Prevalence of chronic fatigue and chronic fatigue syndrome in Korea: community-based primary care study

Fatigue or excessive daytime sleepiness: which is more closely related to depression?

OBJECTIVE/BACKGROUND

This study investigated fatigue and excessive daytime sleepiness to determine which was more closely related to depression in the general population.

PATIENTS/METHODS

Participants were investigated across 15 South Korean districts. Excessive daytime sleepiness, fatigue, and depression were evaluated using the Epworth Sleepiness Scale (ESS), Fatigue Severity Scale (FSS), and Patient Health Questionnaire-9 (PHQ-9), respectively. Depression was defined as PHQ-9 ≥ 10. The authors classified the combination of excessive daytime sleepiness and fatigue as excessive daytime sleepiness with fatigue (E+F+, ESS ≥ 11, FSS ≥ 36), fatigue without excessive daytime sleepiness (E-F+, ESS < 11, FSS ≥ 36), excessive daytime sleepiness without fatigue (E+F-, ESS ≥ 11, FSS < 36), and no fatigue and excessive daytime sleepiness (E-F-, ESS < 11, FSS < 36).

RESULTS

Among 2,493 participants (1,257 women), mean age was 47.9 ± 0.3 years. The prevalence of depression, fatigue, and excessive daytime sleepiness was 8.4% (n = 210), 30.8% (n = 767), and 15.3% (n = 382), respectively. The frequency of the four categories with depression (vs. controls) was as follows.: E+F+ (n = 67, 31.9% vs. 7.3%) (P < 0.001), E-F+ (n = 71, 33.8% vs. 20.3%) (P < 0.001), E+F-( n = 16, 7.6% vs. 5.8%) (P = 0.294), and E-F- (n = 56, 26.7% vs. 66.6%) (P < 0.001). After adjusting for covariates, depression was associated with E+F+ (odds ratio, OR 8.804, 95% confidence interval (CI) 5.818-13.132), E-F+ (OR 3.942, 95% CI 2.704-5.747), E+F- (OR 2.812, 95% CI 1.542-5.131), and E-F- (reference). Additionally, we performed logistic regression according to two categories. There was no significant difference in the association of depression between E+F- (reference) and E-F+ (OR 1.399, 95% CI 0.760-2.575).

CONCLUSION

Although fatigue and excessive daytime sleepiness were associated with depression regardless of the presence of each other, we could not clarify which was more closely related to depression.

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS): A preliminary survey among patients in Switzerland

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a multi-factorial systemic chronic debilitating disease of poorly understood etiology and limited systematic evidence. The questionnaire and interview-based survey included 169 ME/CFS patients from the Swiss ME/CFS association. The majority of patients were females (72.2%), single (55.7%) and without children (62.5%). Only one third were working (full/part-time). The mean onset of ME/CFS was 31.6 years of age with 15% of patients being symptomatic before their 18th birthday. In this cohort, patients had documented ME/CFS for a mean 13.7 years, whereby half (50.3%) stated their condition was progressively worsening. Triggering events and times of disease onset were recalled by 90% of the participants. An infectious disease was associated with a singular or part of multiple events by 72.9% and 80.6%, respectively. Prior to disease onset, a third of the patients reported respiratory infections; followed by gastro-intestinal infections (15.4%) and tick-borne diseases (16.2%). Viral infections were recalled by 77.8% of the respondents, with Epstein Barr Virus being the most commonly reported agent. Patients self-reported an average number of 13 different symptoms, all described specific triggers of symptoms exacerbation and 82.2% suffered from co-morbidities. This study collated clinically relevant information on ME/CFS patients in Switzerland, highlighting the extent of disease severity, the associated factors negatively affecting daily life activities and work status as well as potential socio-economic impact.

Effectiveness of Electroacupuncture in Patients with Chronic Fatigue Syndrome: A Systematic Review and Meta-analysis

This review evaluated the efficacy of electroacupuncture (EA) for chronic fatigue syndrome. Randomized controlled trials (RCTs) using EA as an intervention for patients with chronic fatigue syndrome were identified in 6 databases (PUBMED, EMBASE, CNKI, J-STAGE, KMBASE, OASIS). Fatigue indicators were used as the primary outcome measures. The quality-of-life index, efficiency rate, and level of pain were used as secondary outcome measures. There were 408 patients from seven RCTs included in this study. Meta-analysis showed that EA was significantly associated with fatigue relief compared with the control group (n = 141 SMD = -1.55, 95% CI: -2.58 - -0.52, p = 0.003, I² = 92%). In addition, EA had a statistically significant improvement in quality of life compared with the control group (n = 176, SMD = -2.29, 95% CI: -3.68 - -0.90, p = 0.001, I² = 96%). One study reported ten cases of bleeding, however, no serious adverse events were reported in any of the included studies. This review determined that EA may have a greater clinical effect than the control group for fatigue relief and improved quality of life. However, there were several risks of bias identified. Not all of the RCTs accurately reported the research method, all studies were conducted in 1 country (China), and the number of studies included were small.

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.

Fatigue is associated with depression independent of excessive daytime sleepiness in the general population

PURPOSE

This study aimed to investigate sleep problems and comorbid conditions associated with fatigue in the general population.

METHODS

The data were obtained from a nationwide cross-sectional survey conducted in 2018. The Fatigue Severity Scale was used to assess fatigue. We examined sleep habits, such as workday sleep duration, chronotype, and free-day catch-up sleep, excessive daytime sleepiness (EDS), depression, and other comorbid conditions. We conducted multiple logistic regression analysis with the presence of fatigue as a dependent variable.

RESULTS

Of 2,493 adults aged 19 to 92 years, 50% men, mean age was 47.9 ± 16.4 years. The average workday sleep duration was 7.1 ± 1.1 h, and the prevalence of fatigue was 31%. After adjusting for potential confounders, fatigue was associated with EDS (odds ratio [OR] 3.751, 95% confidence interval [CI] 2.928-4.805), depression (OR 3.736, 95% CI 2.701-5.169), perceived insufficient sleep (OR 1.516, 95% CI 1.249-1.839), free-day catch-up sleep (OR 1.123, 95% CI 1.020-1.235), less alcohol intake (OR 0.570, 95% CI 0.432-0.752), and physical inactivity (OR 0.737, 95% CI 0.573-0.948). On subgroup analysis, fatigue was additionally associated with short workday sleep duration (OR 0.899, 95% CI 0.810-0.997) in individuals without EDS. However, among those with EDS, only depression (OR 2.842, 95% CI 1.511-5.343) and less alcohol intake (OR 0.476, 95% CI 0.247-0.915) were associated with fatigue.

CONCLUSION

Fatigue was significantly associated with depression independent of EDS. Further research is warranted to better understand the pathophysiological relationship between fatigue, depression, and sleep.

