The effect of continuous versus intermittent renal replacement therapy on the outcome of critically ill patients with acute renal failure (CONVINT): a prospective randomized controlled trial

Abstract

IntroductionAcute renal failure (ARF) requiring renal replacement therapy (RRT) occurs frequently in ICU patients and significantly affects mortality rates. Previously, few large clinical trials investigated the impact of RRT modalities on patient outcomes. Here we investigated the effect of two major RRT strategies (intermittent hemodialysis (IHD) and continuous veno-venous hemofiltration (CVVH)) on mortality and renal-related outcome measures.MethodsThis single-center prospective randomized controlled trial (“CONVINT”) included 252 critically ill patients (159 male; mean age, 61.5 ± 13.9 years; Acute Physiology and Chronic Health Evaluation (APACHE) II score, 28.6 ± 8.8) with dialysis-dependent ARF treated in the ICUs of a tertiary care academic center. Patients were randomized to receive either daily IHD or CVVH. The primary outcome measure was survival at 14 days after the end of RRT. Secondary outcome measures included 30-day-, intensive care unit-, and intrahospital mortality, as well as course of disease severity/biomarkers and need for organ-support therapy.ResultsAt baseline, no differences in disease severity, distributions of age and gender, or suspected reasons for acute renal failure were observed. Survival rates at 14 days after RRT were 39.5% (IHD) versus 43.9% (CVVH) (odds ratio (OR), 0.84; 95% confidence interval (CI), 0.49 to 1.41; P = 0.50). 14-day-, 30-day, and all-cause intrahospital mortality rates were not different between the two groups (all P > 0.5). No differences were observed in days on RRT, vasopressor days, days on ventilator, or ICU-/intrahospital length of stay.ConclusionsIn a monocentric RCT, we observed no statistically significant differences between the investigated treatment modalities regarding mortality, renal-related outcome measures, or survival at 14 days after RRT. Our findings add to mounting data demonstrating that intermittent and continuous RRTs may be considered equivalent approaches for critically ill patients with dialysis-dependent acute renal failure.Trial registrationNCT01228123, clinicaltrials.gov

Renal replacement therapy for acute kidney injury

“…The largest RCT, which enrolled 360 patients with AKI, showed no difference in 60-day mortality between the CRRT and IRRT groups [40]. The most recent RCT, in which 252 patients with AKI were randomized to receive IHD (n = 129) or CVVH (n = 123), found that the univariate ORs for the IHD group were 1.27 (95 % CI 0.76-2.12, p = 0.36) for 14-day mortality, 1.37 (95 % CI 0.82-2.27, p = 0.22) for 28-day mortality, and 1.26 (95 % CI 0.76-2.10, p = 0.37) for intrahospital mortality [46]. In this way, the newest RCT failed to show that CRRT was superior to IRRT in critically ill patients with AKI requiring RRT.…”

“…RCTs comparing these two modalities have failed to provide evidence for the survival benefits of CRRT over IHD [32][33][34][35][36][37][38][39][40][41][42][43][44][45][46]. The clinical question "which is the best treatment strategy for critically ill patients with AKI requiring RRT ?…”

Renal Failure and Heart Surgery

“…Whether initiation of earlier or prophylactic dialysis prior to the development of symptoms and signs of renal failure offers any clinical or survival benefit is unproven. Several trials have shownthat the modality of RRT-either intermittent or continuous-hasno impact on outcomes in patients with AKI [38]. Treatment with higher intensity continuous RRT or with early RRT also did not provide any additional benefit [39].…”

Continous renal replacement therapy and intermittent hemodialysis in acute kidney injury: equivalent or complementary?

“…Some studies have shown significant hemodynamic instability in critically ill patients during IHD and even during slow low efficiency dialysis (SLED) which uses a lower blood and dialysate flow rate and extends dialysis to 8 or more hours (4,5). However, others have not, especially from centers where the initial blood pump speed is slow, the duration of IHD is extended to 5 or 6 hours and is performed daily so to minimize solute shifts and the amount of fluid removal required (6,7).…”

“…The results of observational studies, randomized clinical trials, and meta-analyses comparing these techniques have failed to demonstrate superiority of either CRRT or IHD in terms of mortality (6)(7)(8)(9)(10)(11)(12)(13)(14). However, a number of observational studies have suggested that initial use of CRRT is associated with lower subsequent dialysis dependency, possibly due to less hemodynamic instability (15)(16)(17)(18).…”