Assessment of Lactulose / Mannitol test parameters for intestinal permeability determination in patients with liver cirrhosis and Crohn´s disease

Dastych M1, Dastych M jr 2, Novotná H 1, Číhalová J 1

1Department of Clinical Biochemistry University Hospital Brno and Department of Laboratory Methods Faculty of Medicine Masaryk University, Czech Republic

2Department of Internal Medicine and Gastroenterology University Hospital Brno, Czech Republic

Introductiom:The purpose of the study was to investigate and compare specificity, sensitivity and AUC (area under curve) of the lactulose/mannitol ratio, lactulose/creatinine ratio and lactulose recovery and their diagnostic value for intestinal permeability assessment within absorption lactulose/mannitol (L/M) test.

Patients and methods: The study comprised 21 men, mean age 57 (47-67) years and 5 women, mean age 52 (40-61) years, diagnosed with alcohol-related liver cirrhosis, CHILD score B-C. Clinically significant ascites was present in six patients. The cohort of patients with Crohn's disease enroled 7 men, mean age 31 (20-45) years and 13 women, mean age 33 (22-47) years with active form of Crohn’s disease (A -CDAI of 220-280) affecting terminal ileum and colon. The control group consisted of 9 men, mean age 35 (24-60) years and 11 women, mean age 27 (22-50) years.

The values of cut-off levels, the sensitivity, the specificity and the AUC (area under curve) were calculated to determine the tested parameters in both cohorts. The diagnostic value of the ratio lactulose/mannitol, lactulose/creatinine and the percentage of urinary lactulose excretion of the ingested dose was expressed as the comparison of their ROC curves.

Results. The value of the lactulose/mannitol ratio, lactulose/creatinine ratio and the percentage of lactulose recovery in Crohn’s disease (0.0763 ± 0.0369; 99.62±67.87; 1.0478±0.6148) and in liver cirrhosis (0.0517±0.0365; 54.65±53.26; 0.838±0.929) were significantly different from the values measured in control group (0.0123±0.0081; 10.95±7.07; 0.2438±0.1568), p<0.0001-0.002.

In Crohn’s disease, specificity, sensitivity and AUC were (100%; 89.5%; 0.987 ) of the lactulose/mannitol ratio at a cut-off level of 0.022. In liver cirrhosis, the test characteristics were (88.5%; 84.2%; 0.910) at a cut-off level 0.018.

Conclusions. The results of our investigation justify the priority given to the L/M ratio used to determine and appraise the degree of the intestinal permeability within L/M test. A further advantage of this ratio is the elimination of errors due to non-mucosal factors, because variables such as rate of gastric emptying, intestinal transit, impairment of renal function and diuresis should affect both sugars similarly.

Supported by MH CZ - DRO (FNBr, 65269705)

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