Table 4. Incidence and Risk of Developing OA and Undergoing Joint Replacement in the Sensitivity Analysis of Patients Treated With Metformin vs a Sulfonylurea.
| Measure | Before PS-matching | After PS-matching | ||
|---|---|---|---|---|
| Metformin (n = 104 471) | Sulfonylurea (n = 8277) | Metformin (n = 8277) | Sulfonylurea (n = 8277) | |
| Incident OA | ||||
| Events, No. (%) | 7154 (6.9) | 703 (8.5) | 530 (6.4) | 703 (8.5) |
| Person-years | 288 795 | 22 588 | 20 890 | 22 588 |
| IR (95% CI),per 1000 person-years | 24.8 (24.2-25.4) | 31.1 (28.8-33.4) | 25.4 (23.3-27.5) | 31.1 (28.8-33.4) |
| IRR (95% CI) | 0.80 (0.77-0.83) | 1 [Reference] | 0.82 (0.77-0.87) | 1 [Reference] |
| Adjusted HR (95% CI)a | 0.79 (0.73-0.85) | 1 [Reference] | 0.77 (0.65-0.90) | 1 [Reference] |
| Joint replacement | ||||
| Events, No. (%) | 782 (0.8) | 64 (0.8) | 63 (0.8) | 64 (0.8) |
| Person-years | 309 650 | 25 040 | 22 384 | 25 040 |
| IR (95% CI), per 1000 person-years | 2.5 (2.3-2.7) | 2.6 (2.0-3.2) | 2.8 (2.1-3.5) | 2.6 (2.0-3.2) |
| IRR (95% CI) | 0.96 (0.84-1.10) | 1 [Reference] | 1.08 (0.90-1.29) | 1 [Reference] |
| Adjusted HR (95% CI)a | 1.04 (0.80-1.34) | 1 [Reference] | 1.04 (0.60-1.82) | 1 [Reference] |
Abbreviations: HR, hazard ratio; IR, incidence rate; IRR, incidence rate ratio; OA, osteoarthritis; PS, propensity score.
a
Adjusted for age, sex, race and ethnicity, Charlson comorbidity score, and treatment duration.