Chronic fatigue syndrome: occupation, medical utilization, and subtypes in a community-based sample

Two symptoms can accurately identify post-exertional malaise in myalgic encephalomyelitis/chronic fatigue syndrome

BACKGROUND

Post-exertional malaise (PEM) is the hallmark symptom of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) yet its diverse manifestations make it difficult to recognize. Brief instruments for detecting PEM are critical for clinical and scientific progress.

OBJECTIVE

To develop a clinical prediction rule for PEM.

METHOD

49 ME/CFS and 10 healthy, sedentary subjects recruited from the community completed two maximal cardiopulmonary exercise tests (CPETs) separated by 24 hours. At five different times, subjects reported symptoms which were then classified into 19 categories. The frequency of symptom reports between groups at each time point was compared using Fisher's exact test. Receiver operating characteristics (ROC) analysis with area under the curve calculation was used to determine the number of different types of symptom reports that were sufficient to differentiate between ME/CFS and sedentary groups. The optimal number of symptoms was determined where sensitivity and specificity of the types of symptom reports were balanced.

RESULTS

At all timepoints, a maximum of two symptoms was optimal to determine differences between groups. Only one symptom was necessary to optimally differentiate between groups at one week following the second CPET. Fatigue, cognitive dysfunction, lack of positive feelings/mood and decrease in function were consistent predictors of ME/CFS group membership across timepoints.

CONCLUSION

Inquiring about post-exertional cognitive dysfunction, decline in function, and lack of positive feelings/mood may help identify PEM quickly and accurately. These findings should be validated with a larger sample of patients.

Long COVID and chronic fatigue syndrome: A survey of elderly female survivors in Egypt

OBJECTIVES

This study aimed to investigate post-COVID-19 symptoms amongst elderly females and whether they could be a risk factor for developing chronic fatigue syndrome (CFS) later on.

METHODS

This was a retrospective cross-sectional study, in the form of an online survey. A total of 115 responses were finally included.

RESULTS

The mean age was 73.18 ± 6.42. Eighty-nine reported symptoms in the post-recovery period; of these 54 had no symptoms of CFS, 60 were possible, and only 1 was probable. Fatigue was reported by 66, musculoskeletal symptoms by 56, and sleep problems by 73. Twenty-nine patients visited a doctor's office as a result. Post-recovery symptoms were significantly related to stress, sadness and sleep disturbances. Also, stress, sadness, sleep disturbances, fatigue, cognitive impairment, and recurrent falls were all significantly associated with CFS-like symptoms.

CONCLUSIONS

From our findings, the presence of fatigue, cognitive impairment, stress, sadness, sleep disturbances and recurrent falls in the post-recovery period were all significantly associated with CFS-like symptoms. To conclude it would be reasonable to screen for long COVID and consider the potential for developing CFS later on. Whether it can be a risk factor for developing CFS-like other viral infections will need more larger scale studies to confirm this.

The association of major life events with chronic fatigue

OBJECTIVE

Major life events have been associated with the onset of unexplained chronic fatigue (CF) and with variability in illness course. The purpose of this study was to characterize the associations of major life events with illness status over time.

METHOD

Sentinel measures of clinical status were collected four times over 18 months in a cohort of 99 persons with CF; participants also were interviewed regarding major life events, which were independently rated by observers.

RESULTS

Over time, more major life events attributed to CF predicted a worse clinical course, suggesting that illness-related major life events rather than stressful life events in general are associated with worse clinical status for persons with CF.

CONCLUSION

This study adds to the literature regarding specific types of life events' relationship to illness course, which has implications for the management of CF.

