Impact of Preoperative Hematocrit Level on Length of Stay after Surgery on the Lumbar Spine

Study Design Retrospective case series. Objective Recent studies suggest that baseline hematocrit (Hct) levels may affect the surgical outcomes after orthopedic procedures. The authors examined whether preoperative Hct values had a significant effect on the hospital length of stay (LoS) after lumbar spinal procedures. Methods We retrospectively reviewed patients who underwent routine lumbar spine procedures from November 2012 through September 2013. Patients were included if they had both a baseline Hct and hospital LoS recorded. Patients were divided into two groups: those with an Hct ≥ 40% (nonanemic) and those with an Hct < 40% (anemic). LoS after surgery was evaluated for each group. Results One hundred seventeen patients underwent lumbar spine procedures for lumbar stenosis (n = 34), symptomatic lumbar disk herniation (n = 39), lumbar spondylolisthesis (n = 26), lumbar adjacent segment disease (n = 8), or symptomatic recurrent lumbar disk herniation (n = 10). Mean LoS was 3.3 and 2.4 days in anemic (27 patients) and nonanemic groups (90 patients), respectively (p = 0.02). The linear regression analysis demonstrated that a decrease in Hct was associated with a longer stay. A decrease from preoperative to postoperative day 1 Hct of 3.5 points resulted in an increased LoS of 1 day (R (2) = 0.145; p = 0.002). The correlation of Hct decrease with longer LoS remained (β = 0.167, p = 0.006) after adjusting for other variables with multivariate regression analysis. Conclusions Lower preoperative Hct or a substantial decrease in Hct may contribute to longer hospitalization after lumbar spine surgery. These findings should prompt an investigation into the strategies for optimizing Hct levels in patients with preoperative anemia prior to lumbar spine procedures.