Table 2.
Factors associated with 30-day readmission in all, younger, and older patients
| Possible factors (reference) | Multivariate analyses in all agesb | Multivariate analyses in younger patients (<65 years)b | Multivariate analyses in older patients (≥65 years)b | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Total study population | AE groupc | Total study population | AE groupc | Total study population | AE groupc | |||||||
| N = 940 | N = 333 | N = 485 | N = 157 | N = 455 | N = 176 | |||||||
| HR (95 % CI) | p value | HR (95 % CI) | p value | HR (95 % CI) | p value | HR (95 % CI) | p value | HR (95 % CI) | p value | HR (95 % CI) | p value | |
| Age, in yearsa | 1.12 (0.78–1.62) | 0.53 | 0.97 (0.54–1.73) | 0.91 | 1.03 (1.01–1.05) | 0.02 | 1.01 (0.97–1.05) | 0.61 | 0.98 (0.95–1.02) | 0.37 | 1.02 (0.96–1.08) | 0.51 |
| Sex (female) | 0.78 (0.55–1.11) | 0.17 | 0.63 (0.35–1.11) | 0.11 | 0.80 (0.49–1.31) | 0.37 | 0.70 (0.31–1.58) | 0.39 | 0.77 (0.46–1.27) | 0.30 | 0.48 (0.20–1.15) | 0.10 |
| CCI (0–2) | 1.45 (0.99–2.12) | 0.06 | 1.31 (0.74–2.33) | 0.35 | 1.59 (0.89–2.83) | 0.12 | 1.84 (0.81–4.19) | 0.15 | 1.16 (0.68–1.96) | 0.59 | 0.90 (0.39–2.08) | 0.81 |
| Number of medications used (0–5) | ||||||||||||
| 5–10 | 0.79 (0.53–1.19) | 0.27 | 0.89 (0.47–1.68) | 0.72 | 0.84 (0.45–1.56) | 0.58 | 0.86 (0.35–2.14) | 0.75 | 0.67 (0.39–1.18) | 0.17 | 0.88 (0.35–2.20) | 0.78 |
| 10–15 | 0.66 (0.34–1.25) | 0.20 | 0.62 (0.25–1.54) | 0.30 | 1.34 (0.50–3.62) | 0.56 | 0.57 (0.13–2.47) | 0.46 | 0.40 (0.17–0.95) | 0.04 | 0.54 (0.16–1.83) | 0.32 |
| >15 | 0.63 (0.20–1.97) | 0.42 | 0.87 (0.22–3.50) | 0.85 | 1.35 (0.29–6.20) | 0.70 | 1.28 (0.19–8.63) | 0.80 | 0.22 (0.03–1.76) | 0.15 | 0.48 (0.05–4.56) | 0.52 |
| ADL dependency | 2.43 (1.10–5.35) | 0.03 | 7.05 (1.61–30.9) | 0.01 | 1.76 (0.25–12.4) | 0.57 | 1.40 (0.12–16.9) | 0.78 | 3.19 (1.27–8.01) | 0.01 | 10.0 (1.62–62.3) | 0.01 |
| Cognitive impairment | 0.54 (0.25–1.17) | 0.12 | 0.26 (0.04–1.57) | 0.14 | 0.74 (0.14–3.91) | 0.72 | – | – | 0.45 (0.18–1.12) | 0.09 | 0.24 (0.03–1.84) | 0.17 |
| Living situation (home) | 0.67 (0.29–1.56) | 0.36 | 0.24 (0.04–1.40) | 0.11 | 0.41 (0.03–5.45) | 0.50 | – | – | 0.91 (0.36–2.33) | 0.85 | 0.25 (0.04–1.82) | 0.17 |
| AE as reason for the index admission | 1.20 (0.83–1.75) | 0.33 | NA | NA | 1.12 (0.65–1.95) | 0.68 | NA | NA | 1.12 (0.66–1.91) | 0.68 | NA | NA |
| Length of stay (linear) | 1.01 (0.99–1.02) | 0.45 | 0.99 (0.96–1.03) | 0.67 | 1.02 (0.99–1.04) | 0.21 | 1.0 (0.94–1.06) | 0.93 | 0.99 (0.96–1.02) | 0.53 | 0.99 (0.95–1.03) | 0.65 |
| Season of discharge (summer) | ||||||||||||
| Spring | 0.83 (0.52–1.33) | 0.44 | 0.71 (0.32–1.55) | 0.39 | 0.74 (0.37–1.48) | 0.39 | 0.65 (0.21–2.03) | 0.46 | 0.93 (0.48–1.81) | 0.84 | 0.92 (0.29–2.91) | 0.89 |
| Autumn | 0.60 (0.36–1.01) | 0.05 | 0.50 (0.22–1.14) | 0.10 | 1.03 (0.52–2.02) | 0.94 | 0.62 (0.20–1.95) | 0.41 | 0.33 (0.14–0.77) | 0.01 | 0.42 (0.12–1.49) | 0.18 |
| Winter | 1.10 (0.69–1.76) | 0.69 | 0.84 (0.40–1.77) | 0.66 | 1.12 (0.57–2.19) | 0.75 | 0.86 (0.30–2.46) | 0.78 | 1.01 (0.51–1.98) | 0.98 | 0.82 (0.27–2.51) | 0.83 |
| Day of discharge (weekday) | 1.10 (0.71–1.70) | 0.66 | 1.46 (0.77–2.76) | 0.24 | 1.27 (0.71–2.27) | 0.42 | 1.26 (0.52–3.06) | 0.61 | 0.93 (0.47–1.85) | 0.85 | 1.59 (0.62–4.07) | 0.33 |
Numbers in italic show significant differences
HR hazard ratio, CI confidence interval, CCI Charlson comorbidity index, ADL activity in daily living, AE adverse event, NA not applicable
aIn the multivariate analyses of all ages, age was included as binominal covariate (≤65 and >65 years), in the multivariate analyses in younger and older patients, age was included as linear covariate
bIADL was omitted out of the equation due to collinearity with ADL. Because of insufficient cases, admission reasons could not be included in the analyses. In the AE group of younger patients, cognition and living situation could not be included in the analyses due to insufficient cases
cLogistic regression analysis performed in the subgroup of patients with an index admission because of an AE