Table 6. Effects of demographic and case-mix variables on the use of rural inpatient care, by rural Medicare beneficiaries: Fiscal year 1987.

Predictors	Logistic regression coefficient (b)	Standard error	T	Relative risk
Age	0.0224	0.0004	56.48	1.023
Sex	0.0644	0.0062	10.42	1.067
Disabled	0.3129	0.0135	23.10	1.367
Chronic renal disease	−0.8511	0.0482	−17.64	0.427
Exempt unit	−1.1140	0.2701	−41.25	0.328
Transferred to another hospital	0.6654	0.2036	32.69	1.945
Length of stay	−0.0085	0.0004	−19.53	0.991
Intensive care unit days	−0.0121	0.0013	−9.13	0.988
Coronary care unit days	−0.0702	0.0025	−27.77	0.932
Number of diagnoses	0.0629	0.0023	27.48	1.064
Surgery	−0.5691	0.0111	−51.29	0.566
Number of procedures	−0.1628	0.0047	−34.81	0.850
DRG weight	−0.0725	0.0046	−15.91	0.930
Craniotomy and spinal procedures	−1.5464	0.0594	−26.04	0.213
Major head and neck procedures	−0.9239	0.1244	−7.43	0.397
Ear, nose, and throat procedures	−1.1689	0.0935	−12.51	0.310
Cardiovascular procedures	−1.6797	0.0174	−96.35	0.186
Kidney procedures	−0.9697	0.0649	−14.94	0.379
Hysterectomy	−2.0091	0.2831	−7.10	0.134
Splenectomy and BFO procedures	−0.5656	0.1363	−4.15	0.568
Neoplasms	−1.1343	0.0696	−16.29	0.322
Radiotherapy	−1.8396	0.1038	−17.71	0.159
Chemotherapy	−1.4868	0.0273	−54.38	0.226
Injury procedures	−0.7788	0.0451	−17.26	0.459
Rehabilitation	−1.1743	0.0619	−18.98	0.309
Intercept	−0.3855	—	—	—
N = 577,712
Dependent variable mean = 0.688
Likelihood ratio X2 = 76,395.68 with 25 degrees of freedom
Percent correctly classified = 72.8 percent
Proportional reduction in error = 0.128
F = 2,741.40 at (25, 577, 111) degrees of freedom
R2 = 0.1061

NOTE: DRG is diagnosis-related group.

SOURCE: Health Care Financing Administration, Bureau of Data Management and Strategy: Data are from the Medicare Provider Analysis Survey, 1987.