Background A change of 0.25 in HAQ score has been considered as clinically meaningful.
Objectives This study is to evaluate the clinical meaningfulness of the HAQ change from health economic perspectives in patients with rheumatoid arthritis using real-world data.
Methods This is a retrospective cross-sectional study using data in ADELPHI Disease-Specific Program collected in 2014 (EU5 and US). Patients with clinically diagnosed RA (N=1032) were enrolled and completed self-reported outcomes measures including physical function by Health Assessment Questionnaire-disability index (HAQ-DI), employment status, work productivity by Work Productivity and Activity Impairment Questionnaire-General Health (WPAI-GH) and general health status by EQ visual analogue scale (EQ VAS). Clinical characteristics include disease activity defined by DAS28. Correlations between HAQ-DI score and other outcomes were analyzed using univariate or multiple regression analysis.
Results The majority of patients were female (72.1%) with average age of 55 years old and disease duration of about 9 years. The mean (SD) HAQ-DI score was 0.76 (0.69) with 42.2% having a HAQ-DI score ≥1, indicating moderate to severe physical disability. 58% of patients were currently unemployed. Patients with a HAQ-DI score of >1.0, 77% were unemployed with a EQ VAS of 54.2, while patients with normal HAQ score of ≤0.5, 40% were unemployed with a EQ VAS of 75.6. HAQ-DI score was significantly correlated with the unemployed in multivariate logistic regression model (p<0.001), and correlated with time lost from work (p<0.001) and general health status by EQ VAS (p<0.001) by multivariate linear regression model. After adjustment for demographic characteristics including age, gender, and disease duration, an 0.25 increase in HAQ-DI score was associated with a 30% increase in likelihood for unemployed status (OR=1.30, 95% CI=1.22, 1.39).
Conclusions Physical function measured by HAQ-DI is a valid measure to predict employment status and general health status in patients with RA.
Disclosure of Interest C. Han Employee of: Janssen Global Services, LLC, N. Li Employee of: Janssen Global Services, LLC, S. Peterson Employee of: Janssen Global Services, LLC