Thirty-Day Postoperative Mortality Risk Estimates and 1-Year Survival in Veterans Health Administration Surgery Patients.

Abstract

For more than 2 decades, the Veterans Health Administration (VHA) has relied on risk-adjusted, postoperative, 30-day mortality data as a measure of surgical quality of care. Recently, the use of 30-day mortality data has been criticized based on a theory that health care professionals manage patient care to meet the metric and that other outcome metrics are available. To determine whether postoperative mortality data identify a delay in care to meet a 30-day mortality metric and to evaluate whether 30-day mortality risk score groups stratify survival patterns up to 365 days after surgery in surgical procedures assessed by the Veterans Affairs Surgical Quality Improvement Program (VASQIP). Patients undergoing VASQIP-assessed surgical procedures within the VHA from October 1, 2011, to September 30, 2013, were evaluated. Data on 365-day survival follow-up of 212 733 surgical cases using VHA Vital Status and admission records were obtained with 10 947 mortality events. Data analysis was conducted from September 3, 2014, to November 9, 2015. Survival up to 365 days after surgery for the overall cohort divided into 10 equal groups (deciles). There were 10 947 mortality events identified in a cohort of 212 733 surgical patients. The mean probability of death was 1.03% (95% CI, 1.01%-1.04%). Risk estimate groups in the 212 733 surgical cases analyzed showed significantly different postoperative survival, with consistency beyond the time frame for which they were developed. The lowest risk decile had the highest 365-day survival probability (99.74%; 95% CI, 99.66%-99.80%); the highest risk decile had the lowest 365-day survival probability (72.04%; 95% CI, 71.43%-72.64%). The 9 lowest risk deciles had linear survival curves from 0 to 365 postoperative days, with the highest risk decile having early survival risk and becoming more linear after the first 180 days. Survival curves between 25 and 35 days were consistent for all risk deciles and showed no evidence that mortality rates were affected in the immediate period beyond day 30. The setting of mortality varied by postoperative day ranges, with index hospitalization events declining and deaths outside of the hospital increasing up to 365 days. Deciles of 30-day mortality estimates are associated with significantly different survival outcomes at 365 days even after removing patients who died within the first 30 postoperative days. No evidence of delays in patient care and treatment to meet a 30-day metric were identified. These findings reinforce the usefulness of 30-day mortality risk stratification as a surrogate for long-term outcomes.