View Abstract

A6337 - Determining the Minimal Clinically Important Difference (MCID) for the PEmbQoL Questionnaire, A Measure of PE-Specific Quality of Life
Author Block: A. Akaberi1, F. Klok2, C. Danny3, A. Hirsch4, J. T. Granton5, S. Kahn6; 1Epidemiology, Center for Clinical Epidemiology, Lady Davis Institute, Montreal, QC, Canada, 2Department of Thrombosis and Hemostasis, Leiden University Medical Center, Leiden, Netherlands, 3Department of Vascular Medicine, Academic Medical Center, University of Amsterdam, Amsterdam, Netherlands, 4Department of Medicine, Jewish General Hospital, Montreal, QC, Canada, Montreal, QC, Canada, 5Department of Medicine, University of Toronto, Toronto, ON, Canada, 6Epidemiology, Center for Clinical Epidemiology, Lady Davis Institute, Montreal, QC, Canada.
Background: Pulmonary embolism (PE) reduces quality of life (QOL). The PEmbQoL questionnaire, a PE-related QOL measure (score ranges from 0-100), was recently developed and validated and has been used to quantify disease-specific QOL in clinical studies of patients with PE. However, to date, interpretation of PEmbQoL scores has been limited by a lack of information on the minimal clinically important difference (MCID) of this measure. Objective: To determine the MCID for PEmbQoL and its subscales using anchor-based and distribution-based statistical approaches. Methods: We analysed data from the ELOPE (Evaluation of Longterm Outcomes after PE) Study, a prospective, multicenter cohort study of longterm outcomes after PE (www.clinicaltrials.gov NCT01174628). Patients ≥18 years old with a 1st episode of acute PE diagnosed at 5 Canadian centers were potentially eligible to participate in ELOPE. At Baseline, 1, 3, 6 and 12 months after PE, we measured generic QOL (SF-36 questionnaire), PE-specific QOL (PEmbQoL), and dyspnea severity (UCSD Shortness of Breath Questionnaire [SOBQ]), and calculated within-patient changes in these measures from baseline to the remaining time points. Using SF-36 and SOBQ as anchors (for which, based on the available literature, ≥4 point change in PCS and MCS scores and ≥5 point change in SOBQ score represents one unit of MCID, respectively), we used time-varying repeated measures mixed-effect models to estimate anchor-based MCID for PEmbQoL. In sensitivity analyses, we estimated MCID 1) adjusted for age, sex and BMI; and 2) after multiple imputations for missing data. Effect sizes of changes over time were used to estimate distribution-based MCID. Results: 100 (67%) patients consented to participate. Mean age was 50 years, 57% were male, 80% were outpatients and 33% had concomitant DVT. Using both anchor- and distribution-based analytic approaches, the MCID for PEmbQoL appears to be a 15 point change (range, 10-18 points). Based on this MCID, 42%, 59%, 66%, and 75% of patients experienced at least one MCID unit of improvement in PEmbQoL from baseline to 1, 3, 6, and 12 months, respectively. Conclusion: Our results provide new, practical and important information on the MCID of PEmbQoL, a PE-specific QOL questionnaire that can be used by researchers and clinicians to measure and interpret changes in PE-specific QOL over time, or as an outcome measure in clinical trials of interventions to treat PE. The proportion of patients with at least one MCID unit of improvement in PEmbQoL increased over time, to 75% at 12 months after PE.