Treatment of vitamin D deficiency: divergence between clinical practice and expert advice
Postgraduate Medical Journal, 04/26/2012Exclusive Author Commentary
Findlay M et al. - The authors have shown a divergence between clinical practice and even the most conservative expert advice for vitamin D replacement therapy. Possible explanations are conflicting advice on treatment and difficulty obtaining suitable vitamin D preparations, particularly high dose vitamin D and vitamin D without calcium, in the UK.
The authors examined all requests for serum 25OHD over a 12-month period, from September 2009 to 2010 in southwest Scotland.
The authors wrote to all 33 general practices asking whether they usually started replacement therapy with a loading dose and/or recommended over-the-counter maintenance preparations.
The authors accessed the Emergency Care Summary for all patients with serum 25OHD <25 nmol/l to determine whether they had been prescribed maintenance therapy.
Serum 25OHD was requested in 1162 patients.
Levels were <25 nmol/l in 282 (24%) patients, only 173 (61%) of whom were receiving vitamin D replacement therapy 3–15 months after diagnosis.
Only four (1.4%) were prescribed a loading dose.
One hundred and fifty-three (54%) were treated with cholecalciferol or ergocalciferol and 19 (7%) with alfacalcidol or calcitriol.
The median dose of chole/ergocalciferol was 800 IU per day, usually in combination with 1200 mg calcium per day.
An audit conducted in south west Scotland revealed that when vitamin D status is assessed more than 50% of patients are deficient as judged by a serum 25 OHD <50nmol/L. Less than two thirds of these patients were receiving any form of replacement. In almost all cases this was 800IU of ergo- or cholecalciferol in combination with 1200mg calcium. Less than 2% of patients were given a loading dose.
Our findings have confirmed that vitamin D deficiency is a common problem, and revealed inconsistencies in management. Of concern, many patients received no replacement therapy. Those that did received doses considered by some authorities as too low in combination with calcium which, anecdotally, renders the tablets unpalatable and affects concordance with therapy. The practice of loading a deficient patient is rare.
Our review of the literature revealed wide variation in current expert advice which we believe has led to inconsistencies in clinical practice. It is currently unclear to the general physician whether loading doses are necessary or safe in patients with proven deficiency. Maintenance doses are often provided with calcium as, in the UK, no licenced calcium-free preparation exists. In rare circumstances some patients have, inappropriately, been prescribed short acting vitamin D analogues.
We have since discovered that a large number of unlicensed vitamin D preparations exist and that it is possible to prescribe both loading and maintenance doses for patients for under £10 per year. At a national level, we are aware that more robust evidence is required to substantiate a link between vitamin D deficiency, cancer and heart disease before clearer recommendations can be made.