Lower phosphate levels following pancreatectomy is associated with postoperative pancreatic fistula formation

Background: Whereas hypophosphatemia following hepatectomy is associated with decreased morbidity, hypophosphatemia following pancreatectomy may be associated with increased morbidity, including the development of postoperative pancreatic fistula (POPF). This study aimed to evaluate the relationship between postoperative hypophosphatemia and POPF formation. Methods: Patients from our institutional Research Patient Data Registry who underwent pancreatectomy from 2001 to 2017 were included. POPF was defined according to the International Study Group for Pancreatic Fistulas (ISGPF) criteria and according to internal criteria for drain removal. Postoperative serum phosphate levels, demographics, and comorbidities were evaluated. Unadjusted and adjusted analyses were performed. Results: 2342 patients underwent pancreatic resection. Mean age was 63.0 years (SD 14.3), 51.2% were male, and 58.7% had pancreatic cancer. Of all resections, 67.7% were pancreaticoduodenectomies. In unadjusted analysis, phosphate levels were significantly and persistently lower on POD 0 and POD 2-5 in patients who developed POPF's. In adjusted analysis, POD 2 phosphate < 1.75 predicted an additional 46% increased odds of POPF (OR 1.46 95% CI 1.06-2.01; p = 0.02). Distal pancreatectomy was independently associated with POPF formation when compared to pancreaticoduodenectomy (OR 1.72 95% CI 1.18-2.51; p = 0.005). Conclusion: Lower phosphate levels in the early post-operative period following both proximal and distal pancreatectomies is associated with increased risk of POPF.