Rubén Queiro1, Daniel Seoane-Mato2, Ana Laiz3, Eva Galíndez Agirregoikoa4, Carlos Montilla5, Hye S Park3, Jose A Pinto-Tasende6, Juan J Bethencourt Baute7, Beatriz Joven Ibáñez8, Elide Toniolo9, Julio Ramírez10, Ana González Marcos11. 1. Rheumatology Service and the Principality of Asturias Institute for Health Research (ISPA), Faculty of Medicine, Universidad de Oviedo, Spain. 2. Research Unit, Spanish Society of Rheumatology, Madrid, Spain. 3. Rheumatology and Autoimmune Disease Department, Hospital Universitari de la Santa Creu i Sant Pau, Barcelona, Spain. 4. Rheumatology Service, Hospital Universitario Basurto, Bilbao, Spain. 5. Rheumatology Service, Hospital Universitario de Salamanca, Spain. 6. Rheumatology Service-INIBIC, Complexo Hospitalario Universitario de A. Coruña, Spain. 7. Rheumatology Service, Hospital Universitario de Canarias, Sta. Cruz de Tenerife, Spain. 8. Rheumatology Service, Hospital Universitario 12 de Octubre, Madrid, Spain. 9. Rheumatology Service, Hospital Universitari Son Llàtzer, Palma de Mallorca, Spain. 10. Arthritis Unit, Rheumatology Department, Hospital Clínic Barcelona, Spain. 11. Department of Computer Engineering, Universidad Autónoma de Madrid, and Knowledge Engineering Institute, Universidad Autónoma de Madrid, Spain.
Abstract
OBJECTIVES: To evaluate the effect of potential confounders on the association between sex and disease impact in recent-onset psoriatic arthritis. METHODS: We performed a multicentre observational prospective study (2-year follow-up, regular annual visits). The study population comprised patients aged ≥18 years who fulfilled the CASPAR criteria and less than 2 years since the onset of symptoms. The dataset was generated using data for each patient at the 3 visits (baseline, first year, and second year of follow-up) matched with the PsAID values at each of the 3 visits. Once variables associated with both PsAID ≥4 and sex were selected, those that led to a difference of >10% between the adjusted and crude estimations were identified as potential confounders in the association between sex and PsAID. Lastly, the final multivariate logistic regression model estimating the association between sex and PsAID was defined. RESULTS: The dataset contained 418 observations (158 at baseline, 135 at the first follow-up visit, and 125 at the second visit). The confounders identified in the multivariate model were HAQ, global pain, level of physical activity, and joint pattern at diagnosis. After adjustment for these variables, no statistically significant association was observed between female sex and PsAID ≥4. CONCLUSIONS: The association between female sex and greater disease impact could be explained by the influence of other variables, specifically higher HAQ score, greater intensity of pain, differences in the level of physical activity and in the joint pattern at diagnosis (lower frequency of the spondylitis pattern in women).
OBJECTIVES: To evaluate the effect of potential confounders on the association between sex and disease impact in recent-onset psoriatic arthritis. METHODS: We performed a multicentre observational prospective study (2-year follow-up, regular annual visits). The study population comprised patients aged ≥18 years who fulfilled the CASPAR criteria and less than 2 years since the onset of symptoms. The dataset was generated using data for each patient at the 3 visits (baseline, first year, and second year of follow-up) matched with the PsAID values at each of the 3 visits. Once variables associated with both PsAID ≥4 and sex were selected, those that led to a difference of >10% between the adjusted and crude estimations were identified as potential confounders in the association between sex and PsAID. Lastly, the final multivariate logistic regression model estimating the association between sex and PsAID was defined. RESULTS: The dataset contained 418 observations (158 at baseline, 135 at the first follow-up visit, and 125 at the second visit). The confounders identified in the multivariate model were HAQ, global pain, level of physical activity, and joint pattern at diagnosis. After adjustment for these variables, no statistically significant association was observed between female sex and PsAID ≥4. CONCLUSIONS: The association between female sex and greater disease impact could be explained by the influence of other variables, specifically higher HAQ score, greater intensity of pain, differences in the level of physical activity and in the joint pattern at diagnosis (lower frequency of the spondylitis pattern in women).