Genitourinary Medicine Clinic, Kings Mill Hospital, Sutton-in-Ashfield, and Department of Psychological Medicine, Division of Neuroscience and Mental Health, Imperial College, London
Central North West London Mental Health NHS Trust, London
Institute of Psychiatry, King's College London
Non-Communicable Disease Epidemiology Unit, London School of Hygiene and Tropical Medicine
Department of Psychological Medicine, Division of Neuroscience and Mental Health, Imperial College, London, UK
Correspondence: Dr Seivewright, Email: h.seivewright{at}imperial.ac.uk
P.S. adapted the CBT intervention for health anxiety and developed the Health Anxiety Inventory. P.T. is the Editor of the British Journal of Psychiatry but had no part in the evaluation of this paper for publication. Funding and trial registration detailed in Acknowledgements.
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Little is known about the management of health anxiety and hypochondriasis in secondary care settings.
Aims
To determine whether cognitive–behavioural therapy (CBT) along with a supplementary manual was effective in reducing symptoms and health consultations in patients with high health anxiety in a genitourinary medicine clinic.
Method
Patients with high health anxiety were randomly assigned to brief CBT and compared with a control group.
Results
Greater improvement was seen in Health Anxiety Inventory (HAI) scores (primary outcome) in patients treated with CBT (n=23) than in the control group (n=26) (P=0.001). Similar but less marked differences were found for secondary outcomes of generalised anxiety, depression and social function, and there were fewer health service consultations. The CBT intervention resulted in improvements in outcomes alongside higher costs, with an incremental cost of £33 per unit reduction in HAI score.
Conclusions
Cognitive–behavioural therapy for health anxiety within a genitourinary medicine clinic is effective and suggests wider use of this intervention in medical settings.
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The cost-effectiveness analysis took a health service perspective, because patients with health anxiety are known to be high users of both primary and secondary care services.3 Health service use in primary and secondary care was collected after the 12-month follow-up from examination of medical records by staff unaware of treatment allocation. Unit costs in GBP (£) for the financial year 2004–05 were attached to each individual service and summed to generate total costs.13,14 The cost of CBT was based on the time spent by the therapist with each patient plus relevant overheads. As a key element of total costs, the cost of CBT was varied in sensitivity analysis by increasing it and decreasing it by 50%.
The primary outcome was chosen in advance as the improvement in the mean HAI score between baseline and 6 months, with secondary outcomes of HAI at 12 months, and changes in social function, anxiety and depression scores at 3, 6 and 12 months.
Procedure
Attendees at the clinic suspected of having significant health anxiety were
given the short form of the
HAI5 with symptoms
assessed over the previous 6 months. Those with a score of 20 or more were
given a simple explanation of the nature of health anxiety, an information
sheet about the study and invited to take part if they satisfied the other
inclusion criteria described. A score of 20 or more on the HAI was chosen
because a previous study had established that people scoring above this
threshold had persistent symptoms over a 6-month
period.6 Patients
allocated to CBT were seen by H.S. and given separate allocated times for
their treatment sessions at the clinic. Each patient also received a manual
prepared by P.S. on the principles of treatment.
Patients who satisfied the criteria for inclusion were randomised within 48 h from a remote centre (London) to the two arms of the trial in a 1:1 ratio based on a computerised randomisation sequence of permutated blocks of size 20. Patients allocated to CBT received the booklet and up to seven sessions of CBT each lasting up to 1 h, with additional booster sessions given if sufficient improvement had not been made. Those allocated to the control arm continued to be seen in the clinic as necessary (by any staff member) but received no psychological input apart from their initial interview.
H.S. also audiotaped her interviews with patients; these were assessed and feedback given by J.G. during treatment, but none of this involved further face-to-face training.
Statistical analysis
Main analysis
Statistical analysis was carried out using STATA version 10 for Windows
primarily by analysis of variance at each time point with adjustment for
baseline differences for each variable. A further regression analysis for
longitudinal data using random effects models was carried out for each
measuring score, with outcomes of repeated measures of the assessment scores
at 6 and 12 months adjusted for the baseline scores, treatment, follow-up and
interaction between follow-up and treatment. These models are essential in the
analysis of panel data-sets with high variability between participants and low
variability within participants. These models produce a matrix-weighted
average of these results. Assessment for baseline scores took place before
randomisation to treatment; however, adjustment for baseline was essential to
correct for the possibility of differences in baseline scores between
treatments.
Missing data
The follow-up scores were incomplete for the HAI, BAI, HADS–A and
HADS–D assessments. The method of multiple imputations was used to
account for missingness in these scores. These method imputes m
plausible values for each missing value, under the assumption of `missing at
random'. Missing at random holds when missing data are different from the
observed data, but the pattern of missing data is traceable from the observed
data.15 Results
were then combined using the rules of multiple imputation. Sensitivity
analysis was carried out to compare differences in the imputed outcome
estimates of the repeated measures of the assessment scores at 6 and 12 months
adjusted for the baseline, to the repeated measures analysis of the incomplete
scores.
