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(Hypertension. 2006;47:29.)
© 2006 American Heart Association, Inc.
Original Articles |
From the Mount Sinai School of Medicine, Englewood Hospital and Medical Center, Englewood, NJ.
Correspondence to Lawrence R Krakoff, Department of Medicine, Englewood Hospital and Medical Center, 350 Engle St, Englewood NJ 07631. E-mail Lawrence.Krakoff{at}ehmc.com
| Abstract |
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Key Words: ambulatory blood pressure monitoring, ambulatory hypertension, white-coat cost benefit analysis
| Introduction |
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When ABPM became available, it was suggested that this technology might be a cost-effective method if used as secondary screening for hypertension.14 This suggestion was based on estimates or best guesses as to the cost of ABPM, the current cost of antihypertensive treatment, the risk of not treating those with WCH, and other factors.15 During the past 15 years, several advances and changes have provided information that is highly relevant to the calculation of the cost-effectiveness for implementing ABPM into a system of care for those who are hypertensive after initial clinic screening. First, the relationships between ambulatory pressures and clinic pressures for hypertensive patients have become better defined with regard to the prediction of mortality and morbidity.46,8 Second, transition rates for the incidence of new hypertension in those with WCH can be more accurately estimated.16 Third, in the United States, the charges for ABPM are somewhat fixed by Centers for Medicare and Medicaid Services policies and are relatively low. Costs for treatment of hypertension can be estimated from various sources, including those from managed care organizations.17 This new information has prompted a reassessment of ABPM for cost-effectiveness when used to confirm the diagnosis of hypertension.
| Methods |
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The overall prevalence of WCH in those with recently detected hypertension has been in the range of 15% to 20% for younger populations and somewhat higher for older groups. Gender and duration of suspected hypertension may also modify the prevalence of WCH. For this analysis, a 20% prevalence of WCH was chosen for most analyses. However, the effect of varying prevalence of WCH from 15% to 25% was also evaluated. This is consistent with current recommendations that the diagnosis of WCH be based on either a daytime pressure <135/85 mm Hg or 24-hour pressures <130/80 mm Hg.12
The cost for ABPM in the United States can now be given because of the setting of prices for this procedure by the CMS. Current procedural terminology (CPT) codes have been assigned to the procedure. The range of prices set by CMS varies within the United States from $56 to $122 for 92 localities. The average price listed is $74 (95% CI, $72 to $76). The source for these prices is the Centers for Medicare and Medicaid Services (available online at http://www.cms.hhs.gov/physicians/mpfsapp). For the calculations used in our analysis, the average figure of $75 was used as the cost of ABPM.
The annual cost for treatment for hypertension for a group of patients is a composite of costs for physician visits, diagnostic tests, and medications. The cost for medications needed to control blood pressure will vary with the choice of drugs.18 Higher overall costs for treatment needed to control hypertension are found for the first year of treatment with lower costs during subsequent years.17,18 A survey from 1 large managed care organization reported that costs were as follows: first year of treatment, &$950; second year, &$575; third year and after, &$420, which resulted in a 5 year total of &$2900 per patient or $580 per treatment-year.17 These amounts are remarkably similar to costs for treatment calculated from a randomized trial when a ß blocker, angiotensin-converting enzyme inhibitor, or calcium blocker were used as initial treatment.18 However, the cost of treatment was 30% to 40% lower if a diuretic was used as the initial treatment. A more recent report has calculated that guideline-based treatment (using diuretics as a base) would reduce the cost of treatment by as much as 40% for a large medical practice compared with current prescribing patterns.19 In this presentation, the estimated costs for the treatment of hypertension used the lower or minimum costs for medication as if guideline-based prescribing were the usual pattern, as follows: first year, $570; second year, $345; and third to fifth year, $252. Thus, the 5-year total cost of treatment for an individual patient is $1671, for an average annual cost per patient of $334.
Estimates for the incidence of new hypertension among previously nonhypertensive subjects, using only clinic methods, have been assessed in the Framingham study2022 and in the Womens Health Initiative.23 The annual incidence of new hypertension for women, with an average age of 45 years and followed for nearly 8 years, is strongly related to baseline pressure. Those with high normal pressure at baseline have a 4% to 7% annual incidence of new hypertension. In this study, baseline C-reactive protein levels added independently and to a small extent to the prediction of future hypertension.23 In the Framingham population, 10- to 25-year estimates of new hypertension, based on screening at 2-year intervals, have varied from &1% to 2% at baseline for those with optimal pressure and 35 to 55 years of age to &15% for those 65 to 94 years of age with high normal pressures at baseline.22 There are no comparable, large longitudinal studies for incidence of hypertension using ABPM or home blood pressures in community-based populations. However, 2 small series studied by serial measurements of ambulatory pressure suggest rates of new sustained hypertension among those with WCH at baseline, which vary from a high of 13% annually24 to lower rates of 3% to 4% annually.16 For this analysis, the estimated annual incidence of new hypertension, based on repeated ABPM for those with WCH, was varied from 5% to 20%.
The estimate of annual dropout or loss to follow-up used in this analysis is 5% for all of the groups and is a conservative one. Although very high rates of retention in treatment have been observed in some clinical trials, such as the Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial,25 lower retention rates have also been observed in practice-based studies.26 It is likely that dropout rates in nonresearch settings, that is, usual clinical practice, are far higher than 5%, but additional surveys are needed to establish this estimate.
