Table 6.

Two-level hierarchical model results

Explaining variables	Dependent variable
	Log (LOS)	Log (expense)	Log (LOS)	Log (expense)
	−1	−2	−3	−4
Complex wounds (vs NO)	0.39***	0.47***
	−0.01	−0.01
Wounds type (vs patients without complex wounds)
Pressure ulcers			0.23***	0.48***
			−0.01	−0.01
Diabetic ulcers			0.18***	0.19***
			−0.01	−0.01
Venous leg ulcers			0.27***	0.14**
			−0.04	−0.04
Non-healing surgical wounds			0.94***	0.81***
			−0.01	−0.01
Other ulcers			0.38***	0.33***
			−0.02	−0.02
Observations†	4 021 677	4 021 677	4 021 677	4 021 677

Cells contain coefficient (and SE). **p<0.01, ***p<0.001. All models had adjusted for patient’s age (continuous, years), gender (male, female or missing), occupation (11 categories: civil servants and active army, professionals and technical, office clerk and manager, worker, agricultural labourer, student, freelancer, self-employed, unemployed, retired, others), social insurance programme (4 categories: Urban Employee Basic Medical Insurance, Urban Resident Basic Medical Insurance, New Rural Cooperative System), whether or not surgery was required (yes or no), Charlson Index (continuous, adjusting for comorbidity), healthcare institution level (6 categories: primary hospitals, secondary hospitals, tertiary hospitals, unassigned hospitals, primary healthcare sectors, other providers) and ownership type (public or private). The full results were displayed in online supplemental appendix table A2.

†Only patients whose principal cause of hospitalisation was not complex wound were selected to fit the two-level hierarchical models.

LOS, length of stay.