The cost-effectiveness analysis combined the primary outcome (HAI score) with total service-use costs and the cost of the intervention at 12-month follow-up. Differences in cost were first compared using standard t-tests, despite the skewed distribution of the cost data, as this method enables inferences to be made about the arithmetic mean.16 Non-parametric bootstrapping was used to assess the robustness of confidence intervals to non-normality of the cost distribution.17 Incremental cost-effectiveness ratios were calculated.
The trial focused specifically on the treatment of health anxiety in order to compare with a previous study.7 Abnormal health anxiety is not necessarily the same condition as hypochondriasis as defined in standard classifications and may include conditions such as abridged hypochondriasis18 that fall short of the criteria for full hypochondriasis status. The nomenclature and status of these disorders remains controversial with none of the labels for the somatoform disorders achieving diagnostic confidence,19 but it is likely that most of those with persistent health anxiety would also satisfy the diagnostic requirements for hypochondriasis.
Sample size and randomisation
The study was carried out specifically to determine whether CBT adapted for
health anxiety is feasible in a medical clinic and to provide pilot data for
an effect-size calculation for a large pragmatic trial, so a formal
calculation of sample size was considered unnecessary.
Inclusion and exclusion criteria
Inclusion criteria: Patients who in addition to having significant
health anxiety (HAI=20) were: (a) aged between 16 and 65 years; (b) were
permanent residents in the immediate area; (c) had sufficient understanding of
English to read and complete the questionnaires; and (d) gave written consent
for the interviews. Audiotaping of treatment sessions and access to their
medical records was requested but not obligatory.
Exclusion criteria: Patients who were: (a) currently under active psychiatric treatment; (b) on psychotropic drugs that had been newly prescribed in the previous 6 months; and (c) actively being investigated for suspected pathology. However, those who had active or pre-existing pathology were not excluded.
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Fig. 1 Flow of patients through trial.
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Efficacy
Using repeated measures analysis of variance with baseline, 6-month and
12-month data, and with imputed missing values, there was significantly
greater improvement for health anxiety (P=0.001), generalised anxiety
with the HADS–A (P=0.036) and depression with the HADS–D
(P=0.002) in the CBT group compared with the control group, with
non-significant improvement in the BAI and social functioning (SFQ) over these
time scales (Table 1 and online
Table DS3), although social function was significantly more improved at 3
months than in the control group (P<0.01).
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Table 1 Significance of random effects models of panel
dataa
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Because the assessments were not masked, even though they were all self-ratings and therefore not subject to observer bias, it was felt important to evaluate the outcome in those assessed by telephone and post only. It was postulated that if H.S. was demonstrating any bias in assessments this would show most prominently in telephone interviews and least in those completed by post. This hypothesis was not supported for any measure. For example, for the health anxiety scores the relative reductions in scores after 1 year for interview ratings in CBT and control groups were 56% and 17%, for telephone ratings 47% and 42%, and postal ratings 43% and 19% respectively.
Economic evaluation
In the CBT group, primary care contacts and out-patient appointments fell
over the 12-month period of the study, whereas contacts in the control group
remained at largely the same level or fell only slightly
(Table 2). The greater part of
the reduction in contacts in the CBT group was in the second 6 months, after
most of the treatment had been completed (online Table DS2).
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Table 2 Mean (s.d.) service use over 12 months of study
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The lower levels of service use over follow-up in the CBT group were reflected in £150 lower mean total service costs per patient (£634 v. £484) (Table 3). However, this difference in cost was not sufficient to offset the cost of the CBT sessions, which were on average £427 per patient. Thus, mean costs per patient over 12 months follow-up were £911 in the CBT group and £634 in the control group. None of these differences in costs was statistically significant.
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Table 3 Mean (s.d.) total costs per patient in GBP (£) over 12 months of
study
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The CBT intervention resulted in improvements in outcomes alongside higher costs, so the incremental cost-effectiveness ratio was calculated at £33 per unit reduction in HAI score. The cost of the CBT intervention was found to be an important cost-driver. When the cost of the intervention was lowered by 50%, the difference in cost between control and CBT groups fell to only £63, generating an incremental cost-effectiveness ratio of only £8 per unit reduction in HAI score. Conversely, when the cost of the intervention was increased by 50%, the difference in cost between the CBT and control group was substantial (£490) and reached statistical significance (P=0.02) and the incremental cost-effectiveness ratio increased to £59 per unit reduction in HAI score.
