Chronisch Vermoeidheidssyndroom: diagnose, behandeling en ...

62 Chronic Fatigue Syndrome KCE reports 88
3.3.2 Incremental health outcomes
Table 10 provides a comparison of the values of the three main health outcomes
reported by the studies.
Table 10. Mean and incremental health outcome (95% confidence interval)
Author Publication Time Incremental outcome: CBT vs
year horizon CBT SG a
Mean health outcome
DN GET CT DN GET CT
Quality adjusted life years
Severens et al. 2004 14 months 0,074 -0,002 0,046 - - 0,028 - -
Mean decrease in fatigue score
McCrone et al. 2004 8 months 2,7 (-0,6–6,0) - - 2,4 (-0,6–5,4) - - 0,3 -
Chisholm et al. 2001 6 months 7,34 (5,5–9,1) - - - 8,28 (6,5–10,0) - - -0,9 (-3,6–1,8)
Percentage of patients with a clinically significant decrease in fatigue
Severens et al. 2004 14 months 27% 11% 20% - - 7% - -
McCrone et al. 2004 8 months 79% - - 73% - - 6% -
a. The comparison between CBT and SG is not performed since SG is dominated by CBT, i.e. SG is more expensive and less clinically
effective than CBT; CBT: cognitive behaviour therapy; SG: guided support group; DN: do nothing; GET: graded exercise therapy; CT:
counselling therapy.
Based on the positive mean values reported by the studies, it appears that all therapies
(with the exception of SG 142 ) considered in the economic evaluations improve the
health outcome of both CFS 142 and chronic fatigue 141, 143 patients between baseline and
follow-up. The degree of statistical significance of this mean improvement is however
hard to assess since confidence intervals around the means are either not reported or
comprise the value zero. 141
In Severens et al., 142 treatment with SG was found to reduce the quality of life of CFS
patients from intake to 14 months follow-up (-0.002). This option was thus discarded by
the authors as a relevant comparator to CBT. Compared to DN, the gain in QALYs
obtained by CBT is small with 0.028 QALYs gained (about 10 days) over a 14 months
follow-up. 142 Although no confidence interval was reported, Severens et al. 142 stated that
this small advantage of CBT over DN is highly statistically uncertain. Likewise, the
percentage of CFS patients with a clinically significant decrease in fatigue was 7% higher
in the CBT group than in the DN group but because confidence intervals were not
reported, it was not possible to assess whether this small advantage of CBT is
statistically significant or not. 142
Treating chronic fatigue patients with CBT resulted in a mean improvement in the
fatigue score of 0.3 units compared to GET, 141 and in a mean deterioration of 0.9 units
compared to CT. 143
Both results did however not show statistical significance since the confidence intervals
of the mean changes of CBT and GET largely overlapped (CBT: 2.7, 95% CI: - 0.6−6.0;
GET: 2.4; 95% CI: - 0.6−5.4) 141 and since the reported confidence interval around the
incremental change between CBT and CT crossed zero (- 0.9; 95% CI: - 3.6−1.8). 143 The
clinical effectiveness of CBT, expressed as mean unit change in the fatigue score, may
thus well be similar to that of GET or CT for chronic fatigue patients. The percentage
of chronic fatigue patients with a clinically significant decrease in fatigue was 6% higher in
the CBT group than in the GET group but no confidence interval around this mean
value was reported in McCrone et al. 141
3.3.3 Cost-effectiveness ratios
The studies results are summarised in Table 11 and are discussed below.
3.3.3.1 CFS patients: CBT versus DN
From the perspective of the payers, Severens et al. 142 reported a cost-effectiveness ratio
for CBT versus DN of €25 147 per additional patient with clinically significant
improvement or €63 250 per QALY gained. The uncertainty around those ICERs was
estimated by plotting the results 1 000 bootstrap replications of the incremental costs
and outcomes on the cost-effectiveness plane and by reporting the proportion of the
dots in each quadrant. From the perspective of the payers, none of the 1 000