Reporting of adverse events related to dietary supplements to a public health center by medical staff: a survey of clinics and pharmacies.

BACKGROUND: Dietary supplements are used by >50% of the adult population in Japan, and adverse events related to these products have been reported with their increased use. Thus, an efficient system to gather and report data on these adverse events is essential. To date, however, reporting has been limited. The aim of this study was to address this deficiency by exploring the routine reporting practices of the medical staff employed at clinics or pharmacies in Japan. METHODS: We conducted a survey of the procedures used by the medical staff to report adverse events related to dietary supplement intake to public health centers in Japan. The survey was conducted in Japan between November 2015 and January 2016. Based on a sample size calculation, questionnaires were administered to 1,700 potential respondents (850 pharmacists and 850 physicians). The questionnaire inquired about the sociodemographic characteristics and dietary supplement-related adverse event-reporting practices. RESULTS: The response rate was 34.7%, including 286 pharmacists and 304 physicians. Although >30% of the pharmacists and physicians had prior experience dealing with such adverse events, <5% had reported these to a public health center. The survey identified several barriers to reporting, such as "difficulty judging the relationship between an adverse event and the dietary supplement" and "lack of clarity regarding the severity of an adverse event". CONCLUSION: This is the first study to explore the routine reporting practices of physicians and pharmacists in terms of adverse events related to dietary supplements. Further studies are required to elucidate the severity of these adverse events. Moreover, standard reporting criteria ought to be introduced to improve public health.

Methods for estimating causal relationships of adverse events with dietary supplements.

OBJECTIVE: Dietary supplement use has increased over past decades, resulting in reports of potentially serious adverse events. The aim of this study was to develop optimised methods to evaluate the causal relationships between adverse events and dietary supplements, and to test these methods using case reports. DESIGN: Causal relationship assessment using prospectively collected data. SETTING AND PARTICIPANTS: 4 dietary supplement experts, 4 pharmacists and 11 registered dietitians (5 men and 14 women) examined 200 case reports of suspected adverse events using the modified Naranjo scale and the modified Food and Drug Administration (FDA) algorithm. PRIMARY OUTCOME MEASURES: The distribution of evaluation results was analysed and inter-rater reliability was evaluated for the two modified methods employed using intraclass correlation coefficients (ICC) and Fleiss' κ. RESULTS: Using these two methods, most of the 200 case reports were categorised as 'lack of information' or 'possible' adverse events. Inter-rater reliability among entire assessors ratings for the two modified methods, based on ICC and Fleiss' κ, were classified as more than substantial (modified Naranjo scale: ICC (95% CI) 0.873 (0.850 to 0.895); Fleiss' κ (95% CI) 0.615 (0.615 to 0.615). Modified FDA algorithm: Fleiss' κ (95% CI) 0.622 (0.622 to 0.622). CONCLUSIONS: These methods may help to assess the causal relationships between adverse events and dietary supplements. By conducting additional studies of these methods in different populations, researchers can expand the possibilities for the application of our methods.