Objectives: To evaluate the prevalence of 25-hydroxyvitamin D [25(OH)D] deficiency in HIV-positive patients, a population at risk for osteoporosis.
Design: Retrospective assessment of vitamin D levels by season and initiation of combined antiretroviral therapy (cART).
Methods: 25(OH)D was measured in 211 HIV-positive patients: samples were taken before initiation of cART from February to April or from August to October as well as 12 (same season) and 18 months (alternate season) after starting cART. 1,25-Dihydroxyvitamin D [1,25(OH)2D] was measured in a subset of 74 patients. Multivariable analyses included season, sex, age, ethnicity, BMI, intravenous drug use (IDU), renal function, time since HIV diagnosis, previous AIDS, CD4 cell count and cART, in particular nonnucleoside reverse transcriptase inhibitor (NNRTI) and tenofovir (TDF) use.
Results: At baseline, median 25(OH)D levels were 37 (interquartile range 20–49) nmol/l in spring and 57 (39–74) nmol/l in the fall; 25(OH)D deficiency less than 30 nmol/l was more prevalent in spring (42%) than in fall (14%), but remained unchanged regardless of cART exposure. In multivariable analysis, 25(OH)D levels were higher in white patients and those with a longer time since HIV diagnosis and lower in springtime measurements and in those with active IDU and NNRTI use. 1-Hydroxylation rates were significantly higher in patients with low 25(OH)D. Hepatitis C seropositivity, previous AIDS and higher CD4 cell counts correlated with lower 1,25(OH)2D levels, whereas BMI and TDF use were associated with higher levels. In TDF-treated patients, higher 1,25(OH)2D correlated with increases in serum alkaline phosphatase.
Conclusion: Based on the high rate of vitamin D deficiency in HIV-positive patients, systematic screening with consideration of seasonality is warranted. The impact of NNRTIs on 25(OH)D and TDF on 1,25(OH)2D needs further attention.
aDivision of Infectious Diseases and Hospital Epidemiology, University Hospital of Zurich, Zurich, Switzerland
bUniversity Clinic for Infectious Diseases, Inselspital and University of Bern, Bern, Switzerland
cDivision of Infectious Diseases and Hospital Epidemiology, University Hospital Basel, Basel, Switzerland
dDivision of Infectious Diseases, Department of Internal Medicine, Cantonal Hospital St. Gallen, St. Gallen, Switzerland
eInfectious Diseases Service, Centre Hospitalier Universitaire Vaudois and University of Lausanne, Lausanne, Switzerland
fDivision of Infectious Diseases, Hospital of Lugano, Lugano, Switzerland
gDivision of Infectious Diseases, Geneva University Hospital, Geneva, Switzerland
hInstitute of Clinical Chemistry, University Hospital Zurich, Switzerland
iCentre on Aging and Mobility, University of Zurich, Switzerland
jDepartment of Rheumatology and Institute of Physical Medicine, University Hospital Zurich, Zurich, Switzerland.
*N.J.M. and C.A.F. contributed equally to the study.
†The members of the Swiss HIV Cohort Study are listed in the Acknowledgements.
Received 16 November, 2009
Revised 14 January, 2010
Accepted 19 January, 2010
Correspondence to Nicolas J. Mueller, MD, Division of Infectious Diseases and Hospital Epidemiology, Department of Medicine, University Hospital Zurich, Rämistrasse 100/ RAE U 70, CH-8091 Zurich, Switzerland. Tel: +41 43 255 3712; fax: +41 43 255 3291; e-mail: Nicolas.Mueller@usz.ch