Measuring patient disability in the peri‐operative period using the WHODAS 2.0 questionnaire: a systematic review

INTRODUCTION: The World Health Organization Disability Assessment Schedule 2.0 (WHODAS 2.0) is recommended by peri-operative core outcome sets as a measure of disability. Despite its growing use, the effect of different surgical procedures on disability measured by WHODAS 2.0 remains poorly understood and heterogeneous reporting across studies limits direct comparison. METHODS: We conducted a systematic review to assess the effect of different surgical procedures on disability measured by WHODAS 2.0, and the reporting of disability endpoints in peri-operative medicine. The primary outcome was the difference in WHODAS 2.0 summary score before and after surgery. Disability scores were calculated as a metric between 0% (no disability) and 100% (complete disability). RESULTS: Thirty-nine studies were included. Pre-operative disability ranged from 2% to 61%. In 21 studies, disability increased by 1% to 17% within 3 months of surgery, with little change between 6 and 12 months (0% to -2%). Studies of orthopaedic surgery generally reported high pre-operative disability (> 35%) but also reductions in disability (10-37% reduction) within 3 months of surgery. In contrast, studies evaluating cancer surgery (n = 12) generally reported lower pre-operative disability (< 20%) but small increases (1-8%) within 3 months of surgery. Cardiovascular surgical studies displayed pre-operative disability between 4% and 17% with a difference in disability of -8% to +3% 3 months after surgery. Three different thresholds to define disability and 13 different WHODAS 2.0 endpoints were used, measured at eight different time-points after surgery. DISCUSSION: The effect of surgical procedures on postoperative disability as measured by WHODAS 2.0 is influenced by the type of surgery. Orthopaedic surgery may decrease disability, whereas cancer surgery may be associated with persistent increases. Standardised reporting of disability endpoints is needed to enhance the quality and comparability of future studies using WHODAS 2.0.