Impact of the number of comorbidities on the outcome measures and on the retention rate of the first anti-TNF in patients with Ankylosing Spondylitis. Two-year follow-up in REGISPONSER-AS

Abstract

Objectives: To evaluate the impact of the number of comorbidities on the outcome measures after two years of follow-up in patients with Ankylosing Spondylitis (AS) and to determine whether the number of comorbidities influences the retention rate of the first anti-TNF.

Methods: This was an observational and prospective study conducted during 2 years of follow-up in the REGISPONSER-AS registry. The patients were divided into three groups according to the number of comorbidities at baseline (0, 1 or ≥2). Linear regression models adjusted for disease duration, age, sex and smoking were constructed to evaluate the association between the number of comorbidities and the Patient Reported Outcomes (PRO) scores. The impact of the number of comorbidities on PROs over two years of follow-up was evaluated using mixed models for repeated measures adjusted for disease duration, age, sex and smoking. Finally, the retention rate of the first anti-TNF antibody across the three groups was evaluated using a log-rank test.

Results: Patients with two or more comorbidities showed higher scores at baseline and during the two years of follow-up for the Global VAS, BASDAI, ASDAS, and BASFI and worse scores for the physical component of the SF12. A higher probability of discontinuation of the first anti-TNF was found in patients with 2 or more comorbidities compared with the patients in the other groups (38.2% vs. 26.6% vs. 25.4% for ≥2 comorbidities, 0 and 1 comorbidity, respectively), although these differences were not significant (log-rank test: p-value = 0.180).

Conclusion: In patients with AS, the presence of 2 or more comorbidities was associated with worse scores on the outcome measures test after two years of follow-up and a greater tendency of discontinuation for the first anti-TNF.