Centre for Health Economics, York
St George's Hospital, London
Centre for Health Economics, York
Imperial College, London
St George's Hospital, London
St Mary's/St Charles Hospital, London
King's/Maudsley Hospital, London
Royal Infirmary, Manchester
Correspondence: Sarah Byford, Centre for Health Economics, University of York, Heslington, York YO10 5DD
Declaration of interest Funded by the UK Department of Health and NHS Research and Development programme.
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ABSTRACT |
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Aims To investigate the cost-effectiveness of intensive compared with standard case management for patients with severe psychosis.
Method 708 patients with psychosis and a history of repeated hospital admissions were randomly allocated to standard (case-loads 30-35) or intensive (case-loads 10-15) case management. Clinical and resource use data were assessed over two years.
Results No statistically significant difference was found between intensive and standard case management in the total two-year costs of care per patient (means £24 550 and £22 700, respectively, difference £1850, 95% Cl - £1600 to £5300). There was no evidence of differential effects in African-Caribbean patients or in the most disabled. Psychiatric in-patient hospital stay accounted for 47% of the total costs, but neither such hospitalisation nor other clinical outcomes differed between the randomised groups.
Conclusion Reduced case-loads have no clear beneficial effect on costs, clinical outcome or cost-effectiveness. The policy of advocating intensive case management for patients with severe psychosis is not supported by these results.
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INTRODUCTION |
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METHOD |
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Patients
Patients were recruited from four inner city areas - three in London (St
George's Hospital, St Mary's Hospital and King's College Hospital) and one in
Manchester (Manchester Royal Infirmary). Patients, identified by review of
in-patient and out-patient registers, were included in the study if they were
aged between 18 and 65 years, had suffered from a psychotic illness of at
least two years and had been admitted to a psychiatric hospital at least
twice, once within the past two years. Diagnoses were determined by a
structured examination of case notes, using the Operational Criteria Checklist
(OPCRIT; McGuffin et al,
1991). Patients were excluded if they had organic brain damage or
a primary diagnosis of substance misuse.
Recruitment was carried out between February 1994 and April 1996. Patients were randomly allocated to two years of either intensive case management (case-load size 10-15) or standard case management (case-load size 30-35) and assessed at base-line, 12 and 24 months by researchers independent of those providing clinical care.
Randomisation was stratified by centre and conducted by an independent statistical centre. Ethical approval for the study was gained from all four local ethics committees.
Intervention
Case management for patients with severe mental illness is a system of care
delivered by trained mental health professional (e.g. nurses, social workers
or psychologists). It can involve the direct provision of care as well as the
coordination of interventions required by this patient group, often including
a wide range of health and social services
(Intagliata & Baker, 1983; Thornicroft, 1991). Intensive
case management can be distinguished from standard case management by the
nature of its reduced case-load size.
In order to ensure consistency of the interventions between the four participating sites, case managers were given a two-day induction course in case management by the Sainsbury Centre for Mental Health, and instruction in outreach practice was given to intensive case managers by a team leader in assertive community treatment from Boulder, Colorado, USA.
Clinical outcomes
The primary outcome measure was days in hospital for psychiatric problems
over 24 months, recorded in a modified World Health Organization (WHO) Life
Chart (WHO, 1992). This
measure was selected because it is the most consistently reported outcome in
case management studies (Holloway et
al, 1995) and is therefore the best benchmark for locating
our results. Furthermore, the two most commonly cited objectives in case
management studies are improved contact and reduced hospitalisation, with
reduced hospitalisation reflecting improved community tenure and social
adjustment.
Secondary measures included clinical status assessed using the
Comprehensive Psychiatric Rating Scale (CPRS)
(sberg
et al, 1978), quality of life assessed using the
Lancashire Quality of Life Profile (Oliver
et al, 1997), unmet needs recorded using the Camberwell
Assessment of Need (Phelan et al,
1995), social disability measured by the WHO Disability Assessment
Schedule (DAS) (Jablensky et al,
1980) and patient satisfaction assessed using a self-report
questionnaire (Tyrer & Remington,
1979).
Cost
The perspective of this trial was that of all service providing sectors in
society, thus enabling the differential impact of case management on each
sector to be clearly quantified. Patient and family costs and the indirect
costs associated with employment were excluded from the analysis to avoid
overburdening respondents already faced with extremely long interview
schedules. However, the likely impact of these exclusions is considered in the
discussion section below.
Information on the use of all hospital and community services was collected prospectively for each patient over the study period. A number of sources were used, including event records of community mental health team (CMHT) activities, clinical records, patient interview at Year 1 and Year 2 follow-up, local authority social services departments and questionnaires completed by case managers.
