Table 2. Case-Level Inpatient Psychiatric Cost Regressions, Based on 1999 Data.
| Independent Variable | Dependent Variable | |||||
|---|---|---|---|---|---|---|
|
| ||||||
| ln (Cost/Case) | ln (Cost/Day) | ln (Cost/Day) | ||||
|
| ||||||
| Coefficient | t | Coefficient | t | Coefficient | t | |
|
|
|
|
||||
| Wage Index: Ln 1999 Wage Index | 0.849 | 44.99 | 0.664 | 108.790 | 0.670 | 124.33 |
| Rural Location Indicator | 0.175 | 20.24 | 0.149 | 53.120 | 0.023 | 9.03 |
| Size: Ln ADC | NA | NA | NA | NA | -0.172 | -164.58 |
| Occupancy: Ln Occupancy Rate | 0.018 | 1.88 | -0.279 | -88.520 | -0.126 | -42.95 |
| Teaching: Ln (1+ Residents to ADC) | 0.402 | 12.53 | 0.523 | 50.340 | 0.598 | 65.17 |
| Age Over 65 indicator | 0.398 | 64.48 | 0.126 | 62.090 | 0.076 | 42.09 |
| Length of Stay Indicators | ||||||
| 1 Day | NA | NA | 0.227 | 50.070 | 0.204 | 50.91 |
| 2-4 Days | NA | NA | 0.116 | 46.300 | 0.092 | 41.45 |
| 5-8 Days | NA | NA | 0.049 | 23.210 | 0.032 | 17.26 |
| Comorbidity Indicators | ||||||
| HIV | -0.056 | -1.38 | 0.081 | 6.200 | 0.077 | 6.66 |
| Hemophilia | 0.045 | 0.26 | 0.122 | 2.160 | 0.137 | 2.74 |
| Tracheostomy | -0.197 | -1.48 | 0.105 | 2.440 | 0.064 | 1.70 |
| Psychiatric | 0.148 | 3.80 | 0.032 | 2.500 | 0.025 | 2.24 |
| Infectious Disease | 0.099 | 4.22 | 0.068 | 8.990 | 0.050 | 7.48 |
| ESRD Renal Failure Acute | 0.021 | 0.36 | 0.090 | 4.780 | 0.071 | 4.28 |
| ESRD Renal Failure Chronic | 0.065 | 2.28 | 0.109 | 11.840 | 0.078 | 9.54 |
| Malignant Neoplasms | 0.033 | 1.07 | 0.089 | 9.030 | 0.065 | 7.48 |
| Diabetes | 0.199 | 3.61 | 0.105 | 5.870 | 0.069 | 4.36 |
| Severe Malnutrition | 0.216 | 2.20 | 0.114 | 3.610 | 0.101 | 3.62 |
| Chemical Dependency | -0.067 | -2.81 | 0.015 | 1.990 | 0.018 | 2.60 |
| Heart and Rheumatic Fever | 0.154 | 1.57 | 0.150 | 4.730 | 0.129 | 4.62 |
| Atherosclerosis with Gangrene | 0.381 | 1.68 | 0.182 | 2.480 | 0.171 | 2.63 |
| Chronic Respiratory Failure | 0.106 | 3.36 | 0.107 | 10.490 | 0.079 | 8.78 |
| Colostomy | 0.172 | 3.56 | 0.108 | 6.910 | 0.070 | 5.06 |
| Osteomelitis Gangrene | 0.074 | 1.51 | 0.114 | 7.210 | 0.082 | 5.90 |
| Poison | -0.292 | -6.97 | 0.136 | 9.990 | 0.096 | 8.04 |
| Diagnosis Related Group (DRG) Indicators | ||||||
| 424 Procedure Principal Group Indicator | 0.690 | 14.42 | 0.206 | 13.280 | 0.173 | 12.62 |
| 425 Acute Adjustment Reaction | -0.260 | -10.75 | 0.092 | 11.730 | 0.064 | 9.20 |
| 426 Depressive Neurosis | -0.455 | -32.62 | -0.003 | -0.700 | -0.008 | -1.92 |
| 427 Neurosis, Except Depressive | -0.462 | -19.28 | 0.005 | 0.690 | 0.006 | 0.89 |
| 428 Disorders of Personality | -0.219 | -7.21 | 0.029 | 2.900 | 0.027 | 3.13 |
| 429 Organic Disturbances | 0.029 | 2.93 | 0.021 | 6.450 | 0.015 | 5.19 |
| 431 Childhood Disorders | -0.131 | -2.86 | -0.002 | -0.160 | -0.015 | -1.14 |
| 432 Other Mental Disorders | -0.184 | -1.89 | -0.070 | -2.220 | -0.024 | -0.87 |
| 433 Alchohol/Drug Use, LAMA | -1.072 | -24.09 | -0.120 | -8.330 | -0.081 | -6.34 |
| 521 Alcohhol/Drug Use, W/CC | -0.322 | -13.93 | 0.027 | 3.630 | 0.031 | 4.76 |
| 522 Alchohol/Drug Use, W/O Rehab | -0.152 | -4.20 | -0.022 | -1.900 | -0.018 | -1.72 |
| 523 Alchohol/Drug Use, W/O Rehab | -0.419 | -29.80 | -0.111 | -24.230 | -0.054 | -13.28 |
| 012 Degenerative Nervous System Discord | 0.066 | 4.45 | 0.061 | 12.700 | 0.014 | 3.30 |
| 023 Non-Traumatic Stupor & Coma | -0.371 | -4.74 | 0.087 | 3.440 | 0.098 | 4.39 |
| Additional Control Variables | ||||||
| Ancillary Indicator | 0.062 | 5.00 | -0.265 | -65.580 | -0.093 | -25.07 |
| Year Indicator | 0.039 | 3.56 | 0.026 | 7.200 | -0.008 | -2.69 |
| Indicator for Occupancy Under 30% | 0.117 | 8.19 | -0.038 | -8.180 | -0.019 | -4.70 |
| Indicator for Occupancy Over 105% | 0.478 | 7.06 | 0.100 | 4.570 | 0.079 | 4.10 |
| Number of Observations | 93,263 | — | 93,263 | — | 93,263 | — |
| Degrees of Freedom | 40 | — | 43 | — | 44 | — |
| R2 | 0.1157 | — | 0.3149 | — | 0.467 | — |
NOTES: NA is not applicable. All LOS coefficients are relative to stays of more than 8 days. All DRG coefficients are relative to DRG 430 (Psychoses). The additional control variables were not used in any of the payment simulations. The ancillary indicator identified facilities that do not charge separately for ancillary services. The year indicator identified cases were 1998 Medicare cost reports were used to backfill for missing 1999 reports in constructing the dependent variable. The two occupancy indicators identified facilities with extremely high and low values.
SOURCE: Cotterill, P.G. and Thomas, F.G., Centers for Medicare & Medicaid Services, 2004.