Prevalence, incidence, and classification of chronic fatigue syndrome in Olmsted County, Minnesota, as estimated using the Rochester Epidemiology Project

[Myalgic encephalomyelitis/chronic fatigue syndrome: an overview of current evidence]

Over the past 5 years both media and scientific interest has surged regarding the disorder myalgic encephalomyelitis and chronic fatigue syndrome (ME/CFS), not least because of the clinically similar manifestation in long COVID or post-COVID. In this review we discuss the process of clinical diagnosis and randomized controlled therapeutic studies on ME/CFS, and the similarities or differences to long COVID and post-COVID. So far, neither clear pathophysiologically causal nor therapeutic evidence-based results on ME/CFS have been identified in the many years of scientific research. Given the evident psychiatric comorbidity rates in patients with a diagnosis of ME/CFS, a psychosomatic etiology of this syndrome should be considered. Furthermore, a precise and reliable diagnostic classification based on stricter criteria would benefit both pathophysiological and therapeutic research.

The Gut Microbiome in Myalgic Encephalomyelitis (ME)/Chronic Fatigue Syndrome (CFS)

Myalgic encephalomyelitis (ME) or Chronic Fatigue Syndrome (CFS) is a neglected, debilitating multi-systemic disease without diagnostic marker or therapy. Despite evidence for neurological, immunological, infectious, muscular and endocrine pathophysiological abnormalities, the etiology and a clear pathophysiology remains unclear. The gut microbiome gained much attention in the last decade with manifold implications in health and disease. Here we review the current state of knowledge on the interplay between ME/CFS and the microbiome, to identify potential diagnostic or interventional approaches, and propose areas where further research is needed. We iteratively selected and elaborated on key theories about a correlation between microbiome state and ME/CFS pathology, developing further hypotheses. Based on the literature we hypothesize that antibiotic use throughout life favours an intestinal microbiota composition which might be a risk factor for ME/CFS. Main proposed pathomechanisms include gut dysbiosis, altered gut-brain axis activity, increased gut permeability with concomitant bacterial translocation and reduced levels of short-chain-fatty acids, D-lactic acidosis, an abnormal tryptophan metabolism and low activity of the kynurenine pathway. We review options for microbiome manipulation in ME/CFS patients including probiotic and dietary interventions as well as fecal microbiota transplantations. Beyond increasing gut permeability and bacterial translocation, specific dysbiosis may modify fermentation products, affecting peripheral mitochondria. Considering the gut-brain axis we strongly suspect that the microbiome may contribute to neurocognitive impairments of ME/CFS patients. Further larger studies are needed, above all to clarify whether D-lactic acidosis and early-life antibiotic use may be part of ME/CFS etiology and what role changes in the tryptophan metabolism might play. An association between the gut microbiome and the disease ME/CFS is plausible. As causality remains unclear, we recommend longitudinal studies. Activity levels, bedridden hours and disease progression should be compared to antibiotic exposure, drug intakes and alterations in the composition of the microbiota. The therapeutic potential of fecal microbiota transfer and of targeted dietary interventions should be systematically evaluated.

Male vs. Female Differences in Responding to Oxygen-Ozone Autohemotherapy (O2-O3-AHT) in Patients with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS)

(1) Background: Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a syndrome that has fatigue as its major symptom. Evidence suggests that ozone is able to relieve ME/CFS-related fatigue in affected patients. (2) Objective: To evaluate whether differences exist between males and females in ozone therapy outputs in ME/CFS. (3) Methods: In total, 200 patients previously diagnosed with ME/CFS (mean age 33 ± 13 SD years) underwent treatment with oxygen–ozone autohemotherapy (O₂-O₃-AHT). Fatigue was investigated via an FSS 7-scoring questionnaire before and following 1 month after treatment. (4) Results: The Mann-Whitney test (MW test) assessed the significance of this difference (H = 13.8041, p = 0.0002), and female patients showed better outcomes than males. This difference was particularly striking in the youngest age cohort (14–29 years), and a KW test resulted in H = 7.1609, p = 0.007 for the Δ = 28.3% (males = 3.8, females = 5.3). (5) Conclusions: When treated with O₂-O₃-AHT, females respond better than males.

