Chronic fatigue syndrome (CFS) symptom-based phenotypes in two clinical cohorts of adult patients in the UK and The Netherlands

Abstract

Objective: Studies have provided evidence of heterogeneity within chronic fatigue syndrome (CFS), but few have used data from large cohorts of CFS patients or replication samples.Methods: 29 UK secondary-care CFS services recorded the presence/absence of 12 CFS-related symptoms; 8 of these symptoms were recorded by a Dutch tertiary service. Latent Class Analysis (LCA) was used to assign symptom profiles (phenotypes). Regression models were fitted with phenotype as outcome (in relation to age, sex, BMI, duration of illness) and exposure (in relation to comorbidities and patient-reported measures).Results: Data were available for 7,041 UK and 1,392 Dutch patients. Almost all patients in both cohorts presented with post-exertional malaise, cognitive dysfunction and disturbed/unrefreshing sleep, and these 3 symptoms were excluded from LCA. In UK patients, six phenotypes emerged:'full' polysymptomatic (median 8, IQR 7-9 symptoms) 32.8%; 'pain-only' (muscle/joint) 20.3%; 'sore throat/painful lymph node' 4.5%; 'oligosymptomatic' (median 1, IQR 0-2 symptoms) 4.7%.Two 'partial' polysymptomatic phenotypes were similar to the 'full' phenotype, bar absence of dizziness/nausea/palpitations (21.4%) or sore throat/painful lymph nodes (16.3%). Women and patients with longer duration of illness were more likely to be polysymptomatic. Polysymptomatic patients had more severe illness and more comorbidities. LCA restricted to 5 symptoms recorded in both cohorts indicated 3 classes (polysymptomatic, oligosymptomatic, pain-only), which were replicated in Dutch data. Conclusions:Adults with CFS may have one of 6 symptom-based phenotypes associated with sex, duration and severity of illness, and comorbidity. Future research needs to determine whether phenotypes predict treatment outcomes, and require different treatments.

Trends in the incidence of chronic fatigue syndrome and fibromyalgia in the UK, 2001–2013: a Clinical Practice Research Datalink study

“…12 Another explanation could be that GPs respond more decisively to the defining symptom of FM (pain) in patients who are likely to be presenting with other symptoms and co-morbidities, 40 whereas the cardinal symptoms of CFS/ME present a more complex and less-specific diagnostic picture, further complicated by CFS/ME-related co-morbidities such as pain and mood disorders. 4 This argument is strengthened by the observation that patients with FM and lower socioeconomic status reported greater symptom severity and functional impairment, 42 although this pattern has also been observed in community-based samples of people diagnosed with CFS/ME. 43 …”

Management of Functional Somatic Syndromes and Bodily Distress

“…Two to three percent of the population have multiple FSS; such individuals have more severe illness, more concurrent anxiety or depressive disorders, and greater impairment [13,42,43]. …”

Adult patients’ experiences of NHS specialist services for chronic fatigue syndrome (CFS/ME): a qualitative study in England

“…Acceptance and identity are recurring central themes in qualitative studies of CFS/ME [8, 9, 12, 13]. These are themes common to chronic illness, but certain aspects of CFS/ME – the long journey to diagnosis, the contested nature of that diagnosis [19, 20], the responses of society [17] and significant others [16, 32], varied symptomatology [1], unknown aetiology, and broad age range of those affected [33] – present particular challenges to patients and clinicians.…”

“…Patients who are ill for a shorter period of time before referral may experience specialist services quite differently, particularly in relation to sub-themes such as ‘Time taken for referral’ and ‘Acceptance’. Our sample was too small to explore patients’ experiences of specialist services in relation to the ME/ME, or in the presence of comorbidities such as depression and fibromyalgia [1]. Our remit to explore the experiences of the ‘majority’ of CFS/ME patients meant that we excluded severely affected patients.…”

“…Chronic Fatigue Syndrome (CFS), also known as ‘ME’, is a long-term disabling condition characterised by debilitating fatigue of unknown cause, post-exertional malaise, cognitive dysfunction and disturbed/unrefreshing sleep, plus other symptoms including muscle and joint pain, headaches, and dizziness [1]. CFS/ME imposes an immense burden on patients, carers and families [2, 3].…”