Between-meal risedronate does not alter bone turnover in nursing home residents

To assess the effect of between-meal weekly risedronate and daily calcium 630 mg and vitamin D 400 IU on bone turnover markers.

Randomized,double-blind,placebo-controlled trial.

Skilled nursing home (NH).

Sixty skilled-NH residents (46 men, 14 women), mean age+/-standard deviation of 76+/-6, were randomized to receive risedronate 30 mg (n=31) or matching placebo (n=29) once weekly for 12 weeks. All received 315 mg calcium with 200 IU vitamin D twice daily.

Bone-specific alkaline phosphatase (BSAP), N-telopeptide of type 1 collagen (NTx), 25-hydroxyvitamin D (25OHD), and parathyroid hormone were measured at baseline and 6 and 12 weeks.

Risedronate reduced BSAP significantly more than placebo (P<.05) at 6 weeks but not at 12 weeks; no treatment effect on serum NTx was observed. Defining hypovitaminosis D as a serum 25OHD concentration below 32 ng/mL, 50 of 53 (94%) study participants were low at baseline (mean 25OHD 19 ng/mL). Vitamin D levels remained insufficient in 74% of participants after 12 weeks.

In this NH population, weekly risedronate administered using a between-meal dosing schedule reduced serum BSAP at 6 weeks of treatment; this effect was not observed at 12 weeks. The overall lack of change in bone turnover markers suggests that this risedronate dose and schedule would not be expected to increase bone density or reduce fracture risk in this population. Hypovitaminosis D was common and not reliably corrected by 400 IU of vitamin D daily. Despite an extremely high osteoporotic fracture risk in NH residents, additional study is required to determine under which conditions pharmacological treatment is efficacious in this population and define approaches that assure vitamin D repletion.