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Cost-effectiveness of the lower treatment goal (of JNC VI) for diabetic hypertensive patients |
Elliott W J, Weir D R, Black H R |
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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 The lower treatment goal, as defined by the Sixth Report of the Joint National Committee on Prevention, Detection, Eradication, and Treatment of High Blood Pressure (JNC VI): to lower blood pressure (BP) in diabetic patents to less than 130/85 mmHg.
Type of intervention Treatment and secondary prevention.
Economic study type Cost-effectiveness analysis.
Study population A hypothetical population of 60-year-old diabetic persons with hypertension, who were initially free of cardiovascular or end stage renal disease (ESRD).
Setting Hospital. The economic study was carried out in the USA.
Dates to which data relate Effectiveness and resource use data were collected from studies published between 1987 and 1999. Cost data were derived from studies published between 1991 and 1998. The price year was 1996.
Source of effectiveness data Effectiveness data were derived from a literature review.
Modelling A lifetime 24-cell Markov decision analytic model was used to determine the cost-effectiveness of lower BP goals.
Outcomes assessed in the review The review assessed incidence rates for stroke, MI, heart failure, ESRD, severity, fatality, and long-term survival in morbid states, mortality, and effects of further reductions in BP.
Study designs and other criteria for inclusion in the review Population-based studies were used, but no further details were given.
Sources searched to identify primary studies MEDLINE was searched, using the MESH headings of "diabetes mellitus", and the subheadings of "complications, epidemiology, and prevention and control". The bibliography of each reference was also reviewed.
Criteria used to ensure the validity of primary studies The criteria used were not stated.
Methods used to judge relevance and validity, and for extracting data Summary statistics from individual studies were used. No further details were provided.
Number of primary studies included At least 24 studies were included.
Methods of combining primary studies Most studies were not combined and provided separate inputs to the model.
Investigation of differences between primary studies Results of the review The annual incidence varied between 0.00155 and 0.01460 for minor stroke, 0.00155 and 0.01460 for severe stroke, 0.00890 and 0.01900 for MI, 0.00490 and 0.02500 for heart failure (HF), and between 0.00030 and 0.00660 for ESRD. The relative risk varied between 1 and 5.7 after MI, 1 and 3 after minor stroke, and 0 and 3 after severe stroke. The event fatality rate varied between 0 and 0.5. The disease state mortality rate varied between 0.01 and 0.2. The relative risk at JNC VI guidelines varied between 0.65 and 0.90. 95% confidence intervals for the relative risk of the new goal BP were 0.60 - 0.70 for minor stroke, 0.60 - 0.70 for severe stroke, 0.82 - 0.95 for MI, 0.52 - 0.77 for HF, and 0.5 - 0.82 for ESRD.
Measure of benefits used in the economic analysis The number of life years gained was used as the measure of benefits. Benefits were discounted at an annual rate of 3%.
Direct costs Direct costs were discounted at an annual rate of 3%. Quantities and costs were reported separately. Direct costs included costs of intensified treatment, costs of stroke, MI, initial hospitalisation for heart failure, institution of ESRD therapy, costs of follow-up, and nursing home costs. The quantity/cost boundary adopted was that of the health service. The estimation of quantities and costs was based on actual data. Cost estimates were collected from published studies. The price year was 1996.
Indirect Costs Indirect costs were not included.
Sensitivity analysis One-way sensitivity analysis and break-even analyses were conducted on all model parameters.
Estimated benefits used in the economic analysis For a 60-year-old, reducing BP from 140/90 to 130/85 mmHg would increase life expectancy by 0.48 discounted years, while actual life expectancy would increase from 16.5 to 17.4 years.
For a 50-year-old the increase would be 0.48 discounted years, with actual life expectancy increasing from 23.0 to 24.0 years.
For a 70-year-old the increase would be with 0.39 discounted years.
Cost results Lifetime medical costs decreased from $59,495 to $58,045 for a 60 year old, increased from $61,827 to $62,628 for a 50 year old, and decreased by $3,212 for a 70 year old.
Synthesis of costs and benefits Reducing BP from 140/90 to 130/85 mmHg was cost saving for a 60- and 70-year-old. The cost-effectiveness ratio was $1,664 per life year gained for a 50-year-old person. The break-even annual cost for achieving the lower treatment goal BP was $414 for a 60-year-old person, $251 for a 50-year-old person, and $634 for a 70-year-old person. The results were not sensitive to changes in model parameters.
Authors' conclusions The lower treatment goal recommended for high-risk hypertensive patients compares favourably in cost-effectiveness with many other frequently recommended treatment strategies, and saves money overall for patients aged 60 years and older.
CRD COMMENTARY - Selection of comparators A justification was given for the comparators used, namely the previous recommended BP goal. You, as a user of the database, should decide if these issues are relevant to your setting.
Validity of estimate of measure of benefit The authors did not state that a systematic review of the literature had been undertaken. More details could have been provided about the design of the review and the method of combining primary effectiveness estimates. The estimation of benefits was obtained directly from the effectiveness analysis.
Validity of estimate of costs Some good features of the analysis included the following: all relevant cost categories were included; quantities and costs were reported separately; sensitivity analyses were conducted on costs and on quantities; costs were used to proxy prices; and the price year was reported. However, the costs of any non-fatal stroke following major stroke were ignored, as acknowledged by the authors.
Other issues The authors did make appropriate comparisons of their findings with those from other studies but did not explicitly address the issue of generalisability to other settings. The authors did not present their results selectively. The study considered high-risk hypertensive patients and this was reflected in the authors' conclusions. The authors reported that the analysis did not consider treatment for hypertensive diabetic patients whose BP is not controlled. Furthermore, the cost-effectiveness of the BP goal of 130/85 mmHg may have been underestimated for several reasons. The model used conservative effectiveness estimates, it neglected the prevention of second and subsequent MIs, it did not consider the cost-effectiveness of other treatments for heart failure and ESRD, and it did not account for the benefit of the lower BP goal in reducing the rate of progression of hypertension to higher stages. Potential additional benefits of lowered BP on, for instance, improved quality of life were also ignored.
Implications of the study The authors felt that the lower BP goal recommended by JNC VI for high-risk patients is not only effective in preventing expensive cardiovascular events, but is also cost saving in the long term.
Source of funding Supported in part by an unrestricted educational grant from Hoechst Marion Roussel Inc, Kansas City, MO, to Rush-Presbyterian-St Luke's Medical Center on behalf of the authors, and the National Institute on Aging, Bethesda, MD (K01 AG 00703).
Bibliographic details Elliott W J, Weir D R, Black H R. Cost-effectiveness of the lower treatment goal (of JNC VI) for diabetic hypertensive patients. Archives of Internal Medicine 2000; 160: 1277-1283 Indexing Status Subject indexing assigned by NLM MeSH Aged; Aged, 80 and over; Antihypertensive Agents /economics /therapeutic use; Computer Simulation; Cost-Benefit Analysis; Diabetes Mellitus /drug therapy /economics; Drug Therapy /economics; Humans; Hypertension /drug therapy /economics; Middle Aged AccessionNumber 22000008173 Date bibliographic record published 31/05/2001 Date abstract record published 31/05/2001 |
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