The ADR characteristics, prognosis and medical consumptions of study subjects
| Variables | ADRs (n=539) Frequency (%) or mean±SD | Control group (n=1854) Frequency (%) or mean±SD | P value |
| Naranjo score | |||
| Possible (≤4) | 451 (83.7) | ||
| Probable (5–8) | 83 (15.4) | ||
| Definite (≥9) | 5 (0.9) | ||
| Severity | |||
| Mild | 192 (35.6) | ||
| Moderate | 317 (58.8) | ||
| Severe | 30 (5.6) | ||
| Prognosis | |||
| Discharge | 438 (81.3) | 1640 (88.5) | <0.01 |
| Continued hospitalisation | 21 (3.9) | 45 (2.4) | |
| Death | 80 (14.8) | 169 (9.1) | |
| Drug prescriptions before ADR inception | |||
| Classes* | 14.82±0.43 | 14.76±0.58 | <0.01 |
| Number† | 106.16±19.85 | 98.96±20.01 | <0.01 |
| Drug prescriptions during the whole hospital stay | |||
| Classes* | 14.98±0.14 | 14.95±0.22 | <0.01 |
| <13 | 0 (0.0) | 16 (0.9) | 0.08 |
| 13 | 10 (1.9) | 39 (2.1) | |
| 14 | 75 (13.9) | 302 (16.3) | |
| 15 | 454 (84.2) | 1497 (80.7) | |
| Number† | 113.91±15.44 | 112.86±15.51 | 0.16 |
| Medical consumptions | |||
| Length of stay (days) | 30.8±30.2 | 16.9±14.7 | <0.01 |
| Total medical expenses (US$) | 9531.3±13 634.5 | 4108.9±5180.1 | <0.01 |
| Drug expenses (US$) | 2276.4±4244.1 | 817.0±1806.8 | <0.01 |
*Classes of drug prescriptions according to Anatomical Therapeutic Chemical (ATC) classification (online supplementary appendix 2).
†Number of drug prescriptions according to different ATC codes.
ADR, adverse drug reaction.