engleski

Vitamin D and PTH serum levels and their relationship with some measures of disease activity in a group of patients with established psoriatic arthritis

It is well established that lower levels of vitamin D are associated with higher disease activity in rheumatoid arthritis, SLE and ankylosing spondylitis. From our investigation that was designed to evaluate the correlation between vitamin D serum level and clinical measures of disease activity/severity in patients with psoriatic arthritis and rheumatoid arthritis, (controls were subjects without inflammatory rheumatic conditions), here we present the results for psoriatic arthritis. Thirty-eight consecutive patients (19 men, 19 women), aged 56.610.18 years, with psoriatic arthritis (duration of the disease 180.13102.84 months) were enrolled, during a winter period (Jan, Feb, Mar) from the three University rheumatologic centres in Zagreb (Croatia). Controls were 29 patients of mean age 68.246.68 years, with non-inflammatory osteoartricular conditions. Apart from demographic data, clinical and laboratory measurements of disease activity and severity were collected in patients with PsA, while circulating concentration of 25(OH)D3 and PTH were determined in both groups using ECL- based immunoassay. Level of significance was set up at 0.05. Results. In subjects with PsA vitamin serum level was 59.376.32 nmol/L and was significantly higher than in controls (32.9920.1 nmol/L). PTH serum level for both groups were within normal range with no difference between groups (PsA patients 4.973.06 pmol/L ; controls 6.142.37 pmol/L). There was a significant negative correlation between level of serum vitamin D in controls with serum PTH and age. As for parameters of disease activity we found a significant positive correlation between vitamin D level with ESR and CRP (after adjusting for age and hours of weekly sun exposure). Negative correlation was found between PTH serum level and the duration of morning stiffness. In our cross-sectional study, patients with PsA, with high level of disease activity, had sufficient level of circulating 25(OH)D3 which was significantly higher than in subject with no inflammatory rheumatic disease. The difference might be explained by the fact that controls were older and had significantly correlation of serum vitamin D level with age. Normal levels of serum PTH were found in both groups. Correlations of vitamin D level with some laboratory, although not clinical measures of disease activity were observed, while PTH correlated only with one clinical variable.

Vitamin D; parathyroid hormone; psoriatic arthritis; functional status; illness index severity

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