The Health Assessment Questionnaire - Disability Index (HAQ), used as a disability and outcome measurement in rheumatoid arthritis (RA), has been validated in several languages, but not in Chinese. Our aim was to validate the Chinese version of HAQ (Chinese-HAQ) to suit the needs of Chinese speaking patients with RA in an Asian setting.
The original HAQ was modified in the context of Chinese culture and translated into Chinese by 2 translators aware of the objective of the questionnaire. The Chinese HAQ was self-administered by 42 patients with RA during their routine followup visit and one week later.
The test-retest reliability assessed using Spearman's correlation coefficient was 0.84. Between dimensions measured in the HAQ, the highest test-retest reliability was observed for walking (Spearman correlation coefficient rs=0.80) and the lowest was for eating (rs=0.54). The internal consistency of the scale using Cronbach's alpha was high at 0.86. In terms of criterion validity, the Chinese-HAQ score was found to correlate well with American College of Rheumatology functional status (rs=0.501, p=0.01). The Chinese-HAQ scores also correlated well with markers of disease activity such as patient's perception of pain measured on a visual analog scale (rs=0.55, p < 0.001), grip strength in mm Hg (rs=-0.55. p < 0.001 ), and physician's assessment of disease activity (rs=0.59, p < 0.001).
The Chinese HAQ is a reliable and valid instrument for studies measuring disability of patients with RA in Singapore.