Loris Pironi, Mariacristina Guidetti, Federica Agostini, Caterina Pazzeschi, Rossella Petitto

Center for Chronic Intestinal Failure, University of Bologna, Bologna, Italy

Rationale: Clinical researches showed that plasma citrulline concentration (CIT) < 20 micromol/L  identifies patients with short bowel syndrome (SBS) needing home parenteral nutrition (HPN) for intestinal failure (sensitivity 92%, specificity 90%).These data were obtained in selected patient populations, excluding factors interfering with CIT, like creatinineclearance (CrCl) < 50 ml/min, alterations of hydration status and damage of the residual small bowel. In order to evaluate the applicability of CIT in the clinical practice, the accuracy of CIT in identifying SBS patients needing HPN was investigated in unselected adults with SBS

Methods: Nineteen healthy subjects (HC) and 72 consecutive SBS patients were studied, 50 of whom on HPN (SBS-HPN) and 22 stable on oral diet. The duration of SBS was <=24 months in 27 patients and > 24 months in 45. Inclusion criteria: postduodenal small bowel length £200 cm). Exclusion criteria: none. The followings were evaluated: CIT by HPLC (micromol/L), CrCl by the Cockroft-Gault formula. Statistics: mean±SD and ANOVA.

Results: CIT was 37±6 in HC, 33 ±15 in SBS-OD and 20 ±12 in SBS-HPN (P<0.001). The sensitivity (%), specificity (%), positive and negative predictive value (PPV and NPV, %) of CIT < 20 in identifying SBS-HPN were: 50, 91, 93 and 44 in the whole group of SBS (72); 58, 89, 91 and 52 in SBS with CrCl >=50 (54); 42, 92, 89 and 50 in SBS > 24 months with  CrCl >= 50 (31).

Conclusion: In unselected SBS-patients, CIT < 20 micromol/L has high specificity and PPV and low sensitivity and NPV in identifying patients with SBS requiring HPN. In clinical practice, this means that CIT< 20 indicates the need of HPN, but CIT >= 20 doesn’t exclude it.