Onset Patterns and Course of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome

Background: Epidemiologic studies of myalgic encephalomyelitis/ chronic fatigue syndrome (ME/CFS) have examined different aspects of this disease separately but few have explored them together. Objective: Describe ME/CFS onset and course in one United States-based cohort. Methods: One hundred and fifty subjects fitting Fukuda 1994 CFS criteria completed a detailed survey concerning the initial and subsequent stages of their illness. Descriptive statistics, graphs, and tables were used to illustrate prevalence and patterns of characteristics. Results: The most common peri-onset events reported by subjects were infection-related episodes (64%), stressful incidents (39%), and exposure to environmental toxins (20%). For 38% of subjects, more than 6 months elapsed from experiencing any initial symptom to developing the set of symptoms comprising their ME/CFS. Over time, the 12 most common symptoms persisted but declined in prevalence, with fatigue, unrefreshing sleep, exertion-related sickness, and flu-like symptoms declining the most (by 20-25%). Conversely, cognitive symptoms changed the least in prevalence, rising in symptom ranking. Pregnancy, menopause, and menstrual cycles exacerbated many women's symptoms. Fatigue-related function was not associated with duration of illness or age; during the worst periods of their illness, 48% of subjects could not engage in any productive activity. At the time of survey, 47% were unable to work and only 4% felt their condition was improving steadily with the majority (59%) describing a fluctuating course. Ninety-seven percent suffered from at least one other illness: anxiety (48%), depression (43%), fibromyalgia (39%), irritable bowel syndrome (38%), and migraine headaches (37%) were the most diagnosed conditions. Thirteen percent came from families where at least one other first-degree relative was also afflicted, rising to 27% when chronic fatigue of unclear etiology was included. Conclusions: This paper offers a broad epidemiologic overview of one ME/CFS cohort in the United States. While most of our findings are consistent with prior studies, we highlight underexamined aspects of this condition (e.g., the evolution of symptoms) and propose new interpretations of findings. Studying these aspects can offer insight and solutions to the diagnosis, etiology, pathophysiology, and treatment of this condition.

Deconstructing post-exertional malaise in myalgic encephalomyelitis/ chronic fatigue syndrome: A patient-centered, cross-sectional survey

BACKGROUND

Post-exertional malaise (PEM) is considered to be the hallmark characteristic of myalgic encephalomyelitis/ chronic fatigue syndrome (ME/CFS). Yet, patients have rarely been asked in formal studies to describe their experience of PEM.

OBJECTIVES

To describe symptoms associated with and the time course of PEM.

METHODS

One hundred and fifty subjects, diagnosed via the 1994 Fukuda CFS criteria, completed a survey concerning 11 symptoms they could experience after exposure to two different types of triggers. We also inquired about onset and duration of PEM and included space for subjects to write in any additional symptoms. Results were summarized with descriptive statistics; McNemar's, paired t-, Fisher's exact and chi-square goodness-of-fit tests were used to assess for statistical significance.

RESULTS

One hundred and twenty-nine subjects (90%) experienced PEM with both physical and cognitive exertion and emotional distress. Almost all were affected by exertion but 14 (10%) reported no effect with emotion. Fatigue was the most commonly exacerbated symptom but cognitive difficulties, sleep disturbances, headaches, muscle pain, and flu-like feelings were cited by over 30% of subjects. Sixty percent of subjects experienced at least one inflammatory/ immune-related symptom. Subjects also cited gastrointestinal, orthostatic, mood-related, neurologic and other symptoms. Exertion precipitated significantly more symptoms than emotional distress (7±2.8 vs. 5±3.3 symptoms (median, standard deviation), p<0.001). Onset and duration of PEM varied for most subjects. However, 11% reported a consistent post-trigger delay of at least 24 hours before onset and 84% endure PEM for 24 hours or more.

CONCLUSIONS

This study provides exact symptom and time patterns for PEM that is generated in the course of patients' lives. PEM involves exacerbation of multiple, atypical symptoms, is occasionally delayed, and persists for extended periods. Highlighting these characteristics may improve diagnosis of ME/CFS. Incorporating them into the design of future research will accelerate our understanding of ME/CFS.

Alexithymia and anesthetic bladder capacity in interstitial cystitis/bladder pain syndrome

OBJECTIVE

In contrast to the inconsistent results of organic causes, it has been found that psychological risk factors are reliably related to functional somatic syndromes (FSSs), including interstitial cystitis/bladder pain syndrome (IC/BPS). Compared to patients with acute cystitis, a subgroup of IC/BPS patients with a history of childhood relational trauma reported intensified unregulated affective states (i.e., anxiety and depression) and trauma-related psychopathology (i.e., dissociation). Nevertheless, it remains unknown whether psychosocial risk factors can be separated from bladder-centric factors. This study aimed to verify whether psychosocial factors such as alexithymia, which is a key psychological factor of FSSs, are less likely to be linked to a low bladder capacity in patients with IC/BPS.

