Mismatch between heart failure patients in clinical trials and the real world

Evidence-based medicine urges physicians to translate results from clinical trials to their patients. This, however, can only work, if real world patients are represented in clinical trials.

We searched the literature on chronic heart failure (1950-2/2011) for studies designed to detect effects on mortality (mortality studies, MS) and exercise training studies (ETS) as the leading non-pharmaceutical/non-surgical treatment option in order to compare their characteristics with European (Euro Heart Survey on Heart Failure, EHSHF) and North American (Framingham Heart Study, FHS) epidemiological studies.

After an extensive literature search, we identified 207 ETS and 59 MS. Subjects enrolled in ETS were younger (ETS: 62.5 ± 6.6; MS: 63.9 ± 4.6; EHSHF: 71.0 ± 3.5; FHS: 78.0 years), more often male (ETS: 80.9%; MS: 77.3%; EHSHF: 53.0%; FHS: 49.6%; p<0.001), and had substantially less comorbidities such as diabetes mellitus (ETS: 13.6%; MS: 22.5%; EHSHF: 27.0%; FHS: 25.3%; p<0.001), or hypertension (ETS: 26.3%; MS: 39.1%; EHSHF: 53.0%; FHS: 46.9%; p<0.001). Angiotensin converting enzyme-inhibitors, beta-blockers, and angiotensin-receptor-blockers were more commonly used in ETS than in EHSHF (all p<0.001). Only 16 (10.6%) ETS and 20 (62.5%) MS reported ethnic background.

Heart failure patients in exercise training studies and mortality studies do not represent real world patients. In order to extrapolate data to the general population future exercise training studies as well as mortality studies need to include representative patients. Otherwise, knowledge gained can only be translated to a minority of our patients.