Table 2.
Independent Predictors of 30‐Day Readmission After Index Hospitalization With STEMI
| Predictors | Univariate Regressiona | Multivariate Regressionb | ||
|---|---|---|---|---|
| Unadjusted HR (95% CI) | P Value | Adjusted HR (95% CI) | P Value | |
| Female sex | 1.49 (1.46–1.53) | <0.001 | 1.18 (1.15–1.21) | <0.001 |
| Hypertension | 1.26 (1.23–1.30) | <0.001 | 1.08 (1.05–1.12) | <0.001 |
| Diabetes mellitus | 1.46 (1.43–1.50) | <0.001 | 1.21 (1.17–1.24) | <0.001 |
| Dyslipidemia | 0.87 (0.84–0.89) | <0.001 | 0.93 (0.91–0.96) | <0.001 |
| Family history of coronary artery disease | 0.72 (0.69–0.75) | <0.001 | 0.95 (0.91–0.99) | 0.030 |
| History of CHF | 2.11 (2.06–2.17) | <0.001 | 1.27 (1.23–1.31) | <0.001 |
| Peripheral vascular disease | 1.66 (1.59–1.73) | <0.001 | 1.16 (1.11–1.22) | <0.001 |
| Pulmonary hypertension | 1.90 (1.79–2.03) | <0.001 | 1.11 (1.04–1.19) | 0.002 |
| Chronic pulmonary disease | 1.59 (1.53–1.64) | <0.001 | 1.18 (1.14–1.22) | <0.001 |
| Chronic kidney disease | 2.12 (2.05–2.19) | <0.001 | 1.27 (1.23–1.32) | <0.001 |
| Liver disease | 1.40 (1.27–1.53) | <0.001 | 1.14 (1.04–1.25) | 0.007 |
| Anemia | 1.93 (1.87–2.00) | <0.001 | 1.12 (1.08–1.16) | <0.001 |
| Atrial fibrillation | 1.76 (1.70–1.81) | <0.001 | 1.17 (1.13–1.21) | <0.001 |
| AIDS | 1.48 (1.15–1.91) | 0.002 | 1.37 (1.06–1.76) | 0.017 |
| Collagen vascular disease | 1.38 (1.27–1.49) | <0.001 | 1.13 (1.04–1.22) | 0.002 |
| Fluid/electrolyte disorders | 1.65 (1.60–1.70) | <0.001 | 1.05 (1.02–1.09) | 0.005 |
| Median household income | ||||
| First quartile | 1 (reference) | 1 (reference) | ||
| Second quartile | 0.92 (0.89–0.95) | <0.001 | 0.95 (0.92–0.98) | 0.003 |
| Third quartile | 0.88 (0.85–0.92) | <0.001 | 0.91 (0.88–0.95) | <0.001 |
| Fourth quartile | 0.86 (0.83–0.90) | <0.001 | 0.90 (0.87–0.93) | <0.001 |
| Primary payer | ||||
| Medicare | 1 (reference) | 1 (reference) | ||
| Medicaid | 0.91 (0.87–0.95) | <0.001 | 1.06 (1.00–1.12) | 0.055 |
| Private including HMO | 0.49 (0.47–0.50) | <0.001 | 0.72 (0.69–0.75) | <0.001 |
| Self‐pay/no charge/other | 0.51 (0.49–0.53) | <0.001 | 0.73 (0.69–0.77) | <0.001 |
| Revascularization | ||||
| All PCI | 1 (reference) | 1 (reference) | ||
| CABG only | 1.37 (1.30–1.44) | <0.001 | 0.79 (0.75–0.84) | <0.001 |
| No revascularization | 1.66 (1.60–1.71) | <0.001 | 1.05 (1.01–1.09) | 0.014 |
| IABP | 1.59 (1.53–1.65) | <0.001 | 1.16 (1.11–1.22) | <0.001 |
| Hospital teaching status | ||||
| Teaching | 0.96 (0.93–0.98) | 0.003 | 0.96 (0.93–0.99) | 0.007 |
| Hospital location | ||||