Prevalence of Chronic Fatigue Syndrome (CFS) in Korea and Japan: A Meta-Analysis

Background: Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a long-term disabling illness accompanied by fatigue unsolved by rest. However, ME/CFS is a poorly understood illness that lacks a universally accepted pathophysiology and treatment. A lack of CFS-related studies have been conducted in Asian countries. This study aimed to estimate and compare the prevalence of ME/CFS in Korea and Japan and conducted a meta-analysis. Methods: We searched PubMed, EMBASE, Cochrane, and KMBASE for population-based prevalence studies of the two countries and synthesized the data according to the Fukuda case definition. Results: Of the eight studies (five in Korea, three in Japan) included, the total prevalence rate of Korean studies was 0.77% (95% CI 0.34–1.76), and 0.76% (95% CI 0.46–1.25) for the Japanese studies. The prevalence rate in females was approximately two-fold higher than males in Korean studies (1.31% female vs. 0.60% male), while the gender difference was less obvious in Japanese studies (0.76% female vs. 0.65% male). Conclusions: Further epidemiology studies on the female ME/CFS prevalence rate between countries may be required.

Reflux Esophagitis and Fatigue: Are They Related?

Gastroesophageal reflux disease (GERD) is a chronic, recurrent disease. Reflux esophagitis can interfere with sleep via acid reflux, which can cause daytime sleepiness or fatigue. However, little is known about the association between reflux esophagitis and fatigue. Objectives: We evaluated the association between fatigue and reflux esophagitis in subjects seen at health check-ups. Methods: Consecutive patients who were scheduled for screening endoscopies were enrolled prospectively at the Comprehensive Medical Examination Center of St. Vincent Hospital and Eunpyeong St. Mary’s Hospital, Korea. Three validated questionnaires were used to assess fatigue, daytime hypersomnolence, anxiety, and depression: the Multidimensional Fatigue Inventory—Korean version (MFI-K), Epworth Sleepiness Scale (ESS), and Hospital Anxiety and Depression Scale (HADS). Results: We investigated 497 consecutive eligible subjects. The reflux esophagitis and symptomatic GERD groups comprised 103 (20.7%) and 92 (18.5%) subjects, respectively. The MFI-K total, ESS, HADS-anxiety, and HADS-depression scores did not differ between the esophagitis and non-esophagitis groups (50.0 ± 11.5 vs. 49.7 ± 10.9, p = 0.661; 6.2 ± 2.8 vs. 6.1 ± 3.1, p = 0.987; 5.8 ± 3.1 vs. 5.2 ± 3.2, p = 0.060; 6.2 ± 3.6 vs. 6.0 ± 3.3, p = 0.561). However, the MFI-K total, ESS, HADS-anxiety, and HADS-depression scores were higher in the symptomatic group than in the non-symptomatic group (54.7 ± 12.7 vs. 48.6 ± 10.3, p < 0.001; 7.1 ± 3.5 vs. 5.9 ± 2.9, p = 0.002; 6.4 ± 3.3 vs. 5.1 ± 3.1, p < 0.001; 7.5 ± 4.0 vs. 5.7 ± 3.1, p < 0.001). Multiple regression analysis showed that the MFI-K total was correlated with GERD symptoms (p = 0.021), women (p = 0.001), anxiety (p < 0.001), and depression (p < 0.001). Conclusion: There was no statistically significant association in which reflux esophagitis could cause daytime sleepiness, fatigue, anxiety, or depression. However, fatigue was associated with GERD symptoms, women, anxiety, and depression. Further studies should clarify the association between fatigue and reflux esophagitis.

Efficacy and Safety of Sipjeondaebo-Tang (Shi-Quan-Da-Bu-Tang) for Chronic Fatigue Syndrome: Study Protocol for a Multicenter, Randomized, Double-Blind, Placebo-Controlled Trial

Background. Sipjeondaebo-tang (SDT), also known as Shi-Quan-Da-Bu-Tang, is a treatment for both qi and blood deficiency syndromes in traditional Korean medicine. It is also used to treat chronic fatigue syndrome (CFS) in Korea. Herein, we present the protocol for a study to assess the efficacy and safety of SDT for treating CFS. Methods. This will be a multicenter, randomized, double-blind, controlled trial with two parallel-treatment arms: an SDT group and a placebo group. Ninety-six patients with CFS aged between 19 and 65 years will be recruited from two hospitals in Korea. Participants will be randomly allocated at a ratio of 1 : 1 between the two groups. Participants will receive 3 g doses of SDT or placebo thrice daily for 8 weeks. Follow-up evaluations will be performed for 4–6 weeks after the drug administration period. The primary outcome will be the rating of participants’ fatigue symptoms using the Checklist Individual Strength questionnaire. Outcomes will be assessed at baseline, week 4, and week 8, as well as during follow-up. An efficacy evaluation and safety assessment will be performed. This study will be based on the Consolidated Standards of Reporting Trials (CONSORT) guidelines and the Standard Protocol Items: Recommendations for Interventional Trials (SPIRIT) 2013 statement. This protocol and informed consent guidelines were reviewed and approved by the institutional review board of Kyung Hee University Korean Medicine Hospital at Gangdong in the Republic of Korea (KHNMCOH 2017-06-004-001). The protocol was registered with the Clinical Research Information Service. Written informed consent will be obtained from all study participants prior to enrollment in the study. Results will be published in a peer-reviewed journal and presented at a scientific conference. Discussion. This study is expected to provide novel, accurate information regarding the 38 efficacy and safety of SDT for CFS in adults. Trial Registration. This trial is registered with https://cris.nih.go.kr; CRIS identifier (KCT0002684) registered on February 9, 2018.

Effectiveness a herbal medicine (Sipjeondaebo-tang) on adults with chronic fatigue syndrome: A randomized, double-blind, placebo-controlled trial

Background

Sipjeondaebo-tang (SJDBT, Shi-quan-da-bu-tang in Chinese) is a widely prescribed herbal medicine in traditional Korean medicine. This study aimed to evaluate the effectiveness and safety of SJDBT for treating chronic fatigue syndrome (CFS).

Methods

Ninety-six eligible participants were randomly allocated to either the SJDBT or placebo groups in a 1:1 ratio. Nine grams of SJDBT or placebo granules were administered to the patients for 8 weeks. The primary outcome was the response rate, defined as the proportion of participants with a score of 76 or higher in the Checklist Individual Strength assessment. Other measurements for fatigue severity, quality of life, and qi/blood/yin/yang deficiency were included. Safety was assessed throughout the trial.

