Translating plasma citrulline concentration in clinical practice: Role of cross-sectional assessment in adult patients with short bowel syndrome

Background: Cross-sectional plasma citrulline concentration (CIT) is considered a marker of enterocyte mass. The role of CIT in clinical practice in patients with short bowel syndrome (SBS) is not clearly defined.

Aim: To assess the accuracy of CIT to discriminate SBS from healthy controls (HC) and SBS with intestinal failure (SBS-IF), requiring intravenous supplementation (IVS), from SBS with intestinal insufficiency (SBS-II).

Methods: Cross-sectional study on unselected outpatients (31 SBS-II, 113 SBS-IF) and 19 healthy controls (HC). Demographic data, SBS characteristics, nutritional status, oral intake, intestinal fat absorption, renal function and IF severity, categorized by the volume of the required IVS, were collected at time of CIT evaluation (µmol/L). Data as mean±SD.

Results: CIT was 36.6 ± 6.0 in HC, 30.2 ± 14.0 in SBS-II and 18.8 ± 12.3 in SBS-IF (p < 0.001). CIT cutoff was 31 for the diagnosis of SBS (sensitivity 79 %, specificity 89 %), and 14 for the discrimination between SBS-IF and SBS-II (sensitivity 100 %, specificity 51 %). Wide ranges of CIT were observed in all SBS-IF severity categories.

Conclusions: In unselected SBS patients, CIT was accurate to diagnose SBS, had high sensitivity to diagnose SBS-IF but showed low specificity for SBS-II. In SBS-IF, CIT was not an accurate marker of IF severity.