BackgroundResearch has shown social inequalities in health parameters in the general population, but there is a lack of evidence in medical rehabilitation.ObjectiveTo investigate social inequalities in the utilisation and process of rehabilitation among people with non-specific chronic low back pain (CLBP) and multiple psychological strains undergoing inpatient multidisciplinary orthopaedic rehabilitation (MOR).MethodsThis multicentre study enrolled 910 patients with non-specific CLBP (ICD-10: M51/53/54) and examined the differences in self-initiative to attend rehabilitation, and psychological, work-related, and pain-related parameters prior to MOR stratified by the social class index (lower, middle, upper class). Moreover, socioeconomic differences were investigated in the frequency distributions of psychosocial cut-off scores before rehabilitation, indicating the clinical relevance of the social class index.ResultsCompared with patients in both higher classes, patients in the lower class showed significantly lower self-initiative for rehabilitation as well as unfavourable values for pain self-efficacy and work-related and pain-related parameters.ConclusionsHealth-related inequalities in the inpatient MOR of non-specific CLBP were supported. To promote better health equity, patients should be allocated to rehabilitation according to their needs and individually strengthened in terms of their self-efficacy, health literacy, and ability to cope with pain and work-related stress.