Table 2.
Hazard ratio for all-cause readmission during 30-day periods after index hospitalization for acute exacerbation of chronic obstructive pulmonary disease, according to acute kidney injury, overall and stratified by age category and sex and chronic kidney disease
| 30-day readmission rate | Unadjusted model | Adjusted modela | P for interaction | ||||
|---|---|---|---|---|---|---|---|
| AKI (n = 24,833) | Non-AKI (n = 332,157) | HR (95% CI) | P-value | HR (95% CI) | P-value | ||
| Overall (n = 356,990) | 22.4% | 15.8% | 1.47 (1.43–1.51) | < 0.001 | 1.07 (1.04–1.11) | < 0.001 | |
| Age category | |||||||
| 40–64 years (n = 122,362) | 20.9% | 14.0% | 1.52 (1.43–1.63) | < 0.001 | 1.03 (0.96–1.10) | 0.45 | 0.13 |
| ≥ 65 years (n = 234,628) | 22.7% | 16.8% | 1.41 (1.36–1.45) | < 0.001 | 1.09 (1.05–1.13) | < 0.001 | |
| Sexb | |||||||
| Men (n = 149,333) | 22.0% | 16.7% | 1.36 (1.30–1.41) | < 0.001 | 1.03 (0.99–1.08) | 0.14 | 0.07 |
| Women (n = 207,436) | 22.7% | 15.2% | 1.56 (1.50–1.62) | < 0.001 | 1.12 (1.07–1.17) | < 0.001 | |
| Chronic kidney diseasec | |||||||
| Chronic kidney disease (n = 47,999) | 27.7% | 24.2% | 1.14 (1.09–1.18) | < 0.001 | 1.03 (0.99–1.07) | 0.24 | 0.01 |
| No chronic kidney disease (n = 308,991) | 22.3% | 16.8% | 1.32 (1.26–1.38) | < 0.001 | 1.09 (1.05–1.15) | < 0.001 | |
Abbreviations: AKI Acute kidney injury, HR Hazard ratio, CI Confidence interval
aCox proportional hazards model adjusting for age, sex, race/ethnicity, insurance status, estimated household income, residential status, hospital length-of-stay, hospital state, and Elixhauser comorbidity measures and arrhythmia with generalized estimating equations to account for patient clustering within hospitals
b221 patients with missingness on sex data
cChronic kidney disease was defined by the Elixhauser comorbidities