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Table 4 Sensitivity and specificity for estimated cut-off values. Correct classification rate in different PROM baseline groups

From: Follow-up score, change score or percentage change score for determining clinical important outcome following surgery? An observational study from the Norwegian registry for Spine surgery evaluating patient reported outcome measures in lumbar spinal stenosis and lumbar degenerative spondylolisthesis

  Spinal stenosis Degenerative spondylolisthesis
  Estimated cut-off Correct
classification
Sensitivity Specificity Estimated cut-off Correct
classification
Sensitivity Specificity
ODI follow-up score ≤24   0.83 0.80 ≤24   0.85 0.84
 Low baseline   80%     87%   
 Medium   85%     85%   
 High baseline   80%     84%   
ODI change score ≥13   0.78 0.77 ≥13   0.83 0.71
 Low baseline   72%     77%   
 Medium   84%     86%   
 High baseline   78%     75%   
ODI percentage change ≥30   0.87 0.77 ≥30   0.89 0.77
 Low baseline   83%     88%   
 Medium   85%     85%   
 High baseline   80%     82%   
EQ-5D follow-up score ≥0.692   0.76 0.81 ≥0.692   0.80 0.88
 Low baseline   75%     81%   
 Medium   79%     80%   
 High baseline   80%     82%   
EQ-5D change score ≥0.105   0.77 0.68 ≥0.105   0.81 0.63
 Low baseline   73%     74%   
 Medium   75%     80%   
 High baseline   72%     71%   
Leg pain follow-up score ≤3   0.80 0.83 ≤3   0.79 0.78
 Low baseline   82%     81%   
 Medium   82%     76%   
 High baseline   81%     79%   
Leg pain change score ≥3   0.78 0.75 ≥3   0.78 0.72
 Low baseline   69%     70%   
 Medium   82%     76%   
 High baseline   78%     80%   
Leg pain percentage change ≥40   0.82 0.80 ≥40   0.80 0.73
 Low baseline   79%     75%   
 Medium   81%     76%   
 High baseline   81%     81%   
Back pain follow-up score ≤4   0.84 0.79 ≤4   0.85 0.79
 Low baseline   81%     82%   
 Medium   83%     80%   
 High baseline   82%     87%   
Back pain change score ≥2   0.82 0.66 ≥3   0.78 0.80
 Low baseline   72%     67%   
 Medium   83%     81%   
 High baseline   71%     83%   
Back pain percentage change ≥33%   0.81 0.79 ≥33%   0.83 0.78
 Low baseline   76%     78%   
 Medium   83%     80%   
 High baseline   80%     85%   
  1. The sensitivity describes the probability of correctly classifying an individual replying ‘completely recovered’ or ‘much improved’ (GPE) as a ‘success’ when assessed by the estimated cut-offs for the PROMs. The specificity describes the probability for detecting a ‘non-success’ patient (one with a lower response at the GPE scale)
  2. For each estimated cut-off values the percentage of correctly classified patients (correct classification) into ‘success’ and ‘non-success’ according to the anchor are given separately for patients with low (ODI; 0–32, EQ-5D; −0.59-0.1, NRS leg and back pain; 0–5), medium (ODI; 32–46, EQ-5D; 0.1–0.6, NRS leg and back pain; 6–7), and high (ODI; 46 to 100, EQ-5D; 0.6–1.0, NRS leg and back pain; 8–10) baseline scores