Validity of adopting a Health Assessment Questionnaire Disability Index less than 0.5 as a target in elderly rheumatoid arthritis patients

Objectives: The effect of age on the Health Assessment Questionnaire Disability Index (HAQ-DI) scores of rheumatoid arthritis (RA) patients and the validity of adopting HAQ-DI < 0.5 as the target for functional remission and comprehensive disease control (CDC) under a treat-to-target (T2T) treatment strategy were investigated.

Method: A total of 441 RA patients with > 3-year treatment under T2T were evaluated. The relationships between the HAQ-DI score at follow-up (HAQ) and 28-joint Disease Activity Score with C-reactive protein, Sharp/van der Heijde Score, age at follow-up, and HAQ-DI at baseline were statistically evaluated with best subset regression analysis in groups separated according to age and the EULAR response. CDC status was evaluated with a chi-square test.

Results: The HAQ score significantly correlated with all indices in the group ≥ 65 years old (G-O) and in the group with good or moderate EULAR responses (p < 0.01). No significant correlation was observed in the group < 65 years old (G-Y) or in the group with no EULAR response. The CDC ratio was not significantly different between the age groups, whereas the HAQ failure ratio was significantly greater in G-O than in G-Y (p < 0.01). No significant difference was found between the EULAR response groups.

Conclusions: The HAQ score is influenced by age in patients > 65 years. T2T is appropriate for attaining good disease activity control but does not always lead to functional remission in these patients. The HAQ score < 0.5 is not an appropriate target for functional remission according to the CDC criteria for elderly patients.Key Points• ADL in elderly RA patient aged ≥ 65 years declines corresponding to his/her aging.• Functional remission for elderly RA patients is not the same as that for young RA patients.• The HAQ score < 0.5 in elderly RA patient is not an appropriate target for CDC.