Patients with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) Greatly Improved Fatigue Symptoms When Treated with Oxygen-Ozone Autohemotherapy

(1) Background: Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a chronic syndrome characterized by fatigue as its major and most outstanding symptom. Previous evidence has supported the ability of ozone to relief ME/CFS related fatigue in affected patients (2) Methods: A number of 200 ME/CFS previously diagnosed patients, (mean age 33 ± 13 SD years) were consecutively treated with oxygen-ozone autohemotherapy (O₂-O₃-AHT). Fatigue was evaluated via an FSS 7-scoring questionnaire before and following 30 days after treatment. (3) Results: Almost half (43.5%) of the treated patients evolved their FSS scale from the worst (7) to the best (1) score, assessing the highest improvement from being treated with O₂-O₃-AHT. Furthermore 77.5% of patients experienced significant ameliorations of fatigue, of 4–6 delta score. No patient showed side effects, yet experienced long lasting fatigue disappearance, by three months follow up (4) Conclusions: Treatment with O₂-O₃-AHT greatly improves ME/CFS related fatigue, aside from sex and age distribution.

Nationwide epidemiological characteristics of chronic fatigue syndrome in South Korea

Background

Chronic fatigue syndrome (CFS) is a long-term disabling illness accompanied by medically unexplained fatigue. This study aimed to explore the epidemiological characteristics of CFS in South Korea.

Methods

Using the nationwide medical records provided by the Korean Health Insurance Review & Assessment Service (HIRA), we analyzed the entire dataset for CFS patients diagnosed by physicians in South Korea from January 2010 to December 2020.

Results

The annual mean incidence of CFS was estimated to be 44.71 ± 6.10 cases per 100,000 individuals [95% CI: 40.57, 48.76], and the prevalence rate was 57.70 ± 12.20 cases per 100,000 individuals [95% CI: 49.40, 65.79]. These two rates increased by 1.53- and 1.94-fold from 2010 to 2020, respectively, and showed an increasing trend with aging and an approximately 1.5-fold female predominance.

Conclusions

This study is the first to report the nationwide epidemiological features of CFS, which reflects the clinical reality of CFS diagnosis and care in South Korea. This study will be a valuable reference for studies of CFS in the future.

Systematic review and meta-analysis of the prevalence of chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME)

Background

Chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME) has been emerging as a significant health issue worldwide. This study aimed to systemically assess the prevalence of CFS/ME in various aspects of analyses for precise assessment.

Methods

We systematically searched prevalence of CFS/ME from public databases from 1980 to December 2018. Data were extracted according to 7 categories for analysis: study participants, gender and age of the participants, case definition, diagnostic method, publication year, and country of the study conducted. Prevalence data were collected and counted individually for studies adopted various case definitions. We analyzed and estimated prevalence rates in various angles: average prevalence, pooled prevalence and meta-analysis of all studies.

Results

A total of 1291 articles were initially identified, and 45 articles (46 studies, 56 prevalence data) were selected for this study. Total 1085,976 participants were enrolled from community-based survey (540,901) and primary care sites (545,075). The total average prevalence was 1.40 ± 1.57%, pooled prevalence 0.39%, and meta-analysis 0.68% [95% CI 0.48–0.97]. The prevalence rates were varied by enrolled participants (gender, study participants, and population group), case definitions and diagnostic methods. For example, in the meta-analysis; women (1.36% [95% CI 0.48–0.97]) vs. men (0.86% [95% CI 0.48–0.97]), community-based samples (0.76% [95% CI 0.53–1.10]) vs. primary care sites (0.63% [95% CI 0.37–1.10]), adults ≥ 18 years (0.65% [95% CI 0.43–0.99]) vs. children and adolescents < 18 years (0.55% [95% CI 0.22–1.35]), CDC-1994 (0.89% [95% CI 0.60–1.33]) vs. Holmes (0.17% [95% CI 0.06–0.49]), and interviews (1.14% [95% CI 0.76–1.72]) vs. physician diagnosis (0.09% [95% CI 0.05–0.13]), respectively.