Results

At week 8, the response rate did not significantly differ between the groups (SJDBT: 35.4%; placebo: 54.2%; P =  0.101, effect size [95% confidence interval] = 0.021 [-0.177, 0.218]). However, the scores of the visual analogue scale (P =  0.001, -0.327 [-0.506, -0.128]), Fatigue Severity Scale (P =  0.020, 0.480 [0.066, 0.889]), and Chalder fatigue scale (P =  0.004, -0.292 [-0.479, -0.101]) for the SJDBT group showed significant improvements in fatigue severity at the endpoint. Quality of life was not significantly different. Furthermore, SJDBT significantly ameliorated the severity of qi deficiency compared to that in the placebo group. No serious adverse events were observed.

Conclusion

This trial failed to show a significant improvement in fatigue severity, as assessed by the CIS-deprived response rate. It merely showed that SJDBT could alleviate the severity of fatigue and qi deficiency in patients with CFS. However, the further study is needed to confirm the details.

Association between fatigue, pain, digestive problems, and sleep disturbances and individuals' health-related quality of life: a nationwide survey in South Korea

Background

Physical symptoms such as fatigue, pain, digestive problems, and sleep disturbances are chief reasons individuals seek primary care, as they affect health-related quality of life. We investigated the associations between various combinations of these common symptoms and individuals’ health-related quality of life.

Methods

This large-scale survey study of 1100 Koreans aged ≥19 years was conducted in 2017 using multi-stage stratified sampling based on region, sex, and age. Data were collected using questionnaires administered face-to-face; then, a linear regression analysis was performed to assess how the symptoms were related to participants’ health-related quality of life. Complex symptoms were defined as co-occurrence of two or more of the four symptoms—fatigue, pain, digestive problems, and sleep disturbances.

Results

The most frequently observed stand-alone symptom was fatigue, while the most common combination was fatigue and pain. When examined individually, fatigue, digestive problems, and sleep disturbances were closely associated with mental health-related quality of life, and pain was associated with physical health-related quality of life. Complex symptoms were also related to health-related quality of life. Lower physical health-related quality of life was strongly associated when fatigue and pain or all four symptoms were co-occurring, and the lowest mental health-related quality of life was seen when all four symptoms were present, after adjusting for all variables.

Conclusions

Symptoms can be present in various combinations and are significantly associated with health-related quality of life. Extra attention should be given to patterns accompanying fatigue and pain and to those involving more symptoms. This elucidated the characteristics of symptoms that affect the health-related quality of life of South Korean adults.

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.

Efficacy of Korean red ginseng (Panax ginseng) for middle-aged and moderate level of chronic fatigue patients: A randomized, double-blind, placebo-controlled trial

OBJECTIVES

Chronic fatigue (CF) is unexplained fatigue lasting more than 6 months. Korean red ginseng (KRG) is known to have higher anti-fatigue substance than white ginseng. However, its efficacy and safety for CF is unknown. The purpose of this study was to investigate the effect of KRG on CF by various measurements and objective indicators.

DESIGN

A randomized, double-blind, clinical trial was conducted on 50 patients with CF.

INTERVENTION

Participants were allocated to KRG or placebo group (1:1 ratio) and visited hospital every 2 weeks during taking 3 g KRG or placebo for 6 weeks and followed up 4 weeks after the treatment.

MAIN OUTCOME MEASURES

The primary outcome measurement was fatigue VAS. Secondary outcome measurements included FSS, CFSQ, SRI, scales of various fields (Depression: BDI; Sleep: ISI; Quality of life: EQ-5D 5 L), biochemical test (Antioxidants: d-ROMs, TBARS, BAP, and SOD; Cortisol concentration: salivary cortisol), blinding assessment, and adverse events.

RESULTS

The fatigue VAS declined significantly in each group, but there were no significant differences between the groups. The 2 groups also had no significant differences in the secondary outcome measurements and there were no adverse events. Sub-group analysis indicated that patients with initial fatigue VAS below 80 mm and older than 50 years had significantly greater reductions in the fatigue VAS if they used KRG rather than placebo.

CONCLUSIONS

By our study, KRG did not show absolute anti-fatigue effect but provided the objective evidence of fatigue-related measurement and the therapeutic potential for middle-aged individuals with moderate fatigue.

The Efficacy and Safety of Myelophil, an Ethanol Extract Mixture of Astragali Radix and Salviae Radix, for Chronic Fatigue Syndrome: A Randomized Clinical Trial

Background: There is a strong demand for therapeutics to treat chronic fatigue syndrome (CFS), although there are limitations. Myelophil, which is a combination of extracts from Astragali Radix and Salviae Miltiorrhizae Radix, has been clinically used to treat fatigue-related disorders in South Korea. We conducted a randomized controlled clinical trial of Myelophil in patients with CFS and evaluated its efficacy and safety in two hospitals.

Methods: We enrolled 98 participants (M: 38, F: 60) with CFS in a phase 2 trial of oral Myelophil (2 g daily) or placebo for 12 weeks. The primary end point was a change in the Chalder fatigue scale, as scored by a numeric rating scale (NRS). The secondary end points included changes in the visual analogue scale, fatigue severity scale (FSS), and 36-item short-form health survey (SF-36). Biomarkers of oxidative stress and cytokines were evaluated by blood tests.

Results: Ninety-seven participants (48 in the Myelophil group and 49 in the placebo group) completed the trial. An analysis of all participants showed that Myelophil slightly improved fatigue symptoms compared with those of the placebo, but this effect was not statistically significant (p > 0.05 for the NRS, VAS, FSS, and SF-36). By contrast, an analysis of the subpopulation (53 participants, M: 24, F: 29) with severe symptoms (≥63, median NRS value of total participants) showed a statistically significant improvement in fatigue symptoms in the Myelophil group compared with the placebo (p < 0.05 for NRS, FSS, and SF-36). There were no significant changes in the biomarkers for oxidative stress and cytokines before or after the treatment. No Myelophil-related adverse response was observed during the trial.

Conclusion: These results support the hypothesis that Myelophil can be a therapeutic candidate to manage CFS and provide the rationale for its progression to a phase 3 clinical trial.

Clinical Trial Registration:www.ClinicalTrials.gov, identifier KCT0002317.

[Fatigue - a Common Symptom in General Practice]

Fatigue - a Common Symptom in General Practice Abstract. When patients suffering from fatigue consult a GP surgery, GPs should understand what patients mean by fatigue, how strongly they are affected in everyday life and how they themselves explain the symptom. In a next step, dangerous diseases such as depression, addiction or sleep apnea syndrome must be excluded. The main somatic and psychiatric causes of fatigue should be explored simultaneously with a more in-depth history. A simple physical exam and a few lab examinations are sufficient to capture the major disorders that present with the isolated symptom of fatigue. For further care, a primary biopsychosocial approach with a viable physician-patient relationship is crucial. Rough conclusions based on laboratory findings should be avoided; comorbidities must be considered.

