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A meta-analysis of peritoneal drainage versus laparotomy for perforated necrotizing enterocolitis.

BACKGROUND/PURPOSE
Both primary peritoneal drainage (PPD) and laparotomy (LAP) are used widely for treatment of perforated necrotizing enterocolitis (NEC). Published reports include only anecdotes and small series. The authors used techniques of meta-analysis to determine which treatment is most effective.


METHODS
The authors identified published studies reporting surgical treatment of NEC from January 1, 1978 to December 31, 1999; there were 10 studies (n = 475). The authors were contacted and all available raw patient data for use in meta-analysis (n = 190) were obtained. The authors used logistic regression to determine the relative survival rate after PPD and LAP, controlling for the effect of gestational age and institution.


RESULTS
The combined probability of survival in the 10 published studies did not show an advantage for PPD (55%) or LAP (67%; P =.27). When the authors corrected for the effect of birth weight on survival rate, they still did not observe a difference (P =.67). A marked bias in treatment assignment was found with smaller babies undergoing PPD than LAP (931 g versus 1,615 g, respectively; P =.0004). Analysis of raw data showed an even greater bias in treatment assignment. The authors found increased survival rate for LAP versus PPD (62.3% v 35.6%; P =.0009). However, a logistic regression model could not overcome the bias in assignment of patients with a much higher expected mortality rate to PPD.


CONCLUSIONS
Using currently available data, it is not possible to determine whether PPD or LAP is superior. Bias in treatment assignment precludes conclusions regarding comparative survival. Only a randomized trial will determine which operation is best for the treatment of perforated NEC.