Coronary heart disease and estrogen replacement therapy. Can compliance bias explain the results of observational studies

摘要: The overall risk/benefit of estrogen replacement therapy (ERT) is strongly dependent on assumptions about the effect ERT coronary heart disease (CHD). belief that causes a substantial reduction in risk CHD widespread. studies provide support for this are all nonexperimental ones. Three analyses data from two randomized clinical trials drug treatments have examined association compliance with total mortality persons who complied taking placebo. In these analyses, placebo was associated same magnitude as users ERT. benefit not reduced by adjustment large number variables, both medical and sociodemographic, might affect mortality. Users compliers, possibility bias may account some apparent must be taken seriously.