Long Term Follow up of Young People With Chronic Fatigue Syndrome Attending a Pediatric Outpatient Service

Aim: To determine the reported duration of illness, the functional and educational long-term outcomes, predictive factors for recovery and seek feedback regarding management in pediatric/adolescent myalgic encepahalomyelitis/chronic fatigue syndrome (ME/CFS). Methods: A cohort observational study of 784 young people, mean age 14.6 (6-18) years, with ME/CFS diagnosed at a specialist pediatric hospital and receiving regular care, was conducted with follow-up for a mean 8 (range 1-21) years after onset. Baseline symptoms, history, depression and anxiety questionnaires were available from 418. The remaining 366, did not have similar standardized baseline information. Questionnaires requested functional rating, persistent symptoms, duration of illness if "recovered," social engagement and school/work attendance. Feedback was sought regarding management, support services, useful information, helpful interventions or personnel and use of alternative therapies. Reported recovery and function were compared with baseline information and between the two groups. Results: Follow-up data were returned from 81.8%. There was no significant difference in functional score (if reported recovery) or illness duration related to provision of baseline data. The mean duration of illness was 5 (range 1-15) years in the 50% who reported recovery. By 5 years 38% and by 10 years 68% reported recovery. At 10 years the mean functional score was 8/10 (range 2-10) with 5% scoring <6. Depression, anxiety or severity of illness at diagnosis was not predictive of non-recovery. Designing and monitoring their own management plan that included educational, social, physical and enjoyable activities, as well as having symptom management and understanding professionals were highly valued. However, remaining engaged in an education system that flexibly accommodated their illness and aspirations was consistently reported as crucial for long term functioning. Conclusions: ME/CFS in young people has a mean duration of 5 years (1-15) with 68% reporting recovery by 10 years. All improved functionally with 5% remaining very unwell and a further 20% significantly unwell. There were no obvious baseline predictors for recovery. However, depression, anxiety, orthostatic intolerance and to a lesser extent pain at follow up were identified as hampering recovery or function. Supportive professionals, remaining engaged in education and management strategies were identified as helpful.

Three-Component Herbal Tea Alleviates Prolonged Fatigue and Improves Sleep Quality: A Randomized Controlled Pilot Study

INTRODUCTION

Prolonged fatigue is common among adults, yet only a small percentage of affected individuals seek medical attention. Following findings that complementary and alternative medicine can be effective strategies for improving fatigue, we evaluated the effect of an herbal tea regimen on prolonged fatigue.

METHODS

In this pilot randomized controlled trial, participants with prolonged fatigue were randomly allocated to either a tea (n = 20) or control (n = 20) group. The tea group consumed herbal tea consisting of Astragali Radix, Angelicae gigantis Radix, and Zizyphi Fructus twice daily for 4 weeks, whereas the control group received no intervention. Outcomes were assessed at baseline and 4 and 8 weeks. The primary outcome was fatigue severity, measured using the Chalder Fatigue Scale. Secondary outcomes included sleep quality, depression symptoms, and quality of life.

RESULTS

Among the 40 individuals screened, 35 completed the study. Fatigue severity was significantly lower in the tea group than the control group at 4 weeks, and within the tea group, fatigue severity and sleep quality improved at the 4- and 8-week follow-ups vs. baseline in the tea group. Depression also significantly improved in the tea group at 8 weeks. There were no changes within the control group on any measure.

CONCLUSION

The findings suggest that our herbal tea formulation reduces fatigue severity and improves sleep quality in adults with prolonged fatigue.

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.

Chronic fatigue syndrome - an update

BACKGROUND

Chronic fatigue syndrome is a widespread condition with a huge impact not only on a patient's life, but also on society as evidenced by substantial losses of productivity, informal costs, and medical expenses. The high prevalence rates (0.2-6.4%) and the low employment rates (27-41%) are responsible for the enormous burden imposed on society, with loss of productivity representing the highest cost. The objective of this review is to systematically review the recent literature on chronic fatigue syndrome/myalgic encephalomyelitis.

METHODS

The published literature between 1 January 1990 and 1 April 2015 was searched using the MEDLINE, Cochrane Library, and Web of Sciences databases. The reference lists of the selected articles were screened for other relevant articles.

RESULTS AND CONCLUSIONS

Despite extensive research, none of the proposed etiological factors have shown strong, reproducible scientific evidence. Over the years, the biopsychosocial model integrating many of the proposed hypotheses has been gaining popularity over the biomedical model, where the focus is on one physical cause. Since the etiological mechanism underlying chronic fatigue syndrome is currently unknown, disease-specific treatments do not exist. Various treatments have been investigated but only cognitive behavior therapy (CBT) and graded exercise therapy (GET) have shown moderate effectiveness.

Placenta Peptide Can Protect Mitochondrial Dysfunction through Inhibiting ROS and TNF-α Generation, by Maintaining Mitochondrial Dynamic Network and by Increasing IL-6 Level during Chronic Fatigue

Background: Level of fatigue is related to the metabolic energy available to tissues and cells, mainly through mitochondrial respiration, as well fatigue is the most common symptom of poorly functioning mitochondria. Hence, dysfunction of these organelles may be the cause of the fatigue seen in Chronic fatigue (CF). Placenta has been used for treatment of fatigue and various disease, moreover peptides has known protect mitochondrial viability, and alleviate fatigue. These properties of placenta and peptides may link with its effect on mitochondria; therefore, it is highly important to investigate the effectiveness of placenta peptide on fatigue and mitochondrial dysfunction. Methods: After administration of sheep placenta peptide (SPP) for 1 month, mice's were forced to swim till exhaustion for 90 min to induce chronic fatigue. Electron microscopic examination of skeletal muscle mitochondrial structure, tissue Malondialdehyde (MDA), mitochondrial SOD and serum inflammatory cytokines level were investigated in order to determine the potential effect of SPP on mitochondria during CF. Rat skeletal muscle (L6 cell) were also treated with different concentration of SPP to determine the effect of SPP on cell viability using Thiazoyl blue tetrazolium assay. Results: Our finding revealed that forced swimming induced fatigue model can cause mitochondrial damage through Reactive oxygen species (ROS) mediated lipid peroxidation and Tumor Necrosis factor alpha (TNF-α) elevation. Whereas SPP protected fatigue induced mitochondrial dysfunction through preventing ROS and TNF-α generation, by maintaining mitochondrial dynamic network and by increasing serum IL-6 level. Conclusion: SPP can protect damage in mitochondrial components which will allow proper functioning of mitochondria that will in turn inhibit progression of chronic fatigue. Therefore, SPP may represent a novel therapeutic advantage for preventing mitochondrial dysfunction in patients with chronic fatigue.

Validation of the qi blood yin yang deficiency questionnaire on chronic fatigue

Background

Chronic fatigue (CF) reflects an imbalance of inter-organ functions or of the four essential physiological components qi, blood (xue), yin, and yang. CF can be subdivided into different patterns. However, there are no diagnostic methods for CF. This study aimed to clinically validate a pattern identification method by identifying correlations between CF and responses to the qi blood yin yang deficiency questionnaire (QBYY-Q).

