Potentially inappropriate testing for vitamin D deficiency: a cross-sectional study in Switzerland

Non-indicated vitamin B12- and D-testing among Dutch hospital clinicians: a cross-sectional analysis in data registries

OBJECTIVES

To assess the extent of non-indicated vitamin B12- and D-testing among Dutch clinicians and its variation among hospitals.

DESIGN

Cross-sectional study using registration data from 2015 to 2019.

PARTICIPANTS

Patients aged between 18 and 70 years who received a vitamin B12- or D-test.

PRIMARY AND SECONDARY OUTCOME MEASURES

The proportion of non-indicated vitamin B12- and D-testing among Dutch clinicians and its variation between hospitals (n=68) over 2015-2019.

RESULTS

Between 2015 and 2019, at least 79.0% of all vitamin B12-tests and 82.0% of vitamin D-tests lacked a clear indication. The number of vitamin B12-tests increased by 2.0% over the examined period, while the number of D-tests increased by 12.2%. The proportion of the unexplained variation in non-indicated vitamin B12- and D-tests that can be ascribed to differences between hospitals remained low. Intraclass correlation coefficients ranged between 0.072 and 0.085 and 0.081 and 0.096 for non-indicated vitamin B12- and D-tests, respectively. The included casemix variables patient age, gender, socioeconomic status and hospital size only accounted for a small part of the unexplained variation in non-indicated testing. Additionally, a significant correlation was observed in non-indicated vitamin B12- and D-testing among the included hospitals.

CONCLUSION

Hospital clinicians order vitamin B12- and D-tests without a clear indication on a large scale. Only a small proportion of the unexplained variation could be attributed to differences between hospitals.

Renal insufficiency and magnesium deficiency correlate with a decreased formation of biologically active cholecalciferol: a retrospective observational study

BACKGROUND

Vitamin D is synthesized in the skin or supplied. Cholecalciferol is hydroxylated in the liver to 25(OH) vitamin D [25D]. 25D is further hydroxylated in the kidney to 1,25(OH) vitamin D [1,25D]. Catabolism occurs by further hydroxylation. Magnesium is a cofactor of all involved hydroxylases.

AIM

To investigate the association between renal function and serum magnesium levels, and the biologically active hormone 1,25D.

METHOD

Anonymised serum values of 25D, 1,25D, magnesium and creatinine measured in an outpatient cohort over 2 years were analysed.

RESULTS

Renal function and magnesium level did not influence 25D values (r = - 0.144 and 0.030, respectively). Mean serum 1,25D values decreased from 106.5 ± 44.3 pmol/l in individuals with normal renal function to 51.7 ± 18.9 pmol/l in those with severe renal insufficiency (p < 0.01). A weak positive correlation was observed between 1,25D and eGFR (r = 0.317), and between 1,25D and serum magnesium (r = 0.217).

CONCLUSION

Impaired renal function and low magnesium serum levels are slightly associated with low 1,25D concentrations. Measuring 25D, but not 1,25D, may overestimate the patient's vitamin D status. In patients with renal insufficiency adequate magnesium supply should be ensured.

Factors Associated with Potentially Inappropriate Screening for Vitamin D Deficiency among Women in Medically Underserved Regions of West Texas

Testing for vitamin D deficiency (VDD) has been on the increase due to its association with several diseases. However, inappropriate testing for VDD, defined as screening for VDD among individuals with a low risk, has been reported. The aim of this study was to evaluate the prevalence and factors associated with potentially inappropriate screening for VDD among medically underserved populations in West Texas. Data were from 21,407 women who were hospitalized from 2016 to 2018 at a large regional health system. Logistic regression was used to calculate odds ratios (ORs) and 95% confidence intervals (CIs). The median age of patients was 40 years. While the proportion of patients tested for VDD reduced from 8.9% to 7.6% (p = 0.013) from 2016 to 2018, the prevalence of inappropriate testing increased from 32.3% to 46.8% (p < 0.001), with the 3-year prevalence of VDD being 27.6%. White race (OR = 2.71, CI: 1.95-3.78), an age ≥ 65 years (OR = 3.07, CI: 2.05-4.59), the use of public-sponsored insurance (OR = 1.62, CI: 1.20-2.17), cardiovascular disease (OR = 0.75, CI: 0.63-0.90), and vitamin D supplement use (OR = 7.05, CI: 5.82-8.54) were associated with inappropriate testing for VDD. In this study, an increasing prevalence of potentially inappropriate testing for VDD was observed. Sociodemographic and health-related conditions were associated with potentially inappropriate testing for VDD.

