Risk Factors Of Post-Operative Pneumonia In Elderly Patients With Gastric Cancer: A Retrospective Cohort Study

Background: Post-operative pneumonia is a major complication after general elective surgery in elderly patients and is often caused by aspiration associated with oesophageal reflux. The aim of this study was to identify the risk factors of post-operative pneumonia after gastrectomy in elderly patients with gastric cancer with two potential risk factors of ageing and oesophageal reflux.Methods: We retrospectively examined the data of 251 patients >= 75 years old who underwent gastrectomy between January 2014 and December 2018 in our institution. The reconstruction methods were Billroth-I or Roux-Y after distal gastrectomy, jejunal interposition or double tract after proximal gastrectomy and Roux-Y after total gastrectomy. The severity of pneumonia was evaluated by the Clavien-Dindo classification.Results: Post-operative pneumonia was identified in 15 patients (5.9%) and was significantly associated with an age >= 80 years old, poor performance status, history of smoking and cardia-non-preserving gastrectomy (total gastrectomy and proximal gastrectomy) in univariate analyses. Multivariate analyses showed that a poor performance status and cardia-non-preserving gastrectomy were independent risk factors for post-operative pneumonia. The patients who suffered post-operative pneumonia required a longer hospital stay than those without post-operative pneumonia (P = 0.002).Conclusion: We identified a poor performance status and cardia-non-preserving gastrectomy, which are likely to lead to oesophageal reflux, as risk factors for post-operative pneumonia in elderly patients with gastric cancer. These results warrant further prospective studies to evaluate their utility for reducing the rate of post-operative pneumonia in elderly patients through cardia-preserving gastrectomy or anti-reflux reconstruction.