Disorders of calcium metabolism and osteoporosis

Hypercalcemia is uncommon in HIV infection. Primary hyperparathyroidism with hypercalcemia occurs at the same rate as the non-infected population. If hypercalcaemia is found with low parathyroid hormone (PTH) levels, underlying infection, malignancy or lymphoma require active exclusion.

Bone loss, low bone density and osteoporosis are found in HIV wasting syndrome and patients receiving long term cART (44). Multiple factors specific to HIV-infection and its treatment contribute, including viral effects, medication effects (tenofovir, protease inhibitors) and low androgen levels. Other secondary causes for osteoporosis should be excluded, such as hypogonadism, thyrotoxicosis, primary hyperparathyroidism, Cushing’s syndrome, renal phosphate wasting, coeliac disease and multiple myeloma. In patients with established osteopaenia or osteoporosis, clinicians should ensure an adequate intake of dietary calcium (at least 1000 mg/d) and that serum levels of 25-hydroxy vitamin D are about 80 nmol/L or higher. Weight bearing physical activity is encouraged (20 minutes of walking at least thrice weekly and, if possible, a weight training, core strengthening program), in addition to other lifestyle interventions such as reducing excessive alcohol and caffeine consumption and smoking cessation. In men with androgen deficiency, treatment with androgen supplementation has shown benefit (45). Other therapies such as the bisphosphonates alendronate and zoledronic acid have been shown of benefit in HIV-infected people with osteoporosis (46,47). Consensus expert opinion on osteoporosis treatment in treated-HIV infection recently recommended medication switches: tenofovir to abacavir or raltegravir; and protease inhibitor-based regimens to raltegravir-based regimens (47).