P55. Do patients accurately recall symptoms pre and post lumbar epidural steroid injection: A cohort study of recall bias in patient reported outcomes

Abstract

<h3>BACKGROUND CONTEXT</h3> Although patient-reported outcomes (PROs) have become important in the evaluation of spine surgery patients, the accuracy of patient recall of pre or post-intervention symptoms following epidural steroid injection remains unknown. <h3>PURPOSE</h3> The purpose of this study was 1) to characterize the accuracy of patient recollection of back/leg pain following epidural steroid injection; 2) characterize the direction and magnitude of recall bias; 3) characterize factors that impact patient recollection. <h3>STUDY DESIGN/SETTING</h3> Prospective cohort study. <h3>PATIENT SAMPLE</h3> Consecutive patients 18 years and older undergoing lumbar epidural steroid injection presenting with neurogenic claudication or radiculopathy secondary to degenerative lumbar spinal stenosis <h3>OUTCOME MEASURES</h3> Numeric pain scale (NPS) for back pain and leg pain. <h3>METHODS</h3> Using standardized questionnaires, we recorded numeric pain scores (NPS) for patients undergoing lumbar epidural steroid injections at our institution. Baseline pain scores were obtained prior to injection, 4 hours and 24-hours post-injection. At a minimum of 2 weeks following the injection, patients were asked to recall their symptoms pre-injection and at 4 hours and 24-hours post-injection. Actual and recalled scores at each time point were compared using paired t-tests. Multivariable linear regression was used to identify factors that impacted recollection. <h3>RESULTS</h3> Sixty-one patients with a mean age of 61.4 years (56% female) were included. Compared to their pre-injection pain score, patients showed considerable improvement at both 4 hours [Mean Difference (MD) = 2.18, 95% Confidence Interval (CI) 1.42 to 2.94)) and 24 hours (MD = 2.64, 95% CI 1.91 to 3.34) post-injection. Patient recollection of pre-injection symptoms was significantly more severe than actual (MD = 1.39, 95% CI 4.82 to 6.08). The magnitude of recall bias was moderate to severe and exceeded the minimal clinically important difference (MCID). Patient recollection of symptoms was also significantly more severe than actual at 24 hours (MD = 0.63, 95% CI -1.17 to -0.07), mild magnitude of bias that did not exceed MCID. No significant recall bias was noted on patient recollection of post-injection symptoms at 4 hours (MD = 0.41, 95% CI -1.05 to 0.23). Linear regression models for differences between actual and recalled pain scores reveal that for recall at 4 hours post-injection, older patients were better at recalling pain. <h3>CONCLUSIONS</h3> Relying on patient recollection does not provide an accurate measure of pre-injection status after lumbar epidural steroid injection, although patients did recall their 4 hour and 24-hour post-injection status. These findings support previous studies indicating that relying on patient recollection does not provide an accurate measure of pre-intervention symptoms. Patient recollection of post-intervention symptoms, however, may have some clinical utility and requires further study. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.