Identification of Risk Factors for Abnormal Postoperative Chemistry Labs after Primary Shoulder Arthroplasty

Background: The purpose of this study was to determine patient-specific risk factors and clinical intervention rates for abnormal postoperative Chem-7 panels in shoulder arthroplasty patients. Methods: Retrospectively, all primary anatomic total (aTSA) and reverse shoulder (RTSA) arthroplasties (between 2007-2013) performed at a single institution were identified. All patients underwent routine preoperative and postoperative day one (POD1) chemistry panels. Each clinically significant component of the Chem-7 panel was independently evaluated using a multivariate analysis to identify risk factors for abnormal results. Associated clinical intervention rates were also calculated. Results: Data from 1,012 patients (248 RTSA; 764 aTSA) was analyzed. 5.4% of patients had at least one preoperative abnormal chemistry result. On multivariate analysis, patients with abnormal preoperative Chem-7 labs and a history of renal disease had significantly increased risk for abnormal POD1 labs (P<0.001). Although 25.6% (259/1,012) of patients had at least one abnormal POD1 lab result, the total postoperative clinical intervention rate was 15.1% (39/259). Conclusion: Renal disease and a preoperative abnormal chemistry result are important risk factors for abnormal postoperative Chem-7. Optimizing renal status and correcting abnormal blood chemistry results preoperatively may reduce the incidence of abnormal postoperative chemistry results.