Effectiveness of professional and patient-oriented strategies in reducing vitamin D and B12 test ordering in primary care: a cluster randomised intervention study

BackgroundVitamin tests are increasingly ordered by GPs, but a clinical and evidence-based indication is often lacking. Harnessing technology (that is, decision support tools and redesigning request forms) have been shown to reduce vitamin requests.AimTo investigate whether the number of vitamin tests may be reduced by providing a multi-level intervention programme based on training, monitoring, and feedback.Design & settingThis was a cluster randomised intervention study performed in 26 primary care health centres (>195 000 patients) in the Netherlands. The relative reduction in ordered vitamin D and B12 tests was determined after introduction of two de-implementation strategies (1 May 2017 to 30 April 2018).MethodHealth centres randomised to de-implementation strategy 1 received education and benchmarking of their own vitamin test ordering behaviour every 3 months. Health centres in de-implementation strategy 2 received the same education and benchmarking, but supplemented with educational material for patients.ResultsThe number of vitamin D tests decreased by 23% compared to the 1-year pre-intervention period (1 May 2016 to 30 April 2017). For vitamin B12 tests an overall reduction of 20% was found. Provision of patient educational information showed additional value over training and benchmarking of GPs alone for vitamin D test ordering (10% extra reduction, odds ratio [OR] 0.88, 95% confidence interval [CI] = 0.83 to 0.92), but not for vitamin B12 ordering (4% extra reduction, OR 0.96, 95% CI = 0.91 to 1.02). Nationwide, this would result in over €3 200 000 in savings on healthcare expenditure a year.ConclusionA structured intervention programme, including training and benchmarking of GPs regarding their diagnostic test ordering, resulted in a significant reduction in ordered vitamin tests. Additional information provision to patients resulted in a small but still relevant additional reduction. If implemented on a national level, a substantial cost saving could be achieved.