Methods

Participants were recruited between May and June 2014 through the Kyung Hee University Korean Medicine hospital website and via posters and comprised 129 CF patients diagnosed with the United States Centers for Disease Control and Prevention (1994) criteria. Participants who had organic diseases that explained the CF were excluded. A total of 159 participants were asked to complete the QBYY-Q, the fatigue severity scale, and the Chalder fatigue scale. The latter two questionnaires were used to assess convergent validity with the QBYY-Q. Among the 129 CF participants, 70 and 59 had chronic fatigue syndrome and idiopathic chronic fatigue, respectively. Two Korean medical doctors independently assessed participants’ qi, blood, yin, and yang deficiency patterns using QBYY deficiency pattern identification guidelines. Based on the results of a preliminary study of the QBYY-Q, we selected 32 reliable items for symptoms corresponding to each deficiency pattern. The items were used to estimate internal consistency and construct validity. Multinomial logistic regression analysis was performed for scores on each deficiency pattern.

Results

The data were means and standard deviations or numbers of participants and proportions for continuous and categorical variables, respectively. A statistical significance level of P < 0.05 was assumed. The QBYY-Q showed satisfactory internal consistency. Explanatory factor analysis extracted two factors for each deficiency pattern. The percentages of explained variance for qi, blood, yin, and yang deficiency were 45.1, 58.0, 52.2, and 63.4 %, respectively. Each QBYY-Q deficiency score was positively associated with each corresponding deficiency pattern. Qi deficiency was used as a reference category. Odds ratios of blood, yin, and yang deficiency were 10.97, 10.69, and 14.64, respectively.

Conclusion

The QBYY-Q was suitable for estimating the influences of qi, blood, yin, and yang deficiencies in CF.

Trial registration This trial was registered with the Korean Clinical Trial Register (KCT0001199)

Electronic supplementary material

The online version of this article (doi:10.1186/s13020-016-0092-y) contains supplementary material, which is available to authorized users.

Relationship between Changes in Fatigue and Exercise by Follow-Up Period

BACKGROUND

Fatigue is one of the most common presenting symptoms in primary care in Korea. In this study, we aimed to determine the effect of exercise intervention on the severity of fatigue of unknown medical cause during a period of follow-up.

METHODS

We used the data collected from an outpatient fatigue clinic in Seoul National University Bundang Hospital. The study was conducted from March 3, 2010 to May 31, 2014. We measured the body mass index of each patient and evaluated variables including lifestyle factors (smoking, alcohol consumption, and regular exercise), quality of sleep, anxiety, depression, stress severity, and fatigue severity using questionnaires. A total of 152 participants who completed questionnaires to determine changes in fatigue severity and the effect of exercise for each period were evaluated. We used univariate analysis to verify possible factors related to fatigue and then conducted multivariate analysis using these factors and the literature.

RESULTS

Of 130 patients with the complaint of chronic fatigue for over 6 months, over 90 percent reported moderate or severe fatigue on the Fatigue Severity Scale and Brief Fatigue Inventory questionnaires. The fatigue severity scores decreased and fatigue improved over time. The amount of exercise was increased in the first month, but decreased afterwards.

CONCLUSION

There was no significant relationship between changes in the amount of exercise and fatigue severity in each follow-up period. Randomized controlled trials and a cohort study with a more detailed exercise protocol in an outpatient setting are needed in the future.

Validation of the Korean Version of Schedule of Fatigue and Anergia: General Physician Questionnaire

The Schedule of Fatigue and Anergy/General Physician (SOFA/GP) was developed to screen for prolonged fatigue in the primary care setting. We aimed to evaluate the reliability and validity of the Korean version of the SOFA/GP (SOFA/GP-K), which is adapted from the original English version. We performed translation and back translation, and after conducting a pilot study, we tested the final version of the questionnaire for its reliability and validity in a Korean primary care setting. Two hundred participants that visited a health examination center in a university hospital completed the survey between September and November 2012. A second survey was performed within 2 weeks of the primary survey to test for reliability. We evaluated concurrent validity between the SOFA/GP-K score, the Fatigue Severity Scale (FSS), and Brief Fatigue Index (BFI) scores. The Spearman correlation coefficient between SOFA/GP-K and FSS was 0.71 and 0.61 between SOFA/GP-K and BFI. Internal consistency of SOFA/GP-K was observed (Cronbach's alpha = 0.82) and construct validity was confirmed by factor analysis. The Kappa scores for test-retest reliability for each survey item were between 0.28 and 0.64. The SOFA/GP-K is a valid and reliable questionnaire for screening fatigue in a primary care setting.

Experiences with, perceptions of and attitudes towards traditional Korean medicine (TKM) in patients with chronic fatigue: a qualitative, one-on-one, in-depth interview study

OBJECTIVES

To explore perceptions and experiences of patients with chronic fatigue with traditional Korean medicine (TKM) and their motivation for choosing TKM.

DESIGN

Qualitative, one-on-one, in-depth interview study.

SETTING

Primary TKM hospitals in Seoul, Incheon and Daejeon, South Korea.

RESULTS

15 patients with chronic fatigue were interviewed in this study. Patients with chronic fatigue experienced physical and psychological symptoms that resulted in severe difficulties associated with routine daily activities. The motivations for choosing TKM were primarily dissatisfaction with conventional medicine and previous positive experiences with TKM. While undergoing TKM treatment, patients found that TKM practitioners considered fatigue to be a treatable illness; also, patients felt comfortable with the doctor-patient relationship in TKM.

CONCLUSIONS

Healthcare providers need to be concerned about the symptoms of chronic fatigue to a degree that is in line with the patient's own perceptions. Korean patients with chronic fatigue choose TKM as an alternative to fulfil their long-term needs that were unmet by conventional medicine, and they are greatly positively influenced by TKM. TKM may present a possible therapy to alleviate symptoms of diseases that conventional medicine does not address and is an approach that has a considerable effect on Korean patients.

Clinical study on constitutional herbal tea for treating chronic fatigue

Objectives:

This study was designed to evaluate the efficacy and the safety of constitutional herbal tea for treating chronic fatigue with no diagnosed cause, which is called Mibyeong in Korea.

Methods:

Males and females with ages between 40 and 59 years who had complained of fatigue for 1 month consistently or for 6 months intermittently without a definite cause were recruited. At the same time, a Chalder fatigue scale (CFS) score of 19 was essential for participation in this study. Sixty five subjects completed the entire process, including blood tests and tests with medical devices. Five assessments of health status were accomplished over 8 weeks by using the CFS and the visual analogue scale (VAS). To ensure that the constitutional herbal tea was being safely used, we conducted and analyzed renal function and liver function tests. For the diagnosis of the Sasang constitution, the Sasang Constitutional Analysis Tool (SCAT) was used, and a specialist in Sasang constitutional medicine made the final diagnosis based on the SCAT result. Constitutional herbal tea was served four weeks after the first visit. The subjects took the constitutional herbal tea twice a day for one month.

