Characteristics of the initial prescription, overall and per type of opioid, n (%)
| Initial prescription characteristics | Total | Tramadol | Codeine | Long-acting | Short-acting | Ultrafast | P value |
| N | 958 019 | 734 349 (76.65%) | 156 515 (16.34%) | 64 313 (6.71%) | 1587 (0.17%) | 1255 (0.13%) | |
| Duration (days) | |||||||
| Mean (SD) | 24.82 (79.53) | 25.29 (78.42) | 7.86 (33.20) | 61.02 (138.49) | 19.67 (58.38) | 21.87 (39.47) | <0.001 |
| Median (IQR) | 9.00 (5.00, 19.00) | 9.00 (5.00, 19.00) | 5.00 (4.00, 6.00) | 29.00 (14.00, 59.00) | 8.00 (4.00, 14.00) | 9.00 (3.00, 29.00) | |
| Duration, range (days) | |||||||
| 1–3 | 67 173 (7.01%) | 39 349 (5.36%) | 25 686 (16.41%) | 1502 (2.34%) | 314 (19.79%) | 322 (25.66%) | <0.001 |
| 4–7 | 331 618 (34.61%) | 226 692 (30.87%) | 99 895 (63.82%) | 4398 (6.84%) | 418 (26.34%) | 215 (17.13%) | |
| 8–14 | 271 231 (28.31%) | 234 323 (31.91%) | 22 636 (14.46%) | 13 523 (21.03%) | 478 (30.12%) | 271 (21.59%) | |
| 15–30 | 173 001 (18.06%) | 142 923 (19.46%) | 6054 (3.87%) | 23 556 (36.63%) | 210 (13.23%) | 258 (20.56%) | |
| ≥31 | 114 996 (12.00%) | 91 062 (12.40%) | 2244 (1.43%) | 21 334 (33.17%) | 167 (10.52%) | 189 (15.06%) | |
| Daily MME | |||||||
| Mean (SD) | 24.65 (161.82) | 18.08 (25.21) | 26.73 (18.04) | 92.50 (610.99) | 44.95 (71.64) | 105.88 (415.44) | <0.001 |
| Median (IQR) | 15.00 (8.33, 22.50) | 13.33 (8.33, 18.75) | 22.50 (18.00, 30.00) | 41.38 (22.10, 85.71) | 24.00 (12.50, 50.00) | 40.96 (18.29, 86.45) | |
| Daily MME, range | |||||||
| <50 | 889 151 (92.81%) | 701 299 (95.50%) | 148 129 (94.64%) | 37 866 (58.88%) | 1173 (73.91%) | 684 (54.50%) | <0.001 |
| 50–89 | 41 204 (4.30%) | 24 920 (3.39%) | 4866 (3.11%) | 10 944 (17.02%) | 205 (12.92%) | 269 (21.43%) | |
| 90–119 | 8403 (0.88%) | 3464 (0.47%) | 2188 (1.40%) | 2583 (4.02%) | 111 (6.99%) | 57 (4.54%) | |
| ≥120 | 19 261 (2.01%) | 4666 (0.64%) | 1332 (0.85%) | 12 920 (20.09%) | 98 (6.18%) | 245 (19.52%) | |
| Indication of use | |||||||
| Back pain | 266 021 (27.77%) | 233 618 (31.81%) | 11 774 (7.52%) | 20 441 (31.78%) | 55 (3.47%) | 133 (10.60%) | <0.001 |
| Gastrointestinal pain | 42 849 (4.47%) | 37 359 (5.09%) | 3818 (2.44%) | 1511 (2.35%) | 52 (3.28%) | 109 (8.69%) | |
| Miscellaneous | 166 749 (17.41%) | 125 885 (17.14%) | 23 228 (14.84%) | 16 052 (24.96%) | 1013 (63.83%) | 571 (45.50%) | |
| Osteoarticular pain | 173 555 (18.12%) | 151 463 (20.63%) | 6983 (4.46%) | 14 931 (23.22%) | 52 (3.28%) | 126 (10.04%) | |
| Other musculoskeletal pain | 113 496 (11.85%) | 99 811 (13.59%) | 7695 (4.92%) | 5712 (8.88%) | 83 (5.23%) | 195 (15.54%) | |
| Respiratory | 124 850 (13.03%) | 23 143 (3.15%) | 99 587 (63.63%) | 1732 (2.69%) | 307 (19.34%) | 81 (6.45%) | |
| Rheumatoid pain | 70 499 (7.36%) | 63 070 (8.59%) | 3430 (2.19%) | 3934 (6.12%) | 25 (1.58%) | 40 (3.19%) | |
| Overlapping medications | |||||||
| Antipsychotics | 22 746 (2.37%) | 16 189 (2.20%) | 2609 (1.67%) | 3382 (5.26%) | 437 (27.54%) | 129 (10.28%) | <0.001 |
| Benzodiazepines | 236 889 (24.73%) | 188 155 (25.62%) | 25 361 (16.20%) | 22 444 (34.90%) | 575 (36.23%) | 354 (28.21%) | <0.001 |
| Gabapentinoids | 44 039 (4.60%) | 34 776 (4.74%) | 2169 (1.39%) | 6971 (10.84%) | 46 (2.90%) | 77 (6.14%) | <0.001 |
*P values were estimated using χ2 for categorical variables and analysis of variance or Kruskal-Wallis tests for continuous variables.
IQR, Interquartile Range; MME, morphine milligram equivalents; SD, Standard Deviation.