Impact of Oral Alendronate Therapy on Bone Mineral Density in HIV-infected Children and Adolescents With Low Bone Mineral Density

Puberty is a time when the foundation is laid for healthy bone mass. Over the course of puberty, 26% of bone mass is established in the 4-year period of peak height velocity and up to 60% of adult peak bone mass is established. Factors that affect normal bone mineralization include calcium intake, vitamin D status, degree of physical and weight bearing activities, hormones, genetics, body weight, and general health and nutrition status. HIV-infected children, youth, and adults have lower bone mineral density (BMD) than would be expected for healthy people of similar age, weight, and race. As the majority of perinatally HIV-infected U.S. children are entering or in adolescence, the potential for HIV-related impaired BMD during the adolescent peak of bone mass acquisition is of particular concern. The purpose of this study was to compare changes in BMD of the lumbar spine from pre-treatment levels to 24 and 48 weeks after alendronate treatment or placebo in HIV-infected children and adolescents.

Participants were randomized equally into one of three groups: Group 1A received alendronate for 96 weeks; Group 1B received alendronate for 48 weeks followed by placebo for 48 weeks; Group 2 received placebo for 48 weeks followed by alendronate for 48 weeks. All three groups were followed off treatment for an additional 48 weeks. Participants also received vitamin D/calcium for the duration of the study and were asked to perform 60 minutes of weight-bearing exercise each day.

Clinic visits were scheduled every 12 weeks after entry, with telephone contact visits one, four, and 28 weeks after entry and the week 48 visit. A physical exam and dental assessment was conducted at each clinic visit, and a history of adverse events collected. Dual Energy X-ray absorptiometry (DXA), hematology and chemistry panels were conducted at entry and weeks 24, 48, 72, 96 and 144. Lumbar spine and whole body (with head) BMD was measured using Hologic DXA scanners (QDR4500A, QDR4500W or Delphi A models).

The primary analysis compared changes from entry to 24 and 48 weeks in lumbar spine BMD between Groups 1A and 1B combined (both on alendronate for initial 48 weeks) vs. Group 2 (on placebo for 48 weeks). Study participants were unblinded after 96 weeks of follow-up (the primary completion date) but remained on study, off study treatment, for an additional 48 weeks.

Secondary laboratory outcomes listed in the protocol (bone marker turnover and Receptor Activator of Nuclear Factor Kappa-B Ligand/Osteoprotegerin (RANKL/OPG) Ratio) and central fat content, which required application for additional funding for laboratory testing, will not be performed and no results will be available.