Secondary Hyperparathyroidism in HIV-Infected Patients in Central Europe.

Secondary hyperparathyroidism (sHPT) might be a contributor to increased risk of osteoporosis in adult HIV patients but there is little data available on this issue in this particular population. The aim of the study was to investigate the prevalence of sHPT in an HIV-infected population with normal kidney function and to evaluate its risk factors in HIV patients. This cross-sectional study was carried out in a single HIV center in Germany using routine data from patients with normal kidney function attending the clinic between January 1st and December 31st, 2016. In total, 1263 patients were included [998 (79.0%) male, median age 48 (IQR 38-54) years]. In 214 patients (16.9%) elevated PTH levels with low or normal calcium levels were found. Multivariate logistic regression modeling showed significant associations with elevated PTH for African ethnicity [OR: 2.12 (95% CI: 1.42-3.16); p<0.001], low 25-hydroxyvitamin D levels [OR: 1.82 (95% CI: 1.32-2.51); p<0.001], low calcium levels [OR 1.69 (95% CI: 1.22-2.33); p=0.001], and use of tenofovir disoproxil fumarate [OR 2.33 (95% CI: 1.62-3.36); p<0.001]. Additional to common risk factors like vitamin D insufficiency and hypocalcemia, we found a significant association between the use of TDF and sHPT. Prospective data are needed to ascertain whether PTH-mediated bone loss is the underlying mechanism of TDF bone-toxicity. Additional screening of PTH even in HIV-infected patients with normal or low calcium levels may help to identify patients at increased risk of bone mineral density loss.

Tenofovir Disoproxil Fumarate Is Associated with a Set-Point Variation in the Calcium-Parathyroid Hormone-Vitamin D Axis: Results from a German Cohort.

BACKGROUND: Higher levels of parathyroid hormone have been associated with the use of tenofovir disoproxil fumarate (TDF) in people with and without HIV infection. Yet, alterations in calcium levels have never been elucidated in detail. OBJECTIVE: To compare the association of parathyroid hormone with serum calcium levels and other markers of calcium and bone metabolism in people living with HIV on TDF- and non-TDF-containing antiretroviral therapy. PATIENTS AND METHODS: A retrospective single center cohort study in Munich, Germany. Median and interquartile ranges and absolute and relative frequencies were used to describe continuous and categorical variables, respectively. The Mann-Whitney U test and chi2-test were used for comparisons. Multivariate median regression was performed in a stepwise backward approach. RESULTS: 1,002 patients were included (786 (78.4%) male; median age 48 (40-55) years). 564 patients (56.3%) had a TDF-containing ART regimen. PTH concentrations were 46.9 (33.0-64.7) pg/mL and 35.2 (26.4-55.4) pg/mL (P=0.001), 43.3 (30.8-59.8) pg/mL and 31.8 (22.3-49.6) pg/mL (P < 0.001), 46.1 (29.5-65.4) pg/mL and 33.4 (22.6-50.1) pg/mL (P < 0.001), and 37.8 (25.3-57.9) pg/mL and 33.8 (20.1-45.3) pg/mL (P=0.012) within the first, second, third, and fourth quartile of corrected calcium levels for patients with and without TDF-containing ART, respectively. In multivariate median regression, PTH concentration was significantly associated with Cacorr. (-32.2 (-49.8 to -14.8); P < 0.001), female sex (5.2 (1.2-9.2); P=0.010), 25(OH)D (-0.4 (-0.5 to -0.3); P < 0.001), and TDF-use (9.2 (6.0-12.5); P < 0.001). DISCUSSION: Higher levels of PTH seem to be needed to maintain normal calcium levels in PLWH on TDF-containing ART compared to non-TDF-containing ART. Optimal concentrations for 25-hydroxy vitamin D and calcium might therefore be different in people using TDF than expected from general populations but also people living with HIV with non-TDF-containing antiretroviral therapy. This might require different supplementation strategies but warrants further investigation.

Dolutegravir monotherapy as treatment de-escalation in HIV-infected adults with virological control: DoluMono cohort results.

BACKGROUND: The potential toxicity of long-term antiretroviral therapy (ART) requires ongoing investigation of novel strategies for treatment of HIV-infected patients. Monotherapy with the integrase inhibitor (INSTI) dolutegravir (DTG) may offer a favourable safety profile. Additionally, DTG has a high barrier of resistance, crucial for successful maintenance of virological control. However, published data is sparse. METHODS: Retrospective, single-centre cohort study. We enrolled patients on suppressive ART who were switched to DTG monotherapy in routine clinical practice and fulfilled the following inclusion criteria: HIV RNA level <50 copies/ml for ≥6 months at time of switch (one blip <200 copies/ml with re-suppression accepted), no known INSTI resistance or prior INSTI failure, no replicative HBV infection and no history of AIDS. RESULTS: We identified 31 patients with 24-weeks of follow-up data. Previous ART included a non-nucleoside reverse transcriptase inhibitor, a boosted protease inhibitor or an INSTI in 32%, 6% and 61% of patients, respectively. At week 24, HIV RNA remained <50 copies/ml in all but two patients (94%). One patient chose to discontinue DTG monotherapy and another developed confirmed virological failure (HIV RNA 538 copies/ml) with new INSTI mutations (Q148H/G140S). Immune status and renal and metabolic function showed no statistically significant changes, apart from a significant decrease in gamma-glutamyl transferase. CONCLUSIONS: De-escalating to DTG monotherapy in selected patients might be a safe and feasible option. However, in one case evolution of INSTI resistance was observed. Further studies should assess particular risk factors for DTG monotherapy failure. In the meanwhile, caution is warranted.