Table 3.
Changes in OD4 score over four epochs of four years
| Outcome | 1993-6 | 1997-2000 | 2001-4 | 2005-8 |
|---|---|---|---|---|
| Scotland (population 5.2 million in 2008) | ||||
| Drug related deaths: methadone as only drug | 79 | 38 | 43 | 98 |
| Drug related deaths: any mention of methadone | 237 | 269 | 337 | 464 |
| Quantity of methadone prescribed (mg × 1 million) | 245.6 | 559.1 | 1136.3 | 1988.1 |
| Implied methadone patient years (DDD (60 mg)/365) | 11 215 | 25 530 | 51 889 | 90 781 |
| OD4 score: methadone only (95% CI) | 19.3 (15 to 24) | 4.1 (2.8 to 5.4) | 2.3 (1.6 to 2.9)† | 3.0 (2.4 to 3.5)* |
| OD4 score: any mention of methadone (95% CI) | 57.9 (50 to 65) | 28.9 (25 to 32) | 17.8 (15.9 to19.7) | 14.0 (12.7 to 15.3)‡ |
| England (population 51.4 million in 2008) | ||||
| Drug related deaths: methadone as only drug | 605 | 801 | 382 | 555 |
| Drug related deaths: any mention of methadone | 1035 | 1359 | 825 | 1098 |
| Quantity of methadone prescribed (mg × 1 million) | 1341.9 | 1941.5 | 2894.6 | 5730.7 |
| Implied methadone patient years (DDD (60 mg)/365) | 61 274 | 88 653 | 132 174 | 261 676 |
| OD4 score: methadone only (95% CI) | 27.1 (24.9 to 29.2) | 24.8 (23.0 to 26.5)* | 7.9 (7.1 to 8.7) | 5.8 (5.3 to 6.3) |
| OD4 score: any mention of methadone (95% CI) | 46.3 (43 to 49) | 42.0 (40 to 44)§ | 17.1 (15.9 to 18.3) | 11.5 (10.8 to 12.2) |
DDD=defined daily dose.
Z scores are provided when 95% confidence intervals overlap.
*All OD4 changes across epoch were significant, except for those concluding here.
†Z score versus previous epoch=2.42.
‡Z score versus previous epoch=3.25.
§Z score versus previous epoch=2.33.