Preoperative High, as well as Low, Platelet Counts Correlate With Adverse Outcomes After Elective Total Hip Arthroplasty

BACKGROUND: Preoperative laboratory studies are often obtained as part of the workup for surgeries such as total hip arthroplasty (THA). An increasing need exists to be able to identify patients at risk for adverse outcomes. Thus, metrics that correlate with postoperative adverse events and readmissions are increasingly important to optimize patient care. The implications of varying abnormal platelet counts, especially on the high end of the spectrum, have yet to be assessed in large, multicenter patient populations. This study aims to risk stratify THA patients with varying preoperative platelet counts to address these questions. The purposes of this study were to (1) evaluate cutoffs for normal versus abnormal platelet counts for patients undergoing THA by using postoperative complications data and (2) assess the correlation of such values with readmission data using the National Surgical Quality Improvement Program database. METHODS: Patients who underwent elective primary THA were identified in the 2011 to 2015 National Surgical Quality Improvement Program database. Risk of 30-day perioperative complications was calculated as a function of preoperative platelet counts. Based on the risk criteria, patients were categorized into the following three groups: normal platelet counts, abnormally low platelet counts, and abnormally high platelet counts. Multivariate analyses were performed to compare 30-day postoperative complications, readmissions, surgical time, and length of hospital stay between these populations. RESULTS: The current study identified 86,845 THA patients. Using the relative risk threshold of 1.5, platelets counts were divided into abnormally low (≤142,000/mL) and abnormally high (≥417,000/mL) categories. Higher rates of any, major, and minor adverse events and hospital readmission were associated with both the abnormally low and high platelet cohorts. CONCLUSION: This study suggests that preoperative high, as well as low, platelet counts are correlated with perioperative complications after THA, including hospital readmissions. Patients with these laboratory findings warrant further attention with possible preoperative and postoperative optimization.