EFFECTIVENESS OF DIETARY INTERVENTIONS IN CHRONIC KIDNEY DISEASE (CKD): A SYSTEMATIC REVIEW

Purpose: Patients with CKD face complex, challenging dietary modifications to manage their illness; this study evaluates the effectiveness of interventions to improve patients’ dietary adherence. 

Method(s): A survey using systematic review methods of randomised and non-randomised comparison studies with two or more groups in patients with eGFR<60ml/min. CENTRAL, MEDLINE, EMBASE, PsycINFO and CINAHL electronic databases were searched for studies up until September 2014 using terms [Kidney Diseases or Renal Insufficiency or Renal Dialysis] + [Behaviour or Attitude or Life Style or Self Concept or Diet or Patient Compliance] + [Consumer Health Information or Health Education or Patient Education or Motivational Interviewing or Social Support]; key authors, contents pages of key journal, and article reference lists were also searched. Studies evaluating interventions supporting diet adherence to international guidelines were included. Data were synthesised using descriptive analyses due to heterogeneity of study type.

Result(s): Searches identified 2296 records; 1794 records were screened; 117 full-text articles assessed for eligibility and 47 studies were included in the review. Most interventions aimed to increase knowledge about diet; 53% used a theory-based intervention to target beliefs, motivation, skills and self-efficacy. Forty-four studies (94%) noted improvements in at least one adherence outcome including: nutrient/fluid intake, clinical/biochemical markers or inter-dialytic weight gain (IDWG), diet-related knowledge/skill, dietary self-management behaviours, attitudes and beliefs about changing dietary behaviours, satisfaction with diet and quality of life. Seven studies ran for 2 years or more; twenty-one studies (45%) completed their observations by 12 weeks. The quality of evidence in most studies was poor; the majority had a risk of bias. Many used complex interventions with multiple outcomes but few were able to isolate the mechanism that caused the effect. Only six studies measured impact on service delivery, of which only one reported on cost-effectiveness.

Conclusion(s): Providing additional patient resources about diet therapy to usual dietary care affects change on some indicators in the short term. It is unclear what the active ingredients are in these interventions, if the changes to adherence are sustained, and the impact these changes have on service delivery and/or patient wellbeing. Study quality was weak. Further there was little evidence that dietary interventions were embedded in a broader care pathway for patients’ management of their CKD and implementation into their lifestyle.