Health, financial and environmental impacts of unnecessary vitamin D testing: a triple bottom line assessment adapted for healthcare

OBJECTIVE

To undertake an assessment of the health, financial and environmental impacts of a well-recognised example of low-value care; inappropriate vitamin D testing.

DESIGN

Combination of systematic literature search, analysis of routinely collected healthcare data and environmental analysis.

SETTING

Australian healthcare system.

PARTICIPANTS

Population of Australia.

OUTCOME MEASURES

We took a sustainability approach, measuring the health, financial and environmental impacts of a specific healthcare activity. Unnecessary vitamin D testing rates were estimated from best available published literature; by definition, these provide no gain in health outcomes (in contrast to appropriate/necessary tests). Australian population-based test numbers and healthcare costs were obtained from Medicare for vitamin D pathology services. Carbon emissions in kg CO2e were estimated using data from our previous study of the carbon footprint of common pathology tests. We distinguished between tests ordered as the primary test and those ordered as an add-on to other tests, as many may be done in conjunction with other tests. We conducted base case (8% being the primary reason for the blood test) and sensitivity (12% primary test) analyses.

RESULTS

There were a total of 4 457 657 Medicare-funded vitamin D tests in 2020, on average one test for every six Australians, an 11.8% increase from the mean 2018-2019 total. From our literature review, 76.5% of Australia's vitamin D tests provide no net health benefit, equating to 3 410 108 unnecessary tests in 2020. Total costs of unnecessary tests to Medicare amounted to >$A87 000 000. The 2020 carbon footprint of unnecessary vitamin D tests was 28 576 kg (base case) and 42 012 kg (sensitivity) CO2e, equivalent to driving ~160 000-230 000 km in a standard passenger car.

CONCLUSIONS

Unnecessary vitamin D testing contributes to avoidable CO2e emissions and healthcare costs. While the footprint of this example is relatively small, the potential to realise environmental cobenefits by reducing low-value care more broadly is significant.

Mikronährstoffe bei Adipositas und nach bariatrischer Chirurgie

Adipositas hat weltweit eine hohe Prävalenz erreicht und stellt die Gesundheitssysteme vor grosse Herausforderungen. Die bariatrische Chirurgie hat sich zur Behandlung der Adipositas in den letzten 20 Jahren etabliert. Dabei führen die durchgeführten bariatrischen Operationen oft zu Mikronährstoffmängeln, welche systematisch supplementiert werden müssen. Auch ohne Operation bestehen bei Menschen mit Adipositas veränderte Blutwerte, welche das Vorliegen von Mikronährstoffmängeln suggerieren. Die klinische Relevanz dieser Befunde ist jedoch oft ungewiss. In unserer Übersichtsarbeit geben wir einen Überblick über den aktuellen Wissensstand zum Thema Mikronährstoffe bei Adipositas und nach bariatrischer Chirurgie und stellen exemplarisch einige unsererseits erhobene Befunde dar.

Vitamin D retesting by general practitioners: a factor and cost analysis

OBJECTIVES

Vitamin D testing by Primary Care doctors is increasing, placing greater workloads on healthcare systems. There is little data though on vitamin D retesting in Ireland. This study aims to investigate the factors associated with vitamin D retesting by Irish General Practitioners (GPs) and examine the resulting costs.

METHODS

This is a retrospective analysis over 5 years (2014-2018) of GP requested 25-hydroxyvitamin D (25(OH)D) results in 36,458 patients at a major city hospital in Dublin, Ireland. Those with one test were compared with individuals who were retested and samples categorised to determine changes in status between tests.

RESULTS

Nearly one in four patients (n=8,305) were retested. Positive predictors of retesting were female (p<0.001), age (60-69 years, p<0.001), location (Co. Kildare, p<0.001) and initial deficiency (<30 nmol/L, p<0.001) or insufficiency (30-49.9 nmol/L, p<0.001). Vitamin D status improved on retesting, with deficiency halving on first retest (9 vs. 18%, p<0.001) and dropping to 6% on further retests. About 12.2% of retests were done within 3 months and 29% had ≥2 retests within 1 year. 57% of retests were in those initially vitamin D replete (>50 nmol/L). The annual cost of inappropriate testing was €61,976.

CONCLUSIONS

One in four patients were retested and this varied by age, gender and patient location. Over 10% of retests were inappropriately early (<3 months), a third too frequent and over half were in replete individuals incurring significant costs. Clear guidance for GPs on minimum retesting intervals is needed, as well as laboratory ordering systems to limit requests using pre-defined criteria.