The moderating role of the case-mix index in the relationship between medical staff allocation and average cost per inpatient visit

TL;DR

This study shows that the Case-Mix Index (CMI) influences how medical staff allocation affects inpatient visit costs, with higher CMI amplifying these effects.

Contribution

The study identifies CMI as a moderator in the relationship between medical staff allocation and inpatient costs.

Findings

Higher CMI strengthens the negative impact of beds per doctor or nurse on inpatient costs.

Rational CMI benchmarks can help reduce the influence of staff allocation on rising medical expenditures.

Medical staff allocation and CMI are key factors in controlling inpatient visit costs.

Abstract

Greater medical staff allocation and higher Case-Mix Index (CMI) values are both associated with increased patient medical expenditures. However, it remains unclear whether CMI moderates the relationship between medical staff allocation and medical expenditures. The present study focus on whether medical staff allocation predicts the cost per inpatient visit, whether this association is enhanced under conditions of high CMI.

To explore the mechanism underlying the role of the CMI in the relationship between medical staff allocation and the average cost per inpatient visit.

Data were collected from 207 general hospitals in Hubei Province in 2019 using the cluster sampling method. Pearson’s correlations were used to examine the associations between medical staff allocation, the CMI and the cost per inpatient visit. The moderating role of the CMI between medical staff allocation and the average cost per inpatient visit was analyzed using Model 1 of the PROCESS macro.

The number of patients per doctor (r = −0.180, p < 0.01), beds per nurse (r = −0.181, p < 0.01), beds per doctor (r = −0.225, p < 0.01) and the average cost per inpatient visit showed a significant negative correlation. The CMI positively moderated the relationship between the average cost per inpatient visit and both the number of beds per doctor (p < 0.01) and the number of beds per nurse (p < 0.01). The moderating effect was stronger when hospitals had high CMI value influencing average cost per inpatient visit.

CMI value can enhance the negative effects of the number of beds per doctor or nurse on average cost per inpatient visit, revealing that rational CMI benchmark for the hospital or prioritizing disease categories with clinically appropriate treatment complexity can mitigate the extent to which healthcare workforce allocation influences rising medical expenditures. Reasonable medical staff allocation and the CMI serve as important factors in controlling the average cost per inpatient visit.

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