Persistent pain and its predictors after starting anti-tumour necrosis factor therapy in psoriatic arthritis: what is the role of inflammation control?

Abstract

Objective

While considerable focus has been placed on pain due to inflammation in psoriatic arthritis (PsA), less is reported on pain despite inflammation control. Here, we aimed to investigate the occurrence/predictors of persistent pain, including non-inflammatory components, after starting anti-tumour necrosis factor (anti-TNF) therapy.

Method

Bionaïve PsA patients starting a first anti-TNF therapy 2004–2010 were identified (South Swedish Arthritis Treatment Group register; N = 351). Outcomes included unacceptable pain [visual analogue scale (VAS) pain > 40 mm], and unacceptable pain despite inflammation control (refractory pain; VAS pain > 40 mm + C-reactive protein < 10 mg/L + ≤ 1 swollen joint of 28), assessed at 0, 3, 6, and 12 months. Baseline predictors were estimated by logistic regression.

Results

Upon starting anti-TNF therapy, 85% of patients reported unacceptable pain, falling to 43% at 3 months and then remaining stable. After 12 months, refractory pain constituted 63% of all unacceptable pain. Higher baseline VAS pain/global, worse physical function and lower health-related quality-of-life were associated with a higher risk of unacceptable/refractory pain at 12 months. More swollen joints and higher evaluator’s global assessment were associated with a lower risk of 12-month refractory pain.

Conclusions

A substantial proportion of PsA patients reported unacceptable pain throughout the first anti-TNF treatment year. At 12 months, refractory pain constituted about two-thirds of this remaining pain load. More objective signs of inflammation at anti-TNF initiation were associated with less future refractory pain. This highlights insufficient effect of biologics in patients with inflammation-independent pain, warranting alternative treatments.

Acknowledgements

We are indebted to all colleagues and staff in the South Swedish Arthritis Treatment Group for their cooperation and for supplying the data.

Disclosure statement

JKW has received speaker’s bureau fees from AbbVie and Amgen, and research support unrelated to the current work from AbbVie, Amgen, Eli Lilly, Novartisa, and Pfizer. TO has performed consulting tasks for Eli Lilly and Merck Sharp & Dohme unrelated to the present work. All of the other authors report no conflicts of interest.

Ethics and consent

This study was approved by the Regional Ethical Review Board of Lund University (2014/754). Data collection was part of routine care and patients have consented to participate in the register used for the research.

Supplementary material

Supplemental data for this article can be accessed online at https://doi.org/10.1080/03009742.2023.2258644

Additional information

Funding

The study was funded by grants from Greta och Johan Kocks stiftelser and ALF Region Skåne, the Swedish Rheumatism Association, the Kockska Foundation, and the Österlund Foundation.