Background/Purpose: Despite the importance of the Health Assessment Questionnaire (HAQ) in assessing patient-reported functional status, it was originally developed primarily for research studies. As a result, HAQ has been critiqued for being time-consuming, not easily scored, and, thus, not contributing to decisions made in routine clinical care as well as for assessing general health and not specifically the clinical status of Rheumatoid Arthritis (RA).

The aim of this analysis is to describe the correlation of the individual HAQ questions with other outcome measures used in RA as well as to examine whether the instrument could be reduced to better reflect routine clinical practice.

Methods: BioTRAC is an ongoing, prospective registry of patients initiating treatment for RA, AS, or PsA with infliximab or golimumab as first biologics or after having been treated with a biologic for less than 6 months. In this analysis, data from RA patients who were treated with infliximab between January 2002 and June 2011 were used. Parameter correlation was described with the Pearson’s correlation coefficient and the impact of each question on the use of aids/devices/help was assessed with logistic regression. Factor analysis was used to assess variability in HAQ score due to each of the individual questions.

Results: 877 RA patients who had 4,180 complete HAQ assessments were included in the analysis. Higher pain score, patient assessment of global disease activity (PtGA), 28-tender joint count (TJC-28) and, to a lesser extent, 28-swollen joint count (SJC-28) were associated with increased functional impairment. Correlation analysis showed that individual HAQ questions correlated at different extents with each outcome measure (SJC-28) (Table 1). Notably, Q5B showed the lowest correlation with patient outcome measures while the two questions related to “Rising” (Q2A, Q2B) showed the highest overall correlation.

Logistic regression showed that all individual questions were significantly associated with the use of aids/devices/help within their corresponding category with the exception of Q3B and Q8B. In factor analysis, “Dressing and Grooming” was found to account for 66.5% of the matrix variance (Q1A: 60.5%; Q1B: 6.0%) suggesting that the ability to dress/groom alone may be the main driver of the HAQ score.

Conclusion: Results of this analysis show that variability exists in the correlation of individual HAQ questions with patient-reported and clinical outcome measures. Pain and joint tenderness are significantly associated with the individual functions of the HAQ while the number of swollen joints appears to be of minor importance. Furthermore, the ability to dress/groom alone was the main driver of the variability in HAQ which may have implications from an occupational health perspective and in the design of self-report instruments assessing the (dis)ability to perform daily activities.

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