Conclusions

This study comprehensively estimated the prevalence of CFS/ME; 0.89% according to the most commonly used case definition CDC-1994, with women approximately 1.5 to 2 folds higher than men in all categories. However, we observed the prevalence rates are widely varied particularly by case definitions and diagnostic methods. An objective diagnostic tool is urgently required for rigorous assessment of the prevalence of CFS/ME.

Can a Chronic BPPV With a History of Trauma be the Trigger of Symptoms in Vestibular Migraine, Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS), and Whiplash Associated Disorders (WAD)? A Retrospective Cohort Study

BACKGROUND

In patients with chronic benign paroxysmal positional vertigo (BPPV), i.e., chronic vestibular multicanalicular canalithiasis (CVMCC), abnormal signals are transmitted from diseased labyrinths via the healthy vestibular nuclei complex to their end organs. The vestibulo-thalamo-cortical reflex as proposed in vestibular migraine is just one of these reflexes. In a group of patients diagnosed with CVMCC otolith repositioning maneuvers specific for each semicircular canal (SCC) ameliorated pain and other symptoms in 90%. Increased awareness of CVMCC may reduce suffering and continuous medication.

OBJECTIVE

To evaluate if CVMCC can be the trigger of symptoms in vestibular migraine, myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), and whiplash associated disorders (WAD).

STUDY DESIGN

Retrospective consecutive observational cohort study.

SETTING

Ambulatory at a private Otoneurology Centre.

PATIENTS

One hundred sixty-three patients with CVMCC and a history of trauma.

INTERVENTION

Based on the symptoms (structured symptom questionnaire), the patients are post hoc sub grouped according to the criteria of the different diagnoses.

MAIN OUTCOME MEASURE

Frequency of patients with CVMCC who fulfill the criteria of the different diagnoses.

RESULTS

98% of all patients with CVMCC fulfill the Barany Society criteria of a probable vestibular migraine; 17% fulfill the International Classification of Headache Disorders defined vestibular migraine criteria; 63% fulfill the Fukuda criteria of ME/CFS; 100% of the patients with WAD suffer from CVMCC.

CONCLUSION

This survey supports the hypothesis that CVMCC can be the trigger of symptoms in vestibular migraine, ME/CFS, and WAD. The actual diagnosis the patient receives is often in accordance with the patient's dominant symptom.

Elevated blood lactate in resting conditions correlate with post-exertional malaise severity in patients with Myalgic encephalomyelitis/Chronic fatigue syndrome

Elevated blood lactate after moderate exercise was reported in some of patients with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). We hypothesised that blood lactate could be also elevated in resting conditions. We aimed investigating the frequency of elevated lactate at rest in ME/CFS patients, and comparing characteristics of ME/CFS patients with and without elevated lactate. Patients fulfilling international consensus criteria for ME/CFS who attended the internal medicine department of University hospital Angers-France between October 2011 and December 2017 were included retrospectively. All patients were systematically hospitalised for an aetiological workup and overall assessment. We reviewed their medical records for data related to the assessment: clinical characteristics, comorbidities, fatigue features, post-exertional malaise (PEM) severity, and results of 8 lactate measurements at rest. Patients having ≥1 lactate measurement ≥2 mmol/L defined elevated lactate group. The study included 123 patients. Elevated (n = 55; 44.7%) and normal (n = 68; 55.3%) lactate groups were comparable except for PEM, which was more severe in the elevated lactate group after adjusting for age at disease onset, sex, and comorbidities (OR 2.47, 95% CI: 1.10–5.55). ME/CFS patients with elevated blood lactate at rest may be at higher risk for more severe PEM. This finding may be of interest in ME/CFS management.

