30-day hospital readmissions for different classes of drugs based on ATC (N=13 802)
| Drug class | 30-day readmission with no drugs in this class (%) | 30-day readmission with drugs in this class (%) | P value |
| First level, anatomical main group | |||
| Blood and blood-forming organ drugs (B) | 7.1 | 8.0 | NS |
| Dermatologicals (D) | 7.7 | 9.4 | NS |
| Genitourinary system and sex hormones (G) | 7.7 | 8.3 | NS |
| Systemic hormonal preparations, excluding sex hormones and insulins (H) | 7.4 | 9.5 | *** |
| Anti-infectives for systemic use (J) | 8.0 | 7.2 | NS |
| Antineoplastic and immunomodulating agents (L) | 7.6 | 12.6 | *** |
| Drugs for the musculoskeletal system (M) | 8.0 | 6.5 | * |
| Antiparasitic products, insecticides and repellents (P) | 7.8 | 6.6 | *** |
| Respiratory system drugs (R) | 7.4 | 9.9 | *** |
| Sensory organ drugs (S) | 7.8 | 8.4 | NS |
| Second level, therapeutic subgroup | |||
| Stomatological preparations (A01) | 7.8 | 12.2 | NS |
| Drugs for acid-related disorders (A02) | 7.0 | 8.5 | *** |
| Drugs for functional gastrointestinal disorders (A03) | 7.4 | 13.4 | *** |
| Antiemetics and antinauseants (A04) | 7.7 | 27.7 | *** |
| Bile and liver therapy drugs (A05) | 7.8 | 14.3 | NS |
| Drugs for constipation (A06) | 7.3 | 10.8 | *** |
| Antidiarrhoeals, intestinal anti-inflammatory/anti-infective agents (A07) | 7.7 | 12.9 | *** |
| Digestives, including enzymes (A09) | 7.8 | 10.0 | NS |
| Drugs used in diabetes (A10) | 7.4 | 9.5 | *** |
| Vitamins (A11) | 7.5 | 9.9 | *** |
| Mineral supplements (A12) | 7.4 | 8.8 | ** |
| Other alimentary tract and metabolism products (A16) | 7.8 | 6.3 | NS |
| Cardiac therapy (C01) | 7.6 | 8.9 | NS |
| Antihypertensives (C02) | 7.7 | 14.1 | *** |
| Diuretics (C03) | 7.2 | 9.8 | *** |
| Peripheral vasodilators (C04) | 7.8 | 15.2 | NS |
| Vasoprotective drugs (C05) | 7.8 | 9.8 | NS |
| Beta-blocking agents (C07) | 7.1 | 8.6 | *** |
| Calcium channel blockers (C08) | 7.7 | 8.6 | NS |
| Agents acting on the renin–angiotensin system (C09) | 8.7 | 7.1 | *** |
| Lipid-modifying agents (C10) | 8.3 | 7.1 | ** |
| Anaesthetics (N01) | 7.8 | 18.8 | * |
| Analgesics (N02) | 7.8 | 7.8 | NS |
| Antiepileptics (N03) | 7.7 | 9.0 | NS |
| Drugs for Parkinson’s disease (N04) | 7.8 | 6.9 | NS |
| Psycholeptics (N05) | 6.8 | 9.3 | *** |
| Psychoanaleptics (N06) | 7.8 | 7.7 | NS |
| Other nervous system drugs (N07) | 7.9 | 5.1 | NS |
*P<0.05, **P<0.01, ***P<0.001.
ATC, Anatomical Therapeutic Chemical Classification System; NS, non-significant.