Background There have been multiple reports of low vitamin D in Systemic Sclerosis (1, 2). The majority of these reports only measured 25-hydroxyvitamin D (calcifediol) and not 1,25-dihydroxyvitamin D (calcitriol). In our clinical observation, we noted that there may be a population of patients with low calcifediol but normal or high calcitriol.
Objectives We aim to evaluate the frequency of normal or high calcitriol level in systemic sclerosis patient with low calcifediol levels.
Methods We performed a retrospective analysis using data collected from a large private practice. We collected data from systemic sclerosis patients who had calcifediol and calcitriol levels ordered between January 2014 and January 2017, patients with sarcoidosis overlap were excluded.
Results We identified 90 scleroderma patients with documented calcifediol and calcitriol levels and no history of sarcoidosis. Mean calcifediol level was 32.7 ng/mL (SD 20.2) and mean calcitriol level was 60.9 pg/mL (SD 27.6). Total of 42 patients were identified as having calcifediol level of less than 30 (normal >30), only 1 of these patients had calcitriol levels below 10 pg/mL (normal >10) and 6 patients had calcitriol levels above 75 pg/mL. Twenty-three out of 41 patients who had low calcifediol but high calcitriol level also had a CT chest with no diagnostic findings suggestive of sarcoidosis.
Conclusions Our study suggests that while low calcifediol levels are common in systemic sclerosis patients, not all patients are truly vitamin D deficient and a calcitriol level should be checked before supplementation is initiated. There is some documented evidence of sarcoid and scleroderma overlap at greater than expected frequency which is under recognized and elevated calcitriol level in a systemic sclerosis patient should prompt further evaluation for sarcoidosis (3). We have identified a population of scleroderma patients with low calcifediol, elevated calcitriol level, but no evidence of sarcoidosis. Based on this observation we are planning a prospective study to investigate this further.
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Acknowledgements Steven Obrzut, Heather Sickler and Tricia Bartel assisted with data collection.
Disclosure of Interest None declared