Patients with chronic lower back pain (LBP) who had poor coping mechanisms and low pain modulation were associated with poorer physical attributes. These findings from a cross-sectional study were published in Pain.
Researchers recruited adults with recent or recurrent LBP (N=70) through flyer and social media advertising between 2017 and 2019. Patients were assessed by sensory, psychological, and motor factor tests, underwent performance-based walking tests, and self-reported symptoms during a single patient visit.
Participants were aged mean 44.59 (standard deviation [SD], 17.02) years; 51.4% were female, 77.1% were White, and they had a mean Functional Comorbidity Index of 2.0 (SD, 2.0).
With the data collected during the sensory, psychological, and motor tests, a clustering analysis found a 2-cluster solution (absolute coefficient difference, 84.89). The clusters were determined to be “maladaptive” and “adaptive” (c2, 83.17; Wilks’ l, 0.28; P <.001).
The factors that differed significantly between groups were positive coping skills (F[1,68], 29.39; Wilks’ l, 0.70; P <.001), negative coping skills (F[1,68], 39.67; Wilks’ l, 0.63; P <.001), swing-stance ratios (F[1,68], 36.82; Wilks’ l, 0.65; P <.001), flexion-relaxation ratios (F[1,68], 8.44; Wilks’ l, 0.89; P =.005), and conditioned pain modulation (F[1,68], 5.32; Wilks’ l, 0.93; P =.02).
The 2 groups were well balanced for all baseline characteristics except ethnicity. Significantly more individuals in the maladaptive group were White than in the adaptive cohort (Pearson c2, 10.38; P <.05).
Compared with participants in the adaptive group, those in the maladaptive group had lower obstacle approach speed (Cohen’s d, -0.73; P =.007), obstacle crossing speed (Cohen’s d, -0.67; P =.01), walking speed (Cohen’s d, -0.68; P =.048), and higher perceived disability (Cohen’s d, 1.14; P =.002).
They also had more perceived pain interference (Cohen’s d, 1.05; P =.002), timed up-and-go speed (Cohen’s d, 0.86; P =.01), daily pain intensity (Cohen’s d, 0.69; P =.01), and remote pressure pain threshold (Cohen’s d, 0.48; P =.07) compared with those in the adaptive group.
This study may have been limited by not including social, cognitive, or genetic factors, which may all contribute to the significant differences observed among the adaptive and maladaptive individuals with chronic LBP.
The study authors concluded that decreased coping skills and conditional pain modulation traits were associated with lower motility among individuals with LBP; however, those in the maladaptive group could increase their speed when asked. Future research is needed to determine the longitudinal consequences of maladaptive traits coupled with LBP.
Butera KA, Fox EJ, Bishop MD, Coombes SA, George SZ. Empirically derived back pain subgroups differentiated walking performance, pain, and disability. Published online December 7, 2020. Pain. doi:10.1097/j.pain.0000000000002167