METHODS

Ninety-four female IC/BPS patients were recruited from the outpatient departments of urology, obstetrics, and gynecology. Anxiety, depression, dissociation, childhood relational trauma, and alexithymia were assessed using standardized scales, and anesthetic bladder capacity was examined by cystoscopic hydrodistention.

RESULTS

Positive correlations were found between anesthetic bladder capacity and the psychosocial variables, including alexithymia. An increased bladder capacity was associated with anxiety, dissociation, and childhood relational trauma, and a combination of high cognitive and low affective alexithymia mediated the correlations between bladder capacity and the psychosocial variables.

CONCLUSIONS

Psychosocial variables that are associated with an aversive childhood relational environment and affect dysregulation may constitute a pathogenic trajectory that differs from bladder-centric defects such as a lower bladder capacity. The findings of this study support the notion that IC/BPS in some patients may be due to an FSS.

Cost-Utility of Home-Based Fatigue Self-Management versus Usual Care for the Treatment of Chronic Fatigue Syndrome

Background

Chronic fatigue syndrome is a complex chronic condition with large negative impact on patients' function and quality of life. Efficacy and cost-effectiveness of cognitive behavioral intervention remain inconclusive.

Objective

To evaluate the cost-utility of a home-based fatigue self-management (FSM) intervention as compared to usual care among primary care patients with severe chronic fatigue syndrome (CFS).

Methods

An economic evaluation alongside of a randomized controlled study design was used. Cost and utility data were collected from 137 patients with severe CFS at baseline and 1-year follow-up. The FSM group (n=89) received self-delivered cognitive behavioral self-management intervention and the usual care group (n=48) received regular medical care. Cost was measured by total costs (direct, indirect, and intervention costs) during the follow-up period. Quality-adjusted life years (QALY), as the utility measure, were derived from the Medical Outcomes Survey Short Form-36. A societal perspective was adopted. Bootstrapped incremental cost-utility ratios (ICURs) and net monetary benefit were calculated as measures of cost-effectiveness.

Results

Baseline individual characteristics were similar between the two groups. The intervention was well-received by the participants with only minimum attrition. At the end of one year post-intervention, FSM dominated usual care in terms of ICUR in both the intention-to-treat analysis and the complete-cases-only analysis. Net monetary benefit analysis showed that FSM has higher probability of achieving positive net monetary across the entire range of possible societal willingness-to-pay for fatigue symptom management.

CONCLUSIONS

In primary care patients with severe CFS, the low-cost FSM appears to be a cost-effective treatment.

Cost-effectiveness of chronic fatigue self-management versus usual care: a pilot randomized controlled trial

BACKGROUND

Fatigue is a common yet difficult to treat condition in primary care. The objective of this study is to evaluate the cost-effectiveness of a brief cognitive behavioral therapy (CBT) based fatigue self-management (FSM) intervention as compared to usual care among patients with chronic fatigue in primary care.

METHODS

An economic evaluation alongside of a parallel randomized controlled study design was used. Computer-generated variable-sized block randomization plan was used to assign patients into treatment groups and data collection staff were blinded to group assignments. Patients aged between 18 and 65 years with at least six months of persistent fatigue and no medical or psychiatric exclusions were enrolled from a large primary care practice in Stony Brook, New York. The FSM group (n = 37) received two sessions of a nurse-delivered, fatigue self-management protocol and a self-help book and the usual care group (n = 36) received regular medical care. The effectiveness measure was the Fatigue Severity Scale and the cost measure was total health care expenditures derived from monthly health services use diaries during follow-up. A societal perspective was adopted and bootstrapped incremental cost-effectiveness ratios (ICERs) and net monetary benefit (NMB) were calculated as measures of cost-effectiveness.

