Individual treatment expectations predict clinical outcome after lumbar injections against low back pain

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Abstract

Subjective expectations are known to be associated with clinical outcomes. However, expectations exist about different aspects of recovery, and few studies have focused on expectations about specific treatments. Here, we present results from a prospective observational study of patients receiving lumbar steroid injections against low back pain (N = 252). Patients completed questionnaires directly before ($T_1$), directly after ($T_2$), and 2 weeks after ($T_3$) the injection. In addition to pain intensity, we assessed expectations (and certainty therein) about treatment effects, using both numerical rating scale (NRS) and the Expectation for Treatment Scale (ETS). Regression models were used to explain (within-sample) treatment outcome (pain intensity at ) based on pain levels, expectations, and certainty at $T_1$ and $T_2$. Using cross-validation, we examined the models’ ability to predict (out-of-sample) treatment outcome. Pain intensity significantly decreased ($P < 10^{−15}$) 2 weeks after injections, with a reduction of the median NRS score from 6 to 3. Numerical Rating Scale measures of pain, expectation, and certainty from $T_1$ jointly explained treatment outcome ($P < 10^{−15}$, $R^2 = 0.31$). Expectations at $T_1$ explained outcome on its own ($P < 10^{−10}$,$f^2 = 0.19$) and enabled out-of-sample predictions about outcome ($P < 10^{−4}$), with a median error of 1.36 on a 0 to 10 NRS. Including measures from $T_2$ did not significantly improve models. Using the ETS as an alternative measurement of treatment expectations (sensitivity analysis) gave consistent results. Our results demonstrate that treatment expectations play an important role for clinical outcome after lumbar injections and may represent targets for concomitant cognitive interventions. Predicting outcomes based on simple questionnaires might be useful to support treatment selection.

Citation

Müller-Schrader, Matthias, Jakob Heinzle, Alfred Müller, u. a. „Individual Treatment Expectations Predict Clinical Outcome after Lumbar Injections against Low Back Pain“. PAIN 164, Nr. 1 (2023): 132. https://doi.org/10.1097/j.pain.0000000000002674.

@article{muller-schraderIndividualTreatmentExpectations2023,
  title = {Individual Treatment Expectations Predict Clinical Outcome after Lumbar Injections against Low Back Pain},
  author = {{M{\"u}ller-Schrader}, Matthias and Heinzle, Jakob and M{\"u}ller, Alfred and Lanz, Christian and H{\"a}ussler, Oliver and Sutter, Martin and Eggsp{\"u}hler, Andreas and Mare, Stefania and Toussaint, Birte and Pereira, In{\^e}s and Petzschner, Frederike H. and Wiech, Katja and Barth, J{\"u}rgen and Witt, Claudia M. and Stephan, Klaas Enno and Manjaly, Zina-Mary},
  year = {2023},
  month = jan,
  journal = {PAIN},
  volume = {164},
  number = {1},
  pages = {132},
  issn = {0304-3959},
  doi = {10.1097/j.pain.0000000000002674}
}