Neck pain patterns and subgrouping based on weekly SMS-derived trajectories

Abstract

Background Neck and low back pain represent dynamic conditions that change over time, often with an initial improvement after the onset of a new episode, followed by flare-ups or variations in intensity. Pain trajectories were previously defined based on longitudinal studies of temporal patterns and pain intensity of individuals with low back pain. In this study, we aimed to 1) investigate if the defined patterns and subgroups for low back pain were applicable to neck pain patients in chiropractic practice, 2) explore the robustness of the defined patterns, and 3) investigate if patients within the various patterns differ concerning characteristics and clinical findings. Methods Prospective cohort study including 1208 neck pain patients from chiropractic practice. Patients responded to weekly SMS-questions about pain intensity and frequency over 43 weeks. We categorized individual responses into four main patterns based on number of days with pain and variations in pain intensity, and subdivided each into four subgroups based on pain intensity, resulting in 16 trajectory subgroups. We compared baseline characteristics and clinical findings between patterns and between Persistent fluctuating and Episodic subgroups. Results All but two patients could be classified into one of the 16 subgroups, with 94% in the Persistent fluctuating or Episodic patterns. In the largest subgroup, “Mild Persistent fluctuating” (25%), mean (SD) pain intensity was 3.4 (0.6) and mean days with pain 130. Patients grouped as “Moderate Episodic” (24%) reported a mean pain intensity of 2.7 (0.6) and 39 days with pain. Eight of the 16 subgroups each contained less than 1% of the cohort. Patients in the Persistent fluctuating pattern scored higher than the other patterns in terms of reduced function and psychosocial factors. Conclusions The same subgroups seem to fit neck and low back pain patients, with pain that typically persists and varies in intensity or is episodic. Patients in a Persistent fluctuating pattern are more bothered by their pain than those in other patterns. The low back pain definitions can be used on patients with neck pain, but with the majority of patients classified into 8 subgroups, there seems to be a redundancy in the original model.

The clinical course of neck pain: Are trajectory patterns stable over a 1‐year period?

“…Sixteen subgroups based on these criteria matched well with trajectories of LBP, and identified subgroups that also differed in severity on other parameters (Irgens et al, 2020;Kongsted et al, 2017). We have previously found that the same definitions fit readily to NP patients in a chiropractic setting, but also that they needed refinement (Irgens et al, 2020).…”

“…We, therefore, decided to combine the Ongoing and persistent fluctuating variation patterns into one pattern called persistent pattern. In our previous study (Irgens et al, 2020), we found that patients in the minor subgroups of Ongoing episodic and single episode shared similar demographic, functional and psychosocial characteristics, and patients were only negligibly affected by their pain. Also, pain intensity was below what is considered clinically significant (<2 on NRS) (Kovacs et al, 2008;Pool et al, 2007).…”

“…To be able to explore the research question regarding the stability of trajectories over one year, we needed to reduce the previously identified sixteen subgroups into fewer subgroups. We did that according to the suggestions from two previous studies (Irgens et al, 2020;Kongsted et al, 2017). These found that very few patients fit into the Ongoing and single episode variation patterns.…”

“…Previous studies on low back pain (LBP) patients have suggested criteria for classifying trajectories of LBP based on pain variation patterns (ongoing, fluctuating, episodic and recovery) and pain severity (severe, moderate, mild and minor) (Kongsted et al, 2016). Sixteen subgroups based on these criteria matched well with trajectories of LBP, and identified subgroups that also differed in severity on other parameters (Irgens et al, 2020;Kongsted et al, 2017). We have previously found that the same definitions fit readily to NP patients in a chiropractic setting, but also that they needed refinement (Irgens et al, 2020).…”

“…However, trajectories based on frequent pain measures to capture temporal variation also show that a large majority of patients with spinal pain display patterns of initial improvement (Ailliet et al, 2018;Axén et al, 2012;Chen et al, 2018;Dunn et al, 2006Dunn et al, , 2013Kongsted et al, 2015;Pico-Espinosa et al, 2019). Also, patients with long-lasting pain have a dynamic course of pain (Ailliet et al, 2018;Irgens et al, 2020;Kongsted et al, 2016;Pico-Espinosa et al, 2019). A better understanding of various clinical courses may be helpful in communicating the likely pain prognosis with the patient and in decisions regarding treatment.…”