Development and psychometric properties of the Basic Amputee Mobility Score for use in patients with a major lower extremity amputation.

Aim: To develop and examine the psychometric properties, including responsiveness and interrater reliability, of a new outcome measure for the evaluation of basic mobility activities after a major lower extremity amputation - The Basic Amputee Mobility Score (BAMS).

Methods: The four following essential activities were chosen through consensus meetings with experienced amputee physiotherapists: (i) supine in bed to sitting on the edge of the bed; (ii) bed to wheelchair transfer; (iii) indoor wheelchair mobility; and (iv) get up from a wheelchair to standing on the non-amputated leg. Each activity is scored from 0 to 2 (0 = not able to; 1 = able to with assistance/guiding; and 2 = independent), and cumulated to a 1-day BAMS score of 0-8. Validity and responsiveness were established in 106 consecutive in-hospital patients with a major dysvascular lower extremity amputation, while reliability and agreement were examined in an additional sample of 30 patients.

Results: The 30-day mortality risk was reduced by 88% (HR = 0.12, 95% CI 0.02-0.68) for those out of bed (BAMS ≥2 points) at the first physiotherapy assessment, while BAMS scores improved between the first and the discharge assessment, with a standardized response mean of 1.3. Reliability assessments resulted in a weighted Kappa value of 0.98, a standard error of measurement of 0.32 and a minimal detectable change of 0.89 points. No systematic between-rater bias was seen (P = 0.3).

Conclusions: The BAMS was feasible in all patients, and showed a large responsiveness, excellent interrater reliability and with a change of 1 point indicating a real change in performances. Geriatr Gerontol Int 2018; 18: 138-145.