The impact of ICU bed capacity optimization strategy on the average length of hospital stay and cost following the open policy of COVID-19 in China: a differences-in-differences model analysis

<bold>Objectives:</bold> Following China's open policy for COVID-19, the influx of patients with infectious diseases has surged rapidly, necessitating hospitals to adopt temporary requisition and modification of ward beds to optimize hospital bed capacity and alleviate the burden of overcrowded patients. This study aims to investigate the effect of the ICU bed capacity optimization method on the average length of hospital stay (LOS) and cost after the open policy of COVID-19 in China. <bold>Methods:</bold> A differences-in-differences (DID) approach is employed to analyze and compare the LOS and cost in 4 modified ICUs and 8 non-modified ICUs within a tertiary hospital located in southwest China using data from the HIS system for a total of 5944 patients during the two-month periods before and after the release of the open policy in China. <bold>Results:</bold> Significant reduction in LOS (HR -0.67, 95% CI -1.033 to -0.320, p<0.001) and cost (HR -0.234, 95% CI -0.474 to -0.007, p=0.017) among ICU patients after the open policy was found. These results are robust across various sensitivity analyses. However, the effect of the optimization method exhibits heterogeneity among patients admitted through the outpatient and emergency channels. <bold>Conclusions:</bold> This study corroborates the significant positive impact of ICU bed optimization in mitigating the shortage of medical resources following an epidemic outbreak, which contributes to the advancement of resource management practices and the promotion of experiences in dealing with public health emergencies.