Impaired lung function — particularly preserved ratio impaired spirometry (PRISm) — is associated with both the prevalence and incidence of spondyloarthritis (SpA), with the strongest effects observed in axial SpA (axSpA) and ankylosing spondylitis (AS), according to study results published in Therapeutic Advances in Musculoskeletal Disease.
Researchers conducted a cross-sectional study using data from the United Kingdom Biobank cohort to assess the relationship between impaired lung function and the development of SpA.
The original cohort included 502,357 individuals aged from 37 to 73 years.
After excluding those without complete lung function data (n=82,355) or HLA-B27 genotyping (n=8222), 411,780 participants were included in the analysis. For the longitudinal analysis, 409,069 participants without baseline SpA were followed for a median of 14.6 years.
Incorporating routine lung function tests into standard clinical practice could be a valuable strategy for the early identification of high-risk individuals.
Lung function was measured by spirometry, categorizing participants into normal, PRISm, or chronic obstructive pulmonary disease groups according to the Global Initiative for Chronic Obstructive Lung Disease-2024 criteria. Spondyloarthritis diagnoses were identified using electronic codes from medical records, registries, and self-reporting.
Overall, 3306 participants (median age, 58.5 years; 45.83% women; 95.77% White) were determined to have SpA. These individuals were generally older, more often men, more frequently had obesity, and had higher comorbidity rates and inflammatory markers. Axial SpA predominated (54.45%), with AS accounting for 97.00% of cases. Psoriatic arthritis (PsA) made up 81.29% of peripheral SpA cases. HLA-B27 positivity was much higher among participants with SpA (31.46% vs 7.67% overall), especially those with AS (46.85%).
Participants with SpA showed significantly lower lung function than controls, with median forced expiratory volume in 1s predicted percentages (FEV1 Pred%) of 89.35 vs 94.03 and forced vital capacity predicted percentages (FVC Pred%) of 91.97 vs 96.60, respectively. Normal lung function became less common among participants with SpA over time (66.55% vs 77.17%), while PRISm became more prevalent (23.20% vs 14.35%).
Results of cross-sectional analyses showed better lung function strongly protected against SpA, with fully adjusted odds ratios [ORs] of 0.636 (FEV1 Pred%) and 0.643 (FVC Pred%) for the highest vs lowest quartiles (Q); PRISm was associated with a nearly 54.00% higher SpA prevalence (OR, 1.538). Associations were stronger for axSpA (OR, 2.022) and AS (OR, 2.056), while PsA with PRISm showed only modest associations.
Longitudinally, higher lung function was linked to reduced incident SpA risk (FVC Pred% Q4 hazard ratio [HR], 0.782), while impaired lung function conferred a 24.90% increased risk (HR, 1.249). Kaplan-Meier curves showed higher SpA incidence in PRISm, especially among participants aged 45 years or older. Results of restricted cubic spline analyses revealed a nonlinear relationship for FEV1 Pred% and a linear negative association for FVC Pred% with SpA risk.
Study limitations include an inadequate view of the evolving changes in lung function over time, the possibility of unmeasured confounding factors, and the lack of generalizability of the findings.
The study authors concluded, “Incorporating routine lung function tests into standard clinical practice could be a valuable strategy for the early identification of high-risk individuals.”
This article originally appeared on Rheumatology Advisor
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