gms | German Medical Science

Komplexe Interventionen – Entwicklung durch Austausch: 13. Jahrestagung des Deutschen Netzwerks Evidenzbasierte Medizin

Deutsches Netzwerk Evidenzbasierte Medizin e. V.

15.03. - 17.03.2012, Hamburg

Multifactorial lifestyle interventions in the primary and secondary prevention of cardiovascular disease and type 2 diabetes mellitus – a difficult review

Meeting Abstract

Search Medline for

  • corresponding author Klaus Linde - Institute of General Practice, Technische Universität München, Munich, Germany

Komplexe Interventionen – Entwicklung durch Austausch. 13. Jahrestagung des Deutschen Netzwerks Evidenzbasierte Medizin. Hamburg, 15.-17.03.2012. Düsseldorf: German Medical Science GMS Publishing House; 2012. Doc12ebm002

doi: 10.3205/12ebm002, urn:nbn:de:0183-12ebm0022

Published: March 5, 2012

© 2012 Linde.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by-nc-nd/3.0/deed.en). You are free: to Share – to copy, distribute and transmit the work, provided the original author and source are credited.


Outline

Text

This presentation aims to give an example of how problems related to complexity can make a systematic review difficult. It has been shown that lifestyle factors (namely nutrition, physical activity and psychological aspects) are strongly associated morbidity and mortality. Therefore, lifestyle interventions addressing several of these factors simultaneously seem a logical approach. We have summarized the available randomized controlled trials of multifactorial lifestyle interventions in the primary and secondary prevention of cardiovascular disease and type 2 diabetes mellitus. The project was funded by the German Ministry of Education and Research. The final review included a total of 25 trials in a total of 7,703 participants. We found only small effects on surrogate measures (e.g., cholesterol, HbA1c). Effects on major endpoints (e.g. myocardial infarction) seemed more promising but confidence intervals were wide due to low event rates. The findings were published in a relevant specialty journal [1]. While formally this was a successful project it left the author unsatisfied as he felt that many primary studies and the review could not adequately grasp and deal with the complexity of the subject. The interventions varied strongly and we had great problems to assess them adequately. The main questions arising were: Were the interventions conceptually sound? Were they implemented adequately? To which extent did patients adhere to the recommendations? The primary studies were performed in variable settings and differing cultural backgrounds. Could the interventions be implemented on a population level and in other countries? Are the study findings likely to representative? Questions arose also regarding adequate outcome measurement. Could it be that mulitfactorial interventions have, compared to more focussed interventions (e.g. increasing physical activity only), only minor effects on specific surrogate measures but major effects on the relevant endpoints?

These are only a few of the questions arising in the review process. Based on these experiences the author got serious doubts whether the meta-analytic findings of the review are interpretable but peer reviewers exerted great pressure on reporting them comprehensively. Personally, I think that for the evaluation of multifactorial lifestyle interventions future systematic reviews should try to mix conventional synthesis methods with those of realist reviews.


References

1.
Angermayr L, Melchart D, Linde K. Multifactorial lifestyle interventions in the primary and secondary prevention of cardiovascular disease and type 2 diabetes mellitus--a systematic review of randomized controlled trials. Ann Behav Med. 2010 Aug;40(1):49-64. DOI: 10.1007/s12160-010-9206-4 External link