Do nevirapine and efavirenz affect vitamin D homeostasis similarly?

Tenofovir disoproxil fumarate/emtricitabine is associated with a higher risk of hypocalcemia compared to abacavir/lamivudine - results from a German cohort study

Hyperparathyroidism has been described in people living with HIV undergoing tenofovir disoproxil fumarate (TDF)-containing antiretroviral therapy (ART), but differences in calcium levels have never been investigated in detail. We aimed to compare the prevalence of hypocalcemia between patients with and without TDF-containing ART. The patients and methods were a retrospective cohort study in HIV-infected adult patients receiving dolutegravir and either abacavir (ABC)/lamivudine (3TC) or TDF/emtricitabine in a single center in Munich, Germany. Of 172 patients, 126 (73.3%) were male and the median age was 48.5 years (interquartile range 42-54). Average calcium levels were 2.24 (2.21-2.29) mmol/l and 2.21 (2.16-2.26) mmol/l (P < 0.001) with a prevalence of at least one episode of total calcium <2.12 mmol/l of 16.2 and 34.4% in the groups treated with ABC/3TC and TDF/emtricitabine, respectively (P = 0.006). TDF use was independently associated with the occurrence of albumin-corrected calcium levels of <2.12 mmol/l (odds ratio: 6.7 [1.3-35.6]; P = 0.025). Hypocalcemia seems to occur more often in TDF-treated patients. Further research into hypocalcemia with TDF and potential cardiovascular effects may be of benefit based on these findings.

Change in serum 25-hydroxyvitamin D with antiretroviral treatment initiation and nutritional intervention in HIV-positive adults

Low vitamin D level in HIV-positive persons has been associated with disease progression. We compared the levels of serum 25-hydroxyvitamin D (25(OH)D) in HIV-positive and HIV-negative persons, and investigated the role of nutritional supplementation and antiretroviral treatment (ART) on serum 25(OH)D levels. A randomised nutritional supplementation trial was conducted at Jimma University Specialized Hospital, Ethiopia. The trial compared 200 g/d of lipid-based nutrient supplement (LNS) with no supplementation during the first 3 months of ART. The supplement provided twice the recommended daily allowance of vitamin D (10 μg/200 g). The level of serum 25(OH)D before nutritional intervention and ART initiation was compared with serum 25(OH)D of HIV-negative individuals. A total of 348 HIV-positive and 100 HIV-negative persons were recruited. The median baseline serum 25(OH)D level was higher in HIV-positive than in HIV-negative persons (42·5 v. 35·3 nmol/l, P17 kg/m2 were randomised to either LNS supplementation (n 189) or no supplementation (n 93) during the first 3 months of ART. The supplemented group had a 4·1 (95 % CI 1·7, 6·4) nmol/l increase in serum 25(OH)D, whereas the non-supplemented group had a 10·8 (95 % CI 7·8, 13·9) nmol/l decrease in serum 25(OH)D level after 3 months of ART. Nutritional supplementation that contained vitamin D prevented a reduction in serum 25(OH)D levels in HIV-positive persons initiating ART. Vitamin D replenishment may be needed to prevent reduction in serum 25(OH)D levels during ART.

The Association of Gender, Age, Efavirenz Use, and Hypovitaminosis D Among HIV-Infected Adults Living in the Tropics

