Exploring GP and patient attitudes towards the use and deprescribing of dietary supplements: a survey study in Switzerland.

Background: Dietary supplements are commonly used by older adults, but their inappropriate use may lead to adverse events. To optimise medication use, general practitioners (GPs) ideally are aware of all substances that patients use, including supplements. This cross-sectional study explored the use of dietary supplements by older patients with polypharmacy, the rate at which they disclosed this use to their GPs, and compared patients' and GPs' attitudes towards discontinuing dietary supplements.

Methods: Ten GPs in Swiss primary care recruited five to ten of their older patients taking ≥ 5 regular medications. Both GPs and their patients completed a survey on patients' use of dietary supplements and attitudes towards deprescribing those. We described and compared their responses. We assessed the association of supplement disclosure with patient characteristics using multilevel logistic regression analysis.

Results: Three out of ten GPs (30%) were female, and GPs' average age was 52 years (SD = 8). 45% of patients were female (29/65). Most patients (n = 45, 70%) were taking ≥ 1 supplement. On average, patients reported to be using three supplements (SD = 2). In 60% (n = 39) of patients, GPs were unaware of ≥ 1 supplement used. We did not find evidence for an association between supplement disclosure to GPs and patient characteristics. Only 8% (n = 5) of patients and 60% (n = 6) of GPs reported ≥ 1 supplement they would be willing to deprescribe and none of the supplements reported by GPs and patients to deprescribe matched.

Conclusion: Swiss GPs were unaware of many dietary supplements used by their older patients, which may affect medication optimisation efforts.