Mortality after esophagectomy is related more to patient factors than to the volume of procedures performed annually at any given hospital, or even by an individual surgeon, according to an analysis of data extracted from the Nationwide Inpatient Sample.
The study, conducted by Dr. Michael Rodgers and his colleagues at the Oregon Health and Science University in Portland, points up the difficulty of using volume thresholds to choose the best facility or surgeon to perform an esophagectomy.
The average adjusted mortality rate difference between the high- and low-volume hospitals was less than 1%, and the difference between the high- and low-volume surgeons was 3.5% (Arch. Surg. 2007;142:829–38).
Their study group comprised 3,243 esophagectomies performed from 1988 through 2000. The average national inpatient mortality rate was 11%, with a high of 14% in 1988 and low of 8.4% by 1999.
Although there was no significant trend over time, the mortality rate averaged 10% in the last 5 years of the study.
Mortality was significantly associated with gender, age, and race. Women were 1.5 times more likely to die, while blacks and patients older than 65 years faced a doubling of the risk.
Peripheral vascular disease significantly increased the risk of death.
Other comorbidities, including obesity, valvular heart disease, diabetes, and chronic pulmonary disease, were not significantly associated with an increased risk.
Hypertension appeared to be protective, but the authors believed that could be caused by coding issues, and therefore might not be not a real effect.
Mortality rates were similar at urban and rural hospitals and, in the multivariate analysis, teaching hospitals held no mortality advantage over nonteaching facilities.
Hospital volume was initially highly significantly associated with mortality, but that association disappeared when surgeon volume was factored into the analysis.
Surgeons who performed the most procedures had significantly lower patient mortality rates than did surgeons with lower volume; that difference remained significant even after overall hospital volume was factored in to the analysis.
However, the authors noted, the difference in mortality rates between surgeon groups was not great: Average inpatient mortality was 9.25% for high-volume surgeons (six or more cases per year), 7.5% for medium-volume surgeons (two to six cases per year), and 12.75% for low-volume surgeons (fewer than two cases per year).
Because of the wide scatter in each category, picking the best surgeon or hospital based on volume wouldn't work, the authors said.
“This is highlighted by the fact that one hospital with a caseload of more than 13 per year had a mortality rate of 25%, and one surgeon with caseload of more than 6 per year had a mortality rate of 40%. Choosing those particular providers on the basis of volume might well be a mistake,” they noted.
A better alternative, they suggested, would be a national system of outcome benchmarks. “A benchmark-based system simply sets clear guidelines and allows institutions and surgeons to find their own means to achieve them,” the investigators wrote. “In the medium term, it would also reassure patients that the institution they were going to had satisfactory and verified outcomes for that procedure.”