[Developing evidence based guidelines on cardiac rehabilitation - phase 1: a qualitative review]

Guidelines are a means to support effective clinical practice and can be used to implement evidence-based medicine in rehabilitative practice. In 1998 a study on cardiac rehabilitation, funded by Bundesversicherungsanstalt für Angestellte, BfA, concluded that the AHCPR's Guideline on Cardiac Rehabilitation published in 1995 could be used as a reference guideline for the rehabilitation of coronary patients. The AHCPR Guideline and other systematic reviews showed cardiac rehabilitation to be an effective means in coronary care. However, no detailed information is given with regard to the structural and processual details that are required for a multidimensional and comprehensive cardiac rehabilitation scheme. To define those central characteristics, therapeutic interventions that had been proven to be effective for cardiac rehabilitation were analysed. The information derived from these analyses will then be used to develop a more detailed evidence-based guideline.

The analysis was based on the research cited in the AHCPR Guideline. Additionally, a systematic search of the literature identified (randomised) controlled studies published after 1995 for the analysis. Using criteria that had been developed prior to our review, one third (n = 53) of the 159 studies identified were considered suitable for further analysis. Characteristics of the study design, the interventions and the outcomes reported were extracted on a standardised data sheet. In order to facilitate comparisons, studies were arranged according to main intervention and target groups. As it is not possible to present the results in their entirety, this publication focuses on the main aspects which illustrate the method applied.

32 of the 53 studies included dealt with patients after myocardial infarction (MI). In these 32 studies a total of 40 interventions (in 2,912 patients) were investigated. 28 of these interventions dealt with exercise training or exercise training combined with other physical training (i. e. strength training). 7 interventions dealt with counselling only, and 5 interventions had exercise training and counselling as integral parts. Exercise training starts mainly three to four weeks after MI, for 30 - 60 minutes three to 5 times a week. Usually, training intensity is set at 65 - 80 % of the maximum heart rate (or 70 % of the maximum oxygen consumption) reached in standardised exercise testing. All interventions lead to gains in exercise tolerance. Compared to untreated control groups the net benefit ranges from + 11 % to + 30 %. The higher the intensity of the training, the larger the net benefit. The majority of the studies on the effectiveness of exercise training after MI do not report outcomes like psychological well-being, return to work or modification of risk factors.

Despite limitations in report quality and methodology in some of the studies included, a detailed analysis of the interventions investigated can be used to substantiate optimal cardiac rehabilitation. It is possible to quantify important characteristics of the main elements and to define lower and upper limits of treatment. While formulating these limits, it is intended to maintain compatibility with the BfA Classification of therapeutic measures in medical rehabilitation (KTL). As a next step the data from the KTL statistics will be used to assess the scope of German rehabilitative care to define areas which do not comply with the limits defined in the guideline. The results will be consented with experts from science and clinical practice in order to develop an evidence-based, empirically founded, practicable and acceptable guideline for cardiac rehabilitation.