Efficacy, effectiveness, and the evaluation of public health interventions

Based on the analysis of a sample of articles that reported the results obtained in observational epidemiological studies published in major journals, Pocock et al1 raised “serious concerns regarding inadequacies in the analysis and reporting of epidemiological publications”, thereby intensifying the outcry regarding the low quality of these papers and the need for guidelines regulating their publication.2 Moreover, epidemiological studies that fail to identify important associations or in which associations that were reported are later shown in effect not to exist abound in the literature. These errors often result in serious consequences, for example, when they involve the evaluation of interventions that cause adverse effects on human health. One recent case refers to the association between hormone replacement therapy (HRT) and cardiovascular disease (CVD), in which various observational studies systematically pointed in one single and erroneous direction—to the protective role of HRT in the occurrence of CVD.3 Surprisingly, two recently published randomised controlled trials (RCT) showed completely contrasting results—a harmful effect of HRT on the occurrence of CVD.4,5 There is no doubt that this “mistake” has had serious implications in women’s health as for several years millions of women worldwide were prescribed with HRT without doctors and …