Discordance Between Patient and Evaluator Global Assessments Affects TNFi Retention Rates in SpA

Discordance between the patient and evaluator in the global assessment of baseline disease activity can negatively affect retention and remission associated with tumor necrosis factor inhibitor (TNFi) therapies in spondyloarthritis (SpA), according to research results published in Rheumatology.

Because such discordance is common, researchers sought to examine the effect of that difference, described as “patient’s minus evaluator’s global assessment of disease activity” (ΔPEG) on retention and remission rates for first-time TNFi treatments in patients with psoriatic arthritis (PsA) and axial spondyloarthritis (axSpA).

Anonymous data from 11 registries of patients with PsA and axSpA who began TNFi therapy between 2000 and 2017 were pooled for evaluation. In total, 14,868 patients were included (PsA n=5855 and axSpA n=9013). Within the PsA population, time since diagnosis was 6.6±7.3 years and 6.7±7.2 years for women and men, respectively. Median ΔPEG baseline was 17 (0-38) and 10 (0-30) for each subgroup. In the axSpA population, mean time since diagnosis was 5.1±7.4 years and 6.9±8.7 years among women and men. Within these 2 groups, median baseline ΔPEG was 20 for PsA (3-42) and 15 for axSpA (0-37).

At the 6-, 12-, and 24-month follow-up, TNFi retention rates were significantly lower for higher quartiles of ΔPEG in women and men in both groups. After adjusting for age, time since diagnosis, and smoking, investigators found lower TNFi retention rates for higher quartiles of ΔPEG.

In terms of achieving remission, the proportions of patients with PsA who achieved 28-Joint Disease Activity Index for Psoriatic Arthritis and 28-Joint Disease Activity Score With C-reactive protein but not remission, and with axSpA who achieved Bath Ankylosing Spondylitis Disease Activity Index remission and Ankylosing Spondylitis Disease Activity Score inactive disease status were significantly lower for higher quartiles of baseline ΔPEG in both women and men at all 3 follow-up timepoints, except for Disease Activity Index for Psoriatic Arthritis and 28-Joint Disease Activity Score With CRP remission in men at 12 months and women at 24 months.

Using a logistic regression model, adjustment for age, time since diagnosis, and smoking status did not alter this significance, although 6-month ASDAS inactive disease in women and men and 12-month ASDAS in women demonstrated consistently lower point estimates for higher ΔPEG quartiles. This did not reach statistical significance.

Study limitations included a lack of data about extra-articular manifestations in PsA, and the use of 28-joint counts rather than 66/68 joint counts. Researchers also noted that the 2 BASDAI remission cutoffs used in the study have not been validated.

“[H]igh baseline patient’s compared with evaluator’s global assessment was associated with lower 6-, 12-, and 24-months’ retention and remission rates of first TNFi in [women and men with] PsA and axSpA,” the researchers concluded. “The study highlights the negative impact of high baseline ΔPEG on treatment outcomes in PsA and axSpA patients as well as the importance of including remission criteria that objectively reflect disease activity.”

Disclosure: This clinical trial was supported by Novartis. Please see the original reference for a full list of authors’ disclosures.

Reference

Michelsen B, Ørnbjerg LM, Kvien TK, et al. Impact of discordance between patient’s and evaluator’s global assessment on treatment outcomes in 14,868 patients with spondyloarthritis [published online January 20, 2020]. Rheumatology. doi:10.1093/rheumatology/kez656