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Care of asthma: allergy clinic versus emergency room |
Moore C M, Ahmed I, Mouallem R, May W, Ehlayel M, Sorensen R U |
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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 Allergy clinics and emergency room treatment for asthma.
Economic study type Cost-effectiveness analysis.
Study population Asthmatic patients (children) from an inner-city area in the USA. All patients came from low income, working families without medical insurance and were ineligible for Medicaid.
Setting Hospital. The study was carried out at the Medical Center of Louisiana in New Orleans, USA.
Dates to which data relate Effectiveness and resource data were collected over the period December 1992 to March 1993.1994 prices were used.
Source of effectiveness data Effectiveness data were derived from a single study.
Link between effectiveness and cost data Costing was undertaken alongside the same patient sample as that used in the effectiveness study.
Study sample 75 asthmatic patients were included in the study: 25 allergy clinic patients and 50 emergency room patients. It was not stated whether power calculations were used to determine the sample size.
Study design The study used a single-centre retrospective case-control design. Allergy clinic patients and emergency room patients were interviewed using an identical questionnaire. Neither the duration of follow up nor the loss to follow up were reported.
Analysis of effectiveness The analysis of the study was based on intention to treat. The main outcomes were morbidity, mortality, number of admissions (clinic and emergency room), nocturnal cough, steep interruption, and weekly asthma. The groups were shown to be comparable in terms of sex and race distribution, total number of adults in the family, level of education, family income, type and size of dwelling, ages of onset, and severity of the disease. Sex and race distribution, total number of adults in the household, total number of children in the family, family monthly income, type of health insurance, and method of paying for medications, type and size of dwelling, ages of onset, and severity of the disease, were not significantly different in the allergy clinic and emergency room groups. The emergency room patients were younger than the allergy clinic group. The level of education of the patient's caregiver was significantly higher in the allergy clinic group (P=0.02).
Effectiveness results The age-adjusted lifetime number of admissions was 0.67 (+/-0.73) for allergy clinic patients and 1.88 (+/- 0.49) for the emergency room patients (P=0.18). A rank analysis of the average yearly admission yielded a P value of 0.68. The annual number of emergency room visits for the allergy clinic group was 3.45 (+/-0.99), and for the emergency room group, 6.1 (+/- 0.86), (P<0.09). 76% of the allergy clinic patients used the allergy clinic as their primary source of care and 72% of the emergency room patients' use the emergency room (P<0.001). The clinic group had significantly less nocturnal cough (P<0.025), sleep disruption (P<0.001), weekly asthma (P<0.05), and emergency room visits (P<0.09).
Clinical conclusions Allergy clinic patients have less asthma-related morbidity.
Measure of benefits used in the economic analysis No summary benefit measure was used and as such the benefits are assumed to be the same as the effectiveness results. Clinic patients and emergency room patients were interviewed using an identical questionnaire.
Direct costs The cost of emergency room and allergy clinic care was calculated using a chart review. The inpatient and mean yearly cost of care per patient in each group were also calculated.1994 prices were used.
Statistical analysis of costs The Mann-Whitney test based upon rank transformation of the data was used to compare the distributions for the clinic and emergency room groups. Contingency tables were constructed and analyses based upon Pearson's chi squared approximation were performed. In cases where the latter could not be used, a Fisher's exact test was used to compare the two groups. For age-adjusted analysis, the data were analysed using the Mantel-Haenszel test. For continuous variables, a covariant adjustment for agewas used.
Sensitivity analysis Sensitivity analysis was not carried out.
Estimated benefits used in the economic analysis There was a significant decrease in the number of attacks of asthma requiring an emergency room visit in the allergy clinic group. 63% of allergy clinic patients no longer need to go to the emergency room for treatment of their asthma in the 12 months preceding the study.
Cost results The cost comparison of allergy clinic and emergency room patients by source of treatment was:
emergency room, $345 (+/- 96) and $668 (+/- 107), (P=0.02);
inpatient $685 (+/- 390) and $780 (+/- 310), (P=0.8);
mean total cost per patient $1,311 (+/- 443) and $1,448 (+/-341), (P=0.5).
The cost of the allergy clinic was $272 (+/- 41.3) for the allergy clinic group. The mean total cost excluding the subgroup was $552 (+/- 119) per patient per year (P<0.0001).
Synthesis of costs and benefits Costs and benefits were not combined. The difference in the mean cost of care between the two groups was $137 per patient year. 3 patients in the allergy clinic group accounted for 64% of the costs and, excluding this, the difference between the groups was $896.
Authors' conclusions Patients who attended the emergency room and those who attended the allergy-immunology clinic were not demographically or socio-economically different. The decreased morbidity of asthma and the cost of care for the allergy clinic patients, as opposed to the emergency room patients, are likely to be due to the care given in the allergy-immunology clinic.
CRD COMMENTARY - Selection of comparators The reason for the choice of comparator was clear.
Validity of estimate of measure of benefit The estimate of benefits may not be internally valid due to the disparity in sample size associated with each group (50 versus 25). However, a detailed statistical analysis was performed on the results.
Validity of estimate of costs The authors could have specified the cost methodology in more detail. A sub-group of only three allergy clinic patients accounted for all hospital admissions which had a disproportionate impact on the cost results.
Other issues The authors were successful in realising their objective of examining the demographic and socio-economic characteristics of asthmatic patients using the emergency room as their primary care physician and of those attending the allergy-immunology clinic in the same inner-city hospital. However, their comparison of the cost of care could have been more detailed. The issue of generalisability was not addressed although good comparisons with other studies were made. The retrospective nature of the study has its own limitations in terms of accuracy and recall.
Bibliographic details Moore C M, Ahmed I, Mouallem R, May W, Ehlayel M, Sorensen R U. Care of asthma: allergy clinic versus emergency room. Annals of Allergy, Asthma and Immunology 1997; 78(4): 373-380 Indexing Status Subject indexing assigned by NLM MeSH Allergy and Immunology; Asthma /mortality /therapy /economics; Comparative Study; Emergency Service, Hospital /economics /utilization; Health Care Surveys; Hospital Costs; Humans; Louisiana /epidemiology; Outpatient Clinics, Hospital /economics /utilization; Socioeconomic Factors AccessionNumber 21997000598 Date bibliographic record published 28/02/1999 Date abstract record published 28/02/1999 |
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