Vitamin D, which is important for calcium homeostasis and bone metabolism, has several noncalcemic actions. Low vitamin D levels have been observed in HIV-infected patients from high latitudes, with consequently reduced bone mineral density (BMD), but data from the tropics are scarce. We aimed to determine the prevalence of and risk factors for hypovitaminosis D among HIV-infected patients in the tropics. This was a cross-sectional study to determine serum 25-hydroxyvitamin D [25(OH)D] levels in HIV-infected patients who attended our HIV clinic in Bangkok, Thailand from July 2010 to June 2011. Hypovitaminosis D was defined as vitamin D insufficiency and deficiency [25(OH)D 20-30 ng/ml and <20 ng/ml, respectively]. Hypovitaminosis D prevalence was calculated and risk factors were determined using multivariate logistic regression. A total of 673 HIV-infected adults were included. The median age was 41 years and 47% were females. The median body mass index (BMI) was 21.9 kg/m(2) and 93% were using antiretroviral therapy (ART), with a median (IQR) duration of 8.9 (5.0-10.4) years. Thirty-one percent were using efavirenz (EFV). The prevalence of vitamin D insufficiency and deficiency was 40.6% and 29.9%, respectively. In multivariate analysis, female gender [odds ratio: OR (95% confidence interval: 95% CI) 1.7 (1.2-2.3), p = 0.005], age >37 years [OR (95% CI) 1.6 (1.1-2.4), p = 0.01], and EFV use [OR (95% CI) 2.0 (1.3-3.2), p = 0.004] were independent predictors of hypovitaminosis D. Even in tropical areas where the sun is abundant, hypovitaminosis D is highly prevalent. Thus, treatment of low vitamin D in HIV-infected patients at high risk should not be ignored to prevent reductions in BMD and other hypovitaminosis D-related comorbidities.

Change in vitamin D levels and risk of severe vitamin D deficiency over 48 weeks among HIV-1-infected, treatment-naive adults receiving rilpivirine or efavirenz in a Phase III trial (ECHO)

BACKGROUND

This analysis assessed changes in serum 25-hydroxyvitamin D (25[OH]D; the precursor form of active vitamin D) in antiretroviral-naive adults receiving rilpivirine or efavirenz over 48 weeks in a randomized, double-blind, Phase III trial (ECHO).

METHODS

ECHO included 690 patients randomized 1:1 to receive rilpivirine 25 mg once daily (n=346) or efavirenz 600 mg once daily (n=344), plus tenofovir disoproxil fumarate/emtricitabine. 25(OH)D was measured in stored serum samples collected at baseline, and weeks 24 and 48. Proportions of patients with optimal/sufficient (≥30 ng/ml), insufficient (21-29 ng/ml), deficient (10-20 ng/ml) and severely deficient (<10 ng/ml) 25(OH)D levels were determined. Data are presented for patients with paired baseline and week 48 25(OH)D data (rilpivirine, n=292; efavirenz, n=290).

RESULTS

After 48 weeks, mean 25(OH)D levels remained largely unchanged from baseline with rilpivirine (-0.2 ng/ml; P=0.57 versus no change), but were significantly reduced with efavirenz (-2.5 ng/ml; P<0.0001 versus no change). When adjusting for season of randomization and the combined variable of race (Black/African American, White/Caucasian, Asian, other race) and ethnicity (Hispanic or Latino and not Hispanic or not Latino), the conclusion about the treatment difference between the rilpivirine and efavirenz treatment groups remained valid. At baseline the proportion of patients with severe 25(OH)D deficiency was similar in both groups (5%) but was significantly lower with rilpivirine than efavirenz at week 48 (5% versus 9%, respectively; P=0.032). Furthermore, of the patients with 25(OH)D insufficiency/deficiency at baseline, the proportion who developed severe 25(OH)D deficiency at week 48 was significantly lower with rilpivirine than efavirenz (2% versus 8%, respectively; P=0.0079).

CONCLUSIONS

Rilpivirine had little effect on 25(OH)D, whereas efavirenz resulted in a significant reduction in 25(OH)D levels and an increase in the risk of severe 25(OH)D deficiency.

Decline in serum 25 hydroxyvitamin D levels in HIV-HBV-coinfected patients after long-term antiretroviral therapy

BACKGROUND

Vitamin D insufficiency plays an important role in the development of fibrosis in chronic liver disease.

METHODS

This was a cross-sectional study from Thailand. Liver fibrosis was assessed by transient elastography. Serum 25 hydroxyvitamin D (25[OH]D)<30 ng/ml was defined as hypovitaminosis D. 25(OH)D was assessed prior to and following tenofovir disoproxil fumarate (TDF). Factors related to 25(OH)D levels were determined by logistic regression analysis.

