Changes in hospital costs after introducing an intermediate care unit: a comparative observational study

Table 3 Results of final model multiple regression analysis total cost per stay as a 'dependent' outcome variable

Number = 764 Variance explained = 0.680	Unstandardised coefficients		Standardised coefficients
Predictors	B	Standard error	Beta	t	Significance
Period (before → after IMC)	-0.077	0.054	-0.087	-1.420	(0.156)^a
TISS-28 score on 1st day	0.826	0.152	0.207	5.443	(<0.001)^a
Surgical (no → yes)	0.183	0.024	0.207	7.714	<0.001
LOS in the ICU	0.025	0.001	0.688	17.307	(<0.001)^a
LOS in ward	0.016	0.002	0.616	9.940	(<0.001)^a
Primary organ failure (reference category is metabolic)
1. Metabolic → cardiovascular	0.066	0.076	0.070	0.871	0.384
2. Metabolic → multitrauma	0.129	0.080	0.088	1.603	0.109
3. Metabolic → gastrointestinal	0.143	0.086	0.064	1.667	0.096
4. Metabolic → haematological	0.324	0.125	0.066	2.589	0.010
5. Metabolic → renal	0.141	0.093	0.050	1.522	0.129
6. Metabolic → neurologic/neurosurgical	0.120	0.076	0.116	1.580	0.115
7. Metabolic → respiratory	0.152	0.075	0.145	2.022	0.044
8. Metabolic → sepsis	0.081	0.085	0.039	0.955	0.340
TISS × period	0.470	0.178	0.184	2.634	0.009
LOS in the ICU × period	-0.005	0.002	-0.135	-3.161	0.002
LOS in ward × TISS-28	-0.022	0.005	-0.289	-4.526	<0.001
Constant	3.220	0.086		37.259	<0.001

^aP values within brackets should not be taken into account as the predictors involved are also present in an interaction effect. Predictors before the arrow have a score of 0, those after the arrow have a score of 1. In the test, ¹⁰log-transformed costs were analysed. ICU, intensive care unit, IMC, intermediate care unit; LOS, length of stay, TISS-28, Therapeutic Intervention Scoring System with a median value of 28.

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