LBP Flares

Risk Factors for Low Back Pain ‘Flares’ and Definitions | ISSLS PRIZE IN CLINICAL SCIENCE 2021

Goal of the Study?

In this case-crossover study from the European Spine Journal1 the authors’ goals were twofold: (a) identify risk factors of low back pain flares and (b) whether risk factors differed when LBP flares are defined by pain increase (Pain-Defined Flare: PDF) or by a broader definition that considered emotions and coping (Self-Reported Flare: SRF).


Why are they doing this study?

Lower Back Pain (LBP) is an ongoing fluctuating condition characterized by flares interspersed by periods of no or lesser pain.  In this study, a flare is defined as an increase in symptoms that lasts from hours to weeks, is difficult to tolerate and generally impacts your usual activities and/or emotions.  Identifying the risk factors for these flares is important in reducing LBP frequency and/or intensity.


What was done?

Initially, 126 participants that had LBP for greater than 3 months were assessed 3 times a day for 28 days using a smartphone app. This app recorded two definitions of LBP flare.  PDFs were defined as a pain increase of 2 points or more on an 11 point scale.  SRF was identified by positive responses to the multidimensional questions asked each evening.   The case period was defined as the three days prior to a PDF or SDF flare.  Similarly, the control period was defined as the three days preceding a day with no flares. Only subjects with a PDF and/or  SRF flare that were preceded by at least 3 days without a flare were used.  This reduced the number of subjects to 86. Univariate conditional logistic regression determined whether the variables differed during case and control periods.   This allowed for the calculation of the odds ratio for the occurrence of a flare.


What did they find?

A total of 813 flare days were identified, including 465 days with SRF only, 222 with PDF only and 126 with both. Pain was reported every day by 48% of the participants.  The four main findings were:  

  • Fatigue, leisure-time physical activity and fear of physical activity all increased the risk for transient pain increase (PDF).  
  • High pain in the morning, afternoon and/or evening increased the odds of having a PDF or SRF flare in the days following.
  • Risk factors differed when flares were defined by the broader definition (SRF)
  • High sleep quality is protective and significantly reduces the risk regardless of both types of flares.


Why do these findings matter?

Research into  LBP flare has largely been ignored but is more reflective of the LBP experience than conventional definitions of acute and chronic LBP.  This study highlights risk factors for flare and that these differ depending on whether the flare is defined as pain alone (PDF) or a broad multidimensional definition (SRF) is used. Potential strategies to reduce the intensity and/or frequency of LBP flares are identified, with a very strong indication for the potential of sleep interventions to mitigate the LBP flare risk.


Dynamic Disc Designs creates realistic models to help spine professionals translate the science in an artistic way. In this study, ddd models can be used to educate the value of getting a good nights sleep as it relates to disc height hydraulics. Additionally, if low back pain patients experience morning pain, a ddd model can help patients understand the hyperhydration and the related hypermobility that may exist. Education and anatomy is our passion. We hope that is reflected in what we do.