RESULTS

A total of 158 HIV-HBV-coinfected patients (32% female, median age 43 years) were included. Overall, liver disease was mild with 13.4% having a fibrosis score (FS) of 7.1-14 kPa and 2% with a FS>14 kPa. Median (IQR) duration on TDF was 5 years (4-7). The median estimated glomerular filtration rate was 96.9 ml/min/1.73 m(2). The median (IQR) serum 25(OH)D levels prior to and following TDF were 24.8 ng/ml (21.3-30.6) and 22.8 ng/ml (18.0-27.7), respectively; P≤0.001). The proportion of patients with hypovitaminosis D significantly increased from 72.2% (95% CI 64.7, 78.6) prior to TDF to 84.2% (95% CI 77.7, 89.0) after taking TDF (P=0.01). Factors associated with hypovitaminosis D by multivariate analysis were female sex (adjusted OR 3.8, 95% CI 1.1, 13.7; P=0.038) and duration of antiretroviral therapy (ART)>5 years (OR 3.3, 95% CI 1.2, 8.8; P=0.017). Vitamin D levels were not associated with significant liver fibrosis.

CONCLUSIONS

Although our HIV-HBV-coinfected patients live in the tropics, there was a high prevalence of hypovitaminosis D, especially in female patients and those receiving prolonged ART. Since HIV-HBV-coinfection requires long-term use of the HBV-active drug, TDF, which can also contribute to bone loss, routine vitamin D assessment and supplementation as necessary should be considered.

Vitamin D and HIV infection: a review of the clinical evidence

The positive effects of vitamin D in different acute and chronic diseases (e.g., bone and renal disorders, acute and chronic respiratory tract infections, and diabetes mellitus), and regulation of immune system function have been shown. In this review vitamin D status and the effects of its supplementation alone or in combination with other bone-modifying substances like calcium and bisphosphonates on the different aspects of human health have been investigated in HIV+ individuals. Three scientific electronic databases have been investigated for extracting related articles. Searching only PubMed yielded 59 results with ‘HIV OR AIDS’ and ‘Vitamin D’ keywords. Because many of the studies in this field are observational or cross-sectional, designing comprehensive and eligible randomized clinical trials has been recommended by several authors in order to develop evidence-based clinical practice guidelines to determine the best regimen of vitamin D supplementation in HIV-infected patients.

Effects of vitamin D deficiency and combination antiretroviral therapy on bone in HIV-positive patients

OBJECTIVES

In the era of combination antiretroviral therapy (cART), vitamin D deficiency, low bone mineral density (BMD) and fractures have emerged as subjects of concern in HIV-positive patients. Testing for vitamin D deficiency has been widely adopted in clinical practice even though the benefits of vitamin D supplementation in this population remain uncertain. The objective of this review was to evaluate the evidence for such a strategy.

DESIGN

Systematic review of the literature on vitamin D deficiency in HIV infection, the effects of cART on vitamin D status, and the effects of vitamin D deficiency and cART on parathyroid hormone (PTH), bone turnover, BMD and the incidence of fractures in HIV-positive patients.

METHODS

PubMed was used to identify relevant articles up to September 2011.

RESULTS

Vitamin D deficiency, secondary hyperparathyroidism and low BMD are common in HIV-positive patients. Efavirenz is associated with a reduction in 25-hydroxy vitamin D levels, tenofovir with secondary hyperparathyroidism, and cART with increased bone turnover and low BMD. The clinical significance of low BMD, however, remains unclear, especially in younger patients. Although the incidence of fractures may be increased in HIV-positive patients, the contribution of low BMD and vitamin D deficiency to these fractures is uncertain. Limited data on vitamin D supplementation in HIV-positive patients have shown transient, beneficial effects on PTH, but no effects on BMD.

CONCLUSION

The benefits of vitamin D supplementation in this population need to be demonstrated before widespread 'test and treat' policies can be recommended as part of routine clinical practice.