New insights into recovery and recurrences of non-specific low back pain

The broad aims of this thesis are: 1) to develop and validate a clinical prediction model for recovery from an episode of acute low back pain, and 2) to provide a better understanding of recurrences of low back pain and related prognostic factors. Chapter Two describes the development of a clinical prediction model to predict the probability of recovery at three different time points in patients with acute low back pain. The study provided evidence that the developed clinical prediction model could predict the likelihood of recovery from an episode of acute low back pain. However, clinical prediction models need to be tested for external validity before being recommended for clinical practice. Chapter Three presents a validation study of the developed clinical prediction model described in Chapter Two. The study provided evidence that the developed clinical prediction model demonstrated reasonably good external validity when tested in a different population. Chapter Four is a systematic review that investigated the risk of, and prognostic factors for, a recurrence of low back pain in patients who have recovered from a previous episode of low back pain within the last year. The main finding was that the available research does not provide robust estimates of the risk of low back pain recurrence and provides little information about factors that predict recurrence in people recently recovered from an episode of low back pain. The review demonstrated the need for a large, well-designed inception cohort study to investigate risk of recurrences and prognostic factors for a recurrence. Chapter Five is an inception cohort study investigating the risk of recurrences over the first year after recovering from an episode of low back pain. This study also investigated prognostic factors for a recurrence in a cohort of people recently recovered from an episode of low back pain. The study provided evidence that: 1) the estimate of recurrence is much higher than previously reported, and 2) new prognostic factors for a recurrence of low back pain were identified. Chapter Six is a sub-analysis of the inception cohort study aiming to: 1) investigate the personal impact of low back pain over a one-year period in people recently recovered from a previous episode of low back pain; 2) investigate if the personal impact of low back pain is different in people who do and do not experience a recurrence; and 3) investigate the personal impact of low back pain in participants who met three different definitions of a recurrence of low back pain. The study presented evidence that while most people report a recurrence of an episode of low back pain, many recurrences result in little personal impact. In summary, the series of studies described in this thesis have produced new and important information regarding recovery from an episode of low back pain, and recurrences that commonly occur following recovering from an episode of low back pain.