Endocrine Abstracts

Background: Contrast procedures are frequently performed in diabetic patients and are the third most common cause of hospital-acquired renal failure¹. Diabetic patients are at risk of Metformin associated lactic acidosis in the presence of renal failure².

Standards: RCR guidelines³ recommend:

• Recent serum creatinine should be available for patients with renal disease or diabetes

• Metformin should be withheld 48-h prior and post procedure if creatinine is raised or >100 ml contrast or intra-arterial route is used

• If creatinine is raised, renal function should be assessed before re-starting Metformin

Indicators and targets:

• Percentage of high risk patients with recent pre-procedure creatinine value

• Percentage of patients in whom Metformin was withheld appropriately

• Post-procedure renal monitoring in patients with renal failure.

Method: Data was collected retrospectively from the case-notes and electronic records of diabetic patients undergoing inpatient lower limb angiograms in 2007. A total of 19 episodes were audited.

Results: Only 37% of patients had a recent creatinine value available (1 week prior to procedure). Metformin was withheld in 77% of the cases but only half were in accordance with RCR guidelines. Neither of the two patients with renal failure had timely post-procedure creatinine values. Glycaemic management off Metformin was found variable and suboptimal.

Action plan: The audit has highlighted the need for better monitoring of renal function peri-contrast. We plan to develop a local pathway with the Radiology Department incorporating recommendations on glycaemic management during Metformin withdrawal. Awareness of RCR guidelines was raised at local audit meeting. Re-audit is planned in 2 years after pathway implementation.

References:

1. Gleeson G & Bulugahapitiya S. Contrast induced nephropathy. Am J Roentgenol. 2004 183 1673–1689.

2. Nisbet JC, Sturtevant JM & Prins JB. Metformin and serious adverse effects. Med J Aust. 2004 180 53–54.

3. Standards for iodinated intravascular contrast agent administration to adult patients. RCR Guidelines 2005.