RESULTS

The ICER for FSM was -$$2358, indicating that FSM dominates UC and it may generate societal cost savings as compared to usual care. Complete case analysis yielded smaller ICER (-$1199) with greater uncertainties. Net monetary benefit analysis showed that FSM has a probability of 0.833 (95% CI: 0.819, 0.847) to achieve positive NMB and the favorable results were not sensitive to assumptions about informal care or treatment costs.

CONCLUSION

This economic evaluation found initial evidence that a two-session brief CBT-based FSM may be cost-effective as compared to usual care over 12 months. The FSM intervention is potentially a promising intervention for chronic fatigue patients in primary care. Additional research is needed to examine the reproducibility and generalizability of these findings.

TRIAL REGISTRATION

ClinicalTrials.gov (NCT00997451, March 28, 2009).

Chronic fatigue syndrome following infections in adolescents

PURPOSE OF REVIEW

To review the recent epidemiology, pathophysiology, and treatment of postinfectious chronic fatigue syndrome (CFS) in adolescents.

RECENT FINDINGS

Thirteen percent of adolescents (mainly women) met the criteria for CFS 6 months following infectious mononucleosis; the figure was 7% at 12 months and 4% at 24 months. Peak work capacity, activity level, orthostatic intolerance, salivary cortisol, and natural killer cell number and function were similar between adolescents with CFS following infectious mononucleosis and recovered controls. Autonomic system, oxygen consumption, peak oxygen pulse, psychological and cytokine network differences were documented between those who recovered and those who did not.

SUMMARY

The prognosis of CFS is better in adolescents than in adults. Activity level, exercise tolerance, and orthostatic testing could not distinguish patients with CFS from adolescents who have recovered from infectious mononucleosis (controls), while certain cytokine network analyses, life stress factors, and autonomic symptoms could.

Evidence for a heritable predisposition to Chronic Fatigue Syndrome

Background

Chronic Fatigue Syndrome (CFS) came to attention in the 1980s, but initial investigations did not find organic causes. Now decades later, the etiology of CFS has yet to be understood, and the role of genetic predisposition in CFS remains controversial. Recent reports of CFS association with the retrovirus xenotropic murine leukemic virus-related virus (XMRV) or other murine leukemia related retroviruses (MLV) might also suggest underlying genetic implications within the host immune system.

Methods

We present analyses of familial clustering of CFS in a computerized genealogical resource linking multiple generations of genealogy data with medical diagnosis data of a large Utah health care system. We compare pair-wise relatedness among cases to expected relatedness in the Utah population, and we estimate risk for CFS for first, second, and third degree relatives of CFS cases.

Results

We observed significant excess relatedness of CFS cases compared to that expected in this population. Significant excess relatedness was observed for both close (p <0.001) and distant relationships (p = 0.010). We also observed significant excess CFS relative risk among first (2.70, 95% CI: 1.56-4.66), second (2.34, 95% CI: 1.31-4.19), and third degree relatives (1.93, 95% CI: 1.21-3.07).

Conclusions

These analyses provide strong support for a heritable contribution to predisposition to Chronic Fatigue Syndrome. A population of high-risk CFS pedigrees has been identified, the study of which may provide additional understanding.

A natural history study of chronic fatigue syndrome

OBJECTIVE

There is a need for natural history chronic fatigue syndrome (CFS) studies from random, community-based, multi-ethnic populations.

DESIGN

The present study examined the course of CFS from Wave 1 to Wave 2, which spanned over a ten year period of time, and, assessed whether socio-environmental and symptomatology factors were associated with CFS status over the ten year period.

RESULTS

There was relative stability over time on critical measures of disability, fatigue, support, optimism and coping over time. One cardinal symptoms of CFS, post-exertional malaise, best differentiated the CFS group from the others. By Wave 2, of the original group of 32 individuals diagnosed with CFS, 4 had died, and 24 were found and agreed to be re-evaluated, and of this group, 16 continued to have CFS, 5 developed exclusionary illnesses, 2 were classified as Idiopathic chronic fatigue, and one had remitted.

CONCLUSIONS

The current study found that over time in a community-based sample, unbiased by help seeking behavior the CFS group remained rather ill with a variety of different conditions over time.