Sources of unit costs are summarised in Table 1. Where possible, these were calculated on the basis of information provided by the relevant local service providers, thus London costs, with associated London weighting, were applied to the three London sites. Unit costs of services that could not be determined locally and those of relatively small service components were taken from national publications (Schneider, 1996; HM Prison Service, 1997; Netten & Dennett, 1997; British Medical Association, 1998; Chartered Institute of Public Finance and Accountancy (CIPFA), 1998). For London based services only, national unit costs were weighted to take into consideration the higher cost of service provision, where appropriate. All unit costs were calculated for the financial year 1997/98. Published unit costs were inflated to 1997/98 prices where necessary (personal communication, Public Expenditure Survey Team, 1998) and future costs were discounted at an annual rate of 6%.
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Information on all contact and attempts at contact with trial participants by CMHT professionals were based on the prospective completion of event records. Five categories of events were recorded: (a) face-to-face contact with patients; (b) telephone contact with patients; (c) carer contact; (d) care co-ordination; and (e) attempted face-to-face contact with patients. For each professional, a cost per minute was calculated from the mid-point of the relevant 1997/98 salary scales and included employers' national insurance and superannuation contributions, London weighting where appropriate, and 20% for overheads. To take into consideration time spent on non-patient-specific activities such as supervision, training and paperwork, staff costs were inflated assuming a ratio of 1:1 for non-event to event recorded time. This figure was estimated on the basis of time diary exercises, audits of event recording activity and published inflation ratios for similar professionals (Netten & Dennett, 1997).
Statistical methods
Sample size calculations for the cost component of this trial were based on
the results of the Daily Living Programme Study
(Knapp, 1995). A sample size
of 350 patients in each group was anticipated to be able to detect a
difference of £45 in the average weekly cost per patient (e.g. a
reduction from £200 to £155, with standard deviation equal to the
mean) as statistically significant at the 5% level with 80% power
(UK700 Group: Creed et al,
1999).
All clinical and economic analyses were carried out on an intention to treat basis using a statistical analysis plan drawn up before looking at the data (UK700 Group: Creed et al, 1999). Although costs were not normally distributed, analyses compared the mean costs in the two groups using standard t-test methods, with the validity of results confirmed using boot-strapping (Efron & Tibshirani, 1993). The advantage of this approach, as opposed to logarithmic transformation or conventional non-parametric tests, is the ability to make inferences about the arithmetic mean (Barber & Thompson, 1998).
The primary analysis was of total costs but results are also given by cost sector, and individual resource use components are detailed. Multiple regression was used to adjust for baseline characteristics of patients, these being centre, age, gender, ethnic group (African-Caribbean v. other), source (hospital v. community), CPRS, DAS, social class (non-manual, manual, long-term unemployed), duration of illness, days in hospital two years prior to randomisation and OPCRIT diagnosis. Subgroup analyses were performed using tests of interaction. Sensitivity analyses were carried out to assess the robustness of results to assumptions made in the costing procedure. In cost-effectiveness analyses the confidence regions for the incremental costs and effects (van Hout et al, 1994) were calculated using bivariate percentile bootstrap methods (Davison & Hinkley, 1997).
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RESULTS |
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As previously reported, there was no difference between intensive and standard groups in terms of the primary outcome measure, days in hospital for psychiatric problems over 24 months (means 73.5 and 73.1 days, difference 0.4 days, 95% CI -17.4-18.1) (UK700 Group: Burns et al, 1999). Nor were there any significant differences in the secondary outcome measures between the intensive and standard groups: mean CPRS scores 18.5 and 18.1 (difference 0.4, 95% CI -1.8-2.7); mean quality of life scores 4.58 and 4.55 (difference 0.04, 95% CI -0.09-0.16); mean number of unmet needs 1.84 and 2.13 (difference -0.29, 95% CI -0.68-0.11); mean DAS total score 1.10 and 1.13 (difference -0.03, 95% CI -0.16-0.10); and mean patient's satisfaction score 16.7 and 17.1 (difference -0.3, 95% CI -1.2 to 0.5).
Cost
Table 1 details the mean
number of contacts patients had with all services over the two-year follow-up,
along with unit costs and the source of these costs. As would be expected, on
average more event recorded activities per patient were carried out by
intensive case managers compared with standard case managers and over twice as
much time was spent per patient on these activities (means 89 and 36 hours,
respectively). The use of all other services differed little between the two
groups.
Table 2 details the total cost of all services used by the intensive and standard groups over the two-year follow-up period. The distributions of total costs in each group are displayed in Fig. 1. No significant differences were found in the average overall costs of care per patient between the intensive and standard case management groups (means £24 553 and £22 704 respectively; P=0.29). Adjustments for baseline variables did not materially alter these results (P=0.48). It is interesting to note that the difference observed in total costs per patient (£1849) appears to be accounted for mainly by the difference in the cost of case management per patient (£1830), with little impact of intensive case management being observed in the non-health care sectors.
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No statistically significant sectoral differences between intensive and standard groups were found. Case management constituted 13% of the total cost of care of the intensive group (mean £3089) and 6% of the standard group (£1259). The largest proportion of total cost was borne by the health sector (66% in the intensive group and 64% in the standard group). Staffed accommodation also made a relatively large contribution to the total costs of care (25% intensive; 27% standard).