A perspective on causation of the chronic fatigue syndrome by considering its nosology

The causes of chronic fatigue syndrome (CFS) remain unknown, with many failures to replicate new findings. This may be because the condition is hard to diagnose, difficult to classify, or because of its heterogeneous nature. Authors have problems in differentiating CFS from myalgic encephalomyelitis (ME), which leads many to label it as a hybrid CFS/ME or ME/CFS. Attempts to validate the many published criterion-based definitions have ended in failure. The International Classification of Diseases provide several different descriptions to choose from, although the latest 11^th edition has narrowed this down. This paper describes conventional attempts to define and classify the illness, suggesting that this may be what leads to a failure to replicate putative causes. The approach to CFS/ME may require a shift in the assumption that the illness is homogeneous. An alternative approach is provided by studies suggesting that the condition is heterogeneous. CONCLUSION: The way forward may be to be over-inclusive regarding the diagnosis as a first step, while subdividing the condition into likely subgroups as a means of finding valid and reliable associations with potential causes. Studies of aetiology must involve prospective designs since cross-sectional studies cannot inform either aetiology or pathophysiology.

Work Rehabilitation and Medical Retirement for Myalgic Encephalomyelitis/Chronic Fatigue Syndrome Patients. A Review and Appraisal of Diagnostic Strategies

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome leads to severe functional impairment and work disability in a considerable number of patients. The majority of patients who manage to continue or return to work, work part-time instead of full time in a physically less demanding job. The prognosis in terms of returning to work is poor if patients have been on long-term sick leave for more than two to three years. Being older and more ill when falling ill are associated with a worse employment outcome. Cognitive behavioural therapy and graded exercise therapy do not restore the ability to work. Consequently, many patients will eventually be medically retired depending on the requirements of the retirement policy, the progress that has been made since they have fallen ill in combination with the severity of their impairments compared to the sort of work they do or are offered to do. However, there is one thing that occupational health physicians and other doctors can do to try and prevent chronic and severe incapacity in the absence of effective treatments. Patients who are given a period of enforced rest from the onset, have the best prognosis. Moreover, those who work or go back to work should not be forced to do more than they can to try and prevent relapses, long-term sick leave and medical retirement.

Healthcare Utilization in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS): Analysis of US Ambulatory Healthcare Data, 2000-2009

Background: ME/CFS is a complex and disabling illness with substantial economic burden and functional impairment comparable to heart disease and multiple sclerosis. Many patients with ME/CFS do not receive appropriate healthcare, partially due to lack of diagnostic tests, and knowledge/attitudes/beliefs about ME/CFS. This study was to assess the utility of US ambulatory healthcare data in profiling demographics, co-morbidities, and healthcare in ME/CFS. Methods: Data came from the National Ambulatory Medical Care Survey (NAMCS) and the National Hospital Ambulatory Medical Care Survey (NHAMCS) in the U.S. Weighted analysis was performed. We examined 9.06 billion adult visits from 2000 to 2009 NAMCS/NHAMCS data. ME/CFS-related visits were identified by ICD-9-CM code, 780.71, up to tertiary diagnosis. Results: We estimated 2.9 million (95% CI: 1.8-3.9 million) ME/CFS-related visits during 2000-2009, with no statistical evidence (p-trend = 0.31) for a decline or increase in ME/CFS-related visits. Internists, general and family practitioners combined provided 52.12% of these visits. Patients with ME/CFS-related visits were mostly in their 40 and 50 s (47.76%), female (66.07%), white (86.95%), metropolitan/urban residents (92.05%), and insured (87.26%). About 71% of ME/CFS patients had co-morbidities, including depression (35.79%), hypertension (31.14%), diabetes (20.30%), and arthritis (14.11%). As one quality indicator, physicians spent more time on ME/CFS-related visits than non-ME/CFS visits (23.62 vs. 19.38 min, p = 0.065). As additional quality indicators, the top three preventive counseling services provided to patients with ME/CFS-related visits were diet/nutrition (8.33%), exercise (8.21%), and smoking cessation (7.24%). Compared to non-ME/CFS visits, fewer ME/CFS-related visits included counseling for stress management (0.75 vs. 3.14%, p = 0.010), weight reduction (0.88 vs. 4.02%, p = 0.002), injury prevention (0.04 vs. 1.64%, p < 0.001), and family planning/contraception (0.17 vs. 1.45%, p = 0.037). Conclusions: Visits coded with ME/CFS did not increase from 2000 to 2009. Almost three quarters of ME/CFS-related visits were made by ME/CFS patients with other co-morbid conditions, further adding to complexity in ME/CFS healthcare. While physicians spent more time with ME/CFS patients, a lower proportion of ME/CFS patients received preventive counseling for weight reduction, stress management, and injury prevention than other patients despite the complexity of ME/CFS. NAMCS/NHAMCS data are useful in evaluating co-morbidities, healthcare utilization, and quality indicators for healthcare in ME/CFS.

