Preoperative International Normalized Ratio Thresholds in Hip Fracture: An Analysis of the National Surgical Quality Improvement Program

Background: Hip fractures are one of the most common orthopaedic injuries among the elderly, and as life expectancy continues to rise, the incidence of hip fractures has increased. The international normalized ratio (INR) is routinely obtained preoperatively to assess a patient’s readiness for surgery to evaluate bleeding risk. We aimed to 1) assess the relationship between preoperative INR in hip fracture patients and postoperative complication rates and 2) establish an INR threshold under which patients would be safe to proceed to surgery without INR correction. Methods: We retrospectively reviewed cases of hip fracture surgical stabilization in the American College of Surgeons National Surgical Quality Improvement Program from January 1, 2012 to December 31, 2018. Cases were stratified into four groups based on preoperative INR levels: 1) \u3c 1.4, 2) ≥1.4 and Results: Thirty-five thousand nine hundred-ten cases were identified, with 33,484 (93.2%) performed on patients with preoperative INR \u3c 1.4, 867 (2.4%) on INR ≥1.4 and Conclusions: In this study we found a threshold of INR\u3c 1.6 to be safe for patients prior to undergoing hip fracture surgery. Below this value patients avoid an increased risk of both transfusions and 30-day mortality seen at higher INR values. These findings may allow for adjustments to preoperative protocols and improve outcomes of hip fracture surgery in this population

Determining a preoperative international normalised ratio threshold safe for hip fracture surgery.

INTRODUCTION: The purpose of this study was first, to assess the relationship between preoperative INR (international normalised ratio) and postoperative complication rates in patients with a hip fracture, and second, to establish a threshold for INR below which the risk of complications is comparable to those in patients with a normal INR. METHODS: We retrospectively reviewed the American College of Surgeons National Surgical Quality Improvement Program and found 35,910 cases who had undergone surgery for a hip fracture between 2012 and 2018. Cases were stratified into 4 groups based on their preoperative INR levels: \u3c1.4; ⩾1.4 and \u3c1.6; ⩾1.6 and \u3c1.8 and ⩾1.8. These cohorts were assessed for differences in preoperative factors, intraoperative factors, and postoperative course. Multivariate logistic regression was used to assess the risk of transfusion, 30-day mortality, cardiac complications, and wound complications adjusting for all preoperative and intraoperative factors. RESULTS: Of the 35,910 cases, 33,484 (93.2%) had a preoperative INR \u3c 1.4; 867 (2.4%) an INR ⩾1.4 and \u3c1.6; 865 (2.4%) an INR ⩾ 1.6 and \u3c1.8 and 692 (1.9%) an INR ⩾ 1.8. A preoperative INR ⩾ 1.8 was independently associated with an increased risk of bleeding requiring transfusion. A preoperative INR ⩾ 1.6 was associated with an increased risk of mortality. CONCLUSIONS: We found that an INR of \u3c1.6 is a safe value for patients who are to undergo surgery for a hip fracture. Below this value, patients avoid an increased risk of both transfusion and 30-day mortality seen with higher INR values. These findings may allow adjustment of preoperative protocols and improve the outcome of hip fracture surgery in this group of patients