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Limitations
The trial had limitations: its numbers were small, the selection of
patients was more opportunistic than systematic, the assessments were not
masked (even though all were self-ratings), and only one therapist gave the
treatment. However, before the trial, H.S. did not have any experience of any
form of psychological treatment although she had carried out previous research
as an assessor in psychiatric studies. The control group received no treatment
apart from a single interview and so therapy time was not equivalent; a recent
study has shown that the effects of CBT (in a similar population with
medically unexplained symptoms) are largely attenuated when treatment time is
equivalent.19
Implications
Our findings are encouraging and one of their most striking aspects was the
maintenance of therapeutic benefit beyond the period of active treatment. Only
four patients had any treatment after 6 months, yet the differences in scores
between the groups were as great at 12 months as they were at 6 months (online
Table DS3). This is somewhat unusual, as although CBT has been shown to be
effective in the short- and medium-term treatment of many anxiety disorders,
including those with medically related conditions common in liaison
settings,21–23
there is also evidence that its effects diminish in the medium and long
term.23–25
Part of this apparent loss of efficacy is the natural tendency for many of
these disorders to improve over time irrespective of specific treatment, but
this may not apply to health anxiety as it is more
persistent.6 The
level of improvement was substantial and at 12 months the levels of anxiety in
the treatment group (mean HAI score=10.4) were generally well within the
normal range (mean HAI for
controls=9.4).5 This
symptomatic improvement also extended to social functioning as the mean scores
at 6 months (5.1) and 12 months (5.2) were only marginally greater than the
mean of 4.6 found in a large random sample in a national
survey.11
As these gains were achieved with a mean of 4.3 sessions of treatment it appears that this adaptation of CBT for health anxiety in such clinics could offer a significant opportunity to reduce, if not eliminate, an unpleasant, persistent and often undetected form of morbidity, especially in some clinics where health anxiety is particularly severe.26 However, it is not clear to what extent the bibliotherapy component contributed to the improvement. Most of the patients regarded the written material as helpful (online Table DS2), but verbal feedback suggested this was being used as an aid to recognition of abnormal health perception and to work done in therapy. A preliminary study has, however, suggested that bibliotherapy alone may be of benefit without the need for face-to-face contact.27
It is also well known that early trials of many interventions generally demonstrate greater effect sizes than later large trials, for a variety of reasons,28 and it would be unreasonable to expect the same active/control difference in a large trial. H.S. was not masked and this constitutes a limitation to the study, but the fact that all assessments were self-reports and the evidence that there were no differences in the telephone and postal active-control treatment differences suggestive of bias gives more credence to the findings. Although the benefits of this approach, which we accept might accrue from other structured psychological treatments, could be influenced by many factors, we feel that the administration of treatment within the framework of the clinic by one of its regular practitioners was an important one. In this setting there is also the possibility of booster sessions, or even simple reminders, of the essential aspects of treatment that can ward off significant relapse, and the bibliographic component of the treatment may also help in this task. The continuing benefit is also important in offsetting the cost of treatment through reduced consultation.
Planned developments
The results suggest there is no reason, in principle, why future treatment
for health anxiety should not include many other secondary care doctors having
this expertise. This would require much greater training to increase awareness
of psychological aspects of health anxiety as well as teaching health service
staff to use the technique. Such a development is in keeping with recent
recommendations about the expansion of CBT away from classical psychiatric
locations29 and,
more radically, could be the start of what Rief &
Sharpe30 have
called `a move toward a psychologically sophisticated healthcare system in
which psychological assessment and intervention are fully (re)integrated into
medical care'. This would lead to liaison psychiatric services acting not just
as a secondary referral source for a minority of patients, but as an
integrated service within secondary medical care in which both identification
and treatment of health anxiety would be improved and expensive investigations
reserved for those that really require them rather than as a procedure driven
by defensive medicine and clinical doubt.
Our findings also suggest that benefit is likely to be achieved not only in terms of reduced morbidity but in improvement of clinic function by reducing the number of (unnecessary) consultations, although a much larger study would be necessary to have the power to confirm this. Service use by participants in the CBT group was substantially lower than by those in the control group in the second 6 months of the study after treatment had been completed, suggesting that over a longer follow-up period, the cost of the CBT could be offset, but only if the improvements seen over 12 months were maintained. Cognitive–behavioural therapy for health anxiety improved outcomes, but the costs were not entirely offset by reduced service use elsewhere in the health system, and so the total costs were slightly higher. The incremental cost of the intervention was £33 per unit reduction in HAI score. Adoption of CBT for health anxiety would thus depend on decision-makers' willingness to pay for improvements in outcomes. The sensitivity analysis demonstrated that the cost of CBT has a substantial impact on the cost-effectiveness of the intervention. If the costs of CBT can be kept low without having an impact on its effectiveness, then there is an increasing possibility that the costs will be offset by lower levels of service use, as seen in the CBT group, elsewhere in the health system.
The results suggest that CBT is significantly more effective and may have a more positive effect on health service costs than simple control measures, so that the cost per unit improvement effectiveness outcome is low. A pilot study such as this can only provide limited evidence of efficacy and cost equivalence; however, a large-scale study is currently being carried out on the efficacy of this treatment in other medical clinics (www.controlled-trials.com/ISRCTN14565822).
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