Background: Several studies have shown an inverse relationship between vitamin D levels (25OHD) and disease activity in patients with rheumatoid arthritis (RA). However, the existing data in patients with psoriatic arthritis (PsA) are poor, and they use the DAS28 index as a peripheral joint activity marker by extrapolation with RA.

Objectives: To analyze the relationship between 25OHD levels, disease activity and functional capacity in patients with PsA.

Methods: Transversal, observational, descriptive study. We included PsA patients with peripheral joint involvement. We collected demographic variables (gender, age), clinical variables [follow-up, received treatments, TJC (68), SJC (68), VAS] and analytical variables (25OHD, CRP, ESR). We used Disease activity in psoriatic arthritis (DAPSA) score to measure disease activity, and the Health assessment questionnaire (HAQ) to determine functional capacity. Levels of 25 OHD <20 ng/ml and between 20-30 ng/ml were considered deficient and insufficient, respectively. Statistical analysis was made with SPSS 22.0. The descriptive analysis results were expressed as percentage and mean ± SD. We used Pearson’s correlation to assess the association between quantitative variables and T test to compare means between dichotomous variables.

Results: 125 patients were included, the majority women (60.8%), with an average age of 55.4 (SD 12.2) years. The average follow-up was 75.5 (SD 68.3) months. 97.6% of patients had received DMARDs and 40.8% biologics, and almost half of the patients (42.7%) took calcium and 25OHD supplements. The average value of 25OHD was 27.1 (SD 12.1) ng/ml, with 30% of patients having 25OHD deficit and 63.3% insufficiency. The majority of patients had an acceptable disease control, with a mean DAPSA of 10.5 (SD 7,9); and mean of CRP, ESR, TJC and SJC was 6.1 (SD 3.7) mg/l, 10.2 (SD 9.9) mm/h, 1.3 (SD 2.5) and 0.7 (SD 2.1), respectively. The average value of HAQ was 0.6 (SD 0.7). We observed an inverse correlation between 25OHD levels and joint counts, TJC (p=0.02) and SJC (p=0.03). On the other hand, patients with hypovitaminosis D presented a tendency to get higher scores in DAPSA index (P=0.07). We do not observe any relationship between 25OHD and HAQ.

Conclusion: As can be seen in our sample, low values of 25OHD are related to increased disease activity in patients with PsA.

Disclosure of Interests: L Montolio-Chiva: None declared, Ana V Orenes Vera: None declared, Marta Aguilar-Zamora: None declared, C Vergara-Dangond: None declared, I Vázquez-Gómez: None declared, Eduardo Flores: None declared, A Sendra-García: None declared, À Martínez-Ferrer: None declared, Elia Valls-Pascual Grant/research support from: Roche, Novartis, and AbbVie, Speakers bureau: AbbVie, Lilly, Pfizer, MSD, Novartis, Janssen, Bristol Myers Squibb, UCB Pharma, D Ybáñez-García Speakers bureau: Lilly, Roche, Sanofi, V Núñez-Monje: None declared, I Torner-Hernández: None declared, Juanjo J Alegre-Sancho Consultant of: UCB, Roche, Sanofi, Boehringer, Celltrion, Paid instructor for: GSK, Speakers bureau: MSD, GSK, Lilly, Sanofi, Roche, UCB, Actelion, Pfizer, Abbvie, Novartis