Determinants of Serum 25-Hydroxyvitamin D Concentrations and a Screening Test for Moderate-to-Severe Hypovitaminosis D in Chinese Patients Undergoing Total Joint Arthroplasty

Development and Validation of a Predictive Model of Hypovitaminosis D in General Adult Population: SCOPYD Study

The worldwide global increase in serum 25-hydroxyvitamin D (25(OH)D) measurements has led some countries to restrict reimbursement for certain clinical situations only. Another approach could consist in providing physicians with screening tools in order to better target blood test prescription. The objective of the SCOPYD study was to identify the best combination of predictors of serum VitD concentration among adults aged 18–70 years. Potential risk factors for VitD deficiency were collected using a comprehensive self-administered questionnaire. A multivariable linear regression was used to build a predictive model of serum 25(OH)D concentration. Among 2488 participants, 1080 (43.4%) had VitD deficiency (<50 nmol/L) and 195 (7.8%) had severe deficiency (<25 nmol/L). The final model included sunlight exposure in the preceding week and during the last holidays, month of blood sampling, age, sex, body mass index, skin phototype, employment, smoking, sport practice, latitude, and VitD supplementation in preceding year. The area under the curve was 0.82 (95% CI (0.78; 0.85)) for severe deficiency. The model predicted severe deficiency with a sensitivity of 77.9% (95% CI (69.1; 85.7)) and a specificity of 68.3% (95% CI (64.8; 71.9)). We identified a set of predictors of severe VitD deficiency that are easy to collect in routine that may help to better target patients for serum 25(OH)D concentration determination.

VASO (Vitamin D and Arthroplasty Surgery Outcomes) study - supplementation of vitamin D deficiency to improve outcomes after total hip or knee replacement: study protocol for a randomised controlled feasibility trial

BACKGROUND

Vitamin D deficiency has been linked to poor outcomes after total hip replacement (THR) or total knee replacement (TKR), including lower patient-reported outcome measures (PROMs), peri-prosthetic infection and longer hospital stay. We present a randomised feasibility trial protocol designed to prospectively investigate the influence of vitamin D testing, and subsequent supplementation for deficiency, prior to THR/TKR.

METHODS/DESIGN

One hundred adult patients undergoing primary THR/TKR for osteoarthritis at two NHS hospital trusts in North East England will be recruited. Exclusion criteria include lack of mental capacity, revision surgery, participants already taking vitamin D/calcium supplements, or a known contraindication to vitamin D treatment. Participants will be ineligible for the trial if they have an estimated glomerular filtration rate < 30 ml/minute. We will measure patients' vitamin D levels at baseline, and those identified as deficient (vitamin D < 50 nmol/L) will be randomised to receive either vitamin D supplementation or no supplementation prior to, and for 6 months following, surgery. Patients with a normal vitamin D level (≥50 nmol/L) will receive no supplementation. Vitamin D levels will be rechecked on the day of surgery and again at 6 months. Patients will also complete a lifestyle questionnaire, as well as the Oxford hip or knee and EQ-5D-3 L PROM questionnaires, at baseline and at 6 months following surgery. The aims are to determine the feasibility of the methodology and to gather data to inform the conduct of a future, larger trial to investigate if supplementation with vitamin D, in those who are deficient, prior to THR/TKR improves outcomes as measured by PROM scores.

DISCUSSION

Previous reports have measured vitamin D levels and correlated this to outcome, but we can find no randomised trial in which researchers investigated the effect of supplementation. The aim of this trial is to determine if vitamin D deficiency is a modifiable risk factor for poor outcome after THR/TKR.

TRIAL REGISTRATION

ISRCTN Registry, ISRCTN14533082 . Registered on 3 April 2017.