Vitamin D testing patterns among general practitioners in a major Victorian primary health care service

Did changes to recommended testing criteria affect the rate of vitamin D testing among Australian women

We examine whether new government criteria designed to reduce overuse of vitamin D testing changed testing rates in Australian women. Although testing initially declined, the reduction was not sustained. Women who had more doctor visits and who had been tested previously were more likely to have vitamin D testing.

PURPOSE

Vitamin D testing increased substantially in the 2000s in many countries, particularly in women. Because of concerns about potential over-testing, in 2014, the Australian criteria for subsidised testing were restricted to those at high risk of vitamin D deficiency. We aimed to describe vitamin D testing trends in Australian women (1996 to 2019) and investigate sociodemographic and health factors associated with testing under the new criteria.

METHODS

We used joinpoint regression to assess changes in national testing trends in Australian women (aged 15+ years) using universal health insurance system data. Additionally, we investigated the factors associated with vitamin D testing through Poisson regression with robust error variance using survey and linked insurance system data from participants born 1946-51 in the Australian Longitudinal Study on Women's Health (ALSWH).

RESULTS

Between 1996 and 2013, vitamin D testing rates increased in all age groups. Rates declined between 2013 and 2016, but increased again between 2016 and 2019. In the ALSWH cohort, a higher likelihood of testing under the new criteria was associated with 12 or more doctor visits per year compared to two or fewer visits per year (relative risk (RR) 1.85; 95% CI 1.61-2.12), and women who had two or more vitamin D tests between 2012 and 2014 compared to no test (RR 1.55; 95% CI 1.48-1.62).

CONCLUSION

The introduction of new criteria has not led to sustained declines in testing. High testing rates and repeated testing suggest that over-testing for vitamin D deficiency in Australian women is still occurring.

Reducing unnecessary vitamin testing in general practice: barriers and facilitators according to general practitioners and patients

OBJECTIVE

There has been an increase in testing of vitamins in patients in general practice, often based on irrational indications or for non-specific symptoms, causing increasing healthcare expenditures and medicalisation of patients. So far, there is little evidence of effective strategies to reduce this overtesting in general practice. Therefore, the aim of this qualitative study was to explore the barriers and facilitators for reducing the number of (unnecessary) vitamin D and B12 laboratory tests ordered.

DESIGN AND SETTING

This qualitative study, based on a grounded theory design, used semistructured interviews among general practitioners (GPs) and patients from two primary care networks (147 GPs, 195 000 patients). These networks participated in the Reducing Vitamin Testing in Primary Care Practice (REVERT) study, a clustered randomized trial comparing two de-implementation strategies to reduce test ordering in primary care in the Netherlands.

PARTICIPANTS

Twenty-one GPs, with a maximum of 1 GP per practice who took part in the REVERT study, and 22 patients (who were invited by their GP during vitamin-related consultations) were recruited, from which 20 GPs and 19 patients agreed to participate in this study.

RESULTS

The most important factor hampering vitamin-test reduction programmes is the mismatch between patients and medical professionals regarding the presumed appropriate indications for testing for vitamin D and B12. In contrast, the most important facilitator for vitamin-test reduction may be updating GPs' knowledge about test indications and their awareness of their own testing behaviour.

CONCLUSION

To achieve a sustainable reduction in vitamin testing, guidelines with clear and uniform recommendations on evidence-based indications for vitamin testing, combined with regular (individual) feedback on test-ordering behaviour, are needed. Moreover, the general public needs access to clear and reliable information on vitamin testing. Further research is required to measure the effect of these strategies on the number of vitamin test requests.

TRIAL REGISTRATION NUMBER

WAG/mb/16/039555.

Compliance with pathology testing guidelines in Australian general practice: protocol for a secondary analysis of electronic health record data

INTRODUCTION

In Australia, general practitioners usually are the first point of contact for patients with non-urgent medical conditions. Appropriate and efficient utilisation of pathology tests by general practitioners forms a key part of diagnosis and monitoring. However overutilisationand underutilisation of pathology tests have been reported across several tests and conditions, despite evidence-based guidelines outlining best practice in pathology testing. There are a limited number of studies evaluating the impact of these guidelines on pathology testing in general practice. The aim of our quantitative observational study is to define how pathology tests are used in general practice and investigate how test ordering practices align with evidence-based pathology guidelines.

METHODS AND ANALYSIS

Access to non-identifiable patient data will be obtained through electronic health records from general practices across three primary health networks in Victoria, Australia. Numbers and characteristics of patients, general practices, encounters, pathology tests and problems managed over time will be described. Overall rates of encounters and tests, alongside more detailed investigation between subcategories (encounter year, patient's age, gender, and location and general practice size), will also be undertaken. To evaluate how general practitioner test ordering coincides with evidence-based guidelines, five key candidate indicators will be investigated: full blood counts for patients on clozapine medication; international normalised ratio measurements for patients on warfarin medication; glycated haemoglobin testing for monitoring patients with diabetes; vitamin D testing; and thyroid function testing.

