title: Appendectomy correlates with increased risk of pyogenic liver abscess: A population-based cohort study in Taiwan.
abstract: Little is known on the association between appendectomy and pyogenic liver abscess. The objective of this study was to investigate the association between appendectomy and the risk of pyogenic liver abscess in Taiwan.This population-based retrospective cohort study was conducted using the hospitalization dataset of the Taiwan National Health Insurance Program. There were 212,530 subjects age 20 to 84 years with newly diagnosed appendectomy as the appendectomy group since 1998 to 2010, and 850,099 randomly selected subjects without appendectomy as the nonappendectomy group. Both appendectomy and nonappendectomy groups were matched with sex, age, comorbidities, and index year of diagnosing appendectomy. The incidence of pyogenic liver abscess at the end of 2011 was estimated in both groups. The multivariable Cox proportional hazards regression model was applied to investigate the hazard ratio (HR) and 95% confidence interval (CI) for risk of pyogenic liver abscess associated with appendectomy and other comorbidities including alcoholism, biliary stone, chronic kidney disease, chronic liver diseases, and diabetes mellitus.The overall incidence of pyogenic liver abscess was 1.73-fold greater in the appendectomy group than that in the nonappendectomy group (3.85 vs 2.22 per 10,000 person-years, 95% CI 1.71, 1.76). The multivariable regression analysis disclosed that the adjusted HR of pyogenic liver abscess was 1.77 for the appendectomy group (95% CI 1.59, 1.97), when compared with the nonappendectomy group.Appendectomy is associated with increased hazard of pyogenic liver abscess. Further studies remain necessary to confirm our findings.
authors.affiliation: aCollege of Medicine, Tzu Chi University, Hualien bDepartment of Internal Medicine, Taichung Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Taichung cCollege of Medicine, China Medical University, Taichung dDepartment of Family Medicine, China Medical University Hospital, Taichung eManagement Office for Health Data, China Medical University Hospital, Taichung fDepartment of Surgery, Taichung Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Taichung, Taiwan.
authors.forename: Kuan-Fu
authors.initials: KF
authors.lastname: Liao
authors.forename: Shih-Wei
authors.initials: SW
authors.lastname: Lai
authors.forename: Cheng-Li
authors.initials: CL
authors.lastname: Lin
authors.forename: Sou-Hsin
authors.initials: SH
authors.lastname: Chien
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001062:Appendectomy / Q000009:adverse effects*; D015331:Cohort Studies; D005260:Female; D006801:Humans; D046290:Liver Abscess, Pyogenic / Q000453:epidemiology / Q000209:etiology*; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000453:epidemiology; D012189:Retrospective Studies; D018570:Risk Assessment; D013624:Taiwan; D055815:Young Adult