Infopoints: NHS Economic Evaluation Database for healthcare decision makers -- Nixon et al. 321 (7252): 32 Data Supplement

Appendix: Example NHS EED abstract

Cost effectiveness of community leg ulcer clinics: randomized controlled trial

Morrell C J, Walters S J, Dixon S, Collins K A, Brereton L M L, Peters J, Brooker C G D

British Medical Journal, 1998, 316, pp.1487-1491

This record was compiled by CRD commissioned reviewers according to a set of guidelines developed in collaboration with a group of leading health economists.

Health technology

Clinic-based weekly treatment of leg ulcers with four layer bandaging or usual home-based care by district nurses.

Disease

Skin and connective tissue diseases.

Type of intervention

Treatment.

Hypothesis/study question

The objective of the study was to assess the cost-effectiveness of using clinic-based weekly treatment of leg ulcers with four layer bandaging versus using the usual home-based care by district nurses for the treatment of venous leg ulcers. Home-based care was explicitly considered as the comparator since it represented the common practice in dealing with venous leg ulcers.

Economic study type

Cost-effectiveness analysis.

Study population

The study population comprised patients who had had a venous ulcer below the knee to the foot for at least 3 months and who were able to travel to the clinic.

Setting

Community and primary care. The economic study was carried out in Sheffield, UK.

Dates to which data relate

The effectiveness data and resources use data were gathered between September 1994 and May 1995. 1995 prices were used.

Source of effectiveness data

The evidence for the final outcomes was derived from a single study.

Links between effectiveness and cost data

The costing was undertaken prospectively on the same patient sample as that used in the effectiveness study.

Single study

Study sample

Power calculations were used to determine the sample size. A total of 328 subjects attended for assessment, of whom 233 were randomly assigned: 113 to the home group and 120 to the clinic group. Patients (93) from the original 328 with an ankle brachial pressure index of <0.8 were excluded from the clinic group and returned to home care. Two patients refused to participate and were returned to home care.

Study design

The study was a randomised controlled trial carried out in eight centres (Sheffield, Nottingham, Derby and Sutton-in-Ashfield). The duration of the follow-up was 1 year and the drop out rates were 14.2% for the clinic and 20.3% for the home group. A random assignment schedule and serially numbered, sealed, opaque allocation envelopes were prepared in advance for each of the eight clinic sites.

Analysis of effectiveness

The analysis of the effectiveness study was based on intention to treat. The primary health outcomes were the initial healing time of the ulcers, the cumulative percentage of ulcer healed at 12 weeks, the ulcer recurrence rate from the initial ulcer healed time to first ulcer recurrence, the average ulcer-free time over the 12 month follow-up period, and health status measured by the 36 item short form health survey (SF-36), the EuroQol (EQ), the McGill short form pain questionnaire (SF-MPQ), and the Frenchay activities index. The groups were shown to be comparable in health status and demographic features. The effects of confounding variables such as age, ulcer area, ulcer duration, and history of deep vein involvement on healing times were adjusted using Cox proportional hazards regression analysis.

Effectiveness results

The clinic group had a better record in initial healing times (P= 0.03) and had a higher rate of cumulative percentage of ulcer patients healed at 12 weeks (34% versus 24% in the home group, 95% CI for the difference was -2% to 22%). The patients in the clinic group were 1.45 times more likely to be healed from the initial ulcer (95% CI: 1.04 - 2.03). When adjusted for confounding variables the clinic group were 1.65 times (1.15 to 2.35) more likely to be healed. The clinic group experienced a higher rate of ulcer recurrence after the initial healing (35% versus 23% in the home group). The study revealed no difference in the time to first ulcer recurrence between the groups (log rank test 0.78; df=1; P=0.38). The average ulcer-free time over a one year follow-up period was 20.1 weeks for the clinic group and 14.2 weeks for the home group (95% CI for the difference was 1.2 to 10.5). According to the health status measures, no significant differences between the groups were identified.

