Inadequate PTH Response to Hypocalcemia in People Living with HIV.

BACKGROUND: Small experimental studies suggest that PTH-secretion following hypocalcemia might be blunted in people living with HIV. OBJECTIVE: The aim of the study was to estimate the frequency of inadequately low concentrations of parathyroid hormone in the presence of hypocalcemia in people living with HIV. METHODS: This was a retrospective study that was conducted among PLWH enrolled in the ongoing ArcHIV study between 2016 and 2017. PLWH with routine measurements for both calcium and parathyroid hormone levels were included in this analysis. The proportion of patients with a combination of low levels of both calcium and parathyroid hormone was the primary endpoint of this analysis. RESULT: 496 PLWH were included (mean age 47.1 (± 10.2) years, 393 (79.2 %) men). In 14 (2.8 %) PLWH, low calcium levels with low levels of PTH were observed in the assessment conducted in both years. Undergoing a tenofovir disoproxil-containing treatment in both years was the only explanatory variable significantly associated with inadequately low levels of PTH in the presence of hypocalcemia in both years (OR 4.3 [CI95: 1.4; 16.0]). CONCLUSION: The combination of low levels of both calcium and PTH was found more frequent in our study sample when compared to what is expected from the general population. Interestingly, undergoing a tenofovir disoproxil-containing therapy was associated with this combination throughout both the years.

Humoral response to SARS-CoV-2 vaccines in people living with HIV.

PURPOSE: To describe the humoral immune response to COVID-19 vaccines in people living with HIV and identify factors associated with the magnitude of anti-SARS-CoV-2 antibody concentrations. METHODS: Retrospective analysis of electronic patient files in a big single HIV center in Munich, Germany. Non-parametric methods were used for descriptive and comparative statistics. Generalized linear models were used to analyze associations of general and HIV-specific variables with anti-SARS-CoV-2 antibody concentrations after standard vaccination. RESULT: Overall, 665 people living with HIV were included into the analysis (median age: 53 [IQR: 43; 59]), 560 [84.2%] males). Median concentration of anti-SARS-CoV-2-antibodies was 1400 (IQR 664; 2130) BAU/mL. In 18 (2.7%) subjects, antibody concentrations below the threshold of 34 BAU/mL were found. Among PLWH with CD4 cell count < 200 cells/µL, median anti-SARS-CoV-2-Abs were 197 (IQR 44.6; 537.2) as compared to 1420 (IQR 687; 2216) for the group ≥ 200 cells/µL (p < 0.001). In a cumulative logit model, a vaccination scheme including an mRNA vaccine [OR: 4.64 (3.58; 6.02)], being female [OR: 2.14 (1.76; 2.61)], and having higher CD4 cells [OR per 100 cells/µL: 1.06 (1.04; 1.08)] were significantly associated with anti-SARS-CoV-2 antibody concentrations in higher quartiles, when adjusted for the time after vaccination. CONCLUSION: We found a robust antibody response in people living with HIV undergoing standard vaccination against SARS-CoV-2. mRNA-containing vaccination schemes, being female, and having a higher CD4 cell count was associated with a higher concentration of antibodies in people living with HIV in our study sample. Particularly in the subgroup with CD4 cell counts < 200 cells/µL, antibody response was poor.

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.