Subgroup analyses
No significant differences in the effect of intensive case management on
costs were found between the four centres
(Table 3). Analyses according
to ethnic group (African-Caribbean v. other) and severity of social
functioning, measured by the DAS (moderate v. severe) also showed no
evidence of differential effects (Table
3).
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Cost-effectiveness analysis
Given that neither form of case management demonstrated dominance in terms
of either costs or effects, a formal cost-effectiveness analysis is not
required in this trial. However, an exploration of the relationship between
costs and the primary clinical outcome measure highlights the correlation
between days in hospital for psychiatric problems and total costs
(Fig. 2). Psychiatric
in-patient costs comprised almost half of the total costs of care for the
patients in both the standard (48%) and intensive groups (47%).
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Figure 3 shows the 95% joint confidence region for the average differences between intensive and standard case management in costs and in psychiatric hospitalisation. The interior of the ellipse gives the range of values for the true average cost and in-patient differences that are compatible (at a 95% confidence level) with the data from the trial. The orientation of the ellipse is a consequence of the strong relationship between total costs and hospitalisation seen in Fig. 2. The zero origin is near the centre of the region, showing the lack of evidence of differences in either costs or hospitalisation. There is thus no evidence that intensive case management is more cost-effective than standard case management, or indeed vice versa.
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Sensitivity analyses
Variation of unit cost assumptions made in the analysis did not change the
interpretation of the results (Table
4). The discount rate was assumed to be 6% and was varied between
0% and 10%. Capital overheads were assumed to be 20% of the cost of CMHT staff
and these were varied between 0% and 40%.
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Exploration of patient contact data at each of the four sites suggested that an inflation rate of 1:1 for non-event recorded to event recorded time for both standard and intensive case managers may be too simplistic. For intensive case managers, the evidence suggested that the ratio ranged from a minimum of 1:1 to a maximum of 1.5:1, while for standard case managers, with larger case-loads and less time available for non-patient-specific activities, this range was 2/3:1 to 1:1. Three sensitivity analyses were performed using the following ratios: (a) the minimum inflation rate for both intensive and standard case managers (1:1 and 2/3:1, respectively); (b) the maximum inflation rate for both intensive and standard case managers (1.5:1 and 1:1, respectively); and (c), to influence the results against intensive case management, the maximum inflation rate for intensive case manager and the minimum for standard (1.5:1 and 2/3:1, respectively). None of these analyses altered the conclusion of the main analysis (Table 4).
To study the generalisability of the results of this trial to other locations in the UK, the key cost drivers, psychiatric in-patient care and staffed accommodation, were varied. Minimum and maximum values for the UK were taken from statistics produced by the Chartered Institute of Public Finance and Accountancy which detail the cost of accommodation by local authority (CIPFA, 1998) and the cost of hospital in-patient treatment by speciality for all National Health Service trusts (CIPFA, 1997). Again, the conclusions were unaltered (Table 4).
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DISCUSSION |
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Cost
No statistically significant differences were found between intensive and
standard case management in terms of either total two-year costs per patient
or the main clinical outcome measures over the two-year period of the trial.
Sensitivity analyses did not alter this result. The key cost-drivers in this
patient group were in-patient psychiatric costs and staffed accommodation,
which together accounted for approximately 73% of the total costs of care. The
fact that intensive case management failed to reduce the use of either of
these services explains the lack of any significant cost differences between
the two groups.
Cost-effectiveness analysis
Figure 3 clearly shows the
lack of evidence to suggest that intensive case management is more, or indeed
less, cost-effective than standard case management. Although hospitalisation
was both the main clinical outcome and a major driver of overall costs, it
remains relevant to use this measure in the cost-effectiveness evaluation.
However, had one of the secondary outcome measures been used in place of
hospitalisation the result that intensive case management is no more
cost-effective than standard case management would remain unchanged, since
there is no evidence of a difference between randomised groups for any of the
secondary measures.
Perspective
Although the perspective taken in this trial was broad, it was not
societal, having excluded the impact of intensive case management on patients
and families and on the indirect costs associated with employment. Given the
lack of differences between the two groups in outcomes and resource
utilisation, it seems reasonable to assume that patient and family costs would
also differ little. However, the economic impact of case management on
relatives and carers is being explored in one of the four centres and will be
reported separately. Exploration of months in full-time employment and months
unemployed at two-year follow-up revealed no significant differences between
the intensive and standard groups, suggesting that the inclusion of these
indirect costs would not materially alter the results of the trial.
Policy implications
This multi-centre, randomised trial indicates that intensive case
management by mental health workers with a reduced case-load has no clear
beneficial effect on costs, clinical outcome, or cost-effectiveness in
populations with severe psychoses. The policy of advocating intensive case
management for all patients with severe psychosis is not supported by these
results and needs to be re-examined.
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Clinical Implications and Limitations |
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LIMITATIONS
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ACKNOWLEDGMENTS |
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The UK700 trial was funded by grants from the UK Department of Health and NHS Research and Development Programme.
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Received for publication June 4, 1999. Revision received October 20, 1999. Accepted for publication October 26, 1999.