AbstractBackground and purposeLow back pain (LBP) is a lifelong problem for many. In acute episodes, or as a persistent condition, LBP is fluctuating in nature, with pain and other features of the condition varying in intensity and duration over time. Symptom flares (also known as flare ups) contribute to this variation and can have a great impact on the lives of those who have LBP. An important goal of treatments for, and research on, LBP is arguably to decrease symptom flare in both frequency and severity. However, this goal is problematic with little research, and no consensus, on how to define LBP flare. In particular, patients’ understandings of LBP flare have received limited attention in the literature. To appropriately address this issue, we sought to understand how flares are conceptualized by individuals with LBP.MethodsWe used an inductive, predominantly qualitative methodology, conducting an online survey with 130 individuals who self-reported experiencing LBP. The survey investigated participants’ views on LBP flare including its meaning, features and symptoms, and whether ‘flare’ and ‘pain increase’ were synonymous. Qualitative analysis of responses involved thematic and content analysis with descriptive statistics used for the quantitative component.ResultsOur data analysis found that participants identified many aspects of a flare to be important. Qualitative analyses highlighted a number of themes including that LBP flare was conceptualized as: (1) on increase in pain and other uncomfortable sensations such as paraesthesia or muscle tension, (2) an increase in the area, quality and/or duration of symptoms, (3) a reduction in physical, cognitive and/or social functioning, and (4) negative psychological and/or emotional factors. Flare was also discussed as a change that was difficult to settle. When participants considered whether ‘flare’ and ‘pain increase’ were synonymous, responses were evenly divided between ‘no’ (47%) and ‘yes’ (46%) with remaining participants ‘unsure’.ConclusionsThe key finding was that many people with LBP do not consider their condition to be flared simply on the basis of a pain increase. In general, other features were required to also change. Results highlighted that a narrow focus on pain is unlikely to differentiate minor pain events from a flare. these findings are important as they contrast with most commonly used definitions of a flare that focus predominantly on pain increase.ImplicationsOur findings have implications for understanding the trajectory of LBP over time. Understandings derived from perspectives of individuals with LBP highlight that defining flare in LBP is complex. In order to provide person-centred care, individual context and experiences should be taken into account. Therefore, understandings of LBP flare require consideration of factors beyond simply an increase in pain. A comprehensive, person-centred understanding of flare that includes a number of features beyond simply an increase in pain intensity is likely to be useful to better identify flares in research settings, assisting endeavours to understand and reduce LBP. Similarly, in clinical settings a nuanced conceptualisation of flare is likely to help health professionals communicate understandings of flare when working with individuals to manage their LBP.