Hospital standardized mortality ratio: limits and potential of the indicator for assessing hospital performance in the Brazilian Unified National Health System

Abstract

Comparative analyses based on clinical performance indicators to monitor the quality of hospital care have been carried out for decades in several countries, most notably the hospital standardized mortality ratio (HSMR). In Brazil, studies and the adoption of methodological tools that allow regular analysis of the performance of institutions are still scarce. This study aimed to assess the use of HSMR to compare the performance of hospitals funded by the Brazilian Unified National Health System (SUS). The Hospital Information System was the source of data on adult hospitalizations in Brazil from 2017 to 2019. The methodological approach to estimate HSMR was adapted to the available data and included the causes of hospitalization (main diagnosis) responsible for 80% of deaths. The number of expected deaths was estimated using a logistic regression model that included predictor variables widely described in the literature. The analysis was conducted in two stages: (i) hospitalization level and (ii) hospital level. The final risk adjustment model showed a C-statistic of 0.774, which is considered adequate. The variation in HSMR was wide, especially among the worst-performing hospitals (1.54 to 6.77). Private hospitals performed better than public hospitals. Although the limits of the available data and the challenges still face its more refined use, HSMR is applicable and has the potential to become an important tool for assessing hospital performance in the SUS.