Alternative package leaflets improve people's understanding of drug side effects-A randomized controlled exploratory survey.

BACKGROUND: Current German and EU package leaflets (PLs) do not distinguish to what extent listed side effects are indeed side effects caused by drug intake or instead symptoms that occur regardless of drug use. We recently showed that most health professionals misinterpret the frequencies of listed side effects as solely caused by the drug. The present study investigated whether (1) these misinterpretations also prevail among laypeople and (2) alternative PLs reduce these misinterpretations. METHODS: In March 2017, 397 out of 400 laypeople approached completed an online survey. They were randomized to one of four PL formats: three alternative PLs (drug facts box with/without reading instruction, narrative format with numbers) and one standard PL. Each PL listed four side effects for a fictitious drug: two were presented as occurring more often, one as equally often, and one as less often with drug intake. The alternative formats (interventions) included information on frequencies with and without drug intake and included a statement on the causal relation. The standard PL (control) only included information on frequency ranges with drug intake. Questions were asked on general occurrence and causality of side effects. RESULTS: Participants randomized to the standard PL were unable to answer questions on causality. For side effects occurring more often (equally; less often) with drug intake, only 1.9% to 2.8% (equally: 1.9%; less often: 1.9%) provided correct responses about the causal nature of side effects, compared to 55.0% to 81.9% (equally: 23.8% to 70.5%; less often: 21.0% to 43.2%) of participants who received alternative PLs. It remains unclear whether one alternative format is superior to the others. CONCLUSION: In conclusion, information on the frequency of side effects in current package leaflets is misleading. Comparative presentation of frequencies for side effects with and without drug intake including statements on the causal relation significantly improves understanding.

What Counselors Tell Low-Risk Clients About HIV Test Performance.

In 1998, Gigerenzer et al. studied how heterosexual men with low-risk behavior were counseled about the accuracy of HIV test results. Most professional counselors conveyed the illusions that false positives do not occur and that a positive HIV test result means that the client is certainly infected. To help improve counseling quality, the authors provided feedback to all counseling centers in Germany. Sixteen years later we assessed whether HIV counseling in Germany has improved by replicating the original study with an expanded sample of 32 randomly selected counseling centers across the country. Since the original research, the positive predictive value (PPV) of HIV testing for a low-risk client has improved from about 50% to 96%. Hence, among every 26 low-risk clients who test positive, we can expect that one is actually not infected. Whereas test performance has improved over the last 16 years, counseling has not. About half of professional counselors communicated the illusion of certainty for sensitivity (15 of 30), specificity (16 of 30), and the PPV (18 of 30). Only one of the 30 counselors could correctly state the PPV. In what follows, we explain how to improve counselors' and clients' understanding of the PPV by representing the information in terms of natural frequencies rather than conditional probabilities. Doing so has been shown to improve the quality of counseling in different medical settings and may enhance future HIV counseling as well.