Resource-rich Intensive Care Units vs. Standard Intensive Care Units on Patient Mortality: A Nationwide Inpatient Database Study

INTRODUCTION: In this present study, we aimed to assess whether care in resource-rich intensive care unit (ICU) was associated with lower ICU mortality compared with care in standard ICU. METHODS: This retrospective cohort study used administrative data that are routinely collected in Japan. Using the Japanese Diagnosis Procedure Combination inpatient database, we identified patients aged >15 years who were admitted to the ICU from April 2016 to March 2019. We defined resource-rich ICUs as ICUs with two or more intensivists as full-time employees, ≥20 m(2) per ICU bed, and a medical engineer in the hospital 24 hours per day; other ICUs were categorized as standard ICUs. The primary outcome was ICU mortality. A generalized estimating equation approach with ICUs as the clusters was used to compare ICU mortality between the two groups. RESULTS: Of the 789,630 eligible patients from 458 ICUs, 237,138 (30%) were treated in the 111 resource-rich ICUs, whereas 552,492 (70%) were treated in the 347 standard ICUs. The crude ICU mortality rate was 3.6% (8443/237,138) among patients admitted to resource-rich ICUs, while it was 4.3% (23,490/552,492) among those admitted to standard ICUs. The results of the generalized estimating equation analysis showed that patients treated in resource-rich ICUs tended to have lower ICU mortality compared to patients treated in standard ICUs (difference, −0.4%; 95% confidence interval, −0.8%-0.0%). CONCLUSIONS: The findings of this nationwide study suggest that, compared with care in standard ICUs, care in resource-rich ICUs is associated with lower ICU mortality. This study showed the overall effect of treatment in hospitals with resource-rich ICUs including intensivist staffing and greater hospital resources. Further studies are required to assess the effects of organizational factors on mortality.