Research 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 post-treatment fatigue severity. Baseline overall impairment moderated post-treatment 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.
The Efficacy of Guided Self-instruction for Patients With Idiopathic Chronic Fatigue: A Randomized Controlled Trial, by A Janse, JF Wiborg, G Bleijenberg, M Tummers, H Knoop in J Consult Clin Psychol. 2016 Mar 7 [Epub ahead of print]
Comment by Tom Kindlon, 28 Feb 2017:
A major limitation was not mentioned: no objective outcome measures were used
I was amazed to read the long (906-word) limitations section and find no mention of the limitation that the results rely solely on subjective outcome measures[1].
The most obvious outcome measure to use would have been actometers which measure activity levels objectively. The equipment was available to the researchers as it was used at baseline [“Physical activity was assessed with an actometer, a motion-sensing device worn at the ankle for 14 days”].
The importance of the use of such a measure can be seen in the results of an earlier study using the the same or very similar intervention on people with chronic fatigue syndrome[2]. That study involved two of the current research team with one of them being its corresponding author. That paper reported improvements in the intervention group on the CIS fatigue severity, SIP8 total score and SF–36 physical functional questionnaires (which were also used in the current study). Subsequently to that, data from the actometers were reported in a paper co-authored by three of the current team[3]. Both the intervention group and the control group had the same change in activity, 4.3 units, during the trial. The intervention group finished at a mean of 67.8 units, significantly less than the actometer scores for healthy controls of 91.
Numerous response biases could be at play in this nonblinded study with such interventions causing participants to report improvements without their objectively-measured levels of functioning having improved.
If actometers were used during or after the current study, it is important that the researchers should now release such data, rather than delay for years as they have done with some trials before[3].
References:
1 Janse A, Wiborg JF, Bleijenberg G, Tummers M, Knoop H. The efficacy of guided self-instruction for patients with idiopathic chronic fatigue: A randomized controlled trial. J Consult Clin Psychol. 2016 May;84(5):377-88.
2 Knoop H, van der Meer JW, Bleijenberg G. Guided self-instructions for people with chronic fatigue syndrome: randomised controlled trial. Br J Psychiatry. 2008 Oct;193(4):340-1.
3 Wiborg JF, Knoop H, Stulemeijer M, Prins JB, Bleijenberg G. How does cognitive behaviour therapy reduce fatigue in patients with chronic fatigue syndrome? The role of physical activity. Psychol Med. 2010 Aug;40(8):1281-7.
