Data from: 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.