Clinical conclusions

The study revealed that the clinic-based treatment using four layer bandaging supplied by specially trained nurses was more effective than the usual home-based care provided by district nurses.

Economic analysis

Measure of benefits used in the economic analysis

Ulcer-free time (weeks) was considered by the authors as the most appropriate measure to be included in the economic analysis.

Direct costs

Quantities were reported separately from costs for the home group but not for the clinic group (reported in a separate paper). The average annual total costs were divided into leg ulcer treatment cost per year including staff time, materials, transport, and overheads; the cost of GP services per year; and the cost hospital services per year. The average cost per clinic attendance and per home visit were reported. The cost calculations were undertaken from an NHS point of view. The cost data related to overhead costs were obtained from the service managers. 1995 prices were used. Indirect costs of the patients were not considered.

Indirect costs

Not included.

Currency

UK pounds Sterling (£).

Statistical analysis of costs

Permutation tests were performed to compare the average costs between the groups.

Sensitivity analysis

A series of one-way sensitivity analyses was carried out on treatment costs and overhead costs to assess the effects of changes in baseline values on the average total costs.

Estimated benefits used in the economic analysis

The average ulcer-free time over a one year follow-up period was 20.1 weeks for the clinic group and 14.2 weeks for the home group (95% CI for the difference was 1.2 to 10.5).

Cost results

The average (SD) total costs for the clinic group were £877.6 (674.3) versus £863.09 (865.32) for the home group.

Synthesis of costs and benefits

A synthesis of costs and benefits was carried out by calculating a cost-effectiveness ratio (additional cost required per additional ulcer-free week). The value of the ratio was £2.46 (-£31.94 to £99.12) per ulcer free week. None of the parameters in the sensitivity analysis had significant effects on the average costs of the alternative heath technologies. The authors pointed out that, if the grade of the nurses reduced from G or H to E, and if throughput per session increased to more than 10 patients, the clinic-based treatment would dominate the usual home-based care.

Conclusions, commentary and implications

Author’s Conclusions

Community-based leg ulcer clinics with specially trained nurses, using four layer bandaging, were more effective than traditional home based treatment. This benefit was achieved at a small additional cost and could be delivered at reduced cost if certain service configurations were used.

CRD commentary

Selection of comparators:

The reason for the choice of the comparator is clear. The comparator was chosen because it represented the routine care provided for patients with venous leg ulcers. You should consider whether this is a widely used technology in your own setting.

Validity of estimate of measure of benefit:

The estimates of the measure of benefit are likely to be valid because of randomisation and accounting for the effects of confounding variables. 93 patients were excluded from the trial as they were contraindicated for four layer compression bandages. Additionally, the care provided in the community was not a standard treatment as in the case of the clinic group. These factors may tend to bias the benefit results in favour of the clinic group.

Validity of estimate of costs:

The resource quantities were not reported for the clinic-based treatment. As the authors noted, it would have been more appropriate to have included the indirect costs of the alternative heath technologies. The exclusion of indirect costs might have biased the results in favour of the home-based treatment. Indirect cost analysis would have permitted the adoption of a societal as well as an NHS perspective.

Other issues:

The issue of generalisability to other settings was partially addressed by performing sensitivity analyses on the cost items.

Implications of the study

The findings of the study suggest that for venous leg ulcer clinics (using four-layer compression bandaging) to be a cost-effective option for the NHS, they should only be implemented if they are staffed by appropriately trained nurses in the relevant grades, with an optimal flow of patients.

Country code

United Kingdom.

Review funding body

Study commissioned and funded by the former Trent Regional Health Authority (now NHS Executive Trent).

Address for correspondence

Dr C J Morrell, School of Health and Related Research (ScHARR), University of Sheffield, Sheffield S1 4DA, United Kingdom.

988130 31121998

NHS Centre for Reviews and Dissemination

University of York, York, YO10 5DD

revdis{at}york.ac.uk

We thank Jane Morrell and colleagues at the School of Health and Related Research (ScHARR), University of Sheffield, for their feedback and comments regarding the abstract used in this article.