Table 3.

Among 2,779 postmenopausal women with a history of fracture after age 54 before the 2008–9 medication inventory and a 5-year risk of hip fracture ≥ 1.5%, fracture incidence, hazard ratio, and 95% confidence interval of hip, clinical vertebral, wrist/forearm, and any clinical fracture by duration of bisphosphonate use at 2008–9 medication inventory

Duration of Bisphosphonate Use	Subjects (No.)	Fractures		Adjusted HR (95% CI)b
		No.a	Incidence per 1,000 Person-years
	Hip Fracture
2 y	309	8	9.2	1.00
3–5 y	871	23	9.4	0.65 (0.27–1.54)
6–9 y	498	11	7.5	0.64 (0.24–1.67)
10–13 y	893	32	12.4	0.88 (0.39–2.03)
	Wrist/Forearm Fracture
2 y	213	14	23.6	1.00
3–5 y	624	26	15.5	0.72 (0.35–1.49)
6–9 y	341	14	14.2	0.72 (0.33–1.60)
10–13 y	575	32	19.6	0.99 (0.49–1.98)
	Clinical Vertebral Fracture
2 y	292	13	16.0	1.00
3–5 y	822	50	22.1	1.22 (0.62–2.41)
6–9 y	488	35	24.9	1.62 (0.81–3.24)
10–13 y	816	47	20.3	1.47 (0.75–2.87)
	Any Clinical Fracture
2 y	344	84	96.1	1.00
3–5 y	947	256	106.8	1.10 (0.85–1.43)
6–9 y	542	155	108.3	1.12 (0.85–1.47)
10–13 y	946	300	122.4	1.30 (1.01–1.67)

Abbreviations: CI, confidence interval; HR, hazard ratio.

^aNumber of fractures during all follow-up years;

^bFollow-up period is from completion date of medication inventory to end of study in 2013–14. Estimates are from Cox proportional hazards models adjusted for age, race, education level, BMI, physical function score, general health rating, recreational physical activity, treated diabetes mellitus, severe memory impairment, glucocorticoid use ≥ 3 months, risk of hip fracture within 5 years calculated by WHI 11-item fracture risk algorithm, calcium supplement use, estrogen use during 6–10 years prior to medication inventory, parental hip fracture, smoking status, Parkinson’s disease diagnosis, alcohol ≥ 3 servings/day, rheumatoid arthritis diagnosis, and cancer diagnosis.