Pain and fatigue in primary Sjögren's syndrome

Chronic fatigue, pain and depression are common in patients with primary Sjögren's syndrome. These phenomena mutually affect each other and have a considerable impact on the patients' quality of life. While pain is usually regarded as a fairly somatic phenomenon, both fatigue and depression have traditionally been regarded as more-or-less of psychological origin. There is an increasing understanding that this picture is multifaceted; that there is a genetic foundation, and that biological mechanisms regulate the clinical expression through activation of evolutionary, deeply conserved neuronal pathways in the brain. This pattern is evident not only in primary Sjögren's syndrome, but also in other systemic inflammatory autoimmune diseases, in cancer and in neurodegenerative diseases like Parkinson's disease. This article will mainly focus on the biology of pain and fatigue. We describe how these factors influence each other, and act with the overarching purpose of defending the organism against harm and danger.

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome-Metabolic Disease or Disturbed Homeostasis due to Focal Inflammation in the Hypothalamus?

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a complex disease characterized by debilitating fatigue, lasting for at least 6 months, with associated malaise, headaches, sleep disturbance, and cognitive impairment, which severely impacts quality of life. A significant percentage of ME/CFS patients remain undiagnosed, mainly due to the complexity of the disease and the lack of reliable objective biomarkers. ME/CFS patients display decreased metabolism and the severity of symptoms appears to be directly correlated to the degree of metabolic reduction that may be unique to each individual patient. However, the precise pathogenesis is still unknown, preventing the development of effective treatments. The ME/CFS phenotype has been associated with abnormalities in energy metabolism, which are apparently due to mitochondrial dysfunction in the absence of mitochondrial diseases, resulting in reduced oxidative metabolism. Such mitochondria may be further contributing to the ME/CFS symptomatology by extracellular secretion of mitochondrial DNA, which could act as an innate pathogen and create an autoinflammatory state in the hypothalamus. We propose that stimulation of hypothalamic mast cells by environmental, neuroimmune, pathogenic and stress triggers activates microglia, leading to focal inflammation in the brain and disturbed homeostasis. This process could be targeted for the development of novel effective treatments.

Structural brain changes versus self-report: machine-learning classification of chronic fatigue syndrome patients

Chronic fatigue syndrome (CFS) is a disorder associated with fatigue, pain, and structural/functional abnormalities seen during magnetic resonance brain imaging (MRI). Therefore, we evaluated the performance of structural MRI (sMRI) abnormalities in the classification of CFS patients versus healthy controls and compared it to machine learning (ML) classification based upon self-report (SR). Participants included 18 CFS patients and 15 healthy controls (HC). All subjects underwent T1-weighted sMRI and provided visual analogue-scale ratings of fatigue, pain intensity, anxiety, depression, anger, and sleep quality. sMRI data were segmented using FreeSurfer and 61 regions based on functional and structural abnormalities previously reported in patients with CFS. Classification was performed in RapidMiner using a linear support vector machine and bootstrap optimism correction. We compared ML classifiers based on (1) 61 a priori sMRI regional estimates and (2) SR ratings. The sMRI model achieved 79.58% classification accuracy. The SR (accuracy = 95.95%) outperformed both sMRI models. Estimates from multiple brain areas related to cognition, emotion, and memory contributed strongly to group classification. This is the first ML-based group classification of CFS. Our findings suggest that sMRI abnormalities are useful for discriminating CFS patients from HC, but SR ratings remain most effective in classification tasks.

