TNF-alpha inhibitors reduce the incidence of psoriatic arthritis in patients with psoriasis: a propensity score-matched cohort study.

OBJECTIVES

Conflicting data exist on TNF inhibitors' (TNFi) role in preventing psoriatic arthritis (PsA) in psoriasis. Using propensity score matching, we compared PsA incidence in severe psoriasis patients treated with TNFi versus narrow-band ultraviolet B (nbUVB) phototherapy over a decade of follow up.

METHODS

Consecutive adults with severe psoriasis prescribed TNFi or nbUVB phototherapy between September 2005 and September 2010 were enrolled. Of 946 patients, 497 received TNFi (median follow-up 9.6±2.6 years) and 449 underwent nbUVB (9.4±5.9 years). All had rheumatologist assessment before therapy and for PsA diagnosis. PS matching adjusted for factors linked to PsA, including arthralgia, family history, BMI, PASI, and psoriasis distribution, including nails.

RESULTS

After propensity score matching, the TNFi cohort contributed 2705.5 person-years of follow-up (mean 9.1 ± 2.9 years), and the nbUVB cohort 2654.1 person-years (mean 8.9 ± 5.4 years). The PsA incidence rate per 100 patients was 1.18 (0.84-1.52) in the TNFi group and 2.48 (2.24-2.72) in the nbUVB group, yielding an incidence rate ratio of 2.1 (1.37-2.98, p = 0.0002). A time-dependent Cox model confirmed that TNFi treatment was associated with a significantly lower risk of PsA (HR = 0.32, p < 0.0001). Arthralgia (HR = 7.68, p < 0.0001), nail psoriasis (HR = 1.93, p = 0.0004), and higher PASI score (HR = 1.03 per point, p = 0.0096) were independent predictors of PsA.

CONCLUSION

This PS-matched study shows a clear benefit of TNFi versus nbUVB in PsA reduction in severe psoriasis patients over nearly a decade of therapy.