Five Potentially Modifiable Factors Predict Poor Quality of Life in Ankylosing Spondylitis: Results from the Scotland Registry for Ankylosing Spondylitis

Objective: A chronic inflammatory condition manifesting in young adulthood, ankylosing spondylitis (AS) affects both physical and emotional quality of life (QOL). To inform future intervention strategies, this study aimed to (1) assess the QOL of patients with AS, and (2) identify potentially modifiable factors associated with reporting poor QOL.

Methods: The Scotland Registry for Ankylosing Spondylitis collects clinical and patient-reported data on clinically diagnosed patients with AS across Scotland. QOL is measured using the ASQoL questionnaire [range: 0 (high) to 18 (poor)]. Potentially modifiable factors associated with reporting poor QOL (score 12-18) were examined using Poisson regression models, adjusted for a variety of demographic characteristics, plus various nonmodifiable factors. Results are given as risk ratios (RR) with 95% CI.

Results: Data were available on 959 patients: 74% male, mean age 52 years (SD 13), median ASQoL 7.0 (interquartile range 2-12). Although many factors were univariately associated with poor QOL, 5 were identified as independent predictors: reporting moderate/severe fatigue (RR 1.60, 95% CI 1.13-2.28), poor physical function [Bath Ankylosing Spondylitis Functional Index (BASFI) ≥ 4: 3.46, 1.76-6.82], chronic widespread pain (CWP; 1.92, 1.33-2.75), high disease activity [Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) ≥ 4: 1.52, 1.09-2.12], and poor spinal mobility [Bath Ankylosing Spondylitis Metrology Index (BASMI) ≥ 4: 1.52, 0.93-2.50]. For these factors, population-attributable risks ranged between 20% (disease activity) and 56% (physical function).

Conclusion: We have identified 5 potentially modifiable factors independently associated with poor QOL. These findings provide evidence that in addition to traditional clinical targets (BASDAI, BASFI, and BASMI), focus on nonspecific symptoms (CWP and fatigue), perhaps with nonpharmacological therapies, may yield important improvements in QOL.