Table 3.

RRs of clinical events in metformin users vs nonusers, overall and stratified by age

Clinical events	Overall, crude RR (95% CI)*	Overall, adjusted RR (95% CI)*†	Age groups, adjusted RR (95% CI)*‡
			18 to <40 y	≥40 y
All-cause inpatient encounters	0.53 (0.40-0.71)	0.68 (0.52-0.88)	0.61 (0.41-0.92)	0.73 (0.52-1.02)
Inpatient encounters with SCD codes	0.38 (0.26-0.57)	0.45 (0.30-0.66)	0.45 (0.25-0.82)	0.45 (0.27-0.75)
All-cause ED encounters	0.67 (0.51-0.87)	0.77 (0.60-1.00)	0.78 (0.52-1.17)	0.76 (0.55-1.06)
ED encounters with SCD codes	0.21 (0.13-0.35)	0.34 (0.21-0.54)	0.24 (0.12-0.50)	0.42 (0.23-0.75)
VOEs	0.17 (0.09-0.32)	0.22 (0.12-0.41)	0.22 (0.08-0.57)	0.23 (0.10-0.50)
ACS episodes	0.16 (0.05-0.56)	0.17 (0.05-0.60)	0.20 (0.04-1.02)	0.12 (0.01-1.12)
Stroke events	0.61 (0.28-1.33)	0.87 (0.39-1.91)	0.69 (0.19-2.55)	0.99 (0.37-2.68)
AVN events	0.38 (0.14-1.08)	0.30 (0.11-0.87)	0.53 (0.10-2.85)	0.20 (0.05-0.79)
Gallstone events	0.98 (0.48-2.02)	1.05 (0.52-2.12)	1.12 (0.36-3.45)	1.00 (0.39-2.53)

^*The reference group is the nonmetformin group.

^†RR and 95% CI adjusted for age group, sex, and Charlson Comorbidity Index score.

^‡RR and 95% CI adjusted for sex and Charlson Comorbidity Index score.