Selecting a strategy for prevention of contrast-induced nephropathy in clinical practice: an evaluation of different clinical practice guidelines using the AGREE tool

Background: Contrast-induced acute kidney injury (CI-AKI) is a potential complication of radio-contrast investigations. Many organisations have published guidance documents on the prevention of CI-AKI. Our aim is to explore the scope, content, consistency, practicality in clinical practice and reasons for eventual underlying discrepancies of these documents.

Methods: We searched the literature for guidance documents developed to guide prevention of CI-AKI up to 09/2014. Four reviewers appraised guideline quality using the 23-item AGREE-II instrument, which rates reporting of the guidance development process across six domains: scope and purpose, stakeholder involvement, rigour of development, clarity of presentation, applicability and editorial independence. Total scores were calculated as standardised averages by domain.

Results: Twenty-four guidance documents were evaluated. The guidance documents were produced by radiologists (N = 7), intensivists (N = 2), nephrologists (N = 6) or multidisciplinary teams (N = 9). One document did not mention the background of the authors. Only guidance documents (N = 15) that were not mere adaptations of existing guidelines were evaluated more in depth, using the AGREE tool. Overall, quality was mixed: only one clinical practice guidance document obtained an average score of >50% for all domains. The evidence was rated in a systematic way in only 11, and only 7 graded the strength of the recommendations. The Kidney Diseases Improving Global Outcomes guideline was the only one recommended without adaptions by all assessors. The guidance documents agreed in recommending pre-hydration as the main preventive measure, but there was difference in recommended total volumes, composition, rate and duration of the infused solutions. There was no consensus on the use of NaHCO3, with eight recommending it, six considering it and one not. Five guidance documents mentioned oral pre-hydration as a possibility, and none recommended N-acetylcysteine as solitary preventive measure. More recent guidance documents recommend avoiding hypertonic contrast media, but did not recommend preference of iso-osmolar over low-osmolar contrast media. Most guidance documents recognised pre-existing chronic kidney disease, diabetes, age and cardiovascular comorbidity as risk factors.

Conclusions: There seems to be a relative consensus on the need for adequate pre-hydration to avoid CI-AKI, but recommendations to define at-risk populations for whom these measures should be applied and how they should be implemented differ substantially. Based on accumulating evidence, more recent guidelines do not recommend iso-osmolar over low-osmolar contrast media, whereas all recommend avoiding hypertonic agents.