57% of RCTs of cardiovascular nursing interventions show that they improve at least one outcome for secondary prevention patients; optimum intervention strategy unclear
- Correspondence to Robyn Gallagher
Jones Street, Broadway, NSW 2007, Australia;
Cardiovascular diseases such as coronary artery disease (CAD) and heart failure (HF) are now the leading causes of death worldwide.1 One of the important methods of addressing this issue is secondary prevention in people with existing diagnoses, therefore a major focus of cardiovascular nurses over the last few decades has been secondary prevention. However, until this paper, none of the systematic reviews of secondary prevention interventions published to date has specifically focused on interventions provided by nurses.
In this systematic review, Allen and Dennison conducted a methodical search for randomised trials published in English between 2000 and 2008 in the PubMed and CINAHL databases. Studies were included if they were secondary prevention interventions for CAD and HF primarily conducted by nurses, had less than 25% drop out rates and included intention to treat analyses. A total of 53 articles were included in the review, 33 related to HF and 20 to CAD, with the intervention strategies primarily a combination of education, behavioural counselling and support (65%). A number of limitations in the methods were noted by the authors including: small sample sizes, under representation of women and heterogeneity of outcome measures and intervention strategies, the latter resulting in an inability to pool data for meta-analyses. Instead, significant outcomes were differentiated and the conclusion reached that the majority (57%) of nursing interventions had a positive impact on at least one outcome of blood pressure, smoking, lipids, dietary intake, weight loss, quality of life, psychosocial outcomes and health service use. Most consistently positive outcomes occurred for physical activity (4/5), dietary intake (3/3) and body mass index/weight loss (4/5). However, no particular intervention or combination of interventions could be distinguished as being most effective for any specific outcome or combination of outcomes.
This systematic review used sound methodology to find and assess the quality of the articles so that overall good quality articles were included. Furthermore, the studies included were concisely and accurately summarised, although the level of detail varied between the studies. It is possible that some articles published as conference abstracts may have been missed, and that despite stating that only articles with intention to treat analyses would be included the adapted Jadad scores were as low as one, indicating that this criteria may not have been adhered to. Given the heterogeneity of the studies it was understandable that pooling the study results could not be used to counterbalance the small sample sizes of the studies. However, some outcomes such as time to cardiac event or hospitalisation, survival, blood pressure and lipid levels were frequently used, so the potential for pooling of groups was present.
The results of the review are consistent with previous systematic reviews of secondary prevention for HF and CAD, which also found small improvements in risk factors, quality of life, mortality and cardiac events, although these reviews included meta-analyses. This consistency is not surprising as there was a high level of involvement by nurses in the interventions in these reviews as well. The overall picture of secondary prevention intervention then is that the majority of interventions involve education and support for behaviour change and that these interventions generally result in improved outcomes in CAD and HF.
However, the difficulty remains in determining the timing, depth, intensity, mode of delivery and cost-benefit of strategies for specific outcomes. This is important because it is becoming increasingly difficult to determine where healthcare resources should be allocated, including nursing expertise. Without this detail, translation of tested interventions is not likely to be well embedded into everyday practice for patients with CAD and HF.
Testing of nursing interventions needs to continue, particularly rigorous testing using well-established outcome measures, as well as comparisons of specific subcomponents and detailed reporting of results.
Competing interests None.