Fibromyalgia is a long-term condition causing persistent pain throughout the body. It is common and affects 1 in 20 people. Fibromyalgia is thought to result from abnormal levels of certain chemicals in the body’s nerves, which change how people with fibromyalgia experience pain.
As people with fibromyalgia frequently experience many different symptoms, they often use many healthcare services. They often see their GPs, have tests to investigate their symptoms with normal results, and are treated with lots of ineffective pain medicines. This can be very frustrating for people with fibromyalgia, who are best served by receiving education about their condition, exercise, talking-type treatments, and potentially anti-depressant medicines. It is also an ineffective use of healthcare resources. Understanding how to reduce excessive healthcare use in people with fibromyalgia is important.
This project will help us better understand how people with fibromyalgia use English primary care services. Its findings could be used to help plan healthcare services for people with fibromyalgia. It involves two related studies.
Study 1 will explore if there are groups of people with a recent diagnosis of fibromyalgia that use a lot of healthcare services over time and see how they may differ from groups of people that use less healthcare services (for example, by their age or gender).
Study 2 will compare two possible medicines for pain in fibromyalgia (duloxetine and amitriptyline) to see if one is better than the other at reducing how people with fibromyalgia use healthcare services for pain.
BACKGROUND
Fibromyalgia is a long-term condition, characterised by widespread pain and a broad range of other symptoms. It is common, affecting up to 5% of the general population.
Whilst people with fibromyalgia have high healthcare use levels, it is unknown how this may vary across groups of people with fibromyalgia, nor the impacts of treatment with duloxetine - an antidepressant widely used to treat this condition, shown to improve pain intensity scores in clinical trials - on pain-related healthcare use. Understanding this is important to optimising healthcare service provision to people with fibromyalgia in the English NHS.
OBJECTIVE
To explore how healthcare use differs between groups of people with fibromyalgia, and to examine the potential impact of treatment with duloxetine on pain-related healthcare use in this patient population.
AIMS
1. Explore the presence of distinct classes of healthcare use trajectories in people with incident fibromyalgia, and compare the pain-specific, comorbid, and sociodemographic characteristics of members of different classes.
2. Compare pain-related healthcare use between people with fibromyalgia following newly initiating duloxetine and amitriptyline.
METHODS
Two studies will be conducted using data from English practices in CPRD Aurum.
First, a cohort study will address aim 1, using latent class growth analysis to investigate the existence of distinct classes of people with different trajectories of healthcare use (consultation/admission rates; counts of prescriptions/investigations/referrals). Baseline sociodemographic, pain-specific, and comorbidity characteristics of each trajectory class at cohort entry will be descriptively compared between classes.
Second, an emulated trial will address aim 2, comparing pain-related healthcare use (rates of pain-related consultations/admissions for fibromyalgia [defined using Hospital Episode Statistics data]; analgesic prescription counts) between people with fibromyalgia newly initiating duloxetine to people newly initiating amitriptyline. Confounding variables will be accounted for via an active comparator design and propensity scores.
STUDY 1
(a) All-cause primary care consultation rates; (b) all-cause hospital admission rates; (c) counts for drug prescriptions; (d) counts for investigations; (e) counts for referrals.
STUDY 2
(a) Pain-related consultation rates; (b) hospital admission rates for a primary code of fibromyalgia, (c) number of different prescribed pain medicines.
Ian Scott - Chief Investigator - Keele University
Sara Muller - Corresponding Applicant - Keele University
Ailish Byrne - Collaborator - Keele University
Helen Twohig - Collaborator - Keele University
James Bailey - Collaborator - Keele University
HES Admitted Patient Care;Patient Level Index of Multiple Deprivation