Table 3.

Cumulative incidence of fractures during therapy

Fracture type	Cohort size	Number of women with a fracture	Percent of women with a fracturea	Crude rate ratiob	Adjusted rate ratiob	95% CI	p-value
Time on therapy
Cohort
Nonvertebral
6 Months
Alendronate	21,615	253	1.31	–	–	–	–
Risedronate	12,215	123	1.14	0.87	0.81	0.65–1.00	0.05
12 Months
Alendronate	21,615	343	2.30	–	–	–	–
Risedronate	12,215	164	1.99	0.88	0.82	0.68–0.98	0.03
Hip
6 Months
Alendronate	21,615	54	0.29	–	–	–	–
Risedronate	12,215	19	0.17	0.63	0.54	0.32–0.91	0.02
12 Months
Alendronate	21,615	80	0.58	–	–	–	–
Risedronate	12,215	29	0.37	0.68	0.57	0.37–0.87	0.01

CI = confidence interval of adjusted rate ratio

^aProportion is based on Kaplan-Meier estimate of the survival function.

^bBased on Cox regression model.

^cBased on Cox regression model. Variables selected by forward stepwise selection where criteria for selection p < 0.1. Model for nonvertebral fractures included age, estrogen use, number of medications, rheumatoid arthritis diagnosis, and history of nonvertebral fractures. Model for hip fractures included age, estrogen use, number of medications, and history of hospitalization.