Background/Purpose

Three different anti–tumor necrosis factor α (anti-TNFα) drugs (infliximab, etanercept, and adalimumab) are approved for patients with rheumatoid arthritis (RA) and particular ankylosing spondylitis (AS) in Turkey. Their efficacy has been well shown not only in randomized controlled clinical trials, but also in clinical practice setting. Comparative drug survival analyses across different diagnoses have been published in few studies.  No data is yet available for the Turkish population.

The primary goal of this study was to compare the 1-year drug retention rates of TNF inhibitors in patients with AS and RA who were enrolled in the Turkish biologic registry, TURKBIO.

Methods

TURKBIO biological registry, which was established in October 2011, is a nationwide biological registry contributed by 10 different centers across Turkey. As of December 2013, 3380 patients who are receiving biologic treatment for RA (n=1355, 40.1%) or AS (n=2025, 59.9%) were enrolled in the database. However this analysis includes only 789 patients, who initiated biologic treatment after the participation of the individual centers in TURKBIO. Demographic and clinical data including age, sex, disease type, disease duration, and previous or current treatment with DMARDs and biological drug durations are stored in the database.

Results

Of the 789 patients included in this analysis, 386 patients (48.9%) were being treated for RA and 403 patients (51.1%) for AS.  There were significant differences between the two groups in regard with age, gender distribution, DMARD use at baseline and DMARD use at last visit (Table). Preference for individual anti-TNF agents were also different between the RA and  AS patients; infliximab, etanercept  and  adalimumab  were used by 11.7%, 28.2% and 25.1% of the RA patients, respectively and 26.3%, 32.8% and 32.8 of the AS patients, respectively. AS patients had a shorter diagnosis duration than the RA patients. One year drug survival for the first anti-TNF agent was 60.8% for RA, and 78.3% for AS (P=0.0007).

Conclusion

The proportion of AS patients treated with biologic agents in the TURKBIO registry was slightly higher than that of RA. These results also suggest that the drug survival rate of anti-TNF agents in AS patients seems to be higher than in RA.  This finding may explain the higher percentage of AS patients in the whole registry population, which included patients who had started biologics before the establishment of the TURKBIO registry.

Table 1: Demographical and  clinical features of rheumatoid arthritis (RA) and ankylosing spondylitis (AS) patients at baseline and one year drug survival data

	RA (n=386)	AS (n=403)	P value
Age (years)	49 (38-58)	39 (30-46)	<0.00001
Female (%)	73.1	41.7	P>0.05
Disease duration (years)	7   (3-13)	7 (3-13)	0.09
Diagnosis Duration	4 (2-10)	2 (0.75-6)	<0.00001
Biological duration (months)	9 (5-13)	10 (5-13)	P>0.05
Number of biologic drugs used	1	1	P>0.05
Prior DMARD use  (%)	82.4	73.9	0.005
Number of  DMARD use	4 (2-6)	2 (1-3)	<0.00001
DMARD use  at last visit (%)	67.4	21.6	<0.00001
1-year drug retention rate of TNFi (%)	60.7	78.3	0.0007

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/the-comparative-one-year-drug-survival-rate-of-tumor-necrosis-factor-inhibitors-in-patients-with-rheumatoid-arthritis-and-ankylosing-spondylitis-results-from-turkbio-registry/