Prognostic factors for perceived recovery or functional improvement in non-specific low back pain: secondary analyses of three randomized clinical trials

The objective of this study was to report on secondary analyses of a merged trial dataset aimed at exploring the potential importance of patient factors associated with clinically relevant improvements in non-acute, non-specific low back pain (LBP). From 273 predominantly male army workers (mean age 39 ± 10.5 years, range 20–56 years, 4 women) with LBP who were recruited in three randomized clinical trials, baseline individual patient factors, pain-related factors, work-related psychosocial factors, and psychological factors were evaluated as potential prognostic variables in a short-term (post-treatment) and a long-term logistic regression model (6 months after treatment). We found one dominant prognostic factor for improvement directly after treatment as well as 6 months later: baseline functional disability, expressed in Roland–Morris Disability Questionnaire scores. Baseline fear of movement, expressed in Tampa Scale for Kinesiophobia scores, had also significant prognostic value for long-term improvement. Less strongly associated with the outcome, but also included in our final models, were supervisor social support and duration of complaints (short-term model), and co-worker social support and pain radiation (long-term model). Information about initial levels of functional disability and fear-avoidance behaviour can be of value in the treatment of patient populations with characteristics comparable to the current army study population (e.g., predominantly male, physically active, working, moderate but chronic back problems). Individuals at risk for poor long-term LBP recovery, i.e., individuals with high initial level of disability and prominent fear-avoidance behaviour, can be distinguished that may need additional cognitive-behavioural treatment

A high-intensity lumbar extensor strengthening program is little better than a low-intensity program or a waiting list control group for chronic low back pain: a randomised clinical trial

QuestionIs eight weeks of high-intensity strengthening of the isolated lumbar extensors more effective than low-intensity strengthening or no strengthening? Are any gains maintained 16 weeks later?DesignRandomised, three-arm trial with concealed allocation, assessor blinding, and intention-to-treat-analysis. Participants in the waiting list control group were randomised again, after the first 8 weeks, to either the high-intensity or the low-intensity strengthening program.ParticipantsSixty-five army personnel with non-specific chronic low back pain.InterventionThe high-intensity training group received 10 sessions of 15 to 20 repetitions for the isolated lumbar extensor muscles. The low-intensity training group received a nonprogressive, low-intensity resistance protocol.Outcome measuresPrimary outcomes were global perceived effect and disability. Secondary outcomes were health-related quality of life, fear of movement/(re-)injury, and isometric lumbar extensor muscle strength. Measures were taken before and after the training and 16 weeks later.ResultsAt eight weeks, SF-36 overall score was on average 7% (95% CI 1 to 13) greater in the high-intensity training group compared with the low-intensity training group and the waiting list control group, and self-assessed decrease of back symptoms was on average 39% (95% CI 14 to 64) greater in the high-intensity training group compared with the waiting list control group. There was no difference in improvement between the groups for any other outcome at 8 weeks or 24 weeks.ConclusionsAlthough some beneficial effects were found, the results of this high-intensity strengthening program of the isolated lumbar extensor muscles do not clearly support the generally-claimed beneficial influence of exercise for chronic non-specific low back pain