Results:

The results are as follows: The CFS and the VAS scores were significantly improved for the subjects in the constitutional herbal tea. No abnormalities were found on the blood tests to evaluate safety after taking the constitutional herbal tea. The improvements in the CFS and the VAS scores due to the constitutional herbal tea had no significant differences according to the Sasang constitution.

Conclusion:

Constitutional herbal tea may be used to reduce fatigue and improve health and has no adverse effect on either the kidney or the liver.

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.

The adoption of chronic fatigue syndrome/myalgic encephalomyelitis case definitions to assess prevalence: a systematic review

PURPOSE

Prevalence estimates have been based on several case definitions of chronic fatigue syndrome (CFS). The purpose of this work is to provide a rigorous overview of their application in prevalence research.

METHODS

A systematic review of primary studies reporting the prevalence of CFS since 1990 was conducted. Studies were summarized according to study design, prevalence estimates, and case definition used to ascertain cases.

RESULTS

Thirty-one studies were retrieved, and eight different case definitions were found. Early estimates of CFS prevalence were based on the 1988 Centers for Disease Control and Prevention, Australian, and Oxford. The 1994 Centers for Disease Control and Prevention, however, has been adopted internationally, as a general standard. Only one study has reported prevalence according to the more recent, Canadian Consensus Criteria. Additional estimates were also found according to definitions by Ho-Yen, the 2005 Centers for Disease Control and Prevention empirical definition, and an epidemiological case definition.

CONCLUSIONS

Advances in clinical case definitions during the past 10 years such as the Canadian Consensus Criteria have received little attention in prevalence research. Future assessments of prevalence should consider adopting more recent developments, such as the newly available International Consensus Criteria. This move could improve the surveillance of more specific cases found within CFS.

Diagnosing Chronic Fatigue Syndrome in South Asians: Lessons from a Secondary Analysis of a UK Qualitative Study

BACKGROUND

Chronic fatigue syndrome/myalgic encephalitis (CFS/ME) is rarely diagnosed in South Asia (SA), although the symptoms of this condition are seen in the population. Lessons from UK based South Asian, Black and Minority Ethnic (BME) communities may be of value in identifying barriers to diagnosis of CFS/ME in SA.

OBJECTIVES

To explore why CFS/ME may not be commonly diagnosed in SA.

SETTINGS AND DESIGN

A secondary analysis of qualitative data on the diagnosis and management of CFS/ME in BME people of predominantly South Asian origin in the UK using 27 semi-structured qualitative interviews with people with CFE/ME, carers, general practitioners (GPs), and community leaders.

RESULTS

CFS/ME is seen among the BME communities in the UK. People from BME communities in the UK can present to healthcare practitioners with vague physical complaints and they can hold a biomedical model of illness. Patients found it useful to have a label of CFS/ME although some GPs felt it to be a negative label. Access to healthcare can be limited by GPs reluctance to diagnose CFS/ME, their lack of knowledge and patients negative experiences. Cultural aspects among BME patients in the UK also act as a barrier to the diagnosis of CFS/ME.

CONCLUSION

Cultural values and practices influence the diagnosis of CFS/ME in BME communities. The variations in the perceptions around CFS/ME among patients, carers, and health professionals may pose challenges in diagnosing CFS/ME in SA as well. Raising awareness of CFS/ME would improve the diagnosis and management of patients with CFS/ME in SA.

The prevalence of chronic fatigue syndrome/ myalgic encephalomyelitis: a meta-analysis

Purpose

To perform a meta-analysis to examine variability among prevalence estimates for CFS/ME, according to the method of assessment used.

Methods

Databases were systematically searched for studies on CFS/ME prevalence in adults that applied the 1994 Centers for Disease Control (CDC) case definition.1 Estimates were categorized into two methods of assessment: self-reporting of symptoms versus clinical assessment of symptoms. Meta-analysis was performed to pool prevalences by assessment using random effects modeling. This was stratified by sample setting (community or primary care) and heterogeneity was examined using the I² statistic.

Results

Of 216 records found, 14 studies were considered suitable for inclusion. The pooled prevalence for self-reporting assessment was 3.28% (95% CI: 2.24–4.33) and 0.76% (95% CI: 0.23–1.29) for clinical assessment. High variability was observed among self-reported estimates, while clinically assessed estimates showed greater consistency.

Conclusion

The observed heterogeneity in CFS/ME prevalence may be due to differences in method of assessment. Stakeholders should be cautious of prevalence determined by the self-reporting of symptoms alone. The 1994 CDC case definition appeared to be the most reliable clinical assessment tool available at the time of these studies. Improving clinical case definitions and their adoption internationally will enable better comparisons of findings and inform health systems about the true burden of CFS/ME.

A randomized controlled trial of qigong exercise on fatigue symptoms, functioning, and telomerase activity in persons with chronic fatigue or chronic fatigue syndrome

Background

Chronic fatigue is common in the general population. Complementary therapies are often used by patients with chronic fatigue or chronic fatigue syndrome to manage their symptoms.

Purpose

This study aimed to assess the effect of a 4-month qigong intervention program among patients with chronic fatigue or chronic fatigue syndrome.

Methods

Sixty-four participants were randomly assigned to either an intervention group or a wait list control group. Outcome measures included fatigue symptoms, physical functioning, mental functioning, and telomerase activity.

Results

Fatigue symptoms and mental functioning were significantly improved in the qigong group compared to controls. Telomerase activity increased in the qigong group from 0.102 to 0.178 arbitrary units (p < 0.05). The change was statistically significant when compared to the control group (p < 0.05).

Conclusion

Qigong exercise may be used as an alternative and complementary therapy or rehabilitative program for chronic fatigue and chronic fatigue syndrome.

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

OBJECTIVE

To estimate the prevalence and incidence of chronic fatigue syndrome in Olmsted County, Minnesota, using the 1994 case definition and describe exclusionary and comorbid conditions observed in patients who presented for evaluation of long-standing fatigue.

PATIENTS AND METHODS

We conducted a retrospective medical record review of potential cases of chronic fatigue syndrome identified from January 1, 1998, through December 31, 2002, using the Rochester Epidemiology Project, a population-based database. Patients were classified as having chronic fatigue syndrome if the medical record review documented fatigue of 6 months' duration, at least 4 of 8 chronic fatigue syndrome-defining symptoms, and symptoms that interfered with daily work or activities. Patients not meeting all of the criteria were classified as having insufficient/idiopathic fatigue.

