Hypophosphatemia as a prognostic tool for post-hepatectomy liver failure: A systematic review

BACKGROUND: Post-hepatectomy liver failure (PHLF) is one of the main causes of postoperative mortality and is challenging to predict early in patients after liver resection. Some studies suggest that the postoperative serum phosphorus might predict outcomes in these patients. AIM: To perform a systematic literature review on hypophosphatemia and evaluate it as a prognostic factor for PHLF and overall morbidity. METHODS: This systematic review was performed according to preferred reporting items for systematic reviews and meta-analyses statement. A study protocol for the review was registered in the International Prospective Register of Systematic Reviews database. PubMed, Cochrane and Lippincott Williams & Wilkins databases were systematically searched up to March 31, 2022 for studies analyzing postoperative hypophosphatemia as a prognostic factor for PHLF, overall postoperative morbidity and liver regeneration. The quality assessment of the included cohort studies was performed according to the Newcastle-Ottawa Scale. RESULTS: After final assessment, nine studies (eight retrospective and one prospective cohort study) with 1677 patients were included in the systematic review. All selected studies scored ≥ 6 points according to the Newcastle-Ottawa Scale. Cutoff values of hypophosphatemia varied from < 1 mg/dL to ≤ 2.5 mg/dL in selected studies with ≤ 2.5 mg/dL being the most used defining value. Five studies analyzed PHLF, while the remaining four analyzed overall complications as a main outcome associated with hypophosphatemia. Only two of the selected studies analyzed postoperative liver regeneration, with reported better postoperative liver regeneration in cases of postoperative hypophosphatemia. In three studies hypophosphatemia was associated with better postoperative outcomes, while six studies revealed hypophosphatemia as a predictive factor for worse patient outcomes. CONCLUSION: Changes of the postoperative serum phosphorus level might be useful for predicting outcomes after liver resection. However, routine measurement of perioperative serum phosphorus levels remains questionable and should be evaluated individually.