Central sensitization and functioning in patients with chronic low back pain: A cross-sectional and longitudinal study

Abstract

BACKGROUND: Central sensitization (CS) is present in a subgroup of patients with chronic low back pain (CLBP). Studies on the relationship between CS and functioning have limited operationalizations of CS and functioning. OBJECTIVE: To determine whether CS was related to functioning in patients with CLBP (cross-sectional); and to determine whether changes in CS were related to changes in functioning (longitudinal). METHODS: An observational prospective cohort study with data collected at baseline and discharge of an interdisciplinary pain rehabilitation program was executed. CS indicators: CS Inventory part A (CSI-A), quantitative sensory testing (QST), root mean square of successive differences of heart-rate variability (RMSSD). Functioning measures: lifting capacity, physical functioning subscale of Rand36 (Rand36-PF), Work Ability Score (WAS), Pain Disability Index (PDI). Main analyses included correlation and multiple regression controlling for confounders; cross-sectional with baseline data and longitudinal with deltas (Δ). RESULTS: 76 patients with primary CLBP participated at baseline and 56 at discharge. Most associations were weak (cross-sectional r𝑝𝑎𝑟𝑡𝑖𝑎𝑙=-0.30–0.24; longitudinal r𝑝𝑎𝑟𝑡𝑖𝑎𝑙=-0.37–0.44). Cross-sectional multiple regression significant associations: mechanical pain threshold-QST and lifting capacity (r𝑝𝑎𝑟𝑡𝑖𝑎𝑙=-0.39), parasympathetic/vagal tone-RMSSD and physical functioning–Rand36-PF (r𝑝𝑎𝑟𝑡𝑖𝑎𝑙= 0.26). Longitudinal multiple regression significant associations: Δ parasympathetic/vagal tone-RMSSD and Δ lifting capacity (r𝑝𝑎𝑟𝑡𝑖𝑎𝑙= 0.48), ΔCSI-A and Δdisability-PDI (r𝑝𝑎𝑟𝑡𝑖𝑎𝑙= 0.36). Cross-sectional and longitudinal final regression models explained 24.0%–58.3% and 13.3%–38.0% of total variance. CONCLUSION: CS was weakly related to functioning, and decreases in CS were weakly-moderately related to increases in functioning.

Signs of Central Sensitization in Patients With Musculoskeletal Disorders and Chronic Comorbidities: A Systematic Review and Meta-Analyses of Observational Studies

“…On the other hand, when a subgroup of patients with persistent MSK-D is examined, the presence of signs of CS seems to be present and of marginal importance in giving indications on the course of symptoms, as these will, in any case, only improve to a limited extent. 68,69 Probably, this reason justifies the slightest difference that emerges from this SR in signs of CS found between samples with two persistent MSK-D present at the same time and subjects with only one MSK-D. 44,51…”

To what degree patient‐reported symptoms of central sensitization, kinesiophobia, disability, sleep, and life quality associated with 24‐h heart rate variability and actigraphy measurements?

“…They all used very short HRV measurement protocols (10 min or less) and found little associations with central sensitization, catastrophizing, fear of movement, and disability. [21][22][23] A previous meta-analysis of HRV studies comparing chronic pain subjects with pain-free controls showed evident differences in HRV measures. 8 The results of this meta-analysis were heavily influenced by studies that included subjects with fibromyalgia, which was not the case in our study.…”

“…Only three previous studies have directly assessed the association of PROMs to HRV in CMP subjects. They all used very short HRV measurement protocols (10 min or less) and found little associations with central sensitization, catastrophizing, fear of movement, and disability 21–23 …”

“…Research evidence of associations between CMP‐related PROMs and function changes of the ANS are limited to three studies with 10 or fewer minutes of heart rate variability (HRV) measures. Results found weak‐to‐moderate correlations between HRV parameters and perceived level of disability, catastrophizing, kinesiophobia, and symptoms of central sensitization 21–23 …”

“…Results found weak-to-moderate correlations between HRV parameters and perceived level of disability, catastrophizing, kinesiophobia, and symptoms of central sensitization. [21][22][23] Heart rate variability refers to the temporal variation of beat-to-beat intervals between heartbeats. 24 A growing body of literature suggests that organized variability in the heart rate pattern is a reasonable index of physical and emotional health.…”