Mehta R, McDonald B, Gabbai F, Pahl M, Farkas A, Pascual M,
Fowler W, and Collaborative ARF Group
Continuous versus intermittent dialysis for acute renal failure
in the ICU: results from a randomized multicenter trial
Am Soc Nephrol
J Am Soc Nephrol (abstract)
(Sep) 7:1457 1996
In the last decade CRRT has become an important alternative therapy for
ARF requiring dialysis. In the US, CRRT has been used most often for
hemodynamically unstable patients (Mehta, ASN 1996). However, there
are no prospective randomized trials addressing the comparison of
outcomes between CRRT and IHD in the literature.
Mehta and colleagues conducted a randomized controlled multicentric
trial in order to compare the efficacy of CRRT vs. IHD in ARF
patients requiring dialysis. The exclusion criteria included a mean
arterial pressure of less than 70 mmHg. 374 patients were initially
enrolled, but only 166 patients were randomized to CRRT (84) or IHD
(82). Both groups were different with respect to gender (more males in
the CRRT group), severity of illness scores (APACHE II, APACHE III and
organ failure score) and presence of liver failure, with the more sick
patients in the CRRT group.
In an intention to treat analysis, the CRRT group had higher
mortality in the ICU (59.5% vs. 41.5%; p = 0.02) and higher
in-hospital mortality (65.5% vs. 47.6%; p = 0.02). However, after
adjusting for severity of illness, presence of liver failure and
gender in a logistic regression model, there were no differences for
mortality rates between patients treated with CRRT or IHD. In an
adequate trial of therapy analysis in 131 patients, the results were
similar.
The authors also analyzed patients who crossed over from one therapy
the other. Patients who crossed over from IHD to CRRT had a higher
mortality than patients crossing over from CRRT to IHD (87% vs. 41%, p
< 0.01). Patients who started on CRRT and crossed over to IHD had
also a higher likelihood of recovering renal function (92.3% vs.
59.4%, p = 0.01). The authors concluded that CRRT had higher
unadjusted mortality which could be accounted for by differences in
baseline severity of illness. Subgroup analysis showed there was a
greater likelihood of complete recovery of renal function and shorter
hospital stay with CRRT.
Comment: This is a well designed multicentric randomized
clinical trial addressing the question as to which modality of
hemodialysis (CRRT or IHD) provides the best results for the dialysis
treatment of ARF. However the authors were faced with the difficulties
intrinsic to such a complex clinical study. Less than 50% of ARF
patients were randomized (166 out of 374). Furthermore, although
patients were randomly assigned to each treatment, patients in the
CRRT group were more severely ill than patients in the IHD group.
After controlling for these differences, there was no difference in
outcomes between the two groups. Nonetheless, the sample size may not
have adequate power to detect differences between the groups.
Consequently, the take-home message is that, in centers well prepared
for CRRT, both treatments probably offer similar results for patients
with ARF who are hemodynamically stable. However, CRRT provides
greater flexibility with respect to fluid administration and possibly
better hemodynamic control by removing inflammatory mediators
(Hoffmann, Kidney Int, 1995) and by cooling the body
temperature. Thus, it remains to be elucidated whether CRRT, as
compared to IHD, may be a better option for hemodynamically unstable
ARF patients.
(Miguel Cendoroglo, M.D. and Brian J.G. Pereira, M.D., New
England Medical Center, Boston, MA)
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Am Soc Nephrol
Basic hemodialysis :
(Intermittent) dialysis for ARF
Other extracorporeal therapies :
Continous therapies