title: Long-term outcome of patients with acute cholecystitis receiving antibiotic treatment: a retrospective cohort study.
abstract: BACKGROUND
  Few studies have followed patients who received antibiotic treatment for acute cholecystitis (AC). The present retrospective study investigated recurrence rates of AC and analyzed factors associated with recurrence after antibiotic treatment in adult AC patients.
  
  
  METHODS
  We analyzed patients treated with antibiotics for AC between October 1, 2004, and November 30, 2010. A Cox proportional hazards model was used to identify factors associated with early recurrence. Generalized additive models were applied to detect the nonlinear effects of continuous covariates.
  
  
  RESULTS
  The study included 226 patients (mean age: 62.2 years; 144 men [63.7 %]). The average duration of parenteral antibiotics was 8.0 days. Second-generation cephalosporins were administered to 199 patients (88.1 %). The Kaplan-Meier plot indicated that recurrences were more frequent within 100 days of AC; these were defined as early recurrences. The recurrence rate was 13.7 % (31/226) at a median follow-up of 308.5 days (early recurrences: 19/226 [8.4 %]). The duration of parenteral antibiotic use significantly correlated with early recurrence (hazard ratio: 0.83; 95 % confidence interval, 0.73-0.95; p = 0.005). Generalized additive models revealed that patients using parenteral antibiotics longer than 8 days were less likely to suffer from early recurrence.
  
  
  CONCLUSIONS
  The rate of recurrence of AC in patients who received antibiotics alone was low. The recurrence rate was higher within 100 days of AC. Because of the inherent limitations of a retrospective study, further research is needed to identify factors associated with early recurrence.
authors.affiliation: Department of Emergency Medicine, National Taiwan University and National Taiwan University Hospital, No. 7, Chung-Shan S. Road, Taipei, 100, Taiwan.
authors.forename: Chih-Hung
authors.initials: CH
authors.lastname: Wang
authors.forename: Hao-Chang
authors.initials: HC
authors.lastname: Chou
authors.forename: Kao-Lang
authors.initials: KL
authors.lastname: Liu
authors.forename: Wan-Ching
authors.initials: WC
authors.lastname: Lien
authors.forename: Hsiu-Po
authors.initials: HP
authors.lastname: Wang
authors.forename: Yao-Ming
authors.initials: YM
authors.lastname: Wu
mesh_terms: D000208:Acute Disease; D000368:Aged; D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D002764:Cholecystitis / Q000188:drug therapy*; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012008:Recurrence; D012189:Retrospective Studies; D016896:Treatment Outcome
chemical_list: D000900:Anti-Bacterial Agents