Use of medications by people with chronic fatigue syndrome and healthy persons: a population-based study of fatiguing illness in Georgia

Background

Chronic fatigue syndrome (CFS) is a debilitating condition of unknown etiology and no definitive pharmacotherapy. Patients are usually prescribed symptomatic treatment or self-medicate. We evaluated prescription and non-prescription drug use among persons with CFS in Georgia and compared it to that in non-fatigued Well controls and also to chronically Unwell individuals not fully meeting criteria for CFS.

Methods

A population-based, case-control study. To identify persons with possible CFS-like illness and controls, we conducted a random-digit dialing telephone screening of 19,807 Georgia residents, followed by a detailed telephone interview of 5,630 to identify subjects with CFS-like illness, other chronically Unwell, and Well subjects. All those with CFS-like illness (n = 469), a random sample of chronically Unwell subjects (n = 505), and Well individuals (n = 641) who were age-, sex-, race-, and geographically matched to those with CFS-like illness were invited for a clinical evaluation and 783 participated (48% overall response rate). Clinical evaluation identified 113 persons with CFS, 264 Unwell subjects with insufficient symptoms for CFS (named ISF), and 124 Well controls; the remaining 280 subjects had exclusionary medical or psychiatric conditions, and 2 subjects could not be classified. Subjects were asked to bring all medications taken in the past 2 weeks to the clinic where a research nurse viewed and recorded the name and the dose of each medication.

Results

More than 90% of persons with CFS used at least one drug or supplement within the preceding two weeks. Among users, people with CFS used an average of 5.8 drugs or supplements, compared to 4.1 by ISF and 3.7 by Well controls. Persons with CFS were significantly more likely to use antidepressants, sedatives, muscle relaxants, and anti-acids than either Well controls or the ISF group. In addition, persons with CFS were significantly more likely to use pain-relievers, anti-histamines and cold/sinus medications than were Well controls.

Conclusion

Medical care providers of patients with chronic fatigue syndrome should be aware of polypharmacy as a problem in such patients, and the related potential iatrogenic effects and drug interactions.

Psychiatric comorbidity in persons with chronic fatigue syndrome identified from the Georgia population

OBJECTIVE

To compare the prevalence of psychiatric disorders in persons with chronic fatigue syndrome (CFS) identified from the general population and a chronically ill group of people presenting with subsyndromic CFS-like illness ("insufficient symptoms or fatigue" (ISF)). Previous studies in CFS patients from primary and tertiary care clinics have found high rates of psychiatric disturbance, but this may reflect referral bias rather than true patterns of comorbidity with CFS.

METHODS

We used random digit dialing to identify unwell individuals. A detailed telephone interview identified those with CFS-like illness. These individuals participated in a 1-day clinical evaluation to confirm CFS or ISF status. We identified 113 cases of CFS and 264 persons with ISF. To identify current and lifetime psychiatric disorders, participants completed the Structured Clinical Interview for DSM-IV.

RESULTS

Sixty-four persons (57%) with CFS had at least one current psychiatric diagnosis, in contrast to 118 persons (45%) with ISF. One hundred one persons (89%) with CFS had at least one lifetime psychiatric diagnosis compared with 208 persons (79%) with ISF. Of note, only 11 persons (9.8%) with CFS and 25 persons (9.5%) with ISF reported having seen a mental healthcare specialist during the past 6 months.

CONCLUSIONS

Our findings indicate that current and lifetime psychiatric disorders commonly accompany CFS in the general population. Most CFS cases with comorbid psychiatric conditions had not sought appropriate help during the past 6 months. These results demonstrate an urgent need to address psychiatric disorders in the clinical care of CFS cases.

