B. T. Fry1,2, J. R. Thumma2, J. B. Dimick2,3 3University Of Michigan,Department Of Surgery,Ann Arbor, MI, USA 1University Of Michigan,Medical School,Ann Arbor, MI, USA 2University Of Michigan,Center For Healthcare Outcomes And Policy,Ann Arbor, MI, USA
Introduction: Surgical mortality has declined considerably over the last decade. While most hospitals have reduced mortality to some degree, much can be learned from how hospitals with the largest reductions achieved their improvement. Specifically, the roles of reducing complications and improving rescue from complications once they occur (known as failure to rescue or FTR) remain unclear. This study sought to understand which of these factors plays a larger role in reducing surgical mortality.
Methods: Using Medicare Provider Analysis and Review files, we performed a retrospective, longitudinal cohort study of patients who underwent abdominal aortic aneurysm (AAA) repair, pulmonary resection, colectomy, and pancreatectomy. We then calculated hospital-level risk- and reliability-adjusted rates of 30-day mortality, serious complications, and FTR for these patients in two time periods: 2005-2006 and 2013-2014 (n=699,771 patients). Serious complications were defined as the presence of one or more of eight complications plus a procedure-specific length of stay of greater than the 75th percentile. FTR was defined as death occurring in a patient with at least one serious complication. Hospitals were stratified into quintiles by change in mortality over time with average rates of 30-day mortality, serious complications, and FTR reported for each quintile. Variance partitioning was used to determine the relative contributions of differences in complication and FTR rates to the observed changes in hospital-level surgical mortality between time periods.
Results: After stratifying by reductions in mortality from 2005-2014, the top 20% of hospitals had decreased mortality rates by 3.4% (8.9 to 5.5%, p<0.001), decreased complication rates by 1.8% (15.2 to 13.4%, p<0.001), and decreased FTR rates by 7.4% (25.8 to 18.4%, p<0.001). In contrast, the bottom 20% of hospitals had actually increased mortality rates by 1.1% (6.9 to 8.0%, p<0.001), increased complication rates by 0.9% (14.6 to 15.5%, p<0.001), and increased FTR by 0.6% (22.1 to 22.7%, p<0.001). When examining the factors most associated with reductions in mortality, we found that decreased FTR explained 69% of the improvement in hospitals’ mortality rates over time, whereas decreased complication rates accounted for only 6% of this improvement.
Conclusion: Hospitals with the largest reductions in surgical mortality achieved these improvements largely through reducing FTR rates and not by reducing serious complication rates. This suggests that hospitals aiming to reduce surgical mortality should engage in efforts focused on improving rescue from serious complications.