Appendix Table 3A.

Final predictors for 30-day all-cause re-hospitalization where age and Charlson Index were modeled as non-parametric function

Parameter/Predictor	β-coefficient	SE	p value
Intercept	−1.601	0.120	<.0001
Age*	NA	NA	NA
Gender (reference: women)
Men	0.071	0.023	0.0021
Race/Ethnicity (reference: Non-Hispanic white)
Non-Hispanic black	0.032	0.036	0.38
Hispanic	−0.014	0.062	0.82
Other	0.213	0.085	0.012
Unknown	−0.023	0.069	0.74
Marital status (reference: Married)
Widowed	−0.020	0.026	0.44
Separated/divorced	−0.081	0.041	0.05
Never married	−0.081	0.043	0.059
Unknown	0.015	0.078	0.84
Medicare and Medicaid dual enrollee	0.021	0.029	0.47
Charlson index (log-transformed)*	NA	NA	NA
Length of index hospital stay, days (reference: 3–4)
5–6	0.127	0.029	<.0001
7–9	0.227	0.030	<.0001
10–13	0.363	0.036	<.0001
≥ 14	0.517	0.038	<.0001
No. of any hospitalizations within 6 months before index hospitalization (ref: 0)
1	0.173	0.026	<.0001
≥ 2	0.471	0.029	<.0001
Depression severity (reference: none)
Mild	0.020	0.028	0.47
Moderate	0.026	0.049	0.59
Moderately severe	0.036	0.089	0.68
Severe	0.217	0.159	0.17
Unknown	1.673	0.069	<.0001
Physical limitations (reference: normal or minimal limitation)
Moderate limitation	0.149	0.028	<.0001
Physical dependency	0.422	0.034	<.0001

^*Because age and log-transformed Charlson Index were treated as a non-parametric function using a smoothing spline, parameter estimates were not applicable.