A comparison of patients with chronic fatigue syndrome in two "ideologically" contrasting clinics

Aim of the present study was to compare chronic fatigue syndrome (CFS) patients, attending 2 "ideologically" contrasting clinics for CFS, on various patient and illness characteristics. Fifty-nine CFS patients of each clinic, located in Leuven and Brussels (Belgium), participated. Patients did not differ with regard to age, levels of fatigue, psychopathology, and self-efficacy. However, patients from the psychosocially-oriented clinic had a lower level of education, reported more progressive illness onset, and attributed their illness more to psychological causes. Patients in the biologically-oriented clinic reported more pain, and showed higher levels of social functioning, motivation and vitality, as well as fewer limitations related to emotional problems. It is concluded that CFS patients attending the 2 clinics could not be distinguished along dualistic biological/psychosocial lines, but those reporting sudden illness onset and making somatic attributions were more likely to be represented in the biologically-oriented clinic.

Barriers to healthcare utilization in fatiguing illness: a population-based study in Georgia

BACKGROUND

The purpose of this study was to determine the prevalence of barriers to healthcare utilization in persons with fatiguing illness and describe its association with socio-demographics, the number of health conditions, and frequency of healthcare utilization. Furthermore, we sought to identify what types of barriers interfered with healthcare utilization and why they occurred.

METHODS

In a cross-sectional population-based survey, 780 subjects, 112 of them with chronic fatigue syndrome (CFS), completed a healthcare utilization questionnaire. Text analysis was used to create the emerging themes from verbatim responses regarding barriers to healthcare utilization. Multiple logistic regression was performed to examine the association between barriers to healthcare utilization and other factors.

RESULTS

Forty percent of subjects reported at least one barrier to healthcare utilization. Of 112 subjects with CFS, 55% reported at least one barrier to healthcare utilization. Fatiguing status, reported duration of fatigue, insurance, and BMI were significant risk factors for barriers to healthcare utilization. After adjusting for socio-demographics, medication use, the number of health problems, and frequency of healthcare utilization, fatiguing status remained significantly associated with barriers to healthcare utilization. Subjects with CFS were nearly 4 times more likely to forego needed healthcare during the preceding year than non-fatigued subjects while those with insufficient fatigue (ISF) were nearly 3 times more likely.Three domains emerged from text analysis on barriers to healthcare utilization: 1) accessibility; 2) knowledge-attitudes-beliefs (KABs); and, 3) healthcare system. CFS and reported duration of fatigue were significantly associated with each of these domains. Persons with CFS reported high levels of healthcare utilization barriers for each domain: accessibility (34%), healthcare system (25%), and KABs (19%). In further examination of barrier domains to healthcare utilization, compared to non-fatigued persons adjusted ORs for CFS having "accessibility", "KAB" and "Healthcare System" barrier domains decreased by 40%, 30%, and 19%, respectively.

CONCLUSION

Barriers to healthcare utilization pose a significant problem in persons with fatiguing illnesses. Study results suggested two-fold implications: a symptom-targeted model focusing on symptoms associated with fatigue; and an interactive model requiring efforts from patients and providers to improve interactions between them by reducing barriers in accessibility, KABs, and healthcare system.

Alterations in diurnal salivary cortisol rhythm in a population-based sample of cases with chronic fatigue syndrome

OBJECTIVE

To examine diurnal salivary cortisol rhythms and plasma IL-6 concentrations in persons with chronic fatigue syndrome (CFS), persons not fulfilling a diagnosis of CFS (we term them cases with insufficient symptoms or fatigue, ISF) and nonfatigued controls (NF). Previous studies of CFS patients have implicated the hypothalamic-pituitary-adrenal axis and the immune system in the pathophysiology of CFS, although results have been equivocal.

METHODS

Twenty-eight people with CFS, 35 persons with ISF, and 39 NF identified from the general population of Wichita, Kansas, were admitted to a research ward for 2 days. Saliva was collected immediately on awakening (6:30 AM), at 08:00 AM, 12 noon, 4:00 PM, 8:00 PM and at bedtime (10:00 PM) and plasma was obtained at 7:30 AM. Salivary cortisol concentrations were assessed using radioimmunoassay, and plasma IL-6 was measured using sandwich enzyme-linked immunosorbent assay.

