تفاوت در عملکرد فیزیکی بین بیماران نسبتا فعال و غیر فعال با سندرم خستگی مزمن

Objective According to the Cognitive behavioral therapy (CBT) protocol for patients with Chronic Fatigue Syndrome (CFS), therapists are advised to categorize patients in relatively active and passive patients. However, evidence to support the differences in physical functioning between these subgroups is limited. Using the baseline data from a multicentre randomized controlled trial (FatiGo), the differences in actual and perceived physical functioning between active and passive patients with CFS were evaluated. Methods Sixty patients, who received CBT during the FatiGo trial were included. Based on the expert opinion and using the definitions of subgroups defined in the CBT protocols, the therapist categorized the patient. Data from an activity monitor was used to calculate actual physical functioning, physical activity, daily uptime, activity fluctuations and duration of rest during daily life. Perceived physical functioning was assessed by measuring physical activity, physical functioning and functional impairment with the Checklist Individual Strength, Short Form-36 and Sickness-Impact Profile 8. Results Relatively active patients have a significantly higher daily uptime and show significantly less fluctuations in activities between days. Passive patients experience a significantly lower level of physical functioning and feel more functionally impaired in their mobility. However, no significant differences were found in the other actual or perceived physical functioning indices. Conclusions A clear difference in actual and perceived physical functioning between relatively active and passive patients with CFS as judged by their therapists could not be found. Future research is needed to form a consensus on how to categorize subgroups of patients with CFS.

Chronic Fatigue Syndrome (CFS) is a condition characterized by persistent fatigue, which is not the result of an identifiable organic disease or ongoing exertion and lasts for at least six months. Rest does not alleviate the fatigue. CFS often leads to a substantial limitation in occupational, educational, social and personal activities [1]. Although results are conflicting, several studies found the actual as well as the perceived physical functioning to be lower in patients with CFS compared to healthy, age matched controls [2], [3], [4] and [5]. A possible explanation for the conflicting results in physical functioning might be the large variations in actual and perceived physical functioning within the population of patients with CFS. The study of van der Werf [2] investigated the differences in perceived physical functioning between subgroups of patients. The average daily physical activity level, measured by the actometer of the total group of patients, was used as reference value to form subgroups. The number of days below or above this reference value determined in which subgroup a patient was categorized. Results showed that two subgroups could be identified. A group of pervasively passive patients, reporting less daily activities and perceive more limitations in daily life functioning compared to the other subgroup of relatively active patients. In addition, Prins et al. [6], who studied the effectiveness of Cognitive Behavioral Therapy (CBT) in patients with CFS, found that the individual level of daily physical activity predicted the treatment outcome. Passive patients showed hardly any improvement after CBT. Therefore CBT protocols were adjusted for subgroups of patients (passive patients versus relatively active patients) in order to increase effectiveness of the CBT. In the Netherlands, these tailored CBT protocols for relatively active and passive patients are used frequently In these clinical diagnostic and therapeutic protocols [6] and [7], relatively active patients are assumed to be more physically active, spend less time resting and show infrequent bursts of activity followed by extreme exhaustion during the day and between days (high level of fluctuations of activities). Passive patients with CFS are assumed to stay at home more often, not to walk long distances and lie down most of the day [6] and [7]. Nowadays CBT often incorporates a gradual increase in physical activities. In the CBT protocol for the passive patients, physical activities will be increased from the beginning of therapy. The relatively active patient is first taught to practice at a baseline activity level without bursts of activity in order to stabilize the level of activities and prevent extreme exhaustion. After stabilization has been reached, activities will be increased gradually. According to Prins et al. [8] passive patients do not recover when they receive the CBT protocol for active patients. Therefore it is important to categorize patients correctly, as differences in physical functioning guides treatment content Experts in CBT advise to categorize patients with the use of an actometer [6] and [7]. In clinical practice an actometer or other actual activity monitoring system is usually not available because they are too expensive, time-consuming, complex to analyze and difficult to interpret. Questionnaires on daily physical activity are used instead of the actometer but are still lacking validity [9]. Which method is the most valid for categorization is still unclear and needs further investigation. Currently therapists categorize patients using the definitions in the CBT protocol [6] and [7]. Although categorization of patients is often used in clinical practice, the assumed differences in physical functioning between relatively active and passive patients, as described in clinical protocols, have never been confirmed by measuring the actual daily life activities using an activity monitor. In patients with chronic low back pain (CLBP), it was found that a subgroup of avoiders, who seem to closely resemble the passive patients, had significantly higher disability levels, a lower perceived daily life activity level, and lower daily uptime compared to a subgroup of persisters [10]. However, no differences in the actual daily life activity level and fluctuations of activities over time could be found. In the CBT protocols for CFS [6] and [7] experts on CBT state that a patient's perception on physical activity is often distorted by cognitions regarding activity resulting in a discrepancy between what people say and what they actually do. Therefore, it is important to get insight in the patients' actual level of physical functioning as well as their perceived level of physical functioning, in both subgroups. Hence the first aim of the present study is to evaluate the differences in actual physical functioning between subgroups, i.e. whether passive patients with CFS have a significantly lower actual total physical activity level, spend less time awake and out of bed (daily uptime), spend more time resting, and show less activity fluctuations compared to relatively active patients with CFS. The expert opinion, as this is the most commonly used form, will be used to categorize the patient. A second aim is to evaluate the differences in perceived physical functioning between subgroups, i.e. whether passive patients are significantly more impaired and have a lower perceived daily life activity level compared to relatively active patients with CFS.

A clear difference in actual and perceived physical functioning between relatively active and passive patients with CFS as judged by their therapists could not be found. Discrepancies exist between the patient's perception and the actual measure of physical functioning. Individualizing treatment based on the discrepancy within patients with CFS might be worthwhile. Furthermore, more research is needed with a greater number of participants to form a consensus on how to categorize patients, validate this categorization and tailor treatments based on the categorization in order to increase the effectiveness of treatment.