Hospitalization-related bone loss and the protective effect of risedronate

Abstract

Intercurrent illness and episodes of hospitalization and surgery are common in an aging population, who, at the same time, are experiencing age-related bone loss. The objective was to test the hypotheses (1) that intercurrent illness severe enough to require hospitalization produces clinically important bone loss, and (2) that antiresorptive therapy will reduce that loss. The study was a retrospective analysis of bone mineral density (BMD) change at hip and spine in subjects of the risedronate postmenopausal osteoporosis phase III trials experiencing serious adverse events (SAEs). Subjects were 243 hospitalized for non-skin cancers, pneumonia, myocardial infarction, cerebrovascular accident, gallbladder disease, and pancreatitis, on whom BMD data were available both before and after the SAE; and 286 non-hospitalized control subjects matched to those with SAEs by age, height, weight, prevalent fracture, and visit interval. In hospitalized, placebo-treated participants, the annualized percent change in BMD (mean+/-SEM) across the period of hospitalization was -0.65+/-0.39 at lumbar spine, -1.13+/-0.55 at femoral neck, and -2.66+/-0.58 at femoral trochanter; the corresponding values for the non-hospitalized, placebo controls were +0.46+/-0.28, -0.77+/-0.34, and -0.67+/-0.34. These values were more negative at all three sites for the hospitalized subjects, and significantly so at lumbar spine and femoral trochanter (P=0.019 and 0.002, respectively). By contrast, in the risedronate-treated participants, all sites exhibited bone gain and there was no significant difference between hospitalized and non-hospitalized participants. Intercurrent illness resulting in hospitalization produced a rapid bone loss across the period of illness comparable in magnitude to documented age-related loss. Risedronate in a dose of 5 mg/day effectively abolished this loss.