Table 3.

Risk factors for 30-day hospital readmission in the derivation cohort according to HRDES comorbidity variables

	Derivation cohort (N = 19,528)
Characteristics	Relative risk (95% CI)	Risk difference (95% CI)
Demographic characteristics
Age group, y
65–69	1.00	0.000
70–74	1.11 (1.00, 1.26)	.010 (–.001, .021)
75–79	1.30 (1.15, 1.46)	.027 (.015, .039)
80–84	1.22 (1.08, 1.39)	.023 (.010, .036)
85+	1.28 (1.13, 1.47)	.033 (.018, .048)
Male	1.13 (1.05, 1.23)	.008 (–.000, .016)
African American	1.18 (1.06, 1.32)	.013 (–.003, .028)
Health system variables
Long-term care	2.05 (1.87, 2.26)	.105 (.088, .121)
Medicare and Medicaid	0.83 (0.73, 0.95)	–.009 (–.023, .005)
Non-Medicare	0.70 (0.58, 0.84)	–.024 (–.038, –.010)
Surgery service	0.80 (0.73, 0.89)	–.018 (–.027, –.009)
Comorbidity variables∗
Severe peripheral vascular disease	1.77 (1.42, 2.21)	.091 (.036, .145)
Lymphoma/leukemia	1.76 (1.39, 2.25)	.093 (.049, .138)
Cirrhosis/end-stage liver disease	1.52 (1.17, 1.97)	.072 (.021, .123)
Renal failure (chronic)	1.50 (1.22, 1.85)	.079 (.040, .119)
Major stroke (hemiplegia)	1.42 (1.19, 1.68)	.052 (.020, .084)
Cancer (metastatic)	1.41 (1.17, 1.71)	.046 (.019, .073)
Malnutrition/weight loss	1.40 (1.20, 1.63)	.074 (.040, .108)
Respiratory failure	1.37 (1.18, 1.58)	.047 (.015, .078)
Congestive heart failure	1.34 (1.23, 1.46)	.038 (.026, .051)
Renal failure (acute)	1.25 (1.08, 1.45)	.053 (.024, .082)
Cancer (solid tumor, localized)	1.22 (1.05, 1.41)	.026 (.010, .043)
COPD/chronic lung disease	1.11 (1.00, 1.22)	.017 (.004, .029)
Dementia	0.81 (0.69, 0.97)	–.016 (–.036, .004)
Constant	–	.070 (.051, .090)

∗Comorbidity variables reported in descending order by relative risk.

HRDES indicates High-Risk Diagnoses in the Elderly Scale; CI, confidence interval; COPD, chronic obstructive pulmonary disease.