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Three Part Question

In [patients with acute pancreatitis], is [C-reactive protein better than lactate dehydrogenase] in [assessing the severity of pancreatic necrosis]?

Clinical Scenario

A 50 year old man presents to the Emergency Department with epigastric pain. Acute pancreatitis was diagnosed by routine diagnostic tests. You wonder whether CRP level is better than lactate dehydrogenase level in predicting the severity of the pancreatitis.

Search Strategy

Ovid MEDLINE(R) 1950 to June Week 4 2008.
EMBASE 1980 to 2008 Week 26.
CINAHL 1982 to June Week 4 2008.
The Cochrane Library Issue 2 2008.
Medline/Embase/Cinhal:([pancreatitis.mp. or exp Pancreatitis, Acute Necrotizing/ or exp Pancreatitis/ or exp Pancreatitis, Alcoholic/] AND [exp C-Reactive Protein/ or CRP.mp.] AND [lactate dehydrogenase.mp. or exp L-Lactate Dehydrogenase/]) LIMIT to English Language AND Human.

Cochrane:MeSH descriptor C-Reactive Protein explode all trees AND MeSH descriptor L-Lactate Dehydrogenase explode all trees - 1 record not relevant

Search Outcome

29 articles were available, 3 were relevant. They are shown in the following table:

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses
Uhl W et al, 1991, Germany	52 patients: 29 with acute interstitial oedematous pancreatitis (AIP) 23 with necrotizing pancreatitis (NP) Accuracy of detecting pancreatic necrosis	Diagnostic study	CRP day 1 - 5	Accuracy 86%	No basic data table. No use of sensitivity/ specificity in literature. Reference standard only applied to one group. Sample size not justified.
			LDH day 1 - 5	Accuracy 82%
Chen et al. 1992, Taiwan	57 patients with acute pancreatitis 19 severe and 38 mild Ability to distinguish severe pancreatitis	Diagnostic study	CRP > 5 mg/dL on day 5	Sensitivity 67% Specificity 92% Accuracy 84%	LDH isoenzymes
			CRP > 8 mg/dL on day2	Sensitivity 94% Specificity 76% Accuracy 82%
			LDH-4	No utility
			LDH-5	No utility
Rau B et al, 1998, Germany	70 patients: 39 with necrotizing panreatitis (NP) 31 with acute interstitial oedematous pancreatitis (AIP) Ability to detect pancreatic necrosis	Diagnostic study	CRP on day 3	Sensitivity 83% Specificity 84%	CT scans were not repeated on subsequent days for the AIP group and therefore some necrosis may have been missed. Reference gold standard only applied to one group. Sample size not justified.
			CRP on day 1-4	Sensitivity 71% Specificity 80%
			LDH day 5	Sensitivity 88% Specificity 100%
			LDH day 1-4	Sensitivity 70% Specificity 95%

Comment(s)

Two articles from Germany use laparotomy as their gold standard for detecting necrosis, but only those paitents with evidence of necrosis on a spiral CT scan went on to have laparotomy. The same articles also suggested that CT and CRP have the same diagnostic accuracy and therefore, a gold standard was not applied to the AIP group in both these studies.

Clinical Bottom Line

CRP appears to be better than LDH at detecting necrosis in the first 3 days of acute pancreatitis. By day 5 LDH is the most reliable test.

References

1. Uhl W. Buchler M, Malfertheine Pet al. PMN-Elastase in Comparison with CRP, Antiproteases, and LDH as Indicators of Necrosis in Human Acute Pancreatitis. Pancreas 1991;6:253-259.
2. Chen CC, Wang SS, Chao Y et al. C-reactive protein and lactate dehydrogenase isoenzymes in the assessment of the prognosis of acute pancreatitis. Journal of Gastroenterology & Hepatology. 7(4):363-6, 1992 Jul-Aug.
3. Rau B, Cebulla M, Uhl W et al. The clinical value of human pancreas-specific protein procarboxypeptidase B as an indicator of necrosis in acute pancreatitis: comparison to CRP and LDH. Pancreas 1998;17:134-9.