Lower Mortality for Abdominal Aortic Aneurysm Repair in High-Volume Hospitals Is Contingent upon Nurse Staffing

Objective To determine whether and to what extent the lower mortality rates for patients undergoing abdominal aortic aneurysm (AAA) repair in high-volume hospitals is explained by better nursing. Data Sources State hospital discharge data, Multi-State Nursing Care and Patient Safety Survey, and hospital characteristics from the AHA Annual Survey. Study Design Cross-sectional analysis of linked patient outcomes for individuals undergoing AAA repair in four states. Data Collection Secondary data sources. Principal Findings Favorable nursing practice environments and higher hospital volumes of AAA repair are associated with lower mortality and fewer failures-to-rescue in main-effects models. Furthermore, nurse staffing interacts with volume such that there is no mortality advantage observed in high-volume hospitals with poor nurse staffing. When hospitals have good nurse staffing, patients in low-volume hospitals are 3.4 times as likely to die and 2.6 times as likely to die from complications as patients in high-volume hospitals (p<.001). Conclusions Nursing is part of the explanation for lower mortality after AAA repair in high-volume hospitals. Importantly, lower mortality is not found in high-volume hospitals if nurse staffing is poor.