Validation of the WHO Disability Assessment Schedule (WHODAS 2.0) 12-item tool against the 36-item version for measuring functioning and disability associated with pregnancy and history of severe maternal morbidity

Objective: To validate the WHO Disability Assessment Schedule 2.0 (WHODAS 2.0) 12-item tool against the 36-item version for measuring functioning and disability associated with pregnancy and the occurrence of maternal morbidity.

Methods: This is a secondary analysis of the Brazilian retrospective cohort study on long-term repercussions of severe maternal morbidity (SMM) among women who delivered at a tertiary facility (COMMAG study). We compared WHODAS-12 and WHODAS-36 scores of women with and without SMM using measures of central tendency and variability, tests for instruments' agreement (Bland-Altman plot), confirmatory factor analysis (CFA), and Cronbach alpha coefficient for internal consistency.

Results: The COMMAG study enrolled 638 women up to 5 years postpartum. Although the median WHODAS-36 and -12 scores for all women were statistically different (13.04 and 11.76, respectively; P<0.001), there was a strong linear correlation between them. Furthermore, the mean difference and the differences in variance analyses demonstrated agreement of total scores between the two versions. CFA demonstrated how the WHODAS-12 questions are divided into six previously defined factors and Cronbach alpha showed good internal consistency.

Conclusion: WHODAS-12 demonstrated agreement with WHODAS-36 for total score and was a good instrument for screening functioning and disability among postpartum women, with and without SMM.