Self-reported Health and Pain Sensitivity in  Low Back Pain : Differences between Individuals with and without Pain Radiation to Lower Limbs

Abstract: Background: Low back pain (LBP) is the leading cause of disability and is often accompanied with a back-related leg pain (around 60%), where those with radiating pain show worse overall clinical outcomes. Previous studies comparing these two groups have involved individuals with chronic LBP. It is not known if subjects who currently have LBP differ in pain sensitivity from those who have currently LBP accompanied with pain radiation to lower limbs. Aim: The aim of this study was to investigate whether there are differences in self-reported health and pain sensitivity between individuals currently having LBP with and without pain radiation to lower limbs. Method: Individuals with LBP (n=100) aged 40 to 70 years participated in this study. According the first question of STarT Back Pain Screening Tool about the pain radiation to leg(s), individuals were divided into two groups: radiation group (RG, n=36) and no radiation group (noRG, n=64). To gain the information about self-reported health, following questionnaires were used: Roland-Morris Disability Questionnaire, Fear-Avoidance Beliefs Questionnaire and Hospital Anxiety and Depression Scale. Pressure pain thresholds (PPTs) were measured with algometer (6 sites and 4 points of ’lower body’: gluteal and knee points). Mann-Whitney U-test was used to calculate differences on group and gender level. A logistic regression analyses was calculated (crude model), where belong to RG or not was the dependent variable and all self-reported data and PPTs were independent variables, all data were controlled for gender and age. Results: The RG reported worse disability (p=0.017), higher fear-avoidance beliefs (FAB) about physical activity (p=0.003), worse score in anxiety (p=0.002) and depression (p=0.001), and increased pain sensitivity (p=0.043) in 6 sites PPTs compared to the noRG. Higher score of disability, FAB (physical activity and work), anxiety and depression were associated with an increased risk of belonging to the RG (OR 1.05-1.50, 95% CI 1.01-1.94), controlled for gender and age. Conclusion: Individuals with LBP and pain radiation to lower limbs showed worse self-reported disability and fear-avoidance beliefs about physical activity than those with LBP only. Further, those with pain radiation were more sensitive to pain in general. Worse scores of all studied self-reported data were associated with an increased risk of belonging to the groups with pain radiation. To study gender differences larger sample sizes are needed. Individuals with LBP and pain radiation to lower limbs showed worse outcomes and therefore should receive a different treatment approach than those who have only LBP.