Chronic Fatigue Syndrome prevalence is grossly overestimated using Oxford criteria compared to Centers for Disease Control (Fukuda) criteria in a U.S. population study

BACKGROUND

Results from treatment studies using the low threshold Oxford criteria for recruitment may have been overgeneralized to patients diagnosed by more stringent CFS criteria.

PURPOSE

To compare the selectivity of Oxford and Fukuda criteria in a U.S. population.

METHODS

Fukuda (Center for Disease Control (CDC)) criteria, as operationalized with the CFS Severity Questionnaire (CFSQ), were included in the nationwide rc2004 HealthStyles survey mailed to 6,175 participants who were representative of the US 2003 Census population. The 9 questionnaire items (CFS symptoms) were crafted into proxies for Oxford criteria (mild fatigue, minimal exclusions) and Fukuda criteria (fatigue plus ≥4 of 8 ancillary criteria at moderate or severe levels with exclusions). The comparative prevalence estimates of CFS were then determined. Severity scores for fatigue were plotted against the sum of severities for the 8 ancillary criteria. The 4 quadrants of scatter diagrams assessed putative healthy controls, CFS, chronic idiopathic fatigue, and CFS-like with insufficient fatigue subjects.

RESULTS

The Oxford criteria designated CFS in 25.5% of 2,004 males and 19.9% of 1,954 females. Based on quadrant analysis, 85% of Oxford-defined cases were inappropriately classified as CFS. Fukuda criteria identified CFS in 2.3% of males and 1.8% of females.

DISCUSSION

CFS prevalence using Fukuda criteria and quadrant analysis were near the upper limits of previous epidemiology studies. The CFSQ may have utility for on-line and outpatient screening. The Oxford criteria were untenable because they inappropriately selected healthy subjects with mild fatigue and chronic idiopathic fatigue and mislabeled them as CFS.

Familiality and Heritability of Fatigue in an Australian Twin Sample

Familial factors have previously been implicated in the etiology of fatigue, of which a significant proportion is likely attributable to genetic influences. However, family studies have primarily focused on chronic fatigue syndrome, while univariate twin studies have investigated broader fatigue phenotypes. The results for similar fatigue phenotypes vary between studies, particularly with regard to sex-specific contributions to the heritability of the traits. Therefore, the current study aims to investigate the familiality and sex-specific effects of fatigue experienced over the past few weeks in an older Australian population of 660 monozygotic (MZ) twin pairs, 190 MZ singleton twins, 593 dizygotic (DZ) twin pairs, and 365 DZ singleton twins. Higher risks for fatigue were observed in MZ compared to DZ co-twins of probands with fatigue. Univariate heritability analyses indicated fatigue has a significant genetic component, with a heritability (h2) estimate of 40%. Sex-specific effects did not significantly contribute to the heritability of fatigue, with similar estimates for males (h2= 41%, 95% CI [18, 62]) and females (h2= 40%, 95% CI [27, 52]). These results indicate that fatigue experienced over the past few weeks has a familial contribution, with additive genetic factors playing an important role in its etiology.

Defining Essential Features of Myalgic Encephalomyelitis and Chronic Fatigue Syndrome

Considerable debate surrounds the search for the defining features of patients with Myalgic Encephalomyelitis (ME) and chronic fatigue syndrome (CFS). Current case definitions were created through clinical consensus. Failure to operationalize these case definitions has led to considerable variability in the identification of patients. In addition, some case definitions (e.g., Fukuda et al., 1994) do not require cardinal symptoms of this illness, where as other case definitions do require core symptoms of this illness (Carruthers et al., 2003, 2011), and these latter case criteria appear to identify a more impaired group of patients. Criterion variance is most likely to occur when operationally explicit criteria do not exist for diagnostic categories (Spitzer, Endicott, & Robins, 1978), or when there are varying criteria for contrasting case definitions, which is an impediment to the research in this field. To deal with this problem, it is possible to differentiate those that meet more loosely defined criteria from those that are more narrowly and defined, thus differentiating CFS from ME. In order to progress the search for biological markers and effective treatments, essential features need to be operationalized and broadly used in order to increase the probability that individuals included in samples have the same underlying illness.

