Guided self-instructions for people with chronic fatigue syndrome: randomised controlled trial

A minimal intervention, based on cognitive–behaviouraltherapy for chronic fatigue syndrome and consisting of self-instructionscombined with email contact, was tested in a randomised controlledtrial (ISRCTN27293439). A total of 171 patients participatedin the trial: 85 were allocated to the intervention conditionand 86 to the waiting-list condition. All patients met theCenters for Disease Control and Prevention criteria for chronicfatigue syndrome. An intention-to-treat analysis showed a significantdecrease in fatigue and disability after self-instruction.The level of disability was negatively correlated with treatmentoutcome. Guided self-instructions are an effective treatmentfor patients with relatively less severe chronic fatigue syndrome.

INTRODUCTION

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INTRODUCTION

Cognitive–behavioural therapy (CBT) for chronic fatiguesyndrome is an effective¹ but intensive treatment. It requires13–16 sessions, depending on the protocol used.^2–4 We assumed that for a subgroup of patients with chronic fatiguesyndrome a less intensive treatment sufficed and developeda minimal intervention based on CBT that consisted of self-instructionsand email contact. The effects of self-instructions on fatigueand disabilities were compared with a waiting-list conditionin a randomised controlled trial. The predictive value of thelevel of fatigue and disabilities at baseline for treatmentoutcome was determined.

Method

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Method

Patients referred for CBT to our tertiary care facility wereeligible to enter the study if they were $>=$ 18 years old; spokeand read Dutch; met the 1994 US Center for Disease Controland Prevention criteria for chronic fatigue syndrome;⁵ werenot engaged in a legal procedure concerning disability-relatedfinancial benefits;⁶ scored $>=$ 35 on the Checklist IndividualStrength (CIS),⁷ fatigue severity sub-scale; had a total scoreof >700 on the Sickness Impact Profile–8 (SIP8);⁸and had given written informed consent. The local ethics committeeapproved the study.

After baseline assessment performed by research assistants,patients were offered CBT. If they agreed, they were placedon a waiting list for a period of 6–12 months dependingon available treatment capacity. Patients were informed aboutthe study and if they gave informed consent, were randomly assignedto either the guided self-instructions or the waiting-list condition. Allocation to group was carried out by a therapist using cardsin consecutively numbered opaque and sealed envelopes thatwere opened in the presence of the patient. A researcher checkedevery week whether the sequence was subverted by matching thedate the patient was included with the sequence of the numbersand date of the session. No irregularities were found. A statisticaladvisor prepared the envelopes by coding them according to a computer-generated list of random numbers in blocks of eight.Patients were assessed at baseline and directly following thewaiting period or intervention. This could vary between 6 and12 months depending on the available treatment capacity.

The intervention consisted of a self-instruction booklet containing information about chronic fatigue syndrome and weekly assignments.The programme took at least 16 weeks, but often more if patientsformulated long-term goals such as returning to work. Patientswere asked to email (or telephone if they did not have email)at least once every 2 weeks to report their progress. A cognitive–behaviouraltherapist, trained in regular CBT for chronic fatigue syndrome,responded to this email or call. If patients did not respondevery 2 weeks, a reminder was sent by email or patients were telephoned.

The CIS sub-scale `fatigue severity' was used to measure thelevel of fatigue over the past 2 weeks. Scores ranged from8 (no fatigue) to 56 (severely fatigued).⁷ The weighted totalscore on eight sub-scales of the SIP8 (SIP8 total score) was used to assess functional disability in all domains of functioning.⁸ Physical disabilities were measured with the physical functioningsub-scale of the 36-item Short Form Health Survey (SF–36).⁹ Scores ranged from 0 (maximum physical limitations) to 100(ability to do vigorous activity).

Clinically significant improvement¹⁰ was defined as a reliablechange index >1.96 and a score of <35 on the CIS sub-scalefatigue severity at second assessment. This score is withintwo standard deviations of the mean for healthy adults.⁸ Ascore of <35 would reflect a significant reduction of fatigue.We assumed that in the waiting-list condition 10% of the patientswould have a fatigue score of <35. Power calculation showedthat 98 patients in each condition were needed to detect adifference of 15% in the proportion of patients with a fatiguescore within normal limits, assuming a significance of 5%, powerof 90% and a drop-out rate of 20%.

