Effects of pulsed low-frequency magnetic field therapy on pain intensity in patients with musculoskeletal chronic low back pain: study protocol for a randomised double-blind placebo-controlled trial

IntroductionThe aim of the present study is to investigate the effectiveness of pulsed low-frequency magnetic field (PLFMF) on the management of chronic low back pain (CLBP).Methods and analysisA randomised double-blinded controlled clinical trial will be conducted, involving 200 patients with CLBP. Participants will be randomised in a 1:1 ratio to receive either active PLFMF (experimental arm) or sham treatment (control arm) using a permuted-block design which will be stratified according to three subtypes of musculoskeletal CLBP (nociceptive, peripheral neuropathic or central sanitisation). The intervention consists of three sessions/week for 6 weeks. The primary outcome is the percentage change in Numerical Rating Scale (NRS) pain at week 24 after treatment completion with respect to the baseline. Secondary outcomes include percentage NRS pain during treatment and early after treatment completion, short form 36 quality of life, Roland and Morris Disability Questionnaire; Depression Anxiety Stress Scale 21, Patient Specific Functional Scale, Global perceived effect of condition change, Pittsburgh Sleep Quality Index and Modified Fatigue Impact Scale. Measures will be taken at baseline, 3 and 6 weeks during the intervention and 6, 12 and 24 weeks after completing the intervention. Adverse events between arms will be evaluated. Data will be analysed on an intention-to-treat basis.Ethics and disseminationThe study is funded by Imam Abdulrahman Bin Faisal University (IAU). It has been approved by the institutional review board of IAU (IRB‐ 2017‐03–129). The study will be conducted at King Fahd Hospital of the University and will be monitored by the Hospital monitoring office for research and research ethics. The trial is scheduled to begin in September 2018. Results obtained will be presented in international conferences and will be published in peer-reviewed journals.Trial registration numberACTRN12618000921280, prospectively