Table 1.
Patient characteristics and inter-group differences
| Study population | All patients | Younger patients (<65 years) | Older patients (≥65 years) | |||||||
|---|---|---|---|---|---|---|---|---|---|---|
| N (%) or median (range) | Total study population | Readmission group | No readmission group | p value* | Readmission group | No readmission group | p value* | Readmission group | No readmission group | p value* |
| N = 940 | N = 163 | N = 777 | N = 82 | N = 403 | N = 81 | N = 374 | ||||
| Age, in years | 64 (16–101) | 65 (17–95) | 64 (16–101) | 0.39 | 56 (17–65) | 50 (16–65) | 0.001 | 76 (65–95) | 77 (65–101) | 0.21 |
| Sex, female | 493 (52.4) | 77 (47.2) | 416 (53.5) | 0.14 | 39 (47.6) | 214 (53.1) | 0.36 | 38 (46.9) | 202 (54.0) | 0.25 |
| CCI | 2 (0–11) | 2 (0–9) | 2 (0–11) | 0.04 | 2 (0–8) | 1 (0–11) | 0.005 | 2 (0–9) | 2 (0–9) | 0.96 |
| Number of medications useda | 5.0 (0–25) | 5.0 (0–21) | 5.0 (0–25) | 0.70 | 4.0 (0–21) | 3.0 (0–25) | 0.11 | 5.0 (0–16) | 7.0 (0–20) | 0.006 |
| ADL dependency, yes | 44 (4.7) | 12 (7.4) | 32 (4.1) | 0.08 | 2 (2.4) | 9 (2.2) | 1.0 | 10 (12.3) | 23 (6.1) | 0.05 |
| IADL dependency, yes | 55 (5.9) | 11 (6.7) | 44 (5.7) | 0.59 | 2 (2.4) | 11 (2.7) | 1.0 | 9 (11.1) | 33 (8.8) | 0.52 |
| Cognitive impairmenta, yes | 79 (8.4) | 9 (5.5) | 70 (9.0) | 0.16 | 2 (2.4) | 9 (2.2) | 1.0 | 7 (8.6) | 61 (16.3) | 0.09 |
| Living situation, nursing facility | 65 (6.9) | 9 (5.5) | 56 (7.2) | 0.50 | 1 (1.2) | 7 (1.7) | 1.0 | 8 (9.9) | 49 (13.1) | 0.58 |
| Reason for index admission | ||||||||||
| Gastro-intestinal | 226 (24.0) | 33 (20.2) | 193 (24.8) | 0.21 | 13 (15.9) | 85 (21.1) | 0.28 | 20 (24.7) | 108 (28.9) | 0.45 |
| Infection | 214 (22.8) | 30 (18.4) | 184 (23.7) | 0.14 | 15 (18.3) | 77 (19.4) | 0.86 | 15 (18.5) | 107 (28.6) | 0.06 |
| Malignancy | 167 (17.8) | 54 (33.1) | 113 (14.5) | <0.001 | 28 (34.1) | 59 (14.6) | <0.001 | 26 (32.1) | 54 (14.4) | <0.001 |
| Inflammatory | 83 (8.8) | 16 (9.8) | 67 (8.6) | 0.63 | 12 (14.6) | 45 (11.2) | 0.39 | 4 (4.9) | 22 (5.9) | 1.0 |
| (Auto)-intoxication | 67 (7.1) | 1 (0.6) | 66 (8.5) | <0.001 | 1 (1.2) | 64 (15.9) | <0.001 | 0 | 2 (0.5) | 1.0 |
| Renal and/or electrolyte problems | 49 (5.2) | 9 (5.5) | 40 (5.1) | 0.85 | 5 (6.1) | 16 (4.0) | 0.38 | 4 (4.9) | 24 (6.4) | 0.80 |
| Allergy/anaphylaxis | 19 (2.0) | 1 (0.6) | 18 (2.3) | 0.23 | 1 (1.2) | 12 (3.0) | 0.71 | 0 | 6 (1.6) | 0.60 |
| Syncope | 8 (0.9) | 0 | 8 (1.0) | 0.36 | 0 | 4 (1.0) | 1.0 | 0 | 4 (1.1) | 1.0 |
| Cardiac | 8 (0.9) | 1 (0.6) | 7 (0.9) | 1.0 | 0 | 2 (0.5) | 1.0 | 1 (1.2) | 5 (1.3) | 1.0 |
| Other | 99 (10.5) | 18 (11.0) | 81 (10.4) | 0.82 | 7 (8.5) | 39 (9.7) | 0.75 | 11 (13.6) | 42 (11.2) | 0.55 |
| AE as reason for index admission | 333 (35.4) | 65 (39.9) | 268 (34.5) | 0.19 | 33 (40.2) | 124 (30.8) | 0.10 | 32 (39.5) | 144 (38.5) | 0.87 |
| Length of stay, days | 5 (1–131) | 6 (1–66) | 5 (1–131) | 0.20 | 6 (1–66) | 4 (1–78) | 0.01 | 6 (1–36) | 7 (1–131) | 0.44 |
| Day of discharge, day in weekend | 182 (19.4) | 33 (20.2) | 149 (19.2) | 0.75 | 20 (24.4) | 84 (20.8) | 0.48 | 13 (16.0) | 65 (17.4) | 0.77 |
| Season of discharge | ||||||||||
| Spring | 251 (26.7) | 42 (25.8) | 209 (26.9) | 0.77 | 17 (20.7) | 107 (26.6) | 0.27 | 25 (30.9) | 102 (27.3) | 0.51 |
| Summer | 243 (25.9) | 47 (28.8) | 196 (25.2) | 0.34 | 24 (29.3) | 109 (27.0) | 0.68 | 23 (28.4) | 87 (23.3) | 0.33 |
| Autumn | 234 (24.9) | 29 (17.8) | 205 (26.4) | 0.02 | 20 (24.4) | 106 (26.3) | 0.72 | 9 (11.1) | 99 (26.5) | 0.002 |
| Winter | 212 (22.6) | 45 (27.6) | 167 (21.5) | 0.09 | 21 (25.6) | 81 (20.1) | 0.26 | 24 (29.6) | 86 (23.0) | 0.21 |
Numbers in italic show significant differences
CCI Charlson comorbidity index, ADL activity in daily living, IADL instrumental activity in daily living, AE adverse event
* p values are given for statistical tests between the readmission and the control groups
aData of 2 patients were missing