Simplification From Tenofovir Plus Lamivudine or Emtricitabine Plus Ritonavir-Boosted-Protease Inhibitor to Ritonavir-Boosted-Atazanavir Plus Lamivudine in Virologically-Suppressed-HIVInfected Adults With Osteopenia

Inclusion Criteria: * Human immunodeficiency virus-1-infected subjects with age ≥18 years old * Hip or spine T-scores between \< -1.0 and \>-2.5 by dual-energy X-ray absorptiometry (in the previous 24 weeks) * Stable antiretroviral treatment based on tenofovir and lamivudine or emtricitabine and boosted protease inhibitor for at least 24 weeks. * Having plasma human immunodeficiency virus-1 RNA \<50 copies/mL for at least the previous 24 weeks, including at least two samples. Exclusion Criteria: * Pregnancy, breast-feeding status or plans for pregnancy in the short term * Primary genotypic resistance mutations and/or previous virological failures to atazanavir or lamivudine/emtricitabine * Chronic hepatitis B infection * Patients with indication for therapy for the prevention of bone fractures * 25-OH vitamin D deficiency (\< 10ng/mL) * Hypogonadism (low total testosterone according to local reference range) * Hypothyroidism (low T4 and increased thyroid stimulating hormone levels according to local reference ranges) * Hyperparathyroidism (increased parathyroid hormone level with hypercalcaemia according to local reference ranges) * Having received oral corticosteroids or inhaled fluticasone (daily doses higher than 5 mg/d prednisone equivalent for 3 months or more) * Using anti-resorptive therapy (Calcium and vitamin D supplements are encouraged but not mandated) * Body mass index lower than 19