RESULTS

We identified 686 potential patients with chronic fatigue, 2 of whom declined consent for medical record review. Of the remaining 684 patients, 151 (22%) met criteria for chronic fatigue syndrome or insufficient/idiopathic fatigue. The overall prevalence and incidence of chronic fatigue syndrome and insufficient/idiopathic fatigue were 71.34 per 100,000 persons and 13.16 per 100,000 person-years vs 73.70 per 100,000 persons and 13.58 per 100,000 person-years, respectively. The potential cases included 482 patients (70%) who had an exclusionary condition, and almost half the patients who met either criterion had at least one nonexclusionary comorbid condition.

CONCLUSION

The incidence and prevalence of chronic fatigue syndrome and insufficient/idiopathic fatigue are relatively low in Olmsted County. Careful clinical evaluation to identify whether fatigue could be attributed to exclusionary or comorbid conditions rather than chronic fatigue syndrome itself will ensure appropriate assessment for patients without chronic fatigue syndrome.

Indirect moxibustion (CV4 and CV8) ameliorates chronic fatigue: a randomized, double-blind, controlled study

OBJECTIVES

The antifatigue effect of indirect moxibustion and its antioxidant properties were investigated.

SUBJECTS AND DESIGN

A randomized, double-blind, controlled clinical trial was performed with 44 patients who had idiopathic chronic fatigue. The subjects were treated with a placebo or moxibustion (indirect moxibustion on CV4 and CV8 3 times per week for 4 weeks), and their fatigue severity was monitored using a self-rating numeric scale (NRS) and a visual analog scale (VAS). Serum level of reactive oxygen species and malondialdehyde (MDA), total antioxidant capacity, the activity of catalase, superoxide dismutase, glutathione peroxidase, and glutathione reductase and total glutathione content, were determined before initial moxibustion therapy and after the 12th moxibustion treatment.

RESULTS

The moxibustion group had a significantly lower fatigue severity score compared to the control for both the NRS (p<0.05) and VAS scores (p<0.01). The level of serum MDA was significantly lower in the moxibustion group than in the placebo group (p<0.05), whereas glutathione reductase activity and total glutathione content increased significantly following moxibustion (p<0.05).

CONCLUSIONS

The results provide clinical evidence for an antifatigue effect of indirect moxibustion at CV4 and CV8 and suggest that the effect is due to the antioxidant properties of moxibustion.

Prevalence of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) in three regions of England: a repeated cross-sectional study in primary care

BACKGROUND

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) or chronic fatigue syndrome (CFS) has been used to name a range of chronic conditions characterized by extreme fatigue and other disabling symptoms. Attempts to estimate the burden of disease have been limited by selection bias, and by lack of diagnostic biomarkers and of agreed reproducible case definitions. We estimated the prevalence and incidence of ME/CFS in three regions in England, and discussed the implications of frequency statistics and the use of different case definitions for health and social care planning and for research.

METHODS

We compared the clinical presentation, prevalence and incidence of ME/CFS based on a sample of 143,000 individuals aged 18 to 64 years, covered by primary care services in three regions of England. Case ascertainment involved: 1) electronic search for chronic fatigue cases; 2) direct questioning of general practitioners (GPs) on cases not previously identified by the search; and 3) clinical review of identified cases according to CDC-1994, Canadian and Epidemiological Case (ECD) Definitions. This enabled the identification of cases with high validity.

RESULTS

The estimated minimum prevalence rate of ME/CFS was 0.2% for cases meeting any of the study case definitions, 0.19% for the CDC-1994 definition, 0.11% for the Canadian definition and 0.03% for the ECD. The overall estimated minimal yearly incidence was 0.015%. The highest rates were found in London and the lowest in East Yorkshire. All but one of the cases conforming to the Canadian criteria also met the CDC-1994 criteria, however presented higher prevalence and severity of symptoms.

CONCLUSIONS

ME/CFS is not uncommon in England and represents a significant burden to patients and society. The number of people with chronic fatigue who do not meet specific criteria for ME/CFS is higher still. Both groups have high levels of need for service provision, including health and social care. We suggest combining the use of both the CDC-1994 and Canadian criteria for ascertainment of ME/CFS cases, alongside careful clinical phenotyping of study participants. This combination if used systematically will enable international comparisons, minimization of bias, and the identification and investigation of distinct sub-groups of patients with possibly distinct aetiologies and pathophysiologies, standing a better chance of translation into effective specific treatments.

Characteristics of chronic fatigue syndrome in a Japanese community population : chronic fatigue syndrome in Japan

This study seeks to estimate the prevalence of chronic fatigue syndrome (CFS) and assess the characteristics of CFS in a community population in Japan using laboratory tests and questionnaires for lifestyle, fatigue states, and depression states. The design of this study is a cross-sectional observational study. The setting of this study is a medical health checkup program in a general hospital. This study was conducted with 1,430 Japanese (867 men and 563 women), 20 to 78 years of age. We classified participants who complained of fatigue according to the case definition of CFS proposed by the Centers for Disease Control and Prevention in the USA in 1994. Alcohol, caffeine, catechin and total polyphenol consumption, smoking status, sleep duration, and physical activity were evaluated using questionnaires. The prevalence of CFS was 1.0% (95% CI 0.5-1.6%) of a community population in Japan. Although various lifestyle factors of the participants with CFS were similar to those without chronic fatigue, average sleep duration was significantly shorter among the participants with CFS (5.5 ± 0.8 h) compared to those without chronic fatigue (6.3 ± 0.9 h, P < 0.001). Proportion at subjects having average sleep duration of less than 6 h was 64.3% among the participants with CFS in contrast to only 15.0% in those without chronic fatigue (P < 0.001). Among the eight case-defining symptoms, "Unrefreshing sleep" had high sensitivity and high specificity for screening CFS in Japanese population (92.9% and 87.8%, respectively). The average sleep duration was notably shorter in Japanese suffering from CFS. Further longitudinal study is needed to evaluate the possibility of extreme short sleep duration as a major cause of CFS in Japan.

Daily physical activity of patients with the chronic fatigue syndrome: a systematic review

Objective: To give an overview of the physical activity level of patients with chronic fatigue syndrome in comparison with asymptomatic controls.

Data sources: MEDLINE, Web of Science, EMBASE, PsycINFO, Picarta, the Cochrane Controlled Trial Register that is included in the Cochrane Library and reference tracking.

Review methods: A systematic literature search was conducted focusing on studies concerning physical activity levels of patients with chronic fatigue syndrome compared to controls. A meta-analysis was performed to pool data of the studies.

Results: Seventeen studies were included with 22 different comparisons between patients with chronic fatigue syndrome and controls. Fourteen studies, including 18 comparisons, showed lower physical activity levels in patients with chronic fatigue syndrome as compared to controls. Four studies, including four comparisons, showed no differences between both groups. The meta-analysis included seven studies and showed a daily physical activity level in patients with chronic fatigue syndrome of only 68% of the physical activity level observed in control subjects. The pooled mean coefficient of variation in patients with chronic fatigue syndrome was higher as compared to control subjects (34.3% versus 31.5%), but this difference did not reach significance.

