Patient Perception, Preference and ParticipationThe impact of energy modulation on physical functioning and fatigue severity among patients with ME/CFS☆
Introduction
Chronic fatigue syndrome (CFS), also known as myalgic encephalomyelitis or myalgic encephalopathy (ME), is a highly incapacitating illness with an annual value of lost productivity in the US due to this illness estimated to be $9.1 billion [1]. Moreover, total direct and indirect costs due to CFS range from $18.7 to $24 billion dollars [2]. Patients with CFS are more functionally impaired than those suffering from type II diabetes mellitus, congestive heart failure, multiple sclerosis, and end-stage renal disease [3], [4]. It is estimated that over 800,000 individuals have this illness [5]. Given the prevalence and impact of this illness, there is a need to find ways to develop effective intervention strategies.
One of the more popular treatments for patients with ME/CFS has been cognitive behavior therapy (CBT). Price et al. [6] recently reviewed 15 studies of CBT with a total of 1043 ME/CFS participants. At treatment end, 40% of people in the CBT group showed clinical improvement in contrast to only 26% in usual care, but changes were not maintained at a 1–7-month follow-up when including people who had dropped out. In addition, a survey of 3228 respondents [7] and a separate survey sponsored by the ME Association [8] found that graded exercise, which is a component of CBT, was felt to be the type of treatment that made more people with ME/CFS worse than any other. Two additional studies provide possible reasons for patient reaction to these graded exercise strategies. Jammes et al. [9] found that incremental exercise among individuals with CFS was associated with oxidative stress and marked alterations of muscle membrane excitability. Black et al. [10] found that 28% on average increases in daily physical activity for a 4-week period among a sample of people with CFS resulted in worsening overall mood, muscle pain intensity, and time spent each day with fatigue. Later after a re-analysis of this data, Black and McCully [11] concluded that CFS patients developed exercise intolerance as demonstrated by reduced total activity after 4–10 days.
Other approaches to helping patients with ME/CFS have included Envelope Theory [12] and pacing [13], and these approaches do not unilaterally increase activity for all patients. The Envelope Theory recommends that patients with ME/CFS pace their activity according to their available energy resources [12]. In this approach, the phrase, “staying within the envelope,” is used to designate a comfortable range of energy expenditure, in which an individual avoids both overexertion and underexertion, maintaining an optimal level of activity over time. Some people with ME/CFS need to be encouraged to increase their activity, as they have the appropriate amount of perceived energy to do so. However, there are also people with ME/CFS that need to be encouraged to do less in order to decrease the discrepancy between perceived and expended energy. This theory emphasizes the need to understand the differential needs of subtypes of patients with ME/CFS. The key is to not over-expend their energy supplies or consistently go outside their “envelope” of available energy. Rather than a cure, this approach focuses on improving the ability of patients to cope with this illness.
In evaluating this Energy Envelope Theory, Jason et al. [12] presented evidence that when a patient kept her expended energy levels within the envelope of her perceived energy levels, her fatigue was lower and her perceived energy higher. In a second study, Jason et al. [14] found a positive significant relationship between current fatigue level and self-rated expended energy 2-days ago. Pesek et al. [15] found that when participants with ME/CFS were provided with a buddy to reduce activities and to assist in identifying and reducing discrepancies between perceived and expended energy, overall fatigue severity as well as severity ratings for ME/CFS symptoms decreased. In a correlational study, Jason et al. [16] found that the individuals with ME/CFS experienced a range of negative symptoms and disability when they extend beyond their energy envelope. Unfortunately, the studies above were either correlational or involved small samples.
There is a need to experimentally test out the Envelope Theory with individuals who stay within their energy envelopes versus those who do not, and then assess whether this leads to differences on measures of physical functioning and fatigue. The present study tested out this theory with two groups of patients with ME/CFS. The hypothesis was that significant positive changes on physical functioning and fatigue severity would only occur for those patients with ME/CFS that stayed within their energy envelope.
Section snippets
Participant recruitment
Participants were recruited from a variety of sources, including physician referrals. Information about the non-pharmacologic treatment trial study was disseminated to medical colleagues through mailings, phone communication, and invited grand rounds. In addition, study announcements for new participants were placed in local newspapers and recruitment offers were made at local ME/CFS support group meetings. These efforts were continued throughout the study period until the target enrollment
Results
Of the sample of 81 with data collected at the 12-month follow-up on energy ratings, we classified 49 as staying within their energy envelope and 32 as going beyond their energy envelope. This decision was based on individuals at follow-up who had a score of 150 or less on weekly Energy Quotient. Therefore, 49 individuals were classified as having reduced or maintained a reasonable balance between perceived and expended energy. We also used a more severe criteria, a score of 100 or less (which
Discussion
It is possible that when patients overexert themselves, they experience negative emotional responses due to evaluating stressful experiences as a significant threat and as exceeding available coping resources [29]. Consequently, negative emotional responses can cause distressed clients to engage in behaviors (e.g., altering sleep patterns, alcohol and tobacco use, or decreasing physical activity) which conceivably modify immune responses. In addition, negative emotional states might activate
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The authors appreciate the funding provided by NIAID (grant number AI 49720).