Prospective, comparative cohort studies and their contribution to the benefit assessments of therapeutic options: heart failure treatment with and without Hawthorn special extract WS 1442.

Background: In addition to testing a drug for its efficacy, pharmacological quality and safety, current policies are increasingly demanding evaluations of the therapeutic benefits provided by a drug in general practice with "non-selected" patients and increasingly restrictive economic considerations.

Objective: One of the trials which addresses this task is the WISO cohort study (Efficacy and socio-economic relevance of treatment of chronic heart failure stage NYHA II with Crataegus extract WS 1442). It compares two different therapeutic strategies in the treatment of heart failure stage NYHA II, i.e. a conventional medication and a therapy which also includes hawthorn special extract WS 1442 (Crataegutt novo 450) in addition to chemical-synthetic drugs. In contrast to clinical trials, the patients in cohort studies are expressly not randomised and the physician in charge independently chooses the administered treatment. This comparative, non-interventional observation provides well-founded evidence of the "real-world effectiveness" of the tested preparation.

Patients and methods: 952 patients with heart failure (NYHA II) were enrolled in the study by 217 general practitioners. 588 patients received Crataegus special extract WS 1442 (Crataegutt novo 450) either as an add-on therapy or as a monotherapy (Crataegus cohort) and 364 patients received therapy without hawthorn (comparative cohort). These two groups had the same indication (heart failure NYHA II) but were significantly different regarding gender, age and concomitant cardiovascular disease. Basically, in view of the free choice of therapy made by the physician in charge, such differences are to be expected in comparative observational studies. A sufficient degree of patient comparability was provided by means of the matched-pairs technique, which replaced the randomisation procedure normally used in clinical studies. After 2 years, 130 patient pairs generated by this technique could be included in the interim assessment.

Results: The clinical symptoms with regard to all parameters investigated showed the same or a more pronounced improvement in the Crataegus cohort in the course of 2 years. After 2 years, the three cardinal symptoms of heart failure--fatigue (p = 0.036), stress dyspnoea (p = 0.020) and palpitations (p = 0.048)--were significantly less marked in the Crataegus cohort than in the comparative cohort.

Discussion: The particular design of the cohort study also provides valuable additional information: (1) Hawthorn special extract WS 1442 was prescribed in registered cardiological practices for the treatment of patients with heart failure stage NYHA II, partly as an alternative and partly as a supplement to the used chemical-synthetic drugs. (2) Favourable effects on the clinical symptoms were achieved although the patients in the Crataegus cohort received markedly fewer chemical-synthetic drugs than the patients in the comparative cohort (ACE-inhibitors: 36 vs. 54%, p = 0.004; cardiac glycosides: 18 vs. 37%, p = 0.001; diuretics: 49 vs. 61%, p = 0.061; beta-blockers: 22 vs. 33%, p = 0.052).

Conclusion: The data show a clear benefit for patients with heart failure stage NYHA II treated with WS 1442. The single or add-on administration in addition to a chemical-synthetic medication resulted in objective improvements at comparable costs.