Validation of the Persian version of the Stanford Health Assessment Questionnaire (HAQ) in patients with rheumatoid arthritis

Evaluation of functional disability by using proper instruments, like Stanford Health Assessment Questionnaire (HAQ) in patients with rheumatoid arthritis (RA), is necessary not only for quality of life assessment, but also as a useful marker for disease activity. Stanford HAQ has been translated into many languages. The present study seeks to measure reliability of the Persian version of the Stanford HAQ. Persian version of the Stanford HAQ (PE-HAQ) with culturally necessary modifications of the arising, eating, hygiene, reach and activities category questions was administered to 872 RA patients (87% female; mean age 57.5 years; mean onset age 51.5 years; mean disease duration 6.1 years). The arising, hygiene and activities scores were higher in the PE-HAQ than in the original Stanford HAQ, because futons and squat toilets are very common in Iranian culture and most of patients are bound to praying even in the standing position. Arising from a futon, squatting in a squat toilet and kneeling are generally more difficult for disabled individuals than are arising from a bed, getting on and off the toilet and doing chores, respectively. The overall disability index was higher in the PE-HAQ (0.89 ± 0.84) than in the original Stanford HAQ (0.82 ± 0.79), although the correlation coefficient was high (r=0.881). The test-retest reliability value studied at a 10-day interval, showed a strong correlation coefficient of 0.90 measured on the two occasions. PE-HAQ showed excellent internal consistency (Cronbach’s α= 0.892). The PE-HAQ is a valid and reliable instrument that can be self-administered to Iranian RA patients to evaluate their functional disability.