Associations between comorbidities and patient-reported outcomes in axial spondyloarthritis: data from a single-center real-world cohort.
Background: Comorbidities are frequently present in patients with axial spondyloarthritis (axSpA) and may contribute to poorer health-related outcomes. Patient-reported outcomes (PROs) serve as tools to assess the patient's perspective on the burden of the disease. The study aimed to evaluating the impact of comorbidities on selected PROs in axSpA.
Methods: Adult patients diagnosed with axSpA based on ASAS classification criteria were included in this cross-sectional study. Data collected included comorbidities and PROs [Health Assessment Questionnaire (HAQ), Multi-Dimensional Health Assessment Questionnaire (MDHAQ), 36-Item Short Form Health Survey (SF-36), Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), and Bath Ankylosing Spondylitis Functional Index (BASFI)].
Results: In total, 323 participants were included in the study (44.0% female). Multimorbidity and extended multimorbidity were observed in 63.8% and 38.7% of patients, respectively. Extended multimorbidity was associated with higher HAQ (0.5 [0.1-1.0] vs. 0.3 [0.0-0.8], p < 0.01) and MDHAQ scores (0.3 [0.0-0.6] vs. 0.1 [0.0-0.5], p = 0.03). The BASDAI score was higher in patients with three or more comorbidities than in patients with no comorbidities (2.8 [1.7-4.3] vs. 1.9 [0.9-3.6], p < 0.01). The number of comorbidities was associated with higher scores in the mental health (β = 0.20, p < 0.01) and vitality (β = 0.16, p = 0.02) domains of the SF-36 questionnaire.
Conclusions: Multimorbidity was present in almost two-thirds of cases. Extended multimorbidity was associated with poorer physical functioning, HAQ, MDHAQ, and BASDAI scores, whereas multimorbidity was related to better scores in the mental health and vitality domains. The impact of comorbidities on PROs in axSpA should not be overlooked. Key Points • Multimorbidity is frequent among axial spondyloarthritis' patients. • Only extended multimorbidity (presence of two or more additional diseases, excluding axial spondyloarthritis) was found to be associated with poorer results of patient-reported outcomes, in particular these regarding physical functioning. • Multimorbidity might influence positively some domains of quality of life such as mental health or vitality. • The findings included in the study support the belief that in patients with spondyloarthritis comorbidities might impact patient-reported outcomes which are important when assessing disease activity and response to treatment and should not be disregarded.