Data analyses were performed using SPSS (version 14) for Windows. Significance was assumed at P<0.05. To test whether therewas a difference between the two conditions on outcome measures, ANCOVA¹¹ was used with the score on the second assessmentas the dependent variable, baseline score as the covariateand condition as the fixed factor. To test whether the proportionof patients with a clinically significant improvement differed between conditions, logistic regression with condition andbaseline CIS fatigue as predictors was used. To test whetherthe treatment effect was moderated by patient characteristics,ANCOVA for CIS fatigue on the second assessment was repeatedwith condition (standardised; Z-score with mean=0, s.d.=1),baseline CIS fatigue (standardised), baseline SIP8 total score,conditionxbaseline CIS score, and conditionxbaseline SIP8 scoreas predictors. All comparisons were performed on the basis ofintention to treat. For missing data, the last observationwas carried forward.

Results

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Results

During the study it became clear that the number of patientslost at the second assessment was lower than expected (about5%). The power analysis was repeated but now using an estimateddrop-out rate of 5%, indicating that a sample size of 85 ineach condition sufficed. The inclusion of patients stoppedwhen this sample size was reached (Fig.1).

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Fig. 1 Flow of participants through the study.

Of 84 patients in the self-instructions condition, 55 (66%)emailed, 5 (6%) exclusively used the telephone and 10 (12%)did both. Fourteen patients (16%) had no contact with a therapist:1 patient completed the programme by herself, the remaining13 did not start. There was no significant difference in mean time passed in months between the two assessments for the guided self-instruction (10.5 months, s.d.=4.0) and the waiting-listcondition (9.7 months, s.d.=3.6, t=1.34, d.f.=157, P=0.182).Patients from the intervention condition were significantlyless fatigued (intervention mean=38.9 v. waiting-list mean=46.4),reported fewer disabilities (mean=1079 v. mean=1319), scoredsignificantly higher on the SF–36 physical functioningsub-scale (mean=65.9 v. mean=60.2) and more often showed aclinically significant improvement in fatigue (27% v. 7%) atsecond assessment (online Tables DS1–3).

Of the interaction terms, only the conditionxSIP8 total score interaction effect was significant (B=3.533, t=2.250, P=0.026),indicating that the treatment effect is more than halved forpatients with an SIP8 score of 1 standard deviation above themean.

Discussion

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Discussion

It was already known that individual CBT is an effective treatmentfor chronic fatigue syndrome.¹ Our study showed that a lessintensive intervention based on the same principles also leadsto a decrease of fatigue and disabilities in patients with chronic fatigue syndrome. For the subgroup of patients that showeda clinically significant improvement in fatigue, the minimalintervention sufficed. Self-instructions could form the firststep in a model of stepped care for chronic fatigue syndrome.The results also suggest that more severely disabled patientsbenefit less from the self-instructions and could perhaps bereferred for face-to-face CBT instead.

As we did not use a control condition we cannot be sure thatthe specific elements in the minimal intervention conditionwere responsible for the reduction of fatigue and disabilities.However, two randomised controlled trials that compared theeffect of CBT for chronic fatigue syndrome with a placebo ornon-specific condition both showed CBT to have a superior effect.^2,4 Furthermore, Cho et al¹² showed that the placebo responseof patients with chronic fatigue syndrome to psychologicalinterventions is lower than in other medical conditions.

ACKNOWLEDGMENTS

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ACKNOWLEDGMENTS

Trial register number: ISRCTN27293439. Ethical approval wasobtained from the human ethics committee of the Radboud UniversityNijmegen Medical Centre. We thank the patients who participatedin the study and Thea Berends, Annemarie Gerritsen, Gerrievan de Heijdt, Henriette Vermeer and Hein Voskamp for treatingthe patients in the guided self-instruction condition, Carel Kruip, Tiny Fasotti and Lianne Vermeer for their assistancein data collection, and Rogier Donders for statistical advice.

REFERENCES

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