Complex gastrointestinal surgery: Impact of provider experience on clinical and economic outcomes

Background: Commonly performed elective gastrointestinal surgical procedure s are carried out with low morbidity and mortality in hospitals throughout the United States. Complex operative procedures on the alimentary tract are performed with a relatively low frequency and are associated with higher m ortality. Volume and experience of the surgical provider team have been cor related with better clinical and economic outcomes for one complex gastroin testinal surgical procedure, pancreaticoduodenectomy. This study evaluated whether provider volume and experience were important factors influencing c linical and economic outcomes for a variety of complex gastrointestinal sur gical procedures in one state. Study Design: Complex high-risk gastrointestinal surgical procedures were d efined as those with statewide in hospital mortality of greater than or equ al to 5%, frequency of greater than 200 per year in the state, and requirin g special surgical skill and expertise. Six procedures met these criteria. Using publicly available discharge data, all patients discharged from Maryl and hospitals from July 1989 to June 1997 with a primary procedure code for one of the six study procedures were selected. Hospitals were classified into one of six groups based on the average numbe r of study procedures per year: 10 or less; 11 to 20; 21 to 50; 51 to 100; 101 to 200; and 201 or more procedures per year. A hospital was included if at least one procedure was performed there during the study period. No pro viders fell within the 51 to 100, and 101 to 200 groups, so all analyses we re performed for the remaining four volume groups that were classified, res pectively, as minimal (10 or fewer procedures), low (11 to 20 procedures), medium (21 to 50 procedures)., and high-volume groups (201 or more procedur es). Poisson regression was used to assess the relationship between in-hosp ital mortality and hospital volume after casemix adjustment. Multiple linea r regression models were used to assess differences in average length-of-st ay and average total hospital charges among hospital volume groups. We furt her analyzed mortality, length-of-stay and charges at the procedural level to understand these subgroups of complex gastrointestinal patients. Wk also examined the relationship between provider volume and outcomes for maligna nt versus benign diagnosis groups. Results: Complex gastrointestinal surgical procedures were performed on 4,5 61 patients in Maryland from July 1989 through June 1997. The study populat ion averaged 61.6 years of age, was 55% male, 71% Caucasian, and had predom inantly Medicare as a payment source. After casemix adjustment, patients wh o underwent complex gastrointestinal surgical procedures at the medium-, lo w-, and minimal-volume provider groups had a 2.1, 3.3, and 3.2 times greate r risk of in-hospital death, respectively, than patients at the high-volume provider (p < 0.001 for all comparisons); longer lengths-of-stay, 16.1, 15 .7, and 15.5 days at the low-, medium-, and minimal-volume groups, respecti vely, versus 14.0 days for the high-volume provider (p < 0.001 for all comp arisons). Similarly adjusted charges at the high-volume provider were, on a verage, 14% less than those of the low-volume group, which had the next low est charges. Although mortality rates differed by procedure type, for each procedure, mortality increased as provider volume decreased, following the pattern found in the aggregate analysis. After casemix adjustment, the risk of in-hospital death for patients with malignant diagnoses was significant ly higher for the medium-, low-, and minimal-volume groups compared with pa tients at the high-volume provider, relative risk of 3.1, 4.0, and 4.2, res pectively, (p < 0.001 for all comparisons). Conclusions: This study demonstrates that increased hospital experience is associated with a marked decrease in hospital mortality. The decreased mort ality at the high-volume provider was also associated with shorter lengths- of-stay and lower hospital charges. These findings were more pronounced for malignant diagnoses than for benign conditions. Characteristics of the hig h-volume provider thought to contribute to improved outcomes include overal l experience level of the physicians and staff; specialized staff, faciliti es, and equipment in the operating rooms and intensive care units; and the use of critical pathways and detailed care management plans. (J Am Cell Sur g 1999;189:46-56 (C) 1999 by the American College of Surgeons).