Continuous Venovenous Hemofiltration versus Continuous Venovenous Hemodiafiltration in Critically Ill Patients: A Retrospective Cohort Study from a Canadian Tertiary Centre

BACKGROUND: Studies comparing continuous renal replacement therapy modalities are lacking. Theoretically, continuous venovenous hemofiltration (CVVH) could be more effective than continuous venovenous hemodiafiltration (CVVHDF), and may be associated with fewer complications; however, there are no published data to support this hypothesis. OBJECTIVE: To examine the effect of CVVH on mortality and other clinically important outcomes compared with CVVHDF in the intensive care unit (ICU) setting. METHODS: Using a log of all continuous renal replacement therapy performed at a Canadian tertiary centre between 2007 and 2010, the records of patients meeting the inclusion criteria of being admitted to the ICU, and receiving either CVVH or CVVHDF for management of acute renal failure, were reviewed. The information retrieved included demographic data, death events, and hospital and ICU length of stay. RESULTS: Data from 153 patients were included in the present study. Hospital and 30-day mortality were similar in the CVVH and CVVHDF groups (OR 0.85 [95% CI 0.38 to 1.89]; P=0.69 and OR 1.35 [95% CI 0.62 to 2.95]; P=0.45, respectively). There was no difference in hospital length of stay (mean difference -34.14 [95% CI -72.92 to 4.65]; P=0.08). CONCLUSION: The present retrospective review suggests that the use of CVVH does not reduce mortality or hospital length of stay when compared with CVVHDF. Future randomized trials should control for different patient populations and continue to evaluate the removal of small molecules such as hormones.