| Rural | 1 (reference) | 1 (reference) | ||
| Urban | 1.11 (1.08–1.15) | <0.001 | 1.09 (1.06–1.12) | <0.001 |
| Length of hospital stay, d | ||||
| ≤3 | 1 (reference) | 1 (reference) | ||
| 4 to 5 | 1.73 (1.68–1.78) | <0.001 | 1.40 (1.36–1.45) | <0.001 |
| ≥6 | 2.46 (2.39–2.53) | <0.001 | 1.62 (1.56–1.68) | <0.001 |
| Disposition | ||||
| Home | 1 (reference) | 1 (reference) | ||
| Facilityc | 2.12 (2.05–2.19) | <0.001 | 1.18 (1.13–1.22) | <0.001 |
| AMA/unknown | 1.89 (1.72–2.09) | <0.001 | 1.88 (1.70–2.06) | <0.001 |
| Age group, y | ||||
| <50 | 1 (reference) | 1 (reference) | ||
| 50 to 64 | 1.07 (1.03–1.12) | 0.001 | 0.98 (0.94–1.02) | 0.275 |
| ≥65 | 1.80 (1.73–1.87) | <0.001 | 1.02 (0.97–1.08) | 0.400 |
| Smoking | 0.80 (0.78–0.82) | <0.001 | 0.98 (0.95–1.01) | 0.100 |
| Known coronary artery disease | 0.89 (0.86–0.92) | <0.001 | 1.04 (1.00–1.08) | 0.051 |
| Previous myocardial infarction | 1.17 (1.13–1.22) | <0.001 | 1.03 (0.99–1.08) | 0.125 |
| Previous PCI | 1.07 (1.03–1.11) | 0.001 | 1.03 (0.99–1.07) | 0.162 |
| Previous CABG | 1.33 (1.26–1.42) | <0.001 | 1.02 (0.96–1.08) | 0.622 |
| Other neurological disorders | 1.46 (1.39–1.55) | <0.001 | 1.00 (0.95–1.06) | 0.945 |
| Pulmonary circulation disorders | 2.21 (1.62–3.02) | <0.001 | 0.96 (0.69–1.34) | 0.822 |
| Valvular heart disease | 1.92 (1.56–2.37) | <0.001 | 0.86 (0.69–1.08) | 0.186 |
| Elixhauser comorbidity scores >4 | 2.20 (2.14–2.26) | <0.001 | 1.01 (0.96–1.05) | 0.822 |
| Weekend admission | 0.97 (0.94–0.99) | 0.014 | 1.00 (0.98–1.03) | 0.754 |
| Cardiogenic shock | 1.68 (1.61–1.75) | <0.001 | 1.02 (0.97–1.07) | 0.382 |
| Cardiogenic arrest | 1.25 (1.18–1.33) | <0.001 | 0.95 (0.89–1.00) | 0.065 |
| PLVAD | 1.51 (1.27–1.81) | <0.001 | 0.98 (0.81–1.18) | 0.834 |
AMA indicates against medical advice; CABG, coronary artery bypass graft; CHF, congestive heart failure; CI, confidence interval; HMO, health maintenance organization; HR, hazard ratio; PCI, percutaneous coronary intervention; PLVAD, percutaneous left ventricular assist device; STEMI, ST‐segment‐elevation myocardial infarction.
a
Univariate Cox proportional hazards regression model was created with an outcome of 30‐day readmission for each covariate from Table 1 and the covariates with P<0.1 are listed.
b
Multivariate Cox proportional hazards regression model was created with an outcome of 30‐day readmission including all predictors with P<0.1 in the univariate analysis.
c
Facility includes skilled nursing facility, intermediate care facility, and inpatient rehabilitation facility.