title: Presence of coronary artery disease increases the risk of biliary events in patients with asymptomatic gallstones.
abstract: OBJECTIVE
  Propensity score indicates a probability of having a confounding factor. It is used to match each patient with the closest propensity score between two groups, which is known as propensity score matching. This study aimed to evaluate the gallstone-related biliary events, defined as biliary colic and acute cholecystitis between coronary artery disease (CAD) and non-CAD patients using propensity score matching.
  
  
  METHODS
  This retrospective cohort study evaluated 267 asymptomatic gallstone patients with CAD and 459 asymptomatic gallstone patients without CAD from March 2003 to December 2009 at two tertiary teaching hospitals in the Republic of Korea. After propensity score matching, total 378 patients, including 126 in study group (with CAD) and 252 in control group (without CAD), were evaluated.
  
  
  RESULTS
  During a median follow-up of 47 months, overall gallstone-related biliary event rate was 33.5% in the study group and 27.5% in the control group. The 5-year cumulative rates were 25.3% versus 17.7% in gallstone-related biliary event and 10.9% versus 1.6% in acute cholecystitis (study versus control group). After propensity score adjustment, the risk of gallstone-related biliary events in the CAD patients significantly increased (hazard ratio 2.11, 95% confidence interval 1.14-3.90, P = 0.017 in matched patients).
  
  
  CONCLUSIONS
  In patients with asymptomatic gallstones, the coexistence of CAD can increase the risk of gallstone-related biliary events, particularly acute cholecystitis. Therefore, gallstone patients with CAD should be carefully monitored, even if they are asymptomatic.
authors.affiliation: Department of Internal Medicine, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seoungnam-si, Gyeonggi-do, Republic of Korea.
authors.forename: Yoon Suk
authors.initials: YS
authors.lastname: Lee
authors.forename: Sang Eon
authors.initials: SE
authors.lastname: Jang
authors.forename: Ban Seok
authors.initials: BS
authors.lastname: Lee
authors.forename: Seung-June
authors.initials: SJ
authors.lastname: Lee
authors.forename: Min Geun
authors.initials: MG
authors.lastname: Lee
authors.forename: Joo Kyung
authors.initials: JK
authors.lastname: Park
authors.forename: Sang Hyub
authors.initials: SH
authors.lastname: Lee
authors.forename: Ji Kon
authors.initials: JK
authors.lastname: Ryu
authors.forename: Yong-Tae
authors.initials: YT
authors.lastname: Kim
authors.forename: Yong Bum
authors.initials: YB
authors.lastname: Yoon
authors.forename: Jin-Hyeok
authors.initials: JH
authors.lastname: Hwang
mesh_terms: D000328:Adult; D000368:Aged; D001660:Biliary Tract Diseases / Q000453:epidemiology / Q000209:etiology; D041881:Cholecystitis, Acute / Q000453:epidemiology / Q000209:etiology*; D003085:Colic / Q000453:epidemiology / Q000209:etiology*; D003324:Coronary Artery Disease / Q000150:complications* / Q000453:epidemiology; D005260:Female; D042882:Gallstones / Q000150:complications* / Q000453:epidemiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D057216:Propensity Score; D056910:Republic of Korea / Q000453:epidemiology; D012189:Retrospective Studies; D018570:Risk Assessment / Q000379:methods; D012720:Severity of Illness Index
keywords: coronary artery disease; gallstones; propensity score