Background & Aims: Diverticulitis is often diagnosed in outpatients, yet little evidence exists on diagnostic evidence and demographic/clinical features in various practice settings. We assessed variation in clinical characteristics and diagnostic evidence in inpatients, outpatients, and emergency department cases and effects of demographic and clinical variables on presentation features.

 In a retrospective cohort study of 1749 patients in an integrated health care system, we compared presenting features and computed tomography findings by practice setting and assessed independent effects of demographic and clinical factors on presenting features.

 Inpatients were older and more often underweight/normal weight and lacked a diverticulitis past history and had more comorbidities than other patients. Outpatients were most often Hispanic/Latino. The classical triad (abdominal pain, fever, leukocytosis) occurred in 78 (38.6%) inpatients, 29 (5.2%) outpatients and 34 (10.7%) emergency department cases. Computed tomography was performed on 196 (94.4%) inpatients, 110 (9.2%) outpatients and 296 (87.6%) emergency department cases and was diagnostic in 153 (78.6%) inpatients, 62 (56.4%) outpatients and 243 (82.1%) emergency department cases. Multiple variables affected presenting features. Notably, female sex had lower odds for the presence of the triad features (odds ratio [95% CI], 0.65 [0.45-0.94], P<0.05) and increased odds of vomiting (1.78 [1.26-2.53], P<0.01). Patients in age group 56 to 65 and 66 or older had decreased odds of fever (0.67 [0.46-0.98], P<0.05) and 0.46 [0.26-0.81], P<0.01), respectively, while ≥1 co-morbidity increased the odds of observing the triad (1.88 [1.26-2.81], P<0.01).

There was little objective evidence for physician-diagnosed diverticulitis in most outpatients. Demographic and clinical characteristics vary among settings and independently affect presenting features.

Abbreviations: AD: acute colonic diverticulitis; BMI: body mass index; CT: computed tomography; ED: emergency department; IBS: irritable bowel syndrome; ICD-9-CM: International Classification of Diseases, 9th Revision, Clinical Modification; IP: inpatient; KPSC: Kaiser Permanente Southern California; OP: outpatient.


diverticulitis, abdominal pain, irritable bowel syndrome, fever, leukocytosis, practice setting