Conclusion: Patients with chronic fatigue syndrome appear to be less physically active compared with asymptomatic controls. There is no difference in variation of physical activity levels between patients with chronic fatigue syndrome and healthy control subjects, but the validity and reliability of some methods of measuring physical activity is questionable or unknown.

Perspectives on fatigue from the study of chronic fatigue syndrome and related conditions

Fatigue is a symptom whose causes are protean and whose phenotype includes physical, mood, and behavioral components. Chronic fatigue syndrome (CFS) is an illness that has strong biological underpinnings and no definite etiology. Diagnostic criteria established by the Centers for Disease Control and Prevention have helped classify CFS as an overlap of mood, behavioral, and biological components. These include the presence of fatigue for more than 6 months associated with a diminution of functional activity and somatic symptoms, and pain not attributable to a specific diagnosis or disease. Four of the following criteria need to be present: sore throat, impaired memory or cognition, unrefreshing sleep, postexertional fatigue, tender glands, aching stiff muscles, joint pain, and headaches. Many researchers have observed that CFS shares features in common with other somatic syndromes, including irritable bowel syndrome, fibromyalgia, and temporomandibular joint dysfunction. Correlations between inflammation and infection, augmented sensory processing, abnormalities of neurotransmitters, nerve growth factors, low levels of serotonin and norepinephrine, abnormalities of homeostasis of the stress system, and autonomic dysfunction may be hallmarks of CFS. The relative contributions of each of these abnormalities to the profound fatigue associated with CFS need to be explored further to better evaluate and treat the syndrome.

Effect of human placental extract on menopausal symptoms, fatigue, and risk factors for cardiovascular disease in middle-aged Korean women

OBJECTIVE

In Korea, human placental extract (HPE) has recently been used to treat various diseases (chronic liver diseases, menopause syndrome, chronic fatigue, skin pigment diseases, etc.), but evidence-based studies are not yet sufficient. The aim of this study was to examine the effects of HPE on menopausal symptoms, fatigue, and risk factors for cardiovascular disease in middle-aged Korean women in a randomized controlled trial.

DESIGN

Korean women, aged 40 to 64 years, with menopausal symptoms and fatigue were recruited as participants. The women were randomly assigned to a placebo group or an HPE group. The HPE group received subcutaneous injections of HPE in the abdomen for 8 weeks, whereas the placebo group received normal saline. Then, the Menopause Rating Scale, and Fatigue Severity Scale, and Visual Analog Scale were administered, and risk factors for cardiovascular disease were assessed.

RESULTS

The Menopause Rating Scale total baseline score was not different between the two groups; however, the score of the HPE group decreased significantly at 8 weeks compared with that of the placebo group (P = 0.033). Fatigue Severity Scale and Visual Analog Scale scores of the placebo group did not change, whereas the scores of the HPE group decreased significantly during the study period (Fatigue Severity Scale, P = 0.002; Visual Analog Scale, P = 0.001). The baseline 17beta-estradiol level was not significantly different between the two groups, but the 17beta-estradiol level of the HPE group was significantly increased at 8 weeks compared with that of the placebo group (P = 0.031). No changes in risk factors for cardiovascular disease were observed in either group.

CONCLUSIONS

Menopausal symptoms and fatigue in middle-aged Korean women improved after 8 weeks of HPE treatment, whereas risk factors for cardiovascular disease did not change during the study period.

The relationship between chronic fatigue and somatization syndrome: a general population survey

OBJECTIVE

The objective of this study was to assess the prevalence of chronic fatigue (CF) and its association with somatization syndrome [Somatization Syndrome Index (SSI) 4/6: >/=4 somatoform symptoms in men, 6 in women] in the general population.

METHODS

A representative sample of the German population (N=2412) completed a fatigue questionnaire and a screening instrument for current somatoform symptoms (Screening for Somatoform Symptoms 7).

RESULTS

The prevalence rate of CF was 6.1% (n=147). Females were affected significantly more often as compared with males (7% vs. 5.1%). The mean number of somatoform symptoms was higher in CF cases than in control subjects without CF (11 vs. 2; P<.001). Seventy-two percent of the subjects with CF fulfilled the SSI4/6 criterion for somatization syndrome. Quality of life (EUROHIS-QOL and 8-item Short-Form Health Survey) and well-being (5-item WHO Well-Being Index) were markedly decreased in CF and SSI4/6. The results of regression analyses suggest that fatigue and somatization severity had a similar impact on quality of life.

CONCLUSIONS

The results suggest that CF is relevant in the general population. Its substantial overlap with somatization syndrome supports the hypothesis that the two syndromes are only partially different manifestations of the same underlying processes.

Gene expression profile exploration of a large dataset on chronic fatigue syndrome

OBJECTIVE

To gain understanding of the molecular basis of chronic fatigue syndrome (CFS) through gene expression analysis using a large microarray data set in conjunction with clinically administrated questionnaires.

METHOD

Data from the Wichita (KS, USA) CFS Surveillance Study was used, comprising 167 participants with two self-report questionnaires (multidimensional fatigue inventory [MFI] and Zung depression scale [Zung]), microarray data, empiric classification, and others. Microarray data was analyzed using bioinformatics tools from ArrayTrack.

RESULTS

Correspondence analysis was applied to the MFI questionnaire to select the 23 samples having either the most or the least fatigue, and to the Zung questionnaire to select the 26 samples having either the most or least depression; ten samples were common, resulting in a total of 39 samples. The MFI and Zung-based CFS/non-CFS (NF) classifications on the 39 samples were consistent with the empiric classification. Two differentially-expressed gene lists were determined, 188 fatigue-related genes and 164 depression-related genes, which shared 24 common genes and involved 11 common pathways. Principal component analysis based on 24 genes clearly separates 39 samples with respect to their likelihood to be CFS. Most of the 24 genes are not previously reported for CFS, yet their functions are consistent with the prevailing model of CFS, such as immune response, apoptosis, ion channel activity, signal transduction, cell-cell signaling, regulation of cell growth and neuronal activity. Hierarchical cluster analysis was performed based on 24 genes to classify 128 (=167-39) unassigned samples. Several of the 11 identified common pathways are supported by earlier findings for CFS, such as cytokine-cytokine receptor interaction and neuroactive ligand-receptor interaction. Importantly, most of the 11 common pathways are interrelated, suggesting complex biological mechanisms associated with CFS.

CONCLUSION

Bioinformatics is critical in this study to select definitive sample groups, analyze gene expression data and gain insight into biological mechanisms. The 24 identified common genes and 11 common pathways could be important in future studies of CFS at the molecular level.