The effectiveness of two active interventions compared to self-care advice in employees with non-acute low back symptoms: a randomised, controlled trial with a 4-year follow-up in the occupational health setting

Objective Evaluate the effectiveness of two active interventions, aimed at secondary prevention of low back pain (LBP), in occupational health. Methods We performed a survey of LBP (n¼2480; response rate 71%) and randomized 143 employees (66% males, 45 years) with LBP over 34 mm on VAS into Rehabilitation (n¼43), Exercise (n¼43) or self-care (n¼40) groups. Primary outcomes were LBP, physical impairment (PI) and health-related quality of life (HRQoL) for two years and sickness absence (SA) days during four years (LBP specific, total). Results Compared to self-care, exercise reduced LBP at 12 months (mean difference (MD) � 12 mm; 95% CI � 21 to � 2) and improved HRQoL at 12 and 24 months (0.03; 0.00 to 0.05), but did not reduce PI. The MDs of SA days in four years were � 17 (� 70 to 35, total) and � 15 (� 47 to 13, LBP specific). Exercise reduced the probability of LBP specific SA during the third and fourth year. Compared to self-care, Rehabilitation reduced LBP at 3 months (� 10 mm; � 19 to � 1) and 6 months (� 10 mm; � 20 to � 1), but was not effective in HRQoL or PI. The MDs of SA days in four years were � 41 (� 93 to 8; total) and 5 (� 30 to 47; LBP specific). Rehabilitation reduced the probability of total SA during first and second year and amount of total SA days in the fourth year. Conclusions Among employees with relatively mild LBP, both interventions reduced pain, but the effects on SA and PI were minor. Exercise improved HRQoL. The effect sizes were rather small. Trial registration Number ClinicalTrials.gov NCT00908102.