Determining the minimal clinically important difference for the PEmbQoL questionnaire, a measure of pulmonary embolism‐specific quality of life

Essentials The minimal clinically important difference (MCID) for PEmbQoL has not yet been determined. We estimated the MCID for PEmbQoL and its subscales via anchor- and distribution-based approaches. Our results indicate that MCID for PEmbQoL appears to be 15 points. Our work enables interpretation of changes or differences in PEmbQoL. Summary: Background Pulmonary embolism (PE) reduces quality of life (QOL). The PEmbQoL questionnaire, a PE-related QOL measure, 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 approaches. Methods We analyzed data from the ELOPE Study, a prospective, multicenter cohort study of long-term outcomes after a first episode of acute PE. At baseline and 1, 3, 6 and 12 months after PE, we measured generic QOL (SF-36), PE-specific QOL (PEmbQoL) and dyspnea severity (UCSD Shortness of Breath Questionnaire). We used time-varying repeated-measures mixed-effect models to estimate anchor-based MCID and effect sizes to estimate distribution-based MCID. Results Eighty-two patients participated in this sub-study. Their mean age was 49.4 years, 60% were male and 84% had PE diagnosed in an outpatient setting. Using both anchor- and distribution-based approaches, the MCID for PEmbQoL appears to be 15 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 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 in clinical trials.