Background Vitamin D deficiency is a condition reported both in young adults and in elderly and institutionalized patients. It has been increasingly recognized and, although conflicting data subsists, hypovitaminosis D has been related to a variety of rheumatic conditions from osteoporosis (OP) to inflammatory diseases and generalized pain syndromes.
Objectives To assess vitamin D status in a rheumatic outpatient setting.
Methods Observational, transversal, retrospective study encompassing rheumatic outpatients with at least one 25-hidroxyvitamin D determination since 2014. Data ascertained included gender, age, parathyroid hormone (PTH) and vitamin D levels, rheumatic conditions (<3/patient), co morbidities and therapeutics. Bone mineral density was assessed by densitometry (DXA) and results classified as normal (Tscore >-1), osteopenia (-2.5<Tscore<-1) and osteoporosis (Tscore<-2.5). Statistics: Mann-Whitney, Kruskal-Wallis, ANOVA and Chi-Squared tests and Pearson's correlation; p<0.05. Software: SPSS 17.
Results 370 patients included, 87.3% female, mean age 64.9±13.9 years (y), 151 patients <65y. Most prevalent rheumatic conditions: osteoarthritis (OA; 47.8%), OP (43.5% - 33.5% of which with reported fractures), fibromyalgia (FM; 14.6%) and rheumatoid arthritis (RA; 13.2%); 43.9% patients had inflammatory diseases. Most common co morbidities: arterial hypertension (38.6%), dyslipidemia (32.4%) and depression (22.9%). 38.4% were on synthetic Disease Modifying Anti-Rheumatic Drugs (DMARD); 34.1% on corticosteroids (CTC), 49.2% on bisphosphonates (BF) and 69.5% on calcium/vitamin D (Ca/D) supplements. As for patients with available DXA, 41.4% were classified as having osteopenia and 43.6% as having osteoporosis. Mean vitamin D was 29.7±24.5μg/L; 65.4% patients had vitamin D levels <30μg/L. Mean PTH was 56.6±31.3ng/L and alkaline phosphatase (ALP) was 73.8±31.8U/L. In the group >65y, mean PTH was higher than in the <65y group (61.3±33.6 vs 49.7±26.1, p=0.015); 70.9% of the patients <65y and 61.6% of the patients >65y had vitamin D<30 – not significant. We compared vitamin D in OP vs OP with fractures vs OA vs associated OP/OA and found lower vitamin D levels in patients with isolated OA (38.7±32.5 vs 38.1±33.9 vs 25.9±23.3 vs 30.6±20.7, p=0.012); 76.6% with isolated OA had vitamin D<30. 55.7% of the patients on BF >5y, 61.2% on BF <5y and 72.3% without BF had vitamin D<30 (p=0.013). 68.7% in the group with inflammatory conditions and 62.9% in the group with non-inflammatory conditions had vitamin D <30 – not significant. We further compared vitamin D levels in OA vs AR, AR vs FM and OA vs FM, DMARD and CTC use and Ca/D supplementation and found no difference. There was a positive correlation between age and vitamin D (r=0.111, p=0.033), age and PTH (r=0.208, p=0.010) and vitamin D and ALP levels (r=0.311, p<0.0001).
Conclusions In this study, vitamin D levels <30μg/L were found in nearly 2/3 of patients, across disease groups. There was a tendency for higher vitamin D levels in elderly patients, in the group with OP comparing with OA and in the group on BF, which may be related to previous supplementation. A potential bias is the fact rheumatologists request vitamin D dosing in patients with risk factors/clinical features of hypovitaminosis.
Disclosure of Interest None declared