Low back pain (LBP) is reported to run a recurrent course in the majority of patients [1
]. This means that following an episode of low back pain it is likely that a patient will have further episodes of pain [3
] causing suffering for the patient and time loss from work. A number of treatments have been developed to reduce the risk of recurrent low back pain (recurrent LBP) [4
] with clinical trials conducted to evaluate how effective treatments are in patients with recurrent LBP [12
The area of recurrent LBP is complex; as is the terminology used to describe it. For example, the term ‘recurrent LBP’ is used in many different ways by clinicians and researchers creating much confusion when trying to study this condition. One use of the term recurrent LBP is to describe an outcomeevent (e.g., a recurrence of an episode of LBP). This is applicable to a study design where patients with LBP are given a treatment and then followed over time to determine if they have a recurrence of their original LBP. A second use of the term recurrent LBP is to describe a patientpopulation (e.g., patients with recurrent LBP). This is applicable when recurrent LBP is used as an inclusion criterion for a study investigating treatments for patients with recurrent LBP and we are then interested in how the authors define this type of patient.
While the two uses of recurrent LBP terminology may sound similar, they have quite different meanings. For example, some patients, after recovering from an episode of LBP, will have a recurrence at some future time. However, many researchers and clinicians would say a single episode of recurrence does not constitute the condition “recurrent LBP” but instead the patient has to experience a certain number of recurrences within a defined time period to fit this category.
We recently conducted a systematic review that investigated how recurrence as an outcome event was defined in the LBP literature. We found that definitions of recurrence of an episode of LBP varied widely making comparisons between studies difficult, if not impossible. However, to date, no study has comprehensively evaluated the definitions used in the literature to define recurrent LBP as a patient population.
It is important to clearly define recurrent LBP as a patient population
in order to study treatment efficacy and prognosis for this group of patients. Without an agreed definition it is difficult to interpret the results of trials that evaluate the management of recurrent LBP or observational studies that attempt to estimate the prevalence of recurrent LBP or its prognosis. The only published recommended definition for recurrent LBP that we are aware of following a comprehensive search is that by von Korff in 1994: ‘back pain present on less than half the days in a 12-month period, occurring in multiple episodes over the year’ [2
]. However, it is unclear if this definition is being used in research.
The purpose of this systematic review therefore, is to explore and summarise the definitions of recurrent LBP (as a patient population) that are currently used in the literature.