Table 4.
Association between Tramadol Initiation and Risk of Incident Myocardial Infarction within Six-month Follow-up Comparing with Initiation of Codeine among Patients with Osteoarthritis
| Tramadol | Codeine | |
|---|---|---|
| Primary analysis | ||
| Participants (n) | 42,722 | 42,722 |
| Incident myocardial infarction (n) | 127 | 103 |
| Mean follow-up (year) | 0.49 | 0.49 |
| Rate (1000 person-years)* | 6.1 | 5.0 |
| RD (1000 person-years, 95% CI) | 1.1 (−0.3, 2.5) | 0.0 (reference) |
| HR (95% CI) | 1.23 (0.95, 1.60) | 1.00 (reference) |
| “As-treated” approach** | ||
| Participants (n) | 42,722 | 42,722 |
| Incident myocardial infarction (n) | 66 | 47 |
| Mean follow-up (year) | 0.25 | 0.21 |
| Rate (1000 person-years) | 6.2 | 5.1 |
| RD (1000 person-years, 95% CI) | 1.1 (−1.0, 3.2) | 0.0 (reference) |
| HR (95% CI) | 1.21 (0.83, 1.76) | 1.00 (reference) |
| Incident OA patients | ||
| Participants (n) | 25,104 | 25,104 |
| Incident myocardial infarction (n) | 60 | 59 |
| Mean follow-up (year) | 0.49 | 0.49 |
| Rate (1000 person-years) | 4.9 | 4.8 |
| RD (1000 person-years, 95% CI) | 0.1 (−1.7, 1.8) | 0.0 (reference) |
| HR (95% CI) | 1.01 (0.71, 1.45) | 1.00 (reference) |
| Missing data imputation | ||
| HR (95% CI) | 1.13 (0.88, 1.46) | 1.00 (reference) |
| Conventional covariate adjustment approach | ||
| HR (95% CI) | 1.16 (0.92, 1.47) | 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 codeine cohort was 791 (38.0/1000 person-years) and 822 (39.6 /1000 person-years), respectively.
**
82% and 89% participants discontinued or switched their initiated treatment in tramadol and codeine cohort, respectively.