Sami patients in northern Norway experience longer symptoms duration before psoriatic arthritis diagnosis and have more axial involvement.

Objectives: To compare Sami and non-Sami patients with PsA in northern Norway, where both the human antigen HLA-B27 and psoriasis are prevalent, particularly among the Sami population.

Methods: A total of 536 adult PsA patients were recruited from the Norwegian Arthritis Registry and hospitals in northern Norway. All participants met the Classification Criteria for Psoriatic Arthritis. A questionnaire from the SAMINOR (a study in regions with Sami and Norwegian populations) was used to identify Sami and non-Sami patients. Demographic, clinical and laboratory parameters were compared between these groups. Binary logistic regression was used to adjust for age and gender differences.

Results: The 60 Sami and 476 non-Sami patients identified were comparable in demographic characteristics and disease activity measurements. Sami patients experienced a longer duration of symptoms before diagnosis compared with non-Sami patients (4 years vs 2 years, P = 0.045), with a more pronounced delay among Sami men (5 years vs 1 year, P = 0.003). Sami men also had higher scores for back and/or pelvis pain (42 mm vs 31 mm, P = 0.034). Axial involvement was more frequent among Sami than non-Sami patients (30% vs 18%, P = 0.029), even after adjusting for gender and age (odds ratio 1.91, P = 0.041). Among patients with axial involvement, HLA-B27 was positive in 47.1% of Sami patients compared with 37% of non-Sami patients (P = 0.461).

Conclusions: Sami patients face longer symptom durations before diagnosis and more frequent axial involvement than non-Sami patients. Sami men also report higher back/pelvic pain levels, though no differences between the cohorts in demographics or disease activity were observed.