Background Pharmaco-epidemiological studies on TNF-inhibitors (TNF-I) in rheumatoid arthritis (RA) and spondyloarthritis (SpA) are providing useful data about effectiveness and safety in clinical practice.
Objectives To compare drug survival in RA and SpA according to TNF-I drug using data from a multicentre Italian cohort study.
Methods The patients were selected from the Monitornet database, a prospective cohort study to monitor the long-term safety of biologic therapy involving 27 rheumatology centres across Italy, supported by the Italian regulatory agency AIFA.
For the purpose of these analyses we included RA or SpA patients, who started a first course infliximab (INF), etanercept (ETA) or adalimumab (ADA). Drug survival was primarily defined from start until first discontinuation (overall drug survival) and secondarily due to ineffectiveness or adverse events (AEs).
A first set of analyses assessed the relationship between diagnosis and drug survival using RA as reference category, adjusting for age, gender and comorbidities. A second set of analyses stratified by diagnosis explored the relationship between TNF-I and drug survival using INF as reference category, adjusting for age, gender, comorbidities, disease duration, previous DMARDs, calendar, baseline CRP, disease activity (DAS28 or BASDAI) and severity (HAQ score or BASFI). Drug survival was analyzed using Cox proportional hazards models. Results are presented as hazard ratios (HR) and 95% confidence intervals (CI).
Results 1992 RA patients (79.8% women, mean age 55.5 yrs (SD 12.3), mean disease duration 9.6 yrs (SD 8.0), mean baseline DA28 4.4 (SD 1.9), baseline HAQ 1.4 (SD 0.7), median number of previous DMARDs 2 (IQR 1-3) and 993 SpA patients (55.2% men, mean age 49.6 yrs (SD 12.5), mean disease duration 6.9 yrs (7.5), mean baseline BASDAI 4.7 (SD 2.4), mean baseline BASFI 4.6 (SD 2.5) were included in the analyses. 44.2% RA patients started ETA, 21.4% INF, 34.4% ADA, while 45.8% SpA patients ETA, 22.3% INF, 31.9% ADA.
Using RA as reference, SpA patients showed a lower drug discontinuation (HR 0.92 [95%CI 0.87, 0.99]), due to a lower withdrawal for inefficacy (HR 0.90 [95%CI 0.82, 0.99]).
Both in RA and in SpA, compared to INF, ETA showed a slightly better survival on treatment, also due to lower discontinuation for inefficacy (see table).
Conclusions These data support a better survival on treatment for SpA over RA and for ETA as compared with INF, mainly due to lower discontinuation for ineffectiveness rather than for AEs.
Disclosure of Interest None Declared
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