Demographic and clinical characteristics of the study subjects
| Variables | ADRs (n=539) Frequency (%) or mean±SD | Control group (n=1854) Frequency (%) or mean±SD | P value* |
| Age | 76.12±7.13 | 76.02±7.09 | 0.79 |
| 65≤age<75 | 237 (44.0) | 828 (44.7) | 0.94 |
| 75≤age<85 | 231 (42.9) | 791 (42.7) | |
| Age≥85 | 71 (13.2) | 235 (12.7) | |
| Gender | |||
| Male | 301 (55.8) | 1034 (55.8) | 0.98 |
| Female | 238 (44.2) | 820 (44.2) | |
| Principal diagnosis | |||
| Respiratory diseases | 117 (21.7) | 407 (22.0) | 1.00 |
| Circulatory system | 91 (16.9) | 289 (15.6) | |
| Neoplasms | 70 (13.0) | 250 (13.5) | |
| Digestive system | 46 (8.5) | 151 (8.1) | |
| Infectious and parasitic diseases | 39 (7.2) | 133 (7.2) | |
| Skin and subcutaneous tissue | 37 (6.9) | 135 (7.3) | |
| Genitourinary system | 29 (5.4) | 101 (5.5) | |
| Injury and poisoning | 24 (4.5) | 76 (4.1) | |
| Endocrine, nutritional and metabolic disease and immunity disorders | 16 (3.0) | 50 (2.7) | |
| Musculoskeletal system and connective tissue | 16 (3.0) | 60 (3.2) | |
| Nervous system and sense organs | 14 (2.6) | 44 (2.4) | |
| Symptoms, signs and ill-defined conditions | 12 (2.2) | 41 (2.2) | |
| All supplementary classification | 21 (3.9) | 91 (4.9) | |
| Blood and blood-forming organs | 6 (1.1) | 21 (1.1) | |
| Others | 1 (0.2) | 5 (0.3) | |
| Admission department | |||
| Internal medicine | 311 (57.7) | 1029 (55.5) | 0.01 |
| Surgery | 85 (15.8) | 388 (20.9) | |
| Oncology | 64 (11.9) | 147 (7.9) | |
| Infectious disease | 46 (8.5) | 177 (9.6) | |
| Others | 33 (6.1) | 113 (6.1) | |
| Number of comorbidities | 4.06±1.48 | 3.53±1.08 | <0.01 |
| ≤3 | 90 (16.7) | 472 (25.5) | <0.01 |
| 4 | 378 (70.1) | 1371 (74.0) | |
| >4 | 71 (13.2) | 11 (0.6) | |
| Charlson Comorbidity Index | 1.47±2.16 | 1.39±2.05 | 0.44 |
| 0 | 230 (42.7) | 815 (44.0) | 0.93 |
| 1 | 148 (27.5) | 486 (26.2) | |
| 2 | 76 (14.1) | 266 (14.4) | |
| ≥3 | 85 (15.8) | 287 (15.5) |
*P value was acquired from Χ2 tests for categorical variables and t-test for continuous variables.
ADR, adverse drug reaction.