Clinically most relevant psychometric properties of the Lower Extremity Functional Scale: a systematic review

To systematically review and summarize the literature on minimal detectable change (MDC) and minimal clinically important difference (MCID) values for the Lower Extremity Functional Scale (LEFS).

The databases that were searched included PubMed, Embase, Medline, and CINAHL, from database inception to August 2023. The inclusion criteria were studies that examined the MDC or MCID of the LEFS in various patient populations and languages. The data extracted included information regarding test-retest reliability, MDC, MCID, and the intervals between assessments.

Twenty-four studies defined MDC and five studies MCID values for the LEFS. They review reported a wide range of MDC values, spanning 11 language versions and a variety of diagnoses, with testing intervals ranging from 1 day to 12 months. MCID values were defined with corresponding area under curve, specificity, and sensitivity metrics for three language versions and a variety of diagnoses across timeframes from 4 weeks to 12 months.

The review defined MDC and MCID values that can be applied in clinical practice for the LEFS across a variety of timeframes, diagnoses, and languages. The findings of this study allow clinicians use the identified MDC and MCID values of the LEFS when interpreting clinical outcome data.