Table 2:

Rates and hazard ratios for kidney composite outcomes among patients who persisted on metformin or sulfonylurea in matched weighted cohort in first 360 days and from day 361 onward of reaching reduced kidney function threshold*

Outcomeirst 360 days361 days onward
Metformin
n = 24 883		Sulfonylurea
n = 24 998		Metformin
n = 12 571		Sulfonylurea
n = 12 637
Primary outcome: kidney events or death
 Number of events5767867471033
 Person-time, yr17194182782819128429
 Events per 1000 person-years (95% CI)33.5 (30.9–36.3)43.0 (40.1–46.0)26.5 (24.7–28.5)36.3 (34.2–38.6)
 PS-weighted HR, unadjusted (95% CI)0.78 (0.71–0.85)Ref.0.73 (0.67–0.79)Ref.
 PS-weighted HR, adjusted* (95% CI)0.79 (0.72–0.87)Ref.0.76 (0.70–0.83)Ref.
Secondary outcome: kidney events
 Number of events4956110149
 Person-time, yr17194182782819128429
 Events rates per 1000 person-years (95% CI)2.9 (2.2–3.8)3.1 (2.4–4.0)3.9 (3.2–4.7)5.2 (4.5–6.1)
 PS-weighted HR, unadjusted (95% CI)0.94 (0.67–1.33)Ref.0.73 (0.59–0.91)Ref.
Secondary outcome: death
 Number of events527730642903
 Person-time, yr17201183002824028717
 Events rates per 1000 person-years (95% CI)30.6 (28.2–33.3)40 (37.2–42.9)22.7 (21.0–24.5)31.5 (29.5–33.5)
 PS-weighted HR, unadjusted (95% CI)0.76 (0.69–0.84)Ref.0.72 (0.66–0.79)Ref.

  • Note: HR = hazard ratio, PS = propensity score, Ref. = reference category.

  • ↵* Cox Proportional Hazards model for time to event. Adjusted for demographics, clinical information derived from the electronic health record, comorbidities, use of medications and health care utilization (see Appendix 1, Supplemental Table 1, available at www.cmajopen.ca/content/11/1/E77/suppl/DC1). All continuous variables were modelled as restricted cubic splines. All covariates in PS model included in the PS-weighted and adjusted model (see Appendix 1, Supplemental Table 1).