Estimating power wheelchair battery lifespan based on real-world data

Abstract

Purpose: The purpose of this study was to: (1) estimate battery lifespan in power wheelchairs (PWCs) as measured by the length of time until battery replacement occurs and (2) identify factors associated with variability in battery lifespan after device distribution.

Materials and methods: PWCs distributed between 1 January 2016 and 31 December 2018 were retrieved from the Wheelchair Repair Registry (WRR) and included into this retrospective cohort study. Factors associated with battery lifespan were examined with the stratified Cox proportional hazard model.

Results: A data set of 1268 PWCs from four different manufacturers was analysed. Five hundred and ten PWCs (40.2%) had one battery replacement with median battery lifespan of 22.3 months. The overall cumulative incidences of battery replacement were 14.5%, 56.2% and 88.2% at the end of the first, second and third year after device distribution, respectively. Among PWC manufacturers, manufacturer C (hazard ratio (HR), 2.63; 95% confidence interval (CI), 1.35-5.12; p = 0.004) and manufacturer D (HR, 3.02; 95% CI, 1.51-6.01; p = 0.002) were associated with shorter battery lifespan. PWCs operated in warmer states (65-75 °F annual temperature averages) were associated with longer battery lifespan.

Conclusions: Results showed that the median battery lifespan was 22 months. PWC manufacturer and operating climate temperature were associated with variability in battery lifespan. This research has implications to better inform users, providers, manufacturers and payers to be more aware of battery lifespan across PWC types and manufactures to anticipate replacement timelines and avoid adverse situations associated with battery failures. Implications for rehabilitationThere are differences in battery lifespan across different power wheelchair (PWC) manufactures.Power wheelchair batteries last longer in warmer operating climates.Future attention needs to be sought towards the types of batteries manufacturers are using for PWC group classifications.These types of studies could be useful to justify reasonable timelines and the costs associated with battery replacements.

Keywords: Durable medical equipment; battery lifespan; battery replacement; power wheelchair; wheelchairs.