RESULTS

People with CFS demonstrated lower salivary cortisol concentrations in the morning and higher salivary cortisol concentrations in the evening compared with both ISF and NF groups indicating a flattening of the diurnal cortisol profile. Mean plasma IL-6 concentrations were highest in CFS compared with the other groups, although these differences were no longer significant after controlling for BMI. Attenuated decline of salivary cortisol concentrations across the day and IL-6 concentration were associated with fatigue symptoms in CFS.

CONCLUSIONS

These results suggest an altered diurnal cortisol rhythm and IL-6 concentrations in CFS cases identified from a population-based sample.

Attenuated morning salivary cortisol concentrations in a population-based study of persons with chronic fatigue syndrome and well controls

CONTEXT

A substantial body of research on the pathophysiology of chronic fatigue syndrome (CFS) has focused on hypothalamic-pituitary-adrenal axis dysregulation. The cortisol awakening response has received particular attention as a marker of hypothalamic-pituitary-adrenal axis dysregulation.

OBJECTIVE

The objective of the current study was to evaluate morning salivary cortisol profiles in persons with CFS and well controls identified from the general population.

DESIGN AND SETTING

We conducted a case-control study at an outpatient research clinic. CASES AND OTHER PARTICIPANTS: We screened a sample of 19,381 residents of Georgia and identified those with CFS and a matched sample of well controls. Seventy-five medication-free CFS cases and 110 medication-free well controls provided complete sets of saliva samples.

MAIN OUTCOME MEASURES

We assessed free cortisol concentrations in saliva collected on a regular workday immediately upon awakening and 30 and 60 min after awakening.

RESULTS

There was a significant interaction effect, indicating different profiles of cortisol concentrations over time between groups, with the CFS group showing an attenuated morning cortisol profile. Notably, we observed a sex difference in this effect. Women with CFS exhibited significantly attenuated morning cortisol profiles compared with well women. In contrast, cortisol profiles were similar in men with CFS and male controls.

CONCLUSIONS

CFS was associated with an attenuated morning cortisol response, but the effect was limited to women. Our results suggest that a sex difference in hypocortisolism may contribute to increased risk of CFS in women.

Prevalence of chronic fatigue syndrome in metropolitan, urban, and rural Georgia

Background

Chronic fatigue syndrome (CFS) is a debilitating illness with no known cause or effective therapy. Population-based epidemiologic data on CFS prevalence are critical to put CFS in a realistic context for public health officials and others responsible for allocating resources.

Methods

Based on a random-digit dialing survey we ascertained CFS cases and controls to estimate the prevalence of CFS in metropolitan, urban, and rural populations of Georgia. This report focuses on the 5,623 of 19,381 respondents ages 18 to 59 years old. Fatigued (2,438), randomly selected unwell not fatigued (1,429) and randomly selected well (1,756) respondents completed telephone questionnaires concerning fatigue, other symptoms, and medical history. Subsets of those identified by interview as having CFS-like illness (292), chronic unwellness which was not CFS-like (268 – randomly selected), and well subjects (223, matched to those with CFS-like illness on sex, race, and age) completed a clinical evaluation.

Results

We estimated that 2.54% of persons 18 to 59 years of age suffered from CFS. There were no significant differences in prevalence of CFS between metropolitan, urban or rural populations or between white and black residents of the three regions. However, there were significant differences in female-to-male ratios of prevalence across the strata (metropolitan female: male 11.2 : 1, urban 1.7 : 1, rural 0.8 : 1).

Conclusion

We estimated that 2.54% of the Georgia population suffers from CFS, which is 6- to 10-fold higher than previous population-based estimates in other geographic areas. These differences may reflect broader screening criteria and differences in the application of the case definition. However, we cannot exclude the possibility that CFS prevalence may be higher in Georgia than other areas where it has been measured. Although the study did not identify differences in overall prevalence between metropolitan, urban, and rural Georgia populations, it did suggest the need for additional stratified analyses by geographic strata.

Chronic fatigue syndrome--a clinically empirical approach to its definition and study

BACKGROUND

The lack of standardized criteria for defining chronic fatigue syndrome (CFS) has constrained research. The objective of this study was to apply the 1994 CFS criteria by standardized reproducible criteria.

