Tenofovir disoproxil fumarate-associated hypophosphatemia as determined by fractional excretion of filtered phosphate in HIV-infected patients

Effect of anti-retroviral regimen on proximal tubular function in Zambian adolescents and young adults living with HIV: A cross sectional study

Background: Tenofovir regimens remain the preferred formulations in the HIV guidelines for adolescents and young adults in Zambia and globally. However, some adolescents and young adults are maintained on abacavir by clinicians because of anxiety about possible proximal tubular dysfunction from tenofovir. We assessed the effect of two regimens on proximal tubular function in adolescents and young adults living with HIV. Methods: This was a cross-sectional study involving 180 participants with HIV receiving either tenofovir or abacavir for ≥12 months at the largest tertiary teaching hospital. Two first-morning urine and blood specimens were collected and analyzed for proximal tubular markers, glomerular function, electrolytes, and routine monitoring tests. Proximal tubular function was determined by measuring the fractional excretion of phosphate (FePO4). Proximal tubular dysfunction was defined by FePO4 ≥20% regardless of serum phosphate and FePO4  ≥10-20% when serum phosphate was below 0.81mmol/L. Results: The prevalence of proximal tubular dysfunction was 6% and was higher in the tenofovir group than the abacavir (10% vs. 2%, p<0.058). However, after adjusting for potential confounders, tenofovir was not associated with worse proximal tubular function. Age, urine b2-microglobulin: creatinine ratio, C-reactive protein, and urine protein: creatinine ratio was all associated with worsening proximal tubular dysfunction. Reduced estimated glomelurar filtration rate (eGFR) was found in four (2.2%) participants; three of which were on tenofovir. Conclusions: Proximal tubular dysfunction defined by FePO4 was more prevalent in the tenofovir group than the abacavir group, but not after adjusting for age. Our findings should be interpreted with caution as age differences between the two groups confounded the results.

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

To estimate the frequency of inadequately low concentrations of parathyroid hormone in the presence of hypocalcemia in people living with HIV.

METHODS

Retrospective study in PLWH enrolled in the ongoing ArcHIV study between 2016 and 2017. PLWH with routine measurements for both calcium and parathyroid hormone were included into 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.

RESULTS

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 was found in both years. Being under 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 general populations. Interestingly, being under a tenofovir disoproxil-containing therapy was associated with this combination throughout both years.

Moderate endurance training (marathon-training) - effects on immunologic and metabolic parameters in HIV-infected patients: the 42 KM cologne project

Background

Improved treatment options of HIV have resulted in regular physical activities of many HIV-infected patients. However, data on effects of sports in HIV-patients are scarce.

Methods

21 HIV-infected persons were monitored prospectively while preparing for a marathon run. Multiple parameters with regard to immunology, quality of life and metabolism were measured at 4 time points (at baseline 1 year before the marathon run, 3 and 6 months after beginning of training, and immediately before marathon).

Results

13 out of 21 participants completed the marathon (12 male, 1 female; median age 42 years [27–50]; CD4 = 620/μl [146–1268]; 11 were on ART since 3.5 years [1–7]). 8 participants ceased training early. All reasons for stopping (besides one pre-existing metatarsal fracture) were not regarded as training-related (e.g. time limitation n = 3; newly diagnosed anal cancer n = 1; personal reasons/unknown n = 3).

We observed a significant increase in absolute CD4-T-cells (620/μl [146–1268] vs. 745 [207–1647]; p = 0.001) with simultaneous decrease of CD4-T-cell apoptosis (53% [47–64] vs. 32% [14–42]); p < 0.01). No effects on viral load independent of ART occurred. Systolic blood pressure and cholesterol improved significantly, although moderate and normal at baseline (cholesterol 185 mg/dl [98–250] vs. 167 [106–222], p = 0.02; RRsys 125 mmHg [100–145] vs. 120 [100–140], p = 0.01). Blood count, liver enzymes, creatinine and CK remained unchanged.

Conclusions

The results of this pilot study indicated improved metabolic and immunologic parameters in HIV-infected patients undergoing moderate endurance training. Although training effects or ART cannot be ultimately separated as underlying mechanisms, we conclude that marathon training is safe for HIV-infected patients and potentially improves general health.

Trial registration

DRKS00011592 (retrospectively registered on February 9th 2017).