127. Quantitative prospective patient-reported expectations (PREs) challenge commonly used thresholds for minimal clinically important difference (MCID) in elective spine surgery

BACKGROUND CONTEXT

Patients make decisions about elective spine surgery based on perceptions of severity of the preoperative condition as well as expectations that surgery will improve symptoms, function and/or quality of life. As a result, spine surgery has increasingly focused on patient-reported outcomes (PROs) to measure results with thresholds such as minimal clinically important difference (MCID) used to define clinical success and failure. Despite the importance given, MCID values and methodology vary widely in the reported literature, are retrospectively assessed and do not account for individual patient preference at the time of surgical decision-making. No study to date has utilized PROMIS measures to prospectively define patients' expectations for improvement after surgery and compared them to commonly reported MCID values.

PURPOSE

To compare prospectively obtained, PROMIS-based patient-reported expectations (PREs) to commonly reported MCID values.

STUDY DESIGN/SETTING

Prospective observational cohort study.

PATIENT SAMPLE

Forty-five patients who underwent surgical decompression or decompression and fusion for cervical or lumbar degenerative spine pathology were included.

OUTCOME MEASURES

Baseline preoperative PROMIS Physical Function (PF), PROMIS Pain Interference (PI) and expected postoperative PROMIS PF and PI.

METHODS

Patients undergoing elective spine surgery were consecutively and prospectively identified. PROMIS questionnaires were administered at the first preoperative appointment to assess baseline preoperative PROMIS score and expected postoperative PROMIS score using the following domains: Physical Function (PF) and Pain Interference (PI). Baseline preoperative PROMIS scores were based on the symptoms they were experiencing at the preoperative time point. Patient-reported expectations (PREs) after surgery were determined by asking patients to respond to the same questionnaires by indicating the outcomes they were expecting following surgery. T-tests were used to compare expected postoperative PROMIS scores and baseline preoperative PROMIS scores for both PF and PI. Commonly reported anchor MCID values (8) for these PROMIS measures were obtained from a review of the literature. Regression analysis was performed to determine the impact of patient characteristics or clinical factors. Patients are still being followed out to 12 months to obtain long-term PROMIS outcomes and patient satisfaction results as well as to assess how expectations change over time. These results are not available at the time of abstract submission.

RESULTS

When comparing baseline preoperative PROMIS scores to expected postoperative PROMIS scores, patients expected to improve postoperatively in both PF and PI from baseline with mean difference 5.6 (p <0.001) and -5.9 (p <0.001), respectively. No significant differences for expected postoperative PROMIS scores were found based on age, sex, BMI, ASA classification, procedure or diagnosis. All expected improvements were less than the commonly used anchor MCID of 8.

CONCLUSIONS

This study is the first to compare prospectively collected, PROMIS-based patient expectations before elective spine surgery to established MCID values. Patient-reported expectations (PREs) are significantly different than actual baseline preoperative status as measured by PROMIS PF and PI scores. Patients' expectations are less than the commonly reported MCID of 8, challenging currently accepted standards of success and failure after elective spine surgery.

FDA DEVICE/DRUG STATUS

This abstract does not discuss or include any applicable devices or drugs.