title: Outpatient diverticulitis: mild or myth?
abstract: BACKGROUND
  Diverticulitis is considered common in the outpatient population, with mild variants of described diagnostic criteria: left lower quadrant pain, fever, and leukocytosis. Here, expected criteria utilization among outpatients with a possible diagnosis of diverticulitis is assessed.
  
  
  METHODS
  Primary care acute clinic visits in 2008 for diverticulitis (ICD-9 562.11/562.13) or left lower quadrant pain (789.04) were identified among patients ≥ 40 years old. Encounters were reviewed through structured manual chart abstraction and evaluated for diagnostic accuracy compared to expected criteria. Analysis included inter-rater reliability (kappa tests) and descriptive frequencies by diagnosis code and diverticulitis rating (χ (2) tests).
  
  
  RESULTS
  A total of 376 acute visits were identified with codes for diverticulitis (n=97) or left lower quadrant pain (n=279). High inter-rater reliability was demonstrated for key clinical variables (kappa=0.84-1.0). Left lower quadrant pain was reported in >75% of patients, while temperature and white blood cell count data were frequently unavailable. Lack of these expected criteria resulted in low diagnostic accuracy ratings ("No/unlikely"-53.6% diverticulitis, 88.2% left lower quadrant pain, p<0.001).
  
  
  CONCLUSIONS
  This investigation raises concern for low accuracy in the outpatient diagnosis of diverticulitis due to inconsistent use of expected criteria, suggesting a smaller population with true diverticulitis than previously anticipated, or lack of criteria applicability in this setting.
authors.affiliation: Department of Surgery, University of Wisconsin School of Medicine and Public Health, K4/734 Clinical Science Center, 600 Highland Avenue, Madison, WI 53792-3236, USA.
authors.forename: Erin S
authors.initials: ES
authors.lastname: O'Connor
authors.forename: Maureen A
authors.initials: MA
authors.lastname: Smith
authors.forename: Charles P
authors.initials: CP
authors.lastname: Heise
mesh_terms: D015746:Abdominal Pain / Q000209:etiology; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000553:Ambulatory Care / Q000592:standards / Q000706:statistics & numerical data*; D004239:Diverticulitis, Colonic / Q000150:complications / Q000175:diagnosis*; D005260:Female; D005334:Fever / Q000209:etiology; D019983:Guideline Adherence / Q000706:statistics & numerical data*; D006801:Humans; D007964:Leukocytosis / Q000209:etiology; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D017410:Practice Guidelines as Topic; D010818:Practice Patterns, Physicians' / Q000592:standards / Q000706:statistics & numerical data*; D014922:Wisconsin