For patients with psoriatic arthritis (PsA), improvements in health-related quality of life (HRQOL) with tofacitinib treatment are primarily mediated by itch relief, according to study results published in Journal of Clinical Medicine.
The aim of the current study was to assess the extent to which itch relief mediated improvements in HRQOL in patients with PsA receiving treatment with tofacitinib.
Researchers used pooled data from 468 patients with PsA who participated in 2 phase 3 trials (ClinicalTrials.gov Identifiers: NCT01877668 and NCT01882439). The indirect and direct effects of tofacitinib on dermatology-specific HRQOL were assessed via mediation modelling. Itch Severity Item (ISI) and Physician’s Global Assessment of Psoriasis (PGA-PsO) were considered indirect effects; all other factors were direct effects. The Dermatology Life Quality Index (DLQI) was used to measure dermatology-specific HRQOL.
In the initial mediation model, improvements in itch accounted for 88.5% (P <.0001) of the treatment effect of tofacitinib on DLQI; PGA-PsO accounted for 19.4% (P =.0043) of the treatment effect. The direct effect due to other factors was small and not statistically significant (P =.66). Consider only the indirect effects of itch and PGA-PsO, 17.7% of the treatment effect was attributable to PGA-PsO (P <.0006) and 82.3% to itch (P <.0001).
Limitations of the study included the fact that it was a post-hoc analysis that included data only up to month 3 of treatment; data could not provide evidence for a causal link between itch, PGA-PsO, and DLQI; and other variables not assessed in this study may have had a mediating effect.
According to the researchers, “Further research is needed to explore how the relief of itch contributes to the observed improvements in dermatology-specific [HRQOL].”
Disclosures: This research was supported by Pfizer Inc. Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of disclosures.
Taylor PC, Bushmakin AG, Cappelleri JC, et al. Itch as major mediator of effect of tofacitinib on health-related quality of life in psoriatic arthritis: a mediation analysis. J Clin Med. 2021;10(18):4081. doi:10.3390/jcm10184081