Stephanie McManimen

Variability in symptoms complicates utility of case definitions

Background: Ambiguities in case definitions have created difficulties in replicating findings and estimating the prevalence rates for chronic fatigue syndrome (CFS) and Myalgic Encephalomyelitis (ME). Purpose: The current study examined differences in occurrence rates for CFS and ME cardinal symptoms (i.e. post-exertional malaise, unrefreshing sleep, and neurocognitive deficits). Results: Findings indicated that there is a wide range of occurrence rates on critical symptoms of the case definition, suggesting that either the types of patients recruited differ in various settings or the questions assessing core symptoms vary in their wording or criteria among different researchers. Conclusions: The polythetic nature of the case definition may contribute to the wide ranges of symptom occurrence that was found. In order to increase assessed reliability of the symptoms and case definitions, there is a need to better standardize data collection methods and operationalization of symptoms. This solution would reduce the heterogeneity often seen in populations of CFS patients.

Clinical criteria versus a possible research case definition in chronic fatigue syndrome/myalgic encephalomyelitis

ABSTRACT Background: The Institute of Medicine (IOM) recently developed clinical criteria for what had been known as chronic fatigue syndrome. Given the broad nature of the clinical IOM criteria, there is a need for a research definition that would select a more homogenous and impaired group of patients than the IOM clinical criteria. At the present time, it is unclear what will serve as the research definition. Purpose: The current study focused on a research definition which selected homebound individuals who met the four IOM criteria, excluding medical and psychiatric co-morbidities. Methods: Our research criteria were compared to those participants meeting the IOM criteria. Those not meeting either of these criteria sets were placed in a separate group defined by six or more months of fatigue. Data analyzed were from the DePaul Symptom Questionnaire and the 36-item Short-Form Health Survey (SF-36). Due to unequal sample sizes and variances, Welch’s F tests and Games-Howell post-hoc tests were conducted. Results: Using a large database of over 1000 patients from several countries, we found that those meeting a more restrictive research definition were even more impaired and more symptomatic than those meeting criteria for the other two groups. Conclusion: Deciding on a particular research case definition would allow researchers to select more comparable patient samples across settings, and this would represent one of the most significant methodologic advances for this field of study.

Case definitions integrating empiric and consensus perspectives

Background: There has been considerable controversy regarding how to name and define the illnesses known as myalgic encephalomyelitis (ME) and chronic fatigue syndrome (CFS). The Institute of Medicine (IOM) report has proposed new clinical criteria and a new name for this illness, but aspects of these recommendations have been scrutinized by patients and scientists. Purpose: It is possible that both empiric and consensus approaches could be used to help settle some of these diagnostic challenges. Using patient samples collected in the USA, Great Britain, and Norway (N = 556), the current study attempted to categorize patients using more general as well as more restricted case definitions. Results: Overall, the outcomes suggest that there might be four groupings of patients, with the broadest category involving those with chronic fatigue (N = 62), defined by six or more months of fatigue which cannot be explained by medical or psychiatric conditions. A second category involves those patients who have chronic fatigue that can be explained by a medical or psychiatric condition (N = 47). A third category involves more specific criteria that have been posited both by the IOM report, Canadian Clinical Case criteria, ME-ICC criteria and a more empiric approach. These efforts have specified domains of substantial reductions of activity, post-exertional malaise, neurocognitive impairment, and sleep dysfunction (N = 346). Patients with these characteristics were more functionally impaired than those meeting just chronic fatigue criteria, p < .05. Finally, those meeting even more restrictive ME criteria proposed by Ramsay, identified a smaller and even more impaired group, p < .05. Conclusion: It is important that scientists world-wide develop consensus on how to identify and classify patients using clinical and research criteria, and ultimately develop subtypes within such categories.

