2000 IU vitamin D supplements or a matching weekly and daily placebo regimen. The randomisation list was computer-generated by a non-study statistician with sequence blocks of ten that were stratified by study clinic. Complete allocation concealment was ensured and patients, field team, and investigators were masked to group assignment. The trial follow-up duration was 1 year and the primary efficacy outcomes were death and incident pulmonary tuberculosis. An intention-to-treat analysis was followed for all-cause mortality; participants diagnosed with or receiving treatment for pulmonary tuberculosis at randomisation, or suspected to have tuberculosis at randomisation and who later had that diagnosis confirmed, were excluded from analyses of pulmonary tuberculosis incidence. Safety was assessed in the intention-to-treat population. This study is registered with ClinicalTrials.gov, NCT01798680, and is completed.

Findings: Between Feb 24, 2014, and Feb 24, 2017, 6250 adults initiating ART had serum 25-hydroxyvitamin D screening, 4000 of whom were enrolled in the trial and followed up for 1 year (follow-up of all participants was completed on March 7, 2018). 2001 patients were randomly assigned to the vitamin D supplementation group, and 1999 to the placebo group. 415 deaths were recorded: 211 in the vitamin D group and 204 in the placebo group. Among all randomly assigned participants, there was no overall effect of vitamin D supplementation on the risk of mortality (hazard ratio [HR] 1·04, 95% CI 0·85-1·25; p=0·73). There was also no difference in the overall incidence of pulmonary tuberculosis between the vitamin D (50 events in 1812 patients analysed) and placebo groups (64 events in 1827 patients; HR 0·78, 0·54-1·13; p=0·19). The vitamin D regimen did not increase the risk of hypercalcaemia (three events in the vitamin D group and two events in the placebo group; relative risk 1·25, 95% CI 0·43-3·66; Fisher's exact p=1·00). 101 hospital admissions were reported in the vitamin D group and 94 in the placebo group (incidence rate ratio 1·06, 95% CI 0·80-1·41; p=0·66).

Interpretation: Additional research is needed before vitamin D supplementation should be considered for implementation in HIV care and treatment programmes for the prevention of pulmonary tuberculosis or mortality.

Funding: National Institute of Diabetes and Digestive and Kidney Diseases.