Background The overall assessment of patients with systemic arthritis can not exclude comorbidities, which may impact therapeutic outcomes.
Objectives To assess the impact of baseline modified rheumatic disease comorbidity index1 (mRDCI) on drug survival and effectiveness of biological drugs in patients affected with Rheumatoid arthritis (RA), Spondyloarthritis (SpA), and Psoriatic Arthritis (PsA) in real-world settings.
Methods Patients (nr. 635) with RA (nr. 214), SpA (nr. 213), and PsA (nr. 208) starting a biological drug were retrospectively analysed. mRDCI was scored at baseline, and disease characteristics were recorded at entry and at last observation. Drug retention was analysed using Kaplan–Meier curves. Cox-regression models were used to estimate the association of mRDCI with drug discontinuation and clinical outcomes, the achievement of clinical remission based on 28 joint-Disease Activity Score (DAS28) <2.6 for RA and PsA, and on Ankylosing Spondylitis-C-reactive protein Disease Activity Score (ASDAS-CRP) <1.3 for SpA.
Results Baseline mRDCI significantly correlated with the number of biological drug switches (rho 0.47). Drug persistence was significantly higher in patients with mRDCI=0 (96.4%), than in those with mRDCI ≥2 (83.9%). Compared to mRDCI ≥2 patients, those without comorbidities showed significantly higher drug survival rate in PsA (p=0.0001) or SpA (p=0.02), but not in RA (Figure 1). mRDCI was also found to be a predictor of definitive drug discontinuation (HR 1.53) and of failure to achieve DAS28 based remission in RA (HR 0.66) or PsA (HR 0.77), and ASDAS-CRP driven remission in SpA (HR 0.43).
Conclusions This study provided evidence that baseline mRDCI negatively impacts the persistence on biologic treatments and the clinical outcomes in patients with RA, SpA, and PsA in real-life settings.
Staetgens et al. Content and construct validity of the Rheumatic Diseases Comorbidity Index in patients with gout. Rheumatology (2015)Sep;54(9):1659–1663.
Disclosure of Interest None declared