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Cost-effectiveness of screening for microalbuminuria using immunochemical dipstick tests or laboratory assays in diabetic patients |
Le Floch, J P, Charles, M A, Philippon, C, Perlemuter, L |
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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 traditional laboratory assay versus a laboratory assay only in the case of a positive dipstick result to perform a screening for microalbuminuria.
Study population Diabetic outpatients. Mean age was 53.4 years. Mean systolic and diastolic blood pressure was 141 and 85mmHg respectively. Diabetes had been diagnosed for 11.8 years on average.
Setting Hospital outpatient clinic/primary care. The economic study was carried out in France.
Dates to which data relate Source of effectiveness data Evidence from a clinical trial.
Link between effectiveness and cost data It was not clear if the collection of resource data was prospective or retrospective, or if it related to the effectiveness analysis sample.
Study sample 515 consecutive diabetic outpatient attenders.9 patients were excluded because of urinary infections. No power calculations were undertaken.
Study design The study design was a case series, single centre study. Two different nurses performed the two dipstick tests, each being blind to the outcome of the test by the other nurse.
Analysis of effectiveness Analysis of 505 patients. Principle outcome measurement was sensitivity and specificity of experimental test compared with laboratory based test. The group was not homogeneous for clinical features.
Effectiveness results The sensitivity of the dipstick was 90.8% with a predictive value of a positive result being 55.6%, the specificity was 80.1% with the predictive value of a negative result being 97%. Compared to Strategy I, Strategy II had a sensitivity 90.8%, a specificity and a predictive value of a positive result of 100%, and a predictive value of a negative result of 97.5%.
Modelling A simulation model was used to estimate costs and benefits.
Measure of benefits used in the economic analysis QALYs, generated by the time trade off method using a sample of 30 diabetic clinicians and calculated using a simulation model.
Direct costs The details of cost for laboratory analysis and dipstick data were not shown. A 5% annual inflation rate was assumed. Costs were not discounted.
Sensitivity analysis Sensitivity analysis was performed by one-way simple sensitivity on various parameters, such as the threshold for the diagnosis of microalbuminuria, false positive and negative results, prevalence and incidence of microalbuminuria, costs of tests, and QALYs gained.
Estimated benefits used in the economic analysis The authors estimated that by using dipsticks 2.38 QALYs would be lost in the first 5 years after diagnosis by dipstick. This declined to 0.91 QALYs 30 years after diagnosis.
Cost results Initial screening cost for 10,000 people would be 58,209 for the laboratory method and 41,459 for the dipstick method. At the end of a period of 30 years 8,696 people were still screened in the initial cohort of 10,000, and the costs would be 50,617 and 45,272 for the two strategies respectively.
Synthesis of costs and benefits The cost per QALY gained from using the laboratory method compared to the dipstick method ranged from 5,850 to 7,000 with an average over 30 years of 6,600. Sensitivity analysis found that frequency of false negative results, prevalence and annual incidence were the most important factors likely to influence the cost-effectiveness ratios.
Authors' conclusions The result suggest that the double dipstick method with laboratory assays could be cost-effective for annual screening in diabetic patients exposed to a low risk of microalbuminuria and for frequent screening in patients exposed to a high risk of microalbuminoria.
CRD Commentary In this study there were several weak points: (1) a full description of the costs was not given; (2) the health care costs of delaying diagnosis were not accounted for;(3) it was unclear in the cohort analysis that patients, once diagnosed, were not removed from the cohort, thus incurring costs; (4) costs and benefits were not discounted.
Bibliographic details Le Floch, J P, Charles, M A, Philippon, C, Perlemuter, L. Cost-effectiveness of screening for microalbuminuria using immunochemical dipstick tests or laboratory assays in diabetic patients. Diabetic Medicine 1994; 11: 349-356 Indexing Status Subject indexing assigned by NLM MeSH Adolescent; Adult; Aged; Aged, 80 and over; Albuminuria /diagnosis /epidemiology; Clinical Laboratory Techniques /economics; Cost-Benefit Analysis; Costs and Cost Analysis; Diabetic Nephropathies /diagnosis /urine; Female; Humans; Immunochemistry; Incidence; Male; Mass Screening /economics; Middle Aged; Predictive Value of Tests; Prevalence; Reagent Strips /economics; Sensitivity and Specificity AccessionNumber 21995007061 Date bibliographic record published 28/06/1995 Date abstract record published 28/06/1995 |
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