Establishing Clinically Significant Patient-reported Outcomes for Diverticular Disease

Diverticular disease can undermine health-related quality of life. The diverticulitis quality of life (DV-QOL) instrument was designed and validated to measure patient-reported burden of diverticular disease. However, values reflecting meaningful improvement (i.e., minimal clinically important difference [MCID]) and the patient acceptable symptom state (PASS) have yet to be established. We sought to establish the MCID and PASS of the DV-QOL and describe the characteristics of those with DV-QOL above the PASS threshold.

We performed a prospective cohort study of adults with diverticular disease from seven centers in Washington and California (2016-2018). Patients were surveyed at baseline, then quarterly up to 30 mo. To determine the MCID and PASS for DV-QOL, we applied various previously established distribution- and anchor-based approaches and compared the resulting values.

The study included 177 patients (mean age 57 y, 43% women). A PASS threshold of 3.2/10 distinguished between those with and without health-related quality of life-impacting diverticulitis with acceptable accuracy (area under the curve 0.76). A change of 2.2 points in the DV-QOL was the most appropriate MCID: above the distribution-based MCIDs and corresponding to patient perception of importance of change (AUC 0.70). Patients with DV-QOL ≥ PASS were more often men, younger, had Medicaid, had more serious episodes of diverticulitis, and had an occupational degree or high-school education or less.

Our study is the first to define MCID and PASS for DV-QOL. These thresholds are critical for measuring the impact of diverticular disease and the evaluation of treatment effectiveness.