Background At the end of 2011 we established a protocol in dose reduction of biological therapy in patients with imflammatory diseases. Those who achieved remission by clinical and laboratory tests and showed no radiographic progression or Doppler activity by ultrasound examination, received reduction of dosing. Patients with etanercept (ETN) reduced dose to 25 mg, and patients with adalimumab (ADA) increased injection interval to 3 weeks. Tocilizumab (TCZ) was tapered from 8 to 6 mg/kg. We have achieved optimization rates of 20% in 2012, close to 40% at the end of 2013.
Objectives The aim of this study is to take account of activity flares in optimized patients and their characteristics, in order to describe predictive factors of flare if possible.
Methods Retrospective analysis data from clinical records and database of 105 patients treated with ETN, ADA and TCZ, optimized from January 2012 to June 2013 considering lab tests (ESR, RCP), disease activity (DAS 28, BASDAI),functional capacity indexes (HAQ, BASFI), and GPE (general patient evaluation), at optimization, 6 and 12 months visits. We used SPSS 21.0 for statistical analysis.
Results105 patients (53 female and 52 male), 31% rheumatoid arthritis (RA), 27,5% ankylosing spondylitis (AS), 37,7% psoriatic arthritis (PA), and 3,8% juvenile idiopatic arthritis (JIA), most of them with longstanding disease, (150 months (18-638)). All of them were considered to keep remission by second visit, but at 12 months 32% were diagnosed of flare (24,5% under ADA and 39,2% under ETN; none with TCZ). Patients who flared were RA (30%), AS (29%), PA (37%) and one JIA. Half of the patients with RA, 27,6% of AS and 21,6% of PA. Clinical response was good to increasing of DMARD dosing in 25% and to increasing of biological dosing in 68,7%, but 3 patients (9,3%) required switching to another biological drug.
We applied an univariate regression logistic model using parameters at visit 2, and we found modestly risk of flare related with ESR, DAS 28, number of swelling and tender joints. An increase of one tender joint at visit 2 means OR 3,56 (95% CI: 1,28-9,91), increase of one swelling joint means OR 11,26 (95% CI: 2,23-43,23). Increase of DAS 28 over 0,6 means OR 8 (95% CI: 1,85-34,6), and an increase over 1,2 means OR 60 (95% CI: 6,41-561,96).
Conclusions 1/3 of patients suffered flares of disease activity, mostly happened in RA patients, most of them in the ETN group (not statistically significant). Patients who flared had increased DAS 28 at visit 2, but were considered at clinical remission then. Response to increasing in treatment dosing is usually good. We consider optimization as cost-effective practice among biological treated population. We need wider population to establish other statistically significant conclusions.
Disclosure of Interest None declared