The cognitive impact of research synopses on physicians: a prospective observational analysis of evidence-based summaries sent by email.

BACKGROUND Effective information transfer in primary care is becoming more difficult as the volume of medical information expands. Emailed research synopses are expected to raise awareness and thereby permit more effective information retrieval. OBJECTIVE To identify key factors that influence physicians' self-reported cognitive impact of emailed research synopses. METHOD In this prospective observational study, research synopses sent by email between 8 September 2006 and 30 May 2007 were analysed. Seven characteristics of synopses (number of characters, research design, study setting, number of types of patient populations studied, number of comparisons, number of outcomes, and number of results) were analysed. Each synopsis was classified as either positive or negative based on physician-reported impacts. Logistic regression analysis was used to evaluate the association between a negative impact and the synopsis' characteristics. RESULTS A total of 1960 Canadian physicians submitted 159,442 ratings on 193 synopses. Each synopsis was assessed on average by 826.1 physicians. On average there were 28.3 negative ratings per research synopsis, 146.3 neutral, and 656.2 positive. Out of the seven characteristics analysed, only the number of comparisons (odds ratio (OR) = 0.47, 95% confidence interval (CI) = 0.23-0.93) and the number of results (OR = 0.64, 95% CI = 0.44-0.93) had a statistically significant influence on physician ratings. An increase in the number of comparisons (P = 0.03) or the number of results (P = 0.02) decreased the likelihood of a negative impact. CONCLUSIONS Characteristics of the synopses appear to influence cognitive impact, and there might be lexical patterns specific to these factors. Further research is recommended in order to understand the mechanism for the influence of these characteristics.