Table 3.
Association between Tramadol Initiation and Risk of Incident Myocardial Infarction within Six-month Follow-up Comparing with Initiation of Diclofenac among Patients with Osteoarthritis
| Tramadol | Diclofenac | |
|---|---|---|
| Primary analysis | ||
| Participants (n) | 18,662 | 18,662 |
| Incident myocardial infarction (n) | 58 | 47 |
| Mean follow-up (year) | 0.49 | 0.49 |
| Rate (1000 person-years)* | 6.4 | 5.1 |
| RD (1000 person-years, 95% CI) | 1.2 (−1.0, 3.4) | 0.0 (reference) |
| HR (95% CI) | 1.24 (0.84, 1.82) | 1.00 (reference) |
| “As-treated” approach** | ||
| Participants (n) | 18,662 | 18,662 |
| Incident myocardial infarction (n) | 39 | 27 |
| Mean follow-up (year) | 0.25 | 0.23 |
| Rate (1000 person-years) | 8.4 | 6.2 |
| RD (1000 person-years, 95% CI) | 2.3 (−1.3, 5.8) | 0.0 (reference) |
| HR (95% CI) | 1.32 (0.81, 2.15) | 1.00 (reference) |
| Incident OA patients | ||
| Participants (n) | 9,902 | 9,902 |
| Incident myocardial infarction (n) | 26 | 20 |
| Mean follow-up (year) | 0.49 | 0.49 |
| Rate (1000 person-years) | 5.4 | 4.1 |
| RD (1000 person-years, 95% CI) | 1.3 (−1.5, 4.0) | 0.0 (reference) |
| HR (95% CI) | 1.30 (0.73, 2.33) | 1.00 (reference) |
| Missing data imputation | ||
| HR (95% CI) | 1.04 (0.73, 1.48) | 1.00 (reference) |
| Conventional covariate adjustment approach | ||
| HR (95% CI) | 1.23 (0.88, 1.73) | 1.00 (reference) |
RD, rate difference; HR, hazard ratio; n, number; 95% CI, 95% confidence interval; OA, osteoarthritis.
*
Number (rate) of competing event (i.e., death) in tramadol and diclofenac cohort was 370 (40.6/1000 person-years) and 205 (22.3/1000 person-years), respectively.
**
81% and 86% participants discontinued or switched their initiated treatment in tramadol and diclofenac cohort, respectively.