PURPOSE: The purpose of this study was to assess the all-cause resource utilization and health care costs of patients diagnosed with diverticulitis and to compare them to a matched control population.
METHODS: Medical claims data from the Ingenix IMPACT Managed Care database between 2005 and 2008 were analyzed. The database included medical, hospital discharge, and pharmacy claims. Patients with a primary diagnosis of diverticulitis followed by acute antibiotic treatment were identified (n=36,636). A control group (2:1) without a diagnosis of diverticulitis and matching age (+/- 3 years), gender, and dates of health plan enrollment was identifi ed from the same database (n=73,272). Patients’ first observed diverticulitis diagnosis defined their index date. The index date for controls was assigned as the index date of their respective match from the diverticulitis group. Minimum follow-up was 12 months for both groups (defined by continuous health plan enrollment) and all outcomes were evaluated over 12 months post-index. Generalized linear models with a log-link function and gamma distribution were used to estimate health care costs. Negative binomial regression models were used to estimate resource utilization (eg, count data on number of hospitalizations, medical visits, etc.). Nonparametric t-tests were used to assess differences in cost and resource utilization data between the diverticulitis and control groups. Cost data were adjusted to 2009 dollars.
RESULTS: Rates of resource utilization and health care costs were significantly higher for patients with diverticulitis compared to the control group. Specifically, for diverticulitis patients the rates of hospitalization, ER visit, and office visits were 8-fold (Incidence Rate Ratio (IRR)= 8.1), 4 fold (IRR=3.7), and 2 fold (IRR=2.3) higher than the control group, respectively; all P<0.001. Due to higher resource utilization, adjusted mean total annual health care costs were substantially higher in diverticulitis cases ($16,933 vs. $7,028; P<0.0001). The major drivers for the cost difference were hospitalizations ($6,554 vs. $1,374; P<0.0001), ER ($1,022 vs. $120; P<0.0001), outpatient/ancillary costs ($4,289 vs. $2,168; P<0.0001), and office visits ($2,280 vs. $1,420; P<0.0001).
CONCLUSION: Patients with a diagnosis of diverticulitis are costly. The economic burden is therefore significant to payers, with 12-month all-cause costs 2.6 times higher than patients without diverticulitis. There is a need for newer therapies that improve health outcomes and lower the burden of this disease by preventing recurrences of the disorder.
