Relationship Between Health-Related Quality of Life and Patient Acceptable Symptom State With Disease Activity and Functional Status in Patients With Ankylosing Spondylitis in Thailand.

OBJECTIVE

This study aimed to identify factors associated with EuroQoL-5 Dimensions, 5 Levels and Patient Acceptable Symptom State (PASS) and health utility (HU) in Thai patients with ankylosing spondylitis (AS).

METHODS

This was a cross-sectional study of consecutive AS patients visiting Siriraj Hospital between May 31, 2012, and March 31, 2016. Demographic data and outcomes related to HU (Thai version of EuroQoL-5 Dimensions, 5 Levels), disease activity (Bath Ankylosing Spondylitis Disease Activity Index, Ankylosing Spondylitis Disease Activity Score-erythrocyte sedimentation rate or Ankylosing Spondylitis Disease Activity Score-C-reactive protein, number of tender and swollen joints, and enthesitis), and functional status (Bath Ankylosing Spondylitis Functional Index and Health Assessment Questionnaire) were collected. Regression analysis was used to explore factors associated with each EuroQOL-5 Dimensions (EQ-5D) domain, HU, and PASS.

RESULTS

Among 119 AS patients, the mean age was 40.4 years; 61.3% were male. The mean EQ-5D was 0.75. In univariate analysis, lower disease activity and less impaired function were significantly associated with higher HU and not to mild problems in each EQ-5D domain. In multivariate regression analysis, Bath Ankylosing Spondylitis Disease Activity Index, C-reactive protein, and Health Assessment Questionnaire adjusting for age explained 77.4% of the HU variance. Patients answering yes to PASS were significantly older, had higher HU, and lower disease activity compared with those answering no to PASS. Usual activity and pain problems were importantly related to PASS after adjusting for other domains and age.

CONCLUSIONS

Disease activity and functional status in AS patients were significant factors related to HU and PASS. To improve quality of life, treatment goals should be achieving remission, improving function, and controlling pain.