Fibromyalgia Survey Criteria Are Associated with Increased Postoperative Opioid Consumption in Women Undergoing Hysterectomy

Background:

The current study was designed to test the hypothesis that the fibromyalgia survey criteria would be directly associated with increased opioid consumption after hysterectomy even when accounting for other factors previously described as being predictive for acute postoperative pain.

Methods:

Two hundred eight adult patients undergoing hysterectomy between October 2011 and December 2013 were phenotyped preoperatively with the use of validated self-reported questionnaires including the 2011 fibromyalgia survey criteria, measures of pain severity and descriptors, psychological measures, preoperative opioid use, and health information. The primary outcome was the total postoperative opioid consumption converted to oral morphine equivalents.

Results:

Higher fibromyalgia survey scores were significantly associated with worse preoperative pain characteristics, including higher pain severity, more neuropathic pain, greater psychological distress, and more preoperative opioid use. In a multivariate linear regression model, the fibromyalgia survey score was independently associated with increased postoperative opioid consumption, with an increase of 7-mg oral morphine equivalents for every 1-point increase on the 31-point measure (Estimate, 7.0; Standard Error, 1.7; P &lt; 0.0001). In addition to the fibromyalgia survey score, multivariate analysis showed that more severe medical comorbidity, catastrophizing, laparotomy surgical approach, and preoperative opioid use were also predictive of increased postoperative opioid consumption.

Conclusions:

As was previously demonstrated in a total knee and hip arthroplasty cohort, this study demonstrated that increased fibromyalgia survey scores were predictive of postoperative opioid consumption in the posthysterectomy surgical population during their hospital stay. By demonstrating the generalizability in a second surgical cohort, these data suggest that patients with fibromyalgia-like characteristics may require a tailored perioperative analgesic regimen.

Longitudinal follow-up of employment status in patients with chronic fatigue syndrome after mononucleosis

OBJECTIVE

To examine the effect of early clinical and demographic factors on occupational outcome, return to work or awarded permanent disability pension in young patients with chronic fatigue syndrome (CFS).

DESIGN

Longitudinal cohort study.

INTERVENTION

A written self-management programme including a description of active coping strategies for daily life was provided.

SETTING, PARTICIPANTS

Patients with CFS after mononucleosis were evaluated at Department of Neurology, Haukeland University Hospital during 1996-2006 (contact 1). In 2009 self-report questionnaires were sent to all patients (contact 2).

PRIMARY AND SECONDARY OUTCOME MEASURES

Primary measure was employment status at contact 2. Secondary measures included clinical symptoms, and Fatigue Severity Scale (FSS) scores on both contacts, and Work and Social Adjustment Scale (WSAS) at contact 2.

RESULTS

Of 111 patients at contact 1, 92 (83%) patients returned the questionnaire at contact 2. Mean disease duration at contact 1 was 4.7 years and at contact 2 11.4 years. At contact 1, 9 (10%) were part-time or full-time employed. At contact 2, 49 (55%) were part-time or full-time employed. Logical regression analysis showed that FSS≥5 at contact 2 was associated with depression, arthralgia and long disease duration (all at contact 1).

CONCLUSIONS

About half of younger patients with CFS with long-term incapacity for work experienced marked improvement including full-time or part-time employment showing better outcomes than expected. Risk factors for transition to permanent disability were depression, arthralgia and disease duration.

Two age peaks in the incidence of chronic fatigue syndrome/myalgic encephalomyelitis: a population-based registry study from Norway 2008-2012

BACKGROUND

The aim of the current study was to estimate sex- and age-specific incidence rates of chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME) using population-based registry data. CFS/ME is a debilitating condition with large impact on patients and their families. The etiology is unknown, and the distribution of the disease in the general population has not been well described.

METHODS

Cases of CFS/ME were identified in the Norwegian Patient Register (NPR) for the years 2008 to 2012. The NPR is nationwide and contains diagnoses assigned by specialist health care services (hospitals and outpatient clinics). We estimated sex- and age-specific incidence rates by dividing the number of new cases of CFS/ME in each category by the number of person years at risk. Incidence rate ratios were estimated by Poisson regression with sex, age categories, and year of diagnosis as covariates.

