Prevalence of biologics monotherapy in a cohort of patients with Rheumatoid Arthritis in daily clinical practice

Background: Real-life registry data reveal approximately one-third of patients taking biologic agents use them as monotherapy, in spite that combination therapy with Disease Modifying Drugs is more efficacious than monotherapy. The aim of our study was to assess the prevalence of biologics monotherapy in a cohort of patients with RA followed at a single center, and to analyze the reasons for monotherapy, including patients with prescriptions that do not take the medication. Methods: All patients with Rheumatoid Arthritis, with biologic therapy followed at our Rheumatology Unit were included. Prevalence and reasons for biologics monotherapy was calculated in general, for each biologic course and for each biologic. Prescription data was obtained from the Electronic Medical Record, and drugs acquisition was obtained from the Hospital Administrative database. Drug survival was also calculated and compared between monotherapy and combination therapy. Results: Seventy nine patients with 115 courses of biologic treatments were included. In 40 (35 %, 95 % CI: 26-44 %) of all biologics courses, biologics were initiated as monotherapy. In 27 courses (23 %, 95 % CI: 16-32 %) biologic monotherapy was prescribed by the treating rheumatologists, and in the other 13 (11 %, 95 % CI: 6-18 %) it was initiated as such by decision of the patient regardless of the physician indication. Reasons for prescription of biologic monotherapy by the treating rheumatologists were adverse events with previous DMARDs in 55.5 %, and was not specified in the remaining courses. Only 25 % of biologics' courses were monotherapy from the beginning to the end of the biologic therapy. The overall survival on biologics was 45 % (95 % CI: 35-55 %) at 3 years. There were no statistically differences in biologics survival by modality (monotherapy vs combination) (p = 0.543), course (p = 0.4454), or by biologic drug (p = 0.9612). Conclusions: Almost 1/3 of patients on biologics use them as monotherapy. This is due to physician's preferences in 60 % of the cases, and to patients not compliance with the indication in around 40 % of the cases. Better communications is needed to assure that physicians and patients agree on the prescribed and used medication.