A Population-Based Outcomes Analysis of the Impact of Age on Morbidity and Mortality Following Gastrectomy: An Analysis of 13,799 Patients from the Nationwide Inpatient Sample Database

Abstract

Introduction: Gastric cancer is the 4 th most common malignancy and second leading cause of cancer-related death worldwide, both its incidence and mortality have decreased over the past 70 years. Advancing life expectancy, as well as subtle change in the type and location of gastric cancer in the US, has resulted in an increased number of elderly patients requiring gastric surgery. By 2050, the population older than 85 years is projected to reach 20.9 million, and as a result , the need to assess the operative outcomes and mortality following gastrectomy in this group is imperative. This study sought to assess age-related clinical outcomes following gastric cancer surgery across all age groups to provide more precise data for pre-operative surgical risk stratification. Methods: Discharge data on 40,276,240 patients was collected from Nationwide Inpatient Sample Database (NIS) (2004-2008). Data on patients undergoing gastrectomy as the primary procedure was analyzed including age, gender, elective/non-elective admission, pre-operative length of stay (LOS), total LOS, and mortality. Eight age groups were compared for two procedures : total gastrectomy (TG) and partial gastrectomy (PG). Categorical data was compared using the Chi square test and continuous data using the Student’s t test. Univariate analysis and multivariate regression analysis were performed to assess independent variables. Results: 13,799 patients underwent gastrectomy surgery with 23.7% having TG and 76.3% PG. Gastric carcinoma was the most common indication for TG, while benign gastric disease was more common for PG, especially in years 51 - 70 ( p < 0.001).The mean age for TG and PG groups were 63 ± 12.8 and 64 ± 15 years respectively. Males underwent twice the number of TGs ( p < 0.001), whereas equal number of males and females underwent PG ( p < 0.001). The number of TGs increased over the 5-year study period, with the highest % change noted in those 41 - 50 years (1500%). PGs performed decreased overall, especially in patients <60 years, however PGs increased in patients >81 years with the greatest % change in the oldest patients >91 years (13%). Non-elective admissions were more common for PGs (N = 4844, 41%) than TGs (N = 695, 21.2%). Mean pre-operative LOS and total LOS increased with advancing age for both TG and PG ( p < 0.001). HTN (45%), electrolyte imbalances (28%) and chronic pulmonary disease (18%) were the most prevalent co-morbidities and significantly affected mortality on univariate analysis ( p = 0.001). Respiratory (18%) and GI complications (11%) were the most common post-operative complications following TG, while GI (9.6%) and bile duct fistulas (7.2%) were most common after PG. Overall TG and PG mortality rates were 7.6% and 6.4% respectively. Mortality increased with advancing age in both groups ( p < 0.001). Multivariate analysis identified HTN, valvular disease, anemia, malignancy and non-elective admissions as independent predictors of mortality ( p = 0.001). Conclusions: A dvancing age is not an independent predictor of mortality following gastric surgery. Gastrectomy for gastric cancer is associated with a higher mortality than for benign gastric diseases. Non-elective admission, and pre-existing hypertension, valvular disease and anemia independently predicted increased morbidity and mortality following gastric surgery and should be carefully considered in surgical planning and counseling. Gastric carcinoma is the most common indication for TG, while benign gastric disease is a more common indication for PG. The number of TGs performed is increasing, especially in the males and younger patients, and may reflect an increased incidence of body and cardiac lesions.