[Robustness of Hospital Benchmarking with the Hospital Standardized Mortality Ratio (HSMR): An Analysis of Secondary...

Introduction: Internationally, the hospital standardized mortality ratio is increasingly used as a risk-adjusted simple measure for quality control. Goodness of fit of different risk models in Germany and robustness of hospital comparisons were evaluated with a secondary data analysis. Methods: Anonymized routine data from the year 2012 of 37 hospitals of the association Quality Indicators for Ecclesiastical Hospitals were used. 2 independent risk models and the observed mortality were compared, the risk models considered both the original and the adapted forms. Results: The risk models showed an area under curve between 0.906 [95% CI 0.904-0.908] and 0.920 [0.918-0.922]. There was a significant correlation between the risk models and the observed mortality with a correlation coefficient between 0.388 (p<0.05) and 0.936 (p<0.01). 26 hospitals had an identical assessment in all risk models comparing their HSMR with the group. 2 hospitals achieved a positive and a negative assessment taking into account the observed mortality. Conclusion: The quality of the risk models is high and the hospital comparison with the HSMR remained stable. However, it is unclear whether the differences are caused by quality-related issues or by different structures and case-mix. Therefore, the HSMR is primarily intended for quality management purposes within German hospitals.