Multimorbidity phenotypes in ankylosing spondylitis and their association with disease activity and functional impairment: Data from the prospective study of outcomes in ankylosing spondylitis cohort.

Objectives: To examine the association of multimorbidity phenotypes at baseline with disease activity and functional status over time in ankylosing spondylitis (AS).
Methods: Patient-reported AS morbidities (comorbidities, N = 28 and extra-musculoskeletal manifestations, EMMs, N = 3) within 3 years of enrollment with a prevalence ≥1 %, were included from the Prospective Study of Outcomes in Ankylosing Spondylitis (PSOAS) cohort. We defined multimorbidity as ≥2 morbidities (MM2+) and substantial multimorbidity as ≥5 morbidities (MM5+). Multimorbidity clusters or phenotypes were identified using K-median clustering. Disease activity (ASDAS-CRP) and functional status (BASFI) measures were collected every 6 months. Generalized estimating equation method was used to examine the associations of multimorbidity counts and multimorbidity clusters with measures of disease activity and functional status over time.
Results: Among 1,270 AS patients (9,885 visits) with a median follow-up of 2.9 years (IQ range: 1.0-6.8 years), the prevalence of MM2+ and MM5+ was 49 % and 9 % respectively. We identified five multimorbidity clusters: depression (n = 321, 25 %), hypertension (n = 284, 22 %), uveitis (n = 274, 22 %), no morbidities (n = 238, 19 %), and miscellaneous (n = 153, 12 %). Patients in the depression cluster were more likely to be female and had significantly more morbidities and worse disease activity and functional status compared to those with no morbidities.
Conclusion: Approximately 49 % of AS patients in the PSOAS cohort had multimorbidity and five distinct multimorbidity phenotypes were identified. In addition to the number of morbidities, the type of morbidity appears to be important to longitudinal outcomes in AS. The depression cluster was associated with worse disease activity and function.
Competing Interests: Declaration of Competing Interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Dr. Davis has received consulting fees and/or honoraria from Sanofi-Genzyme (less than $10,000 each), Girihlet (Rights to royalties for licensed technology; none received to date), and research support from Pfizer. Dr. Ogdie has received grant/research support from Amgen (to Forward), Novartis (to Penn) and Pfizer (to Penn) Inc, has been a consultant for AbbVie, Amgen, Bristol-Myers Squibb, Celgene, Corrona, Eli Lilly, Gilead, Janssen, Novartis, Pfizer Inc and UCB. Dr. Reveille has received consulting fees from Eli Lilly and Company (less than $5000). Dr. Weisman has received consulting fees from Eli Lilly and Company, UCB, and Novartis (less than $10,000 each). Dr. Gensler has received consulting fees from AbbVie, Acelyrin, Eli Lilly and Company, Fresenius Kabi, Janssen, Novartis, Pfizer, and UCB (less than $10,000 each) and has received grant support from UCB, Novartis, and Pfizer. Rest of the authors have no competing interests.
(Copyright © 2023. Published by Elsevier Inc.)