Objectives This was an EULAR endorsed patient orientated project to develop and cross-culturally validate a new patient reported outcome questionnaire (PROq) for RA patients as a practical tool to self-estimate if they are in a risk group for vitamin D insufficiency/deficiency related-clinical consequences (D-PROq), and to evaluate its ability to estimate disease activity/severity.
Methods Rheumatologists from 13 European countries together with their patient associations (PARE) were involved in development, local language translation and back translation of the D-PROq. RA patient and controls recruitment was done between December and March, after informed consent and local Ethical Committee approval. 25(OH)D serum samples were shipped and analyzed in central laboratory (Genova) using DiaSorin kits. D-PROq included questions about: skin, finger nails and hair changes, muscle problems, bone pain, fatigue, nervous system problems (Symptoms Risk Score-SRS) as well as dietary habits, daily physical activity and capabilities, insolation, actual treatments and vit D supplementation (Habitus Risk Score-HRS). DAS28, HAQ, RAID were used to evaluate disease activity. SRS and HRS and both together as a Global Risk Score (GRS) were correlated with 25(OH)D serum concentrations. RA patients were stratified according to vitamin D ongoing supplementation. Statistical analysis was carried out by nonparametric procedures, including Mann-Whitney U and Spearman rank correlation tests.
Results 625 RA patients (514 women, 93 men, mean age 55±11 yrs) and 276 healthy controls (sex & age matched) entered the survey. Mean disease duration was 11±9 yrs. 25(OH)D3 serum levels were significantly lower in all RA patients (p<0.01) compared to controls (17.61±9.75 vs 18.95±9.45 ng/ml), especially (p<0.0001) in no-vitD treated subgroup (323 RA patients) (16.23±8.96 vs.19.31±9.62). Significantly higher 25(OH)D concentrations were found in Spain versus the other countries (p<0.0001). In all RA patients a statistically significant negative correlations between 25(OH)D3 values and DAS28 (p<0.001), RAID (p=0.03) and HAQ (p<0.01) were found. A significant correlation was found in all RA patients between DAS28 and SRS and GRS (p<0.0001 and p<0.001), between RAID and SRS and GRS (both p<0.0001) and between HAQ and SRS and GRS (both p<0.0001) while significant negative correlations were found in all RA patients between 25(OH)D3 serum concentrations and SRS (p=0.04), HRS (p=0.02), GRS (p=0.02) (all confirmed in no-vitD supplemented subgroup).
Conclusions D-PROq may be considered a reliable tool for RA patients to self-estimate if they are in a risk condition for vitamin D insufficiency/deficiency related-clinical consequences. The severity of 25(OH)D insufficiency, using D-PROq, negatively correlated with the RA disease activity/severity outcome measures.
Disclosure of Interest None declared