The effectiveness of reducing dietary sodium intake versus normal dietary sodium intake in patients with heart failure on reducing readmission rate: a systematic review protocol Palle Larsen 1,4 Preben U Pedersen 2,4 Amalia Tsiamil 3 1. PhD student, University College Zealand, Denmark 2. Professor, University of Aalborg, Denmark 3. Associate Professor, University of West London, United Kindgom 4. Danish Centre of Systematic Reviews in Nursing: a collaborating centre of the Joanna Briggs Institute Corresponding author Palle Larsen, pla@kliniskeretningslinjer.dk Review question/objective The objective of this review is to identify the effectiveness of reduced dietary salt intake on readmission and mortality rates. More specifically, the objectives are to identify the effectiveness of low dietary salt intake on readmission and mortality in patients with heart failure. Background Heart failure is a disease with one of the highest mortality rates in the Western world. 1 Heart failure patients have a poor prognosis, with a five-year mortality rate of 68.7% and a median survival time of 2.4 years. 2 Heart failure is also associated with reduced quality of life and frequent readmissions to hospital. 3 Recommendations have been developed by the European Cardiology Society (ECS) that guide the use of pharmacological and non-pharmacological interventions for patients with heart failure. 4,5 Non-pharmacological interventions focus mainly on lifestyle changes and changes of behavior in everyday life and must be systematically incorporated into the treatment and rehabilitation of patients with heart failure. 5 These behavioral changes can be interpreted as a significant part of the individual's self-care and a component of their future health behavior. The readmission rate is high for patients with heart failure and this might be an indicator for low self-care behavior. 11 doi:10.11124/jbisrir-2014-1095 Page 125
Self-care encompasses the actions aimed at maintaining physical stability, avoidance of the behaviors that can worsen the condition and detection of the early symptoms of deterioration. Translating non-pharmacological recommendations from the ECS means that patients should be giving increased attention to fluid intake, dietary salt intake and observation of symptoms. 3,6-9 Self-care requires the active involvement of the patient who takes responsibility for the care and treatment they receive and ensures that the recommendations given to them by the health care system are valid and current. A Cochrane review has found that a reduction of dietary sodium intake is generally beneficial for cardiac patients. However, it also indicated that a reduced dietary sodium intake could be harmful for patients with heart failure and may potentially even increase the risk of mortality. 10 Few public health policies have been as widely endorsed for lowering cardiovascular disease (CVD) morbidity and mortality as dietary sodium restriction. 12 This policy can be dated back to Kempner s observation that extreme sodium restriction tempered the hypertensive crisis associated with renal insufficiency. 13 Subsequently, sodium restriction was gradually incorporated into the management of many patients with essential hypertension as an adjunct therapy to antihypertensive drugs. 14 Normal dietary salt intake in the Scandinavian population is reported to be six grams per day for women and nine grams per day for men. Both the European and American guidelines recommend a reduction of dietary sodium intake for patients with heart failure. The recommended levels of sodium intake have been two to three grams per day with further restriction (below two grams per day) to be considered in patients with moderate to severe heart failure. 13,14 These recommendations are based on level C evidence, that is, expert consensus opinion and results from observational studies. However, some studies indicate that this might be harmful for patients; therefore a systematic review of the evidence is needed. An initial search in the data bases CINAHL, JBI COnNECT+, DARE, PubMed, Cochrane Library and PROSPERO showed that no systematic review exists on this topic, or is currently underway. Keywords Heart failure; self-care behavior Inclusion criteria Types of participants This review will consider studies that include adult patients (18 years or older) with heart failure, regardless of gender or ethnicity. Studies including children or pregnant women were excluded. Types of intervention(s)/phenomena of interest This review will consider studies that evaluate reduced dietary salt intake in patients with heart failure. The comparators include usual dietary salt intake, control or placebo diet, or no intervention. Types of outcomes This review will consider studies that evaluate reduced dietary salt intake in patients with heart failure and the outcome will be cardiovascular morbidity and cardiovascular-related hospital admissions. doi:10.11124/jbisrir-2014-1095 Page 126
Types of studies This review will consider any experimental study design including randomized controlled trials, non-randomized controlled trials, quasi-experimental and before and after studies for inclusion. Search strategy The search strategy aims to find both published and unpublished studies. A three-step search strategy will be utilized in this review. An initial limited search of PubMed and CINAHL were undertaken, followed by analysis of the text words contained in the title and abstract and of the index terms used to describe the article. A second search using all identified keywords and index terms will then be undertaken across all included databases. Thirdly, the reference lists of all identified reports and articles will be searched for additional studies, as well as citation searches will be applied. Studies published in English, German, Danish, Swedish and Norwegian will be considered for inclusion in this review. Databases will be searched from their inception to September 2013 and