Patient perceptions of post exertional malaise

ABSTRACT Background: One of the cardinal symptoms of Myalgic Encephalomyelitis (ME) and Chronic Fatigue Syndrome (CFS) is post-exertional malaise (PEM). Almost all ME and CFS case definitions mention this symptom, and there have been several efforts to measure it with self-report items. However, controversy has surrounded how patients feel about the measurement of this symptom. Purpose: The current study presents data on a large patient sample concerning their feelings regarding different aspects of PEM. Results: Findings indicated that the majority of patients did support certain wordings of both the precipitants and consequences of PEM. In addition, considerable approval was also found for a number of ways to phrase items assessing PEM. Overall, findings indicated that screening items from the DePaul Symptom Questionnaire (DSQ) were able to identify 97% of patients, which was higher than any other item. However, the PEM question that was most acceptable from patients was from Ramsay, but other highly endorsed questions were from the ME-ICC and DSQ. Conclusions: As there has not yet been an instrument constructed specifically to measure the complexity of this symptom, these results could be used to develop a prototype for such a questionnaire.

Mortality in patients with myalgic encephalomyelitis and chronic fatigue syndrome

ABSTRACT Background: There is a dearth of research examining mortality in individuals with myalgic encephalomyelitis (ME) and chronic fatigue syndrome (CFS). Some studies suggest there is an elevated risk of suicide and earlier mortality compared to national norms. However, findings are inconsistent. Objective: This study sought to determine if patients are reportedly dying earlier than the overall population from the same cause. Methods: Family, friends, and caregivers of deceased patients were recruited. This study analyzed data including cause and age of death for 56 individuals. Results: The findings suggest patients in this sample are at a significantly increased risk of earlier all-cause (M = 55.9 years) and cardiovascular-related (M = 58.8 years) mortality, and they had a directionally lower age of death for suicide (M = 41.3 years) and cancer (M = 66.3 years) compared to the overall U.S. population [M = 73.5 (all-cause), 77.7 (cardiovascular), 47.4 (suicide), and 71.1 (cancer) years of age]. Conclusions: Results suggest there is an increase in risk for earlier mortality in patients. Due to sample size and over-representation of severely ill patients, the findings should be replicated to determine if the directional differences for suicide and cancer mortality are significantly different from the overall population.

Assessing current functioning as a measure of significant reduction in activity level

ABSTRACT Background: Myalgic encephalomyelitis and chronic fatigue syndrome have case definitions with varying criteria, but almost all criteria require an individual to have a substantial reduction in activity level. Unfortunately, a consensus has not been reached regarding what constitutes substantial reductions. One measure that has been used to measure substantial reduction is the Medical Outcomes Study Short-Form-36 Health Survey (SF-36). [1] Purpose: The current study examined the relationship between the SF-36, a measure of current functioning, and a self-report measure of the percent reduction in hours spent on activities. Results: Findings indicated that select subscales of the SF-36 accurately measure significant reductions in functioning. Further, this measure significantly differentiates patients from controls. Conclusion: Determining what constitutes a significant reduction in activity is difficult because it is subjective to the individual. However, certain subscales of the SF-36 could provide a uniform way to accurately measure and define substantial reductions in functioning.

Suicidal ideation in non-depressed individuals: The effects of a chronic, misunderstood illness:

Chronic illness is a risk factor for suicide but is often explained with depression. Research has shown an increased suicide rate in patients with myalgic encephalomyelitis and chronic fatigue syndrome, but specific risk factors have been unexplored. We qualitatively analyzed responses from 29 patients who endorsed suicidal ideation but did not meet depression criteria. Two themes were developed: (1) feeling trapped and (2) loss of self, loss of others, stigma and conflict. Myalgic encephalomyelitis and chronic fatigue syndrome caused patients severe disability, restructured their lives, and inflicted serious pain. Participants emphasized that they were not depressed, but felt trapped by the lack of treatments available.

