Establishing Clinically Significant Patient-reported Outcomes for Diverticular Disease: A Prospective Cohort Study

Background & Aims: Diverticular disease can undermine health-related quality of life (HRQoL). The diverticulitis quality of life (DV-QOL) instrument was designed and validated to measure the patient-reported burden of diverticular disease. However, in order for the DV-QOL to capture longitudinal outcomes, values reflecting meaningful improvement (i.e., minimal clinically important difference (MCID)) and the patient acceptable symptom state (PASS) need 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. Methods: We performed a prospective cohort study of adults with diverticular disease from 7 centers in Washington and California (2016-2018). Patients were surveyed at baseline, then quarterly up to 30 months. To determine the PASS for DV-QOL, we used an anchor-based approach and performed receiver operating characteristic analyses using baseline data. A range of MCID values were calculated using distribution-based and anchor-based approaches. Results: The study included 177 patients (mean age 57, 43% female). A PASS threshold of 3.2/10 distinguished between those with and without HRQoL-impacting diverticulitis with acceptable accuracy (area under the curve (AUC) 0.76). A change of 2.2 points in the DV-QOL was the most appropriate MCID: above the measurement error and corresponding to patient perception of importance of change (AUC 0.70). Patients with DV-QOL[≥]PASS were more often male, younger, had Medicaid, less educated, and had more serious episodes of diverticulitis. Conclusion: 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.