Differences in psychological factors, disability and fatigue according to the grade of chronification in non-specific low back pain patients: A cross-sectional study.

Differences in pain processing, muscle structure and function have been reported in patients with low back pain (LBP) with different grades of pain chronicity.The present study aims to examine differences in psychological factors, disability and subjective fatigue between subgroups of LBP based on their chronification grade.Twenty-one healthy controls (HC) and 54 LBP patients (categorized based on the grades of chronicity into recurrent LBP (RLBP), non-continuous chronic LBP (CLBP), or continuous (CLBP)) filled out a set of self-reporting questionnaires.The Hospital Anxiety and Depression Scale (HADS) and Multidimensional Pain Inventory (MPI) scores indicated that anxiety, pain severity, pain interference and affective distress were lower in HC and RLBP compared to non-continuous CLBP. Anxiety scores were higher in non-continuous CLBP compared to RLBP, continuous CLBP and HC. The Pain Catastrophizing Scale for Helplessness (PSCH) was higher in non-continuous CLBP compared to HC. The Survey of Pain Attitudes (SOPA) showed no differences in adaptive and maladaptive behaviors across the groups. The Pain Disability Index (PDI) measured a higher disability in both CLBP groups compared to HC. Moreover, the Rolland Morris Disability Questionnaire (RMDQ) showed higher levels of disability in continuous CLBP compared to non-continuous CLBP, RLBP and HC. The Checklist Individual Strength (CIS) revealed that patients with non-continuous CLBP were affected to a higher extent by severe fatigue compared to continuous CLBP, RLBP and HC (subjective fatigue, concentration and physical activity). For all tests, a significance level of 0.05 was used.RLBP patients are more disabled than HC, but have a tendency towards a general positive psychological state of mind. Non-continuous CLBP patients would most likely present a negative psychological mindset, become more disabled and have prolonged fatigue complaints. Finally, the continuous CLBP patients are characterized by more negative attitudes and believes on pain, enhanced disability and interference of pain in their daily lives.