Psoriatic Nail Changes Are Associated With Clinical Outcomes in Psoriatic Arthritis

Background: Nail changes are common in psoriatic arthritis (PsA), with varying relationships existing between skin, nail, and joint disease. Objective: To further characterize relationships between nail changes, psoriasis, and joint involvement in PsA patients. Methods: One hundred eighty-eight PsA patients had skin, fingernail, and rheumatological assessments completed. Hand and fingernail photographs were taken and reviewed by a dermatologist. Results: Higher swollen joint counts were associated with distal interphalangeal (DIP)/periungual psoriasis (P = .001), more splinter hemorrhages (P = .006), and any nail bed change (P = .03). Higher tender joint counts were associated with rough onychorrhexis (P < .001), DIP/periungual psoriasis (P = .03), red lunula (P = .001), nail crumbling (P = .046), any nail matrix (P = .03), and nail bed change (P = .03). Joint involvement was associated with same-digit nail changes; strongest association was swollen or tender DIP with subungual hyperkeratosis, odds ratio = 26.6 (95% CI, 5.1-139.1). Conclusion: The DIP/periungual psoriasis and specific nail changes were associated with higher joint counts and certain nail changes with same-digit joint involvement.