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Improving asthma care through audit |
Ayriss M D, Bruins R H, Davidson M, Goel A |
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Record Status This is a critical abstract of an economic evaluation that meets the criteria for inclusion on NHS EED. Each abstract contains a brief summary of the methods, the results and conclusions followed by a detailed critical assessment on the reliability of the study and the conclusions drawn. Health technology A programme for the improvement of asthma care in young patients was examined. The level of asthma education was improved and changes to the patients' treatment were also carried out. Such changes included increasing the dose of beclomethasone dipropionate or budesonide. A change to fluticasone propionate was made with or without the addition of salmeterol. If the patients were already taking inhaled steroids and were still suffering from persistent symptoms, then salmeterol was added. If the inhaler technique was inadequate, the devices were changed according to the patient's preference.
Economic study type Cost-effectiveness analysis.
Study population The study population comprised patients aged 5 to 19 years with inadequate asthma control, as determined by the frequency of repeat prescriptions for relief medication, or who presented with symptoms at the asthma clinic.
Setting The setting was primary and secondary care. The economic study was carried out at the Riley House Surgery in Enfield, Middlesex, UK.
Dates to which data relate The effectiveness and resource use data were gathered between July 1996 and July 1997. The price year was 1997.
Source of effectiveness data The effectiveness evidence was derived from a single study.
Link between effectiveness and cost data The costing was carried out prospectively on the same sample of patients as that used in the effectiveness study.
Study sample Power calculations to determine the sample size were not reported. A sample of 48 eligible patients was identified at the Riley House Surgery during the study period and was enrolled into the study. The method of sample selection was not described, as it was unclear whether some patients were excluded for any reason from the initial study sample or refused to participate. The participants were aged from 5 to 19 years. Other baseline characteristics were not reported.
Study design This was a prospective, within-group comparison study, which was conducted in a single centre (the Riley House Surgery in Enfield). The patients were followed for one year and data from the preceding 4 months were recorded. No loss to follow-up was observed. The baseline and 12-month data were used to compare the outcomes in the two time periods (standard care versus improved care). The patients were seen during the 12-month follow-up period to check their progress and adjust their treatment, if required.
Analysis of effectiveness It appears that all the patients included in the initial study sample were accounted for in the effectiveness analysis. The health outcomes used were:
the changes in night-time, day-time, or exercise-induced symptoms;
the peak flow rates;
compliance and inhaler technique;
supplementary drug intervention;
supplementary medical intervention; and
the use of drugs and devices.
Effectiveness results At baseline, 46% of the patients experienced night-time symptoms with 33% being woken up every night because of asthma. At the final assessment, all patients except one (98%) were free of night-time symptoms. The difference was highly significant, (p<0.0001).
At baseline, 48% of the patients experienced day-time symptoms and only 17% were symptom-free. At final assessment, 83% of the patients were free of day-time symptoms and 13% suffered from symptoms once or twice per month only. This difference was highly significant, (p<0.0001).
At baseline, 77% of the patients experienced exercise-induced symptoms and 17% experienced symptoms even when walking on the flat. At the final assessment, none of the patients suffered from symptoms when walking on the flat and 75% of patients rarely suffered from exercise-induced symptoms. This difference was highly significant, (p<0.0001).
The median clinic peak flow increased by 50 L/minute (range: 40 - 170). This change was highly statistically significant.
Compliance improved from 90 to 95% and inhaler technique from 98 to 100%.
Fewer supplementary drug interventions and supplementary medical interventions were observed in the last months of the 12-month period, compared with the baseline assessment.
In terms of drug and device usage, there was a trend towards fewer relief medications (average of 3.6 doses/patient per day at baseline to 0.2 at final assessment), more patients taking fluticasone propionate, and fewer prophylactic medications (budesonide, beclamethasone dipropionate and cromoglycate). There was an increase in the use of salmeterol and a shift from metered-dose inhalers to dry-powder devices (mainly Accuhaler).
Clinical conclusions The effectiveness analysis showed that the programme for improving asthma care in young patients was effective in achieving symptom control and a more appropriate use of drugs and devices. This subsequently led to fewer visits and a reduction in the use of drugs.
Measure of benefits used in the economic analysis The health outcomes were left disaggregated and no summary benefit measure was used in the economic evaluation. Consequently, the study was classified as a cost-consequences analysis.
