Clinically important deterioration in patients undergoing lumbar spine surgery: a choice of evaluation methods using the Oswestry Disability Index, 36-Item Short Form Health Survey, and pain scales

Abstract

Object Health-related quality of life (HRQOL) measures have become the mainstay for outcome appraisal in spine surgery. Clinically meaningful interpretation of HRQOL improvement has centered on the minimum clinically important difference (MCID). The purpose of this study was to calculate clinically important deterioration (CIDET) thresholds and determine a CIDET value for each HRQOL measure for patients undergoing lumbar fusion. Methods Seven hundred twenty-two patients (248 males, 127 smokers, mean age 60.8 years) were identified with complete preoperative and 1-year postoperative HRQOLs including the Oswestry Disability Index (ODI), 36-Item Short Form Health Survey (SF-36), and numeric rating scales (0–10) for back and leg pain following primary, instrumented, posterior lumbar fusion. Anchor-based and distribution-based methods were used to calculate CIDET for each HRQOL. Anchor-based methods included change score, change difference, and receiver operating characteristic curve analysis. The Health Transition Item, an independent item of the SF-36, was used as the external anchor. Patients who responded “somewhat worse” and “much worse” were combined and compared with patients responding “about the same.” Distribution-based methods were minimum detectable change and effect size. Results Diagnoses included spondylolisthesis (n = 332), scoliosis (n = 54), instability (n = 37), disc pathology (n = 146), and stenosis (n = 153). There was a statistically significant change (p < 0.0001) for each HRQOL measure from preoperatively to 1-year postoperatively. Only 107 patients (15%) reported being “somewhat worse” (n = 81) or “much worse” (n = 26). Calculation methods yielded a range of CIDET values for ODI (0.17–9.06), SF-36 physical component summary (−0.32 to 4.43), back pain (0.02–1.50), and leg pain (0.02–1.50). Conclusions A threshold for clinical deterioration was difficult to identify. This may be due to the small number of patients reporting being worse after surgery and the variability across methods to determine CIDET thresholds. Overall, it appears that patients may interpret the absence of change as deterioration.

Criteria for failure and worsening after surgery for lumbar disc herniation: a multicenter observational study based on data from the Norwegian Registry for Spine Surgery

“…For instance, severely disabled patients will require disproportionally greater improvements than the less disabled, not to consider the surgery as failed. This is in accordance with findings of other studies and illustrates the importance of taking into account the baseline score while interpreting PROM change scores, regardless of using absolute or percentage change scores [18,41]. Consequently, one should adjust for the baseline score when using such outcome criteria in clinical trials and risk factor analyses.…”

“…In a smaller single-center study from 2013, Gum et al tried to define clinically important deterioration among patients operated with lumbar fusion for various diagnoses, but found it difficult to define cutoffs. They concluded that a larger patient population was needed to identify accurate cutoffs, since worsening is a relatively rare event [41]. We have used a much larger and more condition-specific cohort.…”

Evaluation of the patient acceptable symptom state following hip arthroscopy using the 12 item international hip outcome tool

“…Variations in scores using different methodologies (i.e. anchor based vs distributional) have previously been highlighted in the orthopaedic spinal literature [26][27][28].…”

The Risk of Getting Worse: Predictors of Deterioration After Decompressive Surgery for Lumbar Spinal Stenosis: A Multicenter Observational Study

“…Several studies have investigated the minimum clinically important difference (MICD) for the ODI in lumbar spine surgery patients (10,16,(28)(29)(30). The cut-off value often is interpreted as a significant change for both clinically improvement and deterioration.…”