Denosumab carries severe hypocalcaemia risk in older female dialysis-dependent patients

In the treatment of osteoporosis among older women who are dialysis-dependent, the use of denosumab appears to result in a much higher incidence of severe and very severe hypocalcaemia when compared with oral bisphosphonates, according to a retrospective cohort study.

Researchers looked at the medical records of 2,804 female dialysis-dependent Medicare patients who were 65 years of age or older to examine the incidence and comparative risk of severe hypocalcaemia by treatment. Of the patients, 1,523 received denosumab 60 mg and 1,281 received oral bisphosphonates.

Clinical performance measures including monthly serum calcium were obtained via linkage to the Consolidated Renal Operations in a Web-Enabled Network database. Severe hypocalcaemia was defined as total albumin-corrected serum calcium <7.5 mg/dL (1.88 mmol/L) or a primary hospital or emergency department hypocalcaemia diagnosis (emergent care). Very severe hypocalcaemia was defined as serum calcium <6.5 mg/dL or emergent care.

A total of 607 denosumab-treated patients and 23 oral bisphosphonate–treated patients developed severe hypocalcaemia. The 12-week weighted cumulative incidence of severe hypocalcaemia was significantly higher with denosumab at 41.1 percent than with oral bisphosphonates at 2.0 percent (weighted risk difference, 39.1 percent, 95 percent confidence interval [CI], 36.3–41.9; weighted risk ratio, 20.7, 95 percent CI, 13.2–41.2).

Similar results were obtained for very severe hypocalcaemia, with the 12-week weighted cumulative incidence being 10.9 percent with denosumab versus 0.4 percent with oral bisphosphonates (weighted risk difference, 10.5 percent, 95 percent CI, 8.8–12.0; weighted risk ratio, 26.4, 95 percent CI, 9.7–449.5).