Meta Analysis Acute renal failure in the intensive care unit: A systematic review of the impact of dialytic modality on mortality and renal recovery.
This review may be edited
Summary
Posted By:	brent richards
E-Mail:	brent_richards@health.qld.gov.au
Posted Date:	19/05/03
Title:	Acute renal failure in the intensive care unit: A systematic review of the impact of dialytic modality on mortality and renal recovery.
Authors:	Marcello Tonelli, MD, Braden Manns, MD, David Feller-Kopman, MD
Reference:	American Journal of Kidney Diseases. 40(5), 2002. 875-885
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Abstract:	Background: There is controversy about which dialytic modality should be used for the treatment of acute renal failure (ARF) in the intensive care unit. We performed a systematic review and meta-analysis to determine the relative risks (RRs) of mortality and renal recovery associated with intermittent hemodialysis (IHD) therapy compared with continuous renal replacement therapy (CRRT) in critically ill adults with ARF. Methods: Four databases (MEDLINE, Cochrane Library, Database of Abstracts and Reviews, and Science Citation Index), hand searching of conference proceedings and journals, manual review of bibliographies from identified articles, and contact with experts were used. All randomized trials (published or unpublished in any language) that compared mortality between intermittent and continuous treatments were eligible. Trials for which an RR for mortality could not be calculated or with multiple experimental interventions were excluded. Data were extracted separately by two authors and recorded on a standardized form. Disagreements were resolved by consensus. Results: Six eligible trials were identified; four of these provided data on renal outcomes. RR (mortality) for IHD was 0.96 (95% confidence interval [CI], 0.85 to 1.08; P = 0.50), RR (renal death) was 1.02 (95% CI, 0.89 to 1.17; P = 0.78), and RR (dialysis dependence) in survivors was 1.19 (95% CI, 0.62 to 2.27; P = 0.60; all compared with continuous therapy). Several sensitivity analyses did not change these results. Of the outcomes studied, the risk for dialysis dependence in survivors would be most sensitive to the addition of new trials. Conclusions: In comparison to IHD therapy, CRRT does not improve survival or renal recovery in unselected critically ill patients with ARF. Future studies should focus on well-defined subgroups of such patients using lessons learned from the trials in this meta-analysis. The high cost of chronic dialysis therapy and the relative instability of the RR for dialysis dependence suggest that future trials also should evaluate differences in renal recovery between dialytic modalities.
Are the Results Valid?
1. Did the overview address a focused clinical question?
	Yes; relative risks of mortality and renal recovery associated with intermittent hemodialysis therapy compared with continuous renal replacement therapy in critically ill adults with ARF
2. Were the criteria used to select articles for inclusion appropriate?
	Yes; The authors considered all studies reporting the outcomes of interest.
3. Is it unlikely that important, relevant studies were missed?
	Yes. Medline, Cochrane, DARE, SCI, hand-searched reference lists, reviewed major renal and ICU journals, and North American nephrology meetings were all searched. Abstracts of 2028 studies were reviewed; 116 studies (13 RCTs) were retrieved for review. Eighteen studies (6 RCTs) satisfied inclusion and exclusion criteria.
4. Was the validity of the included studies appraised?
	Yes. Of 6 RCTs, 4 studies reported an intention to treat analysis, and only 1 had adequate allocation concealment reported.
5. Were assessments of studies reproducible?
	A measure of agreement was not reported. Data extracted separately by two authors, disagreements decided by consensus with the aid of a third party.
6. Were the results similar from study to study?
	Yes. Although studies varied in average APACHE and mortality, the Q statistic suggested no significant heterogeneity.
What are the Results?
1. What are the overall results of the overview?
	Overall there was no significant difference in outcome between the two treatment groups, either in mortality or renal recovery.
2. How precise were the results?
	RR (mortality) for IHD was 0.96 (95% confidence interval [CI], 0.85 to 1.08; P = 0.50), RR (renal death) was 1.02 (95% CI, 0.89 to 1.17; P = 0.78), and Renal Recovery (dialysis dependence) in survivors was 1.19 (95% CI, 0.62 to 2.27; P = 0.60; all compared with continuous therapy.
Will the Results Help Me In Caring For My Patients?
1. Can the results be applied to my patient care
	There is still insufficient data to prove inferiority or superiority of either technique, and insuffcient power to demonstrate equivalence. Thus there is no indication for clinicians to switch therapy. There is insufficient data to consider outcomes in subgroups.
2. Were all clinically important outcomes considered?
	Yes. Hard outcomes (mortality and renal recovery) were measured rather than surrogate outcomes (eg. Haemodynamic stability, time to renal recovery). Quality of life could be an important measure for subsequent survivors.
3. Are the benefits worth the harms and costs?
	There is no difference reported in outcome between the groups. Cheaper per treatment IHD costs may be outweighed by long term costs of chronic dialysis, if future trials confirm the trend to poorer renal recovery in the IHD group. A definitive Level I study is required.
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