ETHICS AND DISSEMINATION

Ethics clearance to collect data from general practice facilities has been obtained by the data provider from the RACGP National Research and Evaluation Ethics Committee (NREEC 17-008). Approval for the research group to use these data has been obtained from Macquarie University (5201700872). This study is funded by the Australian Government Department of Health Quality Use of Pathology Program (Agreement ID: 4-2QFVW4M). Findings will be reported to the Department of Health and disseminated in peer-reviewed academic journals and presentations (national and international conferences, industry forums).

Clinical Management of Low Vitamin D: A Scoping Review of Physicians' Practices

The role of vitamin D in the prevention and treatment of non-skeletal health issues has received significant media and research attention in recent years. Costs associated with clinical management of low vitamin D (LVD) have increased exponentially. However, no clear evidence supports vitamin D screening to improve health outcomes. Authoritative bodies and professional societies do not recommend population-wide vitamin D screening in community-dwelling adults who are asymptomatic or at low risk of LVD. To assess patterns of physicians’ management of LVD in this conflicting environment, we conducted a scoping review of three electronic databases and the gray literature. Thirty-eight records met inclusion criteria and were summarized in an evidence table. Thirteen studies published between 2006 and 2015 across seven countries showed a consistent increase in vitamin D lab tests and related costs. Many vitamin D testing patterns reflected screening rather than targeted testing for individuals at high risk of vitamin D deficiency or insufficiency. Interventions aimed at managing inappropriate clinical practices related to LVD were effective in the short term. Variability and controversy were pervasive in many aspects of vitamin D management, shining a light on physicians’ practices in the face of uncertainty. Future research is needed to inform better clinical guidelines and to assess implementation practices that encourage evidence-based management of LVD in adult populations.

Increase of vitamin D assays prescriptions and associated factors: a population-based cohort study

A worldwide increase in the frequency of testing for serum 25-hydroxyvitamin D (25OHD) levels has been observed over the last years. Our aim was to measure the evolution in the number of vitamin D assays performed in France from 2008 to 2013 and to investigate some of the drivers that may explain this increase. Patients within the representative 1/97th sample of the French health insurance system reimbursement database (EGBS database) who had at least one 25OHD or 1-25(OH)₂D assay between 2008 and 2013 were included. Trends over time in number of vitamin D assays were analysed globally and per year in a multivariable Poisson regression model with GEE. Among the 639,163 patients of the EGBS database, 118,509 (18.5%) had at least one vitamin D assay over the 6-year study period. Among the individuals tested, 52.1% had only one test. The number of vitamin D assays (25OHD or 1-25(OH)₂D) increased 7.5-fold from 9,620 in 2008 to 81,641 in 2013. This study confirms the rapid and dramatic increase in vitamin D assays prescriptions and shows that this is mostly due to a global increase of the proportion of patients tested rather than an increase in repetition of tests in some individual patients.

Efficacy of high dose Vitamin D supplementation in improving serum 25(OH)D among migrant and non migrant population: a retrospective study

BACKGROUND

Higher dose of vitamin D supplementation 50000 IU is required for those whose serum 25(OH)D levels are 50 nmol/L and below. The increment in serum 25(OH)D though not significantly affected by race, sex or age it is negatively correlated to the baseline 25(OH)D concentration. This study investigated whether the mean increase in serum 25(OH)D will be higher among participants with lower baseline 25(OH)D levels and whether the duration of supplementation has an influence on the serum 25(OH)D achieved.

METHODS

A clinical audit of patients' medical records from a community health centre in Melbourne for the period 01.01.2010 to 31-12.2012 was undertaken. Paired sample t test was used to determine difference in pre and post dose serum 25(OH)D. Simple and multiple linear regressions were used to examine the association between the difference in pre and post dose serum 25(OH)D and duration of supplementation and baseline serum 25(OH)D, adjusting for socio-demographic factors.

RESULTS

A total of 205 patients were included in the study. Mean difference in serum 25(OH)D was highest 52.8 nmol/L (95 % CI: 46.63-58.92) among those whose serum 25(OH)D was below 25 nmol/L at baseline. Baseline 25(OH)D alone accounted for 13.7 % of variance in the effect size (F(2, 202) = 16.0. p < 0.001), with the effect size significantly higher among participants with a baseline 25(OH)D level of 25-49 nmol/L (β = 11.93, 95 % CI: 0.48, 23.40, p < 0.05). Mean serum 25(OH)D difference was highest, 47.53 nmol/L (95 % CI: 40.95-54.11) when measured within 3 months of supplementation. Duration of supplementation explained 2.9 % of the variance in the effect size (F (1, 203) = 6.11, p < 0.05) and there was an inverse relationship between the length of supplementation and mean pre and post supplementation serum 25(OH)D difference (β = -1.45, 95 % CI: -2.62, -0.29, p = 0.014).

CONCLUSION

Following 50000 IU vitamin D3 for 12 months mean serum 25(OH)D increase was highest among those whose baseline serum 25(OH)D was lower. Migrants especially dark-skinned are at a high risk for vitamin D deficiency in Australia. High dose vitamin D3 50000 IU (cholecalciferol) is effective in achieving sufficient serum 25(OH)D among these populations who tend to have lower baseline serum 25(OH)D.