Psychometric properties of the 12-item WHODAS applied through phone survey: an experience in PERSIAN Traffic Cohort

Abstract

Background Due to limited capability to function in post-injury daily life injury, survivors need to be reliably assessed without need to commute more than necessary. The key action is to determine the level of functioning difficulties. Having the opportunity of conducting a national post-crash traffic safety and health cohort study, we aimed to translate into Persian and assess the psychometric properties of the World Health Organization Disability Assessment Schedule 2.0 (WHODAS 2.0) through phone surveys six month post injury. Methods First, having World Health Organization permission, we tested the translation validity by forward translation, expert panel evaluation, back-translation, pre-testing and cognitive interviewing, and finalizing the Persian WHODAS. Then, through a psychometric study within a national cohort platform, the validity, reliability and applicability of the 12-item WHODAS was assessed through phone surveys. We included data of 255 road traffic injury patients enrolled from the cohort at six-month follow-up. The psychometric assessment (internal consistency reliability and stability reliability) was conducted on test–retest data of 50 patients with an average 7-day time span. An exploratory factor analysis tested the construct validity using extraction method of principal component factor and oblique rotation on data from 255 patients. Regarding the multiple criteria including an eigenvalue > 0.9, Cattell’s scree test, cumulative variance, and the theoretical basis, the minimum number of factors were retained. Data were analyzed using STATA statistical software package. Results The respondents were mostly male (81%), employed (71%), educated (87%), and with a mean age of 37.7(14.9). The Persian version had high internal consistency reliability (Cronbach’s α = 0.93) and excellent stability reliability (ICC = 0.97, 95% CI: 0.92–0.98). An exploratory factor analysis retained four factors defining 86% of all the variance. Factors of Self-care, Mobility, and Cognition were completely retained. Conclusions The brief Pesrian WHODAS 2.0 was highly reliable and valid to be applied through phone interviews post injury.

Validation of the 12‐item World Health Organization Disability Assessment Schedule 2.0 in individuals with schizophrenia, depression, anxiety, and diabetes in Singapore

“…The analysis found that the WHODAS 2.0 test-retest reliability was good (ICC = 0.78), indicating the instrument's ability to produce reproducible results when used repeatedly over a short period of time. This finding appears to be in line with earlier studies, which found the test-retest reliability for the WHODAS 2.0 was in the good range, with ICC of 0.70 or higher in patients with anxiety and stress (ICC = 0.83) [4] and Persian traffic cohort sample (ICC = 0.97) [54]. We also found that the WHODAS 2.0 agreement between self-administered and interviewer-administered modes was good (ICC = 0.89), indicating that functioning and disability ratings by patients and interviewers were generally consistent and therefore considered reliable.…”

WHODAS measurement properties for women with dysmenorrhea

“…In Brazilians with Chagas disease, WHODAS 2.0 showed 3 factors with adequate global internal consistency (Alpha = 0.87) [ 16 ]. The Persian version of WHODAS 2.0 included post-injury daily life injury people and presented 4 factors with excellent total internal consistency (Alpha = 0.92) [ 17 ]. Six factors were reported in the WHODAS 2.0 versions in road traffic trauma victims in Ethiopia [ 18 ] and in children and adolescents with chronic physical illness in Canada [ 19 ].…”

“…Studies have reported different factor structures (e.g., one-factor [ 14 , 15 ], 3-factor [ 16 ], 4-factor [ 17 ], and 6-factor [ 18 , 19 ]) for the 12-item WHODAS 2.0 in varied populations and health conditions that include men and women [ 14 – 19 ]. Thus, it was necessary to assess the structural validity of this WHODAS 2.0 version in a sample of women with dysmenorrhea by exploratory factor analysis and confirmatory factor analysis.…”