the selected studies will be considered for inclusion in this review. The databases to be searched include: PubMed, CINAHL, Embase, Scopus, Swemed+, Health Technology Assessment Database, Turning Research Into Practice (TRIP) Database Additional searching for published literature will include: Hand searching the reference lists and bibliographies of included articles and any relevant systematic reviews identified in the Joanna Briggs Institute Library of Systematic Reviews and Cochrane Database of Systematic Reviews The search for unpublished studies will include searches of the following databases and websites: - MedNar - Sigle - ProQuest Dissertations and Theses (for international dissertations and theses) - National Institutes of Health (NIH) Clinical Trials Databases (Host: NIH(http//clinical trials.gov)) - College of Nurses of Ontario (http://www.cno.org/learn-about-standards-guidelines) - Heart failure relevant web sites Initial keywords to be used include: dietary salt intake, heart failure, readmission Assessment of methodological quality Papers selected for retrieval will be assessed by two independent reviewers for methodological validity prior to inclusion in the review, using standardized critical appraisal instruments from the Joanna Briggs Institute Meta Analysis of Statistics Assessment and Review Instrument (JBI-MAStARI) (Appendix V). doi:10.11124/jbisrir-2014-1095 Page 127
Any disagreements that arise between the reviewers will be resolved through discussion, or with a third reviewer. Data collection Data will be extracted from the papers included in the review using the standardized data extraction tool from JBI-MAStARI (Appendix VI). The data extracted will include specific details about the interventions, populations, study methods and outcomes of significance to the review question and specific objectives. Data extraction will be compiled by a single reviewer and checked by a second. Authors will be contacted where possible to obtain missing information. Data synthesis Quantitative data will, where possible, be pooled in statistical meta-analysis using JBI-MAStARI. All results will be subject to double data entry. Effect sizes expressed as odds ratios (for categorical data) and weighted mean differences (for continuous data) and their 95% confidence intervals will be calculated for analysis. Heterogeneity will be assessed statistically using the standard chi-square test. Where statistical pooling is not possible, the findings will be presented in narrative form including tables and figures to aid in data presentation where appropriate. Conflicts of interest None Acknowledgements None doi:10.11124/jbisrir-2014-1095 Page 128
References 1. Lopez AD, Mathers CD, Ezzati M, Jamison DT, Murray CJL. Global and regional burden of disease and risk factors, 2001: systematic analysis of population health data. Lancet. 2006;367(9524):1747-57. 2. Ko DT. Life expectancy after an index hospitalization for patients with heart failure: a population-based study. The American heart journal. 2008;155(2):324-31. 3. Riegel B. A situation-specific theory of heart failure self-care. The Journal of cardiovascular nursing. 2008;23(3):190-6. 4. Dickstein K, Cohen-Solal A, Filippatos G, McMurray JJV, Ponikowski P, Poole-Wilson PA, et al. ESC Guidelines for the diagnosis and treatment of acute and chronic heart failure 2008: The Task Force for the Diagnosis and Treatment of Acute and Chronic Heart Failure 2008 of the European Society of Cardiology. Developed in collaboration with the Heart Failure Association of the ESC (HFA) and endorsed by the European Society of Intensive Care Medicine (ESICM). European Journal of Heart Failure. 2008;10(10):933-89. 5. McMurray JJV. ESC Guidelines for the diagnosis and treatment of acute and chronic heart failure 2012: The Task Force for the Diagnosis and Treatment of Acute and Chronic Heart Failure 2012 of the European Society of Cardiology. Developed in collaboration with the Heart Failure Association (HFA) of the ESC. European heart journal. 2012;33(14):1787-847. 6. Jaarsma T. Development and testing of the European Heart Failure Self-Care Behaviour Scale. European Journal of Heart Failure. 2003;5(3):363-70. 7. Jaarsma TPRNa, Halfens RPa, Tan FPb, Abu-Saad HHPa, Dracup KDRNc, Diederiks JPd. Self-care and quality of life in patients with advanced heart failure: The effect of a supportive educational intervention. Heart & Lung: Journal of Acute & Critical Care September/October. 2000;29(5):319-30. 8. Jaarsma T, Årestedt KF, Mårtensson J, Dracup K, Strömberg A. The European Heart Failure Self-care Behaviour scale revised into a nine-item scale (EHFScB-9): a reliable and valid international instrument. European Journal of Heart Failure. 2009;11(1):99-105. 9. Riegel B. Self care in patients with chronic heart failure. Nature reviews cardiology. 2011;8(11):644-54. 10. Taylor RS. Reduced dietary salt for the prevention of cardiovascular disease. Cochrane database of systematic reviews. 2011(7):CD009217. 11. Davidson PM, Inglis SC, Newton PJ. Self-care in patients with chronic heart failure. Expert Review of Pharmacoeconomics & Outcomes Research. 2013;13(3):351-9. 12. He FJ. Salt reduction lowers cardiovascular risk: meta-analysis of outcome trials. The Lancet (British edition). 2011;378(9789):380-2. 13. Damgaard M. Hemodynamic and neuroendocrine responses to changes in sodium intake in compensated heart failure. American journal of physiology Regulatory, integrative and comparative physiology. 2006;290(5):R1294-301. 14. McCarron DA, Kazaks AG, Geerling JC, Stern JS, Graudal NA. Normal Range of Human Dietary Sodium Intake: A Perspective Based on 24-Hour Urinary Sodium Excretion Worldwide. American Journal of Hypertension. 2013. doi:10.11124/jbisrir-2014-1095 Page 129
Appendix I: Appraisal instruments MAStARI appraisal instrument doi:10.11124/jbisrir-2014-1095 Page 130
Appendix II: Data extraction instruments MAStARI data extraction instrument doi:10.11124/jbisrir-2014-1095 Page 131