OBJECTIVES: We assessed changes in utilization of common chronic-use medications and generalized all-cause medical services and costs pre- to post-diagnosis in a real-world diverticulitis (DV) population. METHODS: Insurance claims from >40 US health plans representing ~50 million lives were retrospectively analyzed. Inclusion criteria were: primary diagnosis of colonic DV (ICD-9 562.11, 562.13) between January 1, 2005 and December 31, 2008; antibiotic within 3 days post-diagnosis; ≥12 months pre- and post-diagnosis enrollment. Use of non-GI-related medications, as well as overall all-cause utilization and costs (2009 US$), were descriptively evaluated pre- to post-diagnosis. All-cause costs were also evaluated for non-DV controls matched 2:1 on age, gender, and plan enrollment, with index date assigned as diagnosis date of each respective DV match. RESULTS: A total of 25,172 patients met all inclusion criteria (51.2% male, mean age 53 years). The top 5 most prevalent chronic-use medications during pre-index were antihyperlipidemics (30.0% of patients), antihypertensives (27.5%), antidepressants (20.9%), dermatologicals (20.0%) and beta blockers (15.7%). Post-index use of these medications increased by 8.9%, 8.2%, 7.3%, 9.1%, and 11.7%, respectively (all P<0.010). Mean all-cause hospital days and costs per patient increased significantly pre- to post-index (0.9 vs. 2.3 days, $3223 vs. $6341; all P<0.010). Other significant (P<0.010) increases pre- to post-index were seen for ER visits (0.7 vs. 1.2; $432 vs. $1012), prescriptions (22 vs. 27 fills, $1910 vs. $2081), office visits (10 vs. 12, $1747 vs. $2251), and other outpatient/specialty consultations (3 vs. 5, $2676 vs. $4288) (all P<0.010). Total all-cause costs increased by 60% post-diagnosis ($10,419 vs. $16,672; P<0.010). Minimal change occurred for controls ($6299 vs. $6493; P=0.010). CONCLUSIONS: Patients with DV have higher use of common chronic-use prescriptions after diagnosis, as well as significantly higher use and costs of general all-cause medical services. Payers should be aware of increased costs for not only disease-related services, but also other general health care.