ABSTRACT
OBJECTIVE: To determine the efficacy of a cognitive-behavioral intervention for patients meeting U.S. Centers for Disease Control and Prevention (CDC) criteria for idiopathic chronic fatigue (ICF). ICF is thought to be a less severe disorder than chronic fatigue syndrome (CFS). The intervention consisted of a booklet with self-instructions combined with e-mail contact with a therapist. METHOD: Randomized controlled trial conducted at an outpatient facility. All patients suffered from severe and persistent fatigue with moderate impairment levels or fewer than 4 additional symptoms. Patients were randomly allocated to either guided self-instruction or a wait-list control group. Primary outcome measures were fatigue severity assessed with the Checklist Individual Strength and level of overall impairment assessed with the Sickness Impact Profile. Outcome measures were assessed prior to randomization and following treatment or wait-list control group. RESULTS: One hundred patients were randomly allocated to the intervention or a wait-list control group and 95 completed second assessment. An intention-to-treat analysis showed significant treatment effects for fatigue severity (-8.98, 95% confidence interval [CI] [-13.99, -3.97], Cohen's d = 0.68, p < .001) and for overall impairment (-317.19, 95% CI [-481.70, -152.68], Cohen's d = 0.53, p < .01) in favor of the intervention. The number of additional symptoms and overall impairment at baseline did not moderate posttreatment fatigue severity. Baseline overall impairment moderated posttreatment impairment. CONCLUSIONS: Patients with ICF can be treated effectively with a minimal intervention. This is relevant as ICF is more prevalent than CFS and treatment capacity is limited.
Subject(s)
Ambulatory Care , Cognitive Behavioral Therapy , Fatigue Syndrome, Chronic/therapy , Fatigue/prevention & control , Adult , Checklist , Female , Humans , Male , Middle Aged , Netherlands , Severity of Illness Index , Treatment Outcome , Waiting ListsABSTRACT
BACKGROUND: Cognitive behaviour therapy (CBT) is known to reduce fatigue severity in chronic fatigue syndrome (CFS). How this change in symptomatology is accomplished is not yet understood. The purpose of the present study was to determine whether the effect of CBT on fatigue is mediated by an increase in physical activity. METHOD: Three randomized controlled trials were reanalysed, previously conducted to evaluate the efficacy of CBT for CFS. In all samples, actigraphy was used to assess the level of physical activity prior and subsequent to treatment or a control group period. The mediation hypothesis was analysed according to guidelines of Baron & Kenny [Journal of Personality and Social Psychology (1986)51, 1173-1182]. A non-parametric bootstrap approach was used to test statistical significance of the mediation effect. RESULTS: Although CBT effectively reduced fatigue, it did not change the level of physical activity. Furthermore, changes in physical activity were not related to changes in fatigue. Across the samples, the mean mediation effect of physical activity averaged about 1% of the total treatment effect. This effect did not yield significance in any of the samples. CONCLUSIONS: The effect of CBT on fatigue in CFS is not mediated by a persistent increase in physical activity.
