Tenofovir-Linked Hyperparathyroidism Is Independently Associated With the Presence of Vitamin D Deficiency

BACKGROUND: To determine patient and treatment characteristics associated with vitamin D deficiency (VDD) in an UK inner city HIV-1-positive adult cohort. METHODS: Two hundred twenty-seven HIV-positive patients attending prospectively for routine blood tests in winter had serum 25-hydroxyvitamin D and parathyroid hormone (PTH) concentrations and other routine chemistry measured. Those with and without VDD were defined as having serum 25-hydroxyvitamin D concentrations <50 nmol/L and >75 nmol/L, respectively. Characteristics were compared between patients with and without VDD. The effects of VDD, tenofovir use, and their interaction on chemical measures were investigated. RESULTS: VDD was found in 57% (131 of 227) of patients. Independent associations included nonwhite ethnicity [adjusted odds ratio (95% confidence interval): 7.40 (2.52 to 21.7)], higher random blood glucose [2.38 (1.24 to 4.57) per mmol/L], higher estimated glomerular filtration rate [eGFR: 1.04 (1.01 to 1.06)], and higher PTH [1.19 (1.00 to 1.42)]. PTH was higher in those receiving tenofovir (median 7.2 pmol/L) than other patients (4.3; P < 0.001) overall, but high PTH with tenofovir occurred only in the context of VDD. Tenofovir use was not associated with serum creatinine or eGFR overall but interacted with vitamin D status (P = 0.05 and P = 0.08, respectively), being linked to somewhat higher creatinine and lower eGFR among patients without VDD but higher eGFR in VDD patients. CONCLUSIONS: 25(OH) VDD is associated with tenofovir-linked hyperparathyroidism and also with higher eGFR.