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Table 1 A description of the applied regression models for Aim A

From: Pressure pain thresholds in a real-world chiropractic setting: topography, changes after treatment, and clinical relevance?

Aim A objective Method Fixed dependent effect Fixed independent effect Random intercept Reported as
Changes in PPT over time Linear mixed regression PPT Model 1: Time
Model 2: Interaction between time and test site
Subject Mean change value with 95% CI, both dependent and independent of the test site
(I) Distance from test site to SMT site Linear mixed regression PPT change Distance between the tested vertebrae and the closest SMT site (e.g., PPT test at C7 and SMT at C1 = distance of 6) Subject + PPT at baseline + region of pain A Beta coefficient with a 95% CI. A scatter plot with a best fitting regression line
(II) Rapid responder status Linear regression PPT change Responder status (e.g., much better) Between group mean differences for each rapid responder status change values with 95% CI
(III) The baseline PPT value Linear regression PPT change The baseline PPT value (e.g., 5.5 kg) A Beta coefficient with a 95% CI
(IV) Number of SMTs performed Linear regression PPT change Number of SMTs performed (e.g., 3 SMTs) A Beta coefficient with a 95% CI
(V) Region of pain compared to the adjacent or distant region* Linear mixed regression PPT change Pain region (i.e., change in PPT in the pain region (e.g., cervical) compared to change in PPT in the i) adjacent region (e.g., thoracic) or ii) distant region (e.g., lumbar)) Subject Between group mean differences for the pain region and adjacent/distant region with 95% CI
(VI) Other non-SMT treatment provided Linear regression   Non SMT-treatment provided. Categorized as myofascial (compression technique or dryneedling), muscle energy technique, massage, other (Laser or free text field), and none Between group mean differences of the different non-SMT options with 95% CI
  1. *For objective V, we used the mean value for each region (e.g., mean of PPT from L1 and L5), and for those with multiple pain sites, the “pain region” was determined as any point of pain (e.g., for those with lumbar and thoracic pain, both the lumbar and the thoracic PPTs would be flagged as “the pain region” with the cervical region being the “adjacent”). CI = confidence interval, PPT = Pressure pain threshold, SMT = spinal manipulation