Effects of unsupportive social interactions, stigma, and symptoms on patients with myalgic encephalomyelitis and chronic fatigue syndrome

Prior research has found a heightened risk of suicide in patients with myalgic encephalomyelitis (ME) and chronic fatigue syndrome (CFS). It is possible that a number of factors including stigma, unsupportive social interactions, and severe symptoms could lead to the development of depression, suicidal ideation, and heightened risk of suicide in this patient population. Prior studies have indicated that patients often report the legitimacy of their illness being questioned by family, friends, and even their physicians. This study aimed to determine whether stigma experienced, social support, symptomology, and functioning may be associated with depression and endorsement of suicidal ideation (SI) in patients with a self-reported diagnosis of ME or CFS. Findings indicated that participants that endorsed both SI and depression, in contrast to those that did not, experienced more frequent unsupportive social interactions in the form of blame for their illness, minimization of its severity, and social distancing from others. In addition, 7.1% of patients with ME and CFS endorsed SI but do not meet the criteria for clinical depression These findings highlight the importance of stigma and unsupportive social interactions as risk factors for suicidal thoughts or actions among patients with ME and CFS. Community psychologists have an important role to play in helping educate health care professionals and the public to these types of risk factors for patients marginalized by ME and CFS.

The Relationship between Age and Illness Duration in Chronic Fatigue Syndrome

Chronic fatigue syndrome (CFS) is a debilitating illness, but it is unclear if patient age and illness duration might affect symptoms and functioning of patients. In the current study, participants were categorized into four groups based upon age (under or over age 55) and illness duration (more or less than 10 years). The groups were compared on functioning and symptoms. Findings indicated that those who were older with a longer illness duration had significantly higher levels of mental health functioning than those who were younger with a shorter or longer illness duration and the older group with a shorter illness duration. The results suggest that older patients with an illness duration of over 10 years have significantly higher levels of mental health functioning than the three other groups. For symptoms, the younger/longer illness duration group had significantly worse immune and autonomic domains than the older/longer illness group. In addition, the younger patients with a longer illness duration displayed greater autonomic and immune symptoms in comparison to the older group with a longer illness duration. These findings suggest that both age and illness duration need to be considered when trying to understand the influence of these factors on patients.

Variability in symptoms complicates utility of case definitions: a response to Twisk (2015)

Twisk [1] first suggested that the article McManimen et al. [2] assumed myalgic encephalomyelitis (ME) and chronic fatigue syndrome (CFS) are the same clinical entity. This idea was not stated in McManimen et al. [2] and has been clarified in a previous response to Twisk [3]. The purpose of our study was not to compare ME with CFS, but rather to examine the variability within the most widely used case definition, the Fukuda et al. [4] criteria. Each study needs to demarcate its objectives, and while Twisk [1] would prefer that we examine issues involving differentiating ME and CFS, these issues were not the focus of our study. Our study focused solely on the Fukuda et al. [4] case definition, because we believe it is vague and lacks operationally explicit diagnostic criteria. The consequence is heterogeneous patient samples, which might not be comparable across research settings. Specifically, the main purpose stated in McManimen et al. [2] is to demonstrate the problems with the current widely accepted Fukuda case definition. We believe that there is a need to move beyond the Fukuda et al. [4] criteria and develop more empirical methods to determine core features of this illness, which need to be identified in all patients. Twisk’s second claim is that objective measures should be utilized over subjective measures. There are a few problems with implementing this suggestion. First, as noted in our article, many of the objective measures such as two day maximal cardio-pulmonary exercise testing can result in serious long-term symptom exacerbations for patients. Additionally, these exercise tests also require patients to be ambulatory, and patients who are bedbound are not able to physically visit a clinic or testing site. Furthermore, such tests are expensive and sometimes not covered by insurance companies. Finally, there are few exercise physiologists who are trained to administer these types of two day exercise challenges. When trained personnel are available and individuals have the financial resources to engage in two day maximal cardio-pulmonary exercise testing, we certainly would be in favor of such testing, particularly when patients are aware and informed of possible health consequences of such tests. However, subjective measures such as the DSQ [5] allow patients to take breaks as they complete the questionnaires so they do not worsen their symptoms. The DSQ can be completed online so patients are able to participate in the research from the comfort of their homes. As indicated in our article, studies have compared the self-report data with more physiological measures, providing support for