RESULTS

A total of 5,809 patients were registered with CFS/ME during 2008 to 2012. The overall incidence rate was 25.8 per 100,000 person years (95% confidence interval (CI): 25.2 to 26.5). The female to male incidence rate ratio of CFS/ME was 3.2 (95% CI: 3.0 to 3.4). The incidence rate varied strongly with age for both sexes, with a first peak in the age group 10 to 19 years and a second peak in the age group 30 to 39 years.

CONCLUSIONS

Early etiological clues can sometimes be gained from examination of disease patterns. The strong female preponderance and the two age peaks suggest that sex- and age-specific factors may modulate the risk of CFS/ME.

Case definitions for chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME): a systematic review

OBJECTIVE

To identify case definitions for chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME), and explore how the validity of case definitions can be evaluated in the absence of a reference standard.

DESIGN

Systematic review.

SETTING

International.

PARTICIPANTS

A literature search, updated as of November 2013, led to the identification of 20 case definitions and inclusion of 38 validation studies.

PRIMARY AND SECONDARY OUTCOME MEASURE

Validation studies were assessed for risk of bias and categorised according to three validation models: (1) independent application of several case definitions on the same population, (2) sequential application of different case definitions on patients diagnosed with CFS/ME with one set of diagnostic criteria or (3) comparison of prevalence estimates from different case definitions applied on different populations.

RESULTS

A total of 38 studies contributed data of sufficient quality and consistency for evaluation of validity, with CDC-1994/Fukuda as the most frequently applied case definition. No study rigorously assessed the reproducibility or feasibility of case definitions. Validation studies were small with methodological weaknesses and inconsistent results. No empirical data indicated that any case definition specifically identified patients with a neuroimmunological condition.

CONCLUSIONS

Classification of patients according to severity and symptom patterns, aiming to predict prognosis or effectiveness of therapy, seems useful. Development of further case definitions of CFS/ME should be given a low priority. Consistency in research can be achieved by applying diagnostic criteria that have been subjected to systematic evaluation.

A pilot registry of unexplained fatiguing illnesses and chronic fatigue syndrome

Background

Chronic fatigue syndrome (CFS) has no diagnostic clinical signs or biomarkers, so diagnosis requires ruling out conditions with similar signs and symptoms. We conducted a pilot registry of unexplained fatiguing illnesses and CFS to determine the feasibility of establishing and operating a registry and implementing an education outreach initiative. The pilot registry was conducted in Bibb County, Georgia. Patient referrals were obtained from healthcare providers who were identified by using various education outreach initiatives. These referrals were later supplemented with self-referrals by members of a local CFS support group. All patients meeting referral criteria were invited to participate in a screening interview to determine eligibility. If patients met registry criteria, they were invited to a one-day clinic for physical and laboratory evaluations. We classified patients based on the 1994 case definition.

Results

We registered 827 healthcare providers. Forty-two providers referred 88 patients, and 58 patients (66%) completed clinical evaluation. Of the 188 CFS support group members, 53 were self-referred and 46 (87%) completed the clinical evaluation. Of the 104 participants completing evaluation, 36% (n = 37) met the criteria for CFS, 17% (n = 18) had insufficient fatigue or symptoms (ISF), and 47% (n = 49) were found to have exclusionary medical or psychiatric illnesses. Classification varied significantly by type of referral but not by previous history of CFS diagnosis. Healthcare providers referred more patients who were classified as CFS as compared to support group referrals in which more exclusionary conditions were identified. Family practice and internal medicine specialties made the most referrals and had the highest number of CFS cases. We conducted three CME events, held three “Meet and Greet” sessions, visited four large clinical health practices and health departments, mailed five registry newsletters, and conducted in-person office visits as part of education outreach, which contributed to patient referrals.

Conclusions

Referrals from healthcare providers and self-referrals from the patient support group were important to registry enrollment. The number of potentially treatable conditions that were identified highlights the need for continued medical management in this population, as well as the limitations of registries formed without clinical examination. Education initiatives were successful in part because of partnerships with local organizations.