Direct costs Discounting was not relevant since the costs were incurred during less than 2 years. The unit costs were not reported separately from the quantities of resources used. The health services in the economic analysis were medical visits, drug prescriptions and devices for treating asthma events. The cost/resource boundary of the study was that of a practice or a health authority. Resource use was estimated using actual data coming from the sample of patients who were involved in the effectiveness study. No wastage was assumed. The unit costs were estimated from actual medical care costs derived from practice or health authority estimates. The price year was 1997.
Statistical analysis of costs The costs were not treated stochastically.
Indirect Costs The indirect costs were not included.
Sensitivity analysis Sensitivity analyses were not performed.
Estimated benefits used in the economic analysis See the 'Effectiveness Results' section.
Cost results The total costs of treatment rose from 3,378 in the pre-intervention phase to 4,189 in the post-intervention phase. However, the cost of treating asthma events decreased from 985 to 92. Therefore, the total asthma costs were 82 lower at the second assessment (a 1.9% reduction).
Synthesis of costs and benefits Not relevant as a cost-consequences analysis was carried out.
Authors' conclusions The implementation of a programme to improve the care of young asthmatic patients was effective in improving symptom control, decreasing the use of medical resources, and subsequently reducing the overall health care costs associated with the care of these patients.
CRD COMMENTARY - Selection of comparators The choice of the comparator, the standard approach for managing asthmatic patients, was appropriate as it reflected the usual care option. You should decide whether it represents a valid comparator in your own setting.
Validity of estimate of measure of effectiveness The basis of the analysis of effectiveness was a within-group comparison study, which used the same group of patients to compare the pre- and post-intervention outcome measures. The pre-study phase reflected the standard care patients received without any explicit intervention. Therefore, it represented "real life" care. In the authors' mind, this represented an advantage over more controlled study settings such as clinical trials. However, it has to be noted that this design does not allow the accurate identification of factors affecting changes in the outcomes. In addition, it is likely that factors other than the study intervention may have had an impact on the results of the effectiveness analysis. Indeed, the authors noted that some confounding factors could have played a role. Despite possible confounding, the results of the analysis were considered encouraging.
The study sample was likely to have been representative of the study population as no strict enrolment criteria were used. However, the fact that the patients were selected from a single centre limits the transferability of the results. A further limitation to the internal validity of the analysis was the lack of power calculations and the fact that no evidence of an appropriate sample size was provided. In the 'Introduction' section, the authors referred to the aim of improving quality of life, but this outcome was not assessed in the study. It would have been an appropriate measure of effectiveness.
Validity of estimate of measure of benefit No summary benefit measure was used in the analysis because a cost-consequences analysis was conducted.
Validity of estimate of costs The perspective of the study was unclear, but it is likely to have been that of the practice or health authority. As such, all the relevant costs were considered in the analysis. Costs relevant to the patients, such as over-the-counter expenses, which are substantial for asthmatic patients, were not considered since they were not relevant to the perspective of the health authority. The price year was reported, thus making reflation exercises in other settings easy. There were few details on the resource use and cost data and this limits the replication of the study. Resource use was estimated using actual data, which were gathered prospectively. However, the cost estimates were specific to the study setting. No sensitivity analyses or statistical tests were carried out on the cost data. A major assumption concerning no wastage was made, although the authors stated that wastage is quite common, especially with devices such as those considered in the study. Therefore, the actual difference in the costs between the pre- and post-intervention phases might be more modest than observed.
Other issues The authors compared implicitly their findings with those from other studies that found similar results in terms of cost-reductions associated with more tailored forms of care for asthmatic patients. However, the issue of the generalisability of the study results was not addressed and sensitivity analyses were not carried out. Therefore, the external validity of the analysis was low. The authors discussed some limitations of their analysis, which have been reported already. The objective of the analysis was reflected in the authors' conclusions, with the exception of the improvement in patient quality of life, which was not assessed.
Implications of the study The study results suggested that improvements in the management of young asthmatic patients were obtained in a practice where good levels of asthma care were already provided. The freedom to tailor medication to individual needs led to a more appropriate care without increasing the overall costs of care, despite the use of more expensive devices and medications.
Bibliographic details Ayriss M D, Bruins R H, Davidson M, Goel A. Improving asthma care through audit. Journal of Clinical Excellence 2000; 1: 229-234 Indexing Status Subject indexing assigned by CRD MeSH Adolescent; Asthma /therapy; Beclomethasone; Budesonide; Child; Cost-Benefit Analysis; Forced Expiratory Volume; Great Britain; Medical Audit; Nebulizers and Vaporizers; Patient Education as Topic /methods /economics; Self Care AccessionNumber 22000008095 Date bibliographic record published 31/08/2004 Date abstract record published 31/08/2004 |
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