Table 2.

Number of metformin prescriptions and hazard ratio on total knee replacement.

Operationalization of regular metformin use	N (matched cohort) *	Number of total knee replacements among regular metformin users (total number in cohort)	Hazard ratio (95% confidence interval)
Two prescriptions or more in past year	93,446	203 (425)	0.89 (0.74–1.08)
Three prescriptions or more in past year	93,374	193 (415)	0.85 (0.70–1.03)
Four prescriptions or more in past year †	93,330	184 (406)	0.81 (0.67–0.98)
Five precriptions or more in past year	93,218	168 (390)	0.74 (0.61–0.91)

*All cohorts were one-to-one matched cohorts.

^†Main analysis.