Validity and significance of 30-day mortality rate as a quality indicator for gastrointestinal cancer surgeries.

Background and Aim: Benchmarking has proven beneficial in improving the quality of surgery. Mortality rate is an objective indicator, of which the 30-day mortality rate is the most widely used. However, as a result of recent advances in medical care, the 30-day mortality rate may not cover overall surgery-related mortalities. We examined the significance and validity of the 30-day mortality rate as a quality indicator.

Methods: The present study was conducted on cancer surgeries of esophagectomy, total gastrectomy, distal gastrectomy, right hemicolectomy, low anterior resection, hepatectomy, and pancreaticoduodenectomy that were registered in the first halves of 2012, 2013 and 2014 in a Japanese nationwide large-scale database. This study examined the mortality curve for each surgical procedure, "sensitivity of surgery-related death" (capture ratio) at each time point between days 30-180, and the association between mortality within 30 days, mortality after 31 days, and preoperative, perioperative, and postoperative factors.

Results: Surgery-related mortality rates of each surgical procedure were 0.6%-3.0%. Regarding 30-day mortality rates, only 38.7% (esophagectomy) to 53.3% (right hemicolectomy) of surgery-related mortalities were captured. The capture ratio of surgery-related deaths reached 90% or higher for 120-day to 150-day mortality rates. Factors associated with mortality rate within 30 days/after the 31st day were different, depending on the type of surgical procedure.

Conclusion: Thirty-day mortality rate is useful as a quality indicator, but is not necessarily sufficient for all surgical procedures. Quality of surgery may require evaluation by combining 30-day mortality rates with other indicators, depending on the surgical procedure.