Relative reduction of fracture risk for active treatment vs. placebo		Absolute reduction of fracture risk for active treatment (NNT)
Trial	Inclusion criteria (number of patients in the trial)	Dosage	Vertebral fractures	Nonvertebral fractures	Vertebral fractures	Nonvertebral fractures
Risedronate (Actonel)
VERT19	Two or more vertebral fractures or one vertebral fracture and a T-score of −2.0 or lower (2,458)	5 mg per day	65% reduction after 1 year (P < .001)	NR	4% reduction after 1 year (25)	NR
			41% reduction after 3 years (P = .003)	39% reduction after 3 years (P = .02)	5% reduction after 3 years (20)	3.2% reduction after 3 years (31)
VERT21	Two or more vertebral fractures (1,226)	5 mg per day	61% reduction after 1 year (P = .001)	NR	7.4% reduction after 1 year (14)	NR
			49% reduction after 3 years (P < .001)	33% reduction after 3 years (P = .06)	10.9% reduction after 3 years (9)	5.1% reduction after 3 years (20)
HIP20	Osteoporosis or one or more risk factors for osteoporosis (9,331)	2.5 and 5 mg per day	NR	20% reduction after 3 years (P = .03)	NR	1.8% reduction after 3 years(56)
Alendronate (Fosamax)
FIT22	Low femoral-neck BMD (4,432)	5 mg per day for 2 years followed by 10 mg per day for 2 years	44% reduction after 4 years (P = .001)	12% reduction after 4 years (P = .13)	1.7% reduction after 4 years (59)	1.5% reduction after 4 years (67)
FIT23	Low femoral-neck BMD plus one or more clinical vertebral fractures (2,027)	5 mg per day for 2 years followed by 10 mg per day for 1 year	47% reduction after 3 years (P < .001)	20% reduction after 3 years (P = .063)	7% reduction after 3 years (14)	2.8% reduction after 3 years (36)
Alendronate Phase III Osteoporosis Treatment Study31	Osteoporosis (994)	5 or 10 mg per day for 3 years 20 mg per day for two years followed by 5 mg per day for 1 year	48% reduction after 3 years, based on pooling of all data (P = .03)	21% reduction after 3 years (P values not reported; not significant)	3% reduction after 3 years (33)	2.2% reduction after 3 years (45)