401: Trajectories of Primary Healthcare Use in People with Fibromyalgia: A Latent Class Analysis in CPRD

Topic: Clinical Science
Subtopic: Pain category (ICD-11), Chronic primary musculoskeletal pain, Epidemiology, Treatment/management

Background and Aims: Fibromyalgia is a common chronic, widespread pain condition, associated with higher healthcare use than the general population. Difficulty diagnosing and managing fibromyalgia often leads to ineffective or inappropriate healthcare use. Understanding how people with fibromyalgia use healthcare is crucial for service planning, yet it is unclear whether subgroups exist that follow differing patterns or trajectories of use over time. This knowledge could help inform the provision of appropriate and stratified care. This study explored the presence of distinct classes of primary healthcare use trajectories in people with newly diagnosed fibromyalgia over four years and compared their sociodemographic and comorbid characteristics.

Methods: A retrospective cohort study included adults with a diagnostic code for fibromyalgia recorded in the UK Clinical Practice Research Datalink between 2008-2018. Clinical codes indicative of a primary care consultation were extracted, transformed to count per person per quarter for up to 16 quarters from fibromyalgia diagnosis, and modelled longitudinally using a piecewise, zero-inflated negative binomial Latent Class Growth Analysis. Assessment of maximum likelihood ratio, Akaike and Bayesian information criterion, entropy, and classification accuracy were used to establish the optimum number of classes. Baseline comorbidities, sociodemographic characteristics, and medication use were described and compared across classes at fibromyalgia diagnosis.

Results: 49,268 individuals (mean age: 47.6 years (SD 12.6); female: 44,856 (90%); mean quarterly consultations: 4.5 (SD 3.9; range 1–87) were included. Six latent classes were defined: 1. “steady decline, moderate-low” (n=4,572); 2. “initial decline, low flatline” (n=15,773); 3. “high rates, slow decline” (n=9,319); 4. “initial decline, steady increase” (n=13,352); 5. “initial decline, very low flatline” (n=4,436); 6. “very high, slow decrease” (n=1,816). Members of classes three and six were oldest and had highest levels of analgesic prescribing and comorbidity. Members of class 5 were more likely to be male, younger and had lowest levels of analgesic prescribing and comorbidity.

Conclusions: Six distinct primary healthcare use trajectories following fibromyalgia diagnosis were defined. Opioid and gabapentinoid use in the month preceding diagnosis, along with comorbid pain and mental health conditions at baseline, were associated with the greatest levels of primary healthcare use. The class with the lowest number of quarterly consultations had rates comparable to the general UK population. By identifying the characteristics of trajectory classes, these findings could help support the provision of appropriate and effective healthcare.

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Presenting Author: Ms Ailish Katherine Byrne
Submitting Author: Ailish Byrne

Senior Author: Dr Ian Scott

IASP 2026 Global Year theme of Neuropathic Pain: No

• Helen Twohig: Dr - Keele University
• Sara Muller: Professor - Keele University
• Ian Scott: Dr - Keele University