METHODS

This population-based case control study enrolled 227 adults identified from the population of Wichita with: (1) CFS (n = 58); (2) non-fatigued controls matched to CFS on sex, race, age and body mass index (n = 55); (3) persons with medically unexplained fatigue not CFS, which we term ISF (n = 59); (4) CFS accompanied by melancholic depression (n = 27); and (5) ISF plus melancholic depression (n = 28). Participants were admitted to a hospital for two days and underwent medical history and physical examination, the Diagnostic Interview Schedule, and laboratory testing to identify medical and psychiatric conditions exclusionary for CFS. Illness classification at the time of the clinical study utilized two algorithms: (1) the same criteria as in the surveillance study; (2) a standardized clinically empirical algorithm based on quantitative assessment of the major domains of CFS (impairment, fatigue, and accompanying symptoms).

RESULTS

One hundred and sixty-four participants had no exclusionary conditions at the time of this study. Clinically empirical classification identified 43 subjects as CFS, 57 as ISF, and 64 as not ill. There was minimal association between the empirical classification and classification by the surveillance criteria. Subjects empirically classified as CFS had significantly worse impairment (evaluated by the SF-36), more severe fatigue (documented by the multidimensional fatigue inventory), more frequent and severe accompanying symptoms than those with ISF, who in turn had significantly worse scores than the not ill; this was not true for classification by the surveillance algorithm.

CONCLUSION

The empirical definition includes all aspects of CFS specified in the 1994 case definition and identifies persons with CFS in a precise manner that can be readily reproduced by both investigators and clinicians.

Orthostatic instability in a population-based study of chronic fatigue syndrome

PURPOSE

Autonomic nervous system dysfunction has been suggested as involved in the pathophysiology of chronic fatigue syndrome. This population-based case control study addressed the potential association between orthostatic instability (one sign of dysautonomia) and chronic fatigue syndrome.

SUBJECTS AND METHODS

Fifty-eight subjects who fulfilled criteria of the 1994 chronic fatigue syndrome research case definition and 55 healthy controls participated in a 2-day inpatient evaluation. Subjects had been identified during a 4-year population-based chronic fatigue syndrome surveillance study in Wichita, Kan. The present study evaluated subjects' current medical and psychiatric status, reviewed past medical/psychiatric history and medication use, used a stand-up test to screen for orthostatic instability, and conducted a head-up tilt table test to diagnose orthostatic instability.

RESULTS

No one manifested orthostatic instability in the stand-up test. The head-up tilt test elicited orthostatic instability in 30% of eligible chronic fatigue syndrome subjects (all with postural orthostatic tachycardia) and 48% of controls (50% with neurally mediated hypotension); intolerance was present in only nonfatigued (n=7) subjects. Neither fatigue nor illness severity were associated with outcome.

CONCLUSIONS

Orthostatic instability was similar in persons with chronic fatigue syndrome and nonfatigued controls subjects recruited from the general Wichita population. Delayed responses to head-up tilt tests were common and may reflect hydration status. These findings suggest reappraisal of primary dysautonomia as a factor in the pathogenesis of chronic fatigue syndrome.

Chronic fatigue syndrome: the need for subtypes

Chronic fatigue syndrome (CFS) is an important condition confronting patients, clinicians, and researchers. This article provides information concerning the need for appropriate diagnosis of CFS subtypes. We first review findings suggesting that CFS is best conceptualized as a separate diagnostic entity rather than as part of a unitary model of functional somatic distress. Next, research involving the case definitions of CFS is reviewed. Findings suggest that whether a broad or more conservative case definition is employed, and whether clinic or community samples are recruited, these decisions will have a major influence in the types of patients selected. Review of further findings suggests that subtyping individuals with CFS on sociodemographic, functional disability, viral, immune, neuroendocrine, neurology, autonomic, and genetic biomarkers can provide clarification for researchers and clinicians who encounter CFS' characteristically confusing heterogeneous symptom profiles. Treatment studies that incorporate subtypes might be particularly helpful in better understanding the pathophysiology of CFS. This review suggests that there is a need for greater diagnostic clarity, and this might be accomplished by subgroups that integrate multiple variables including those in cognitive, emotional, and biological domains.