In summary, the model begins with 1000 subjects, initially labeled as hypertensive, based on screening using office or clinic pressures. The baseline prevalence of WCH is varied from 15% to 25%, and the incidence of new confirmed hypertension, after initial assessment, is varied from 5% to 20%. Calculations for these groups are made over a 5 year period for the following: (1) number of WCH subjects; (2) number of new confirmed hypertensive subjects who will be treated during follow-up; (3) treatment years; (4) costs for treatment; and (5) costs for use of ABPM initially and for annual follow-up.
| Results |
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Figure 3 displays the total years of antihypertensive treatment over 5 years for the same groups displayed in Figure 1. These are a group without use of ABPM and groups with a baseline prevalence of WCH of 20% and annual incidence of new hypertension varying from 5% to 20%.
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Table 1 displays the estimated costs for treatment and for testing (ABPM) for the 4 groups described in Figure 3. All of the groups who are screened initially and during annual follow-up for WCH have lower costs for treatment and total costs over the 5 years compared with the group that was not screened with ABPM. The lowest cost for the 5-year period occurs when the annual incidence of new hypertension is low (5%). This is because of a much higher annual cost of treatment compared with the much lower cost of screening. When more hypertensive subjects would be detected because of a higher annual incidence of hypertension (20%>10%> 5%), the overall costs for treatment increases relative to the lower costs for testing, because fewer WCH subjects would remain. Thus, the calculated fractions of costs for testing by ABPM of the total costs are in the range of 6% to 10%.
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Table 2 compares the effect of varying the initial prevalence of WCH from 15% to 25% on the total cost of testing and treatment over 5 years using the minimum for treatment costs. Compared with the cost for treatment without using ABPM, $1 546 494, the reductions in costs vary from the minimum of $45 322 to a maximum of $210 024, resulting in savings of 3% to 14%, respectively. However, if treatment costs are higher for the frequent use of calcium channel blockers or angiotensin-converting enzyme inhibitors as the initial treatment,17 the savings for the ABPM strategy to detect WCH will range from $141 363 to $438 984.
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Table 3 compares the effect of varying the initial prevalence of WCH from 15% to 25% on the number of treatment-years over the 5-year interval. If ABPM is not used, the calculated number of treatment-years is 4524. The reduction in treatment-years achieved through use of ABPM would vary from 10% to 23%.
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The cost per treatment-year was calculated for each condition in Table 3 as the "break-even" cost if ABPM were used compared with the nonuse of ABPM and is shown in Table 4. If nonuse of ABPM results in 4524 treatment-years and use of ABPM for a group with an initial prevalence of WCH of 20% and an annual incidence of new hypertension of 10% (3779 treatment-years), then $156 per year per patient would be the amount at which the 2 strategies would have the same cost. The range of break-even costs per year of treatment varies from a maximum of $214 when the prevalence of WCH is 15% and annual incidence of new hypertension is 20% to a minimum of $130 when the prevalence of WCH is 25% and the annual incidence of new hypertension is 5%. These estimates suggest that the ABPM strategy will be cost saving in relation to the current annual cost of treatment per patient of $334, given above.
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| Discussion |
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An ABPM strategy to detect WCH and delay treatment for hypertension will reduce treatment years and may result in sustained quality of life for those not receiving antihypertensive medication who do not need it.28 The use of ABPM to select WCH might then be beneficial, even if the cost of treatment were lower. The annual treatment costs for the break-even calculations in Table 4 are well below the estimated range for annual cost from the guideline-based minimum ($334) to the higher annual figure ($580) that was found in current practice. Thus, an ABPM strategy may be beneficial clinically and cost saving financially.
The calculations used are based on currently available estimates for the prevalence of WCH in recently detected hypertensive groups and costs for ABPM and treatment of hypertension. The estimates for incidence of new hypertension in WCH are based on patterns for new clinic hypertension derived from population studies but consistent with small studies using ABPM with rates for new hypertension varying from <5% to nearly 15%.16,24 By using a range of estimates for new hypertension during follow-up of the WCH subjects, the calculated results may apply to different groups where the expected prevalence of WCH and the incidence of new confirmed hypertension vary in relation to age, level of pressure, and pattern of cardiovascular risk factors.
The results presented in this report are based on the assumption that WCH will not be treated but that annual surveillance will use ABPM for those not treated. Physicians report that the results of ABPM are highly useful for their practices.29 When ambulatory blood pressure is offered to primary care physicians as a support service, a very high percent accept advice to withhold drug treatment when average pressures are <135/85 mm Hg, resulting in a 20% reduction in treatment.30 This pattern agrees well with the predicted reductions given in this presentation. Surveys of patients that have had ABPM indicate a high degree of satisfaction with the test, despite occasional discomfort. Most respondents recognize the value of the results for their management.13,31
The model used for these calculations does not include the use of ABPM to monitor treatment or treated patients with apparent refractory hypertension.32 Using ABPM to monitor treatment might reduce the need for increased but ineffective medication.33 One British study using an economic model predicts that the use of annual ABPM for treated patients would save the cost of treatment and need for visits but would result in a small net increase in annual cost of about £10 per patient.34 In the United States, CMS policies fail to include treated hypertensives as eligible for reimbursement in the use of ABPM. It is not known whether other insurance plans will assist in payment.
ABPM of those with normal clinic pressures has exposed a small and variable fraction with hypertension, "reversed white coat" or "masked" hypertension. These patients may have greater target organ damage than those with ambulatory normal pressures35 and seem to have morbidity and mortality that is more like established hypertension than WCH.36 The prevalence of masked hypertension within the normotensive population is not yet fully established in different populations but may be far lower than the prevalence of established hypertension in those with clinic hypertension.37 Screening of large normotensive groups by ABPM to yield a small fraction for drug treatment is likely to be very costly, so there is the need to develop accurate selection criteria for the use of ABPM in clinic normotension for efficient detection of masked hypertension.38,39
Recently published guidelines for the management of hypertension recognize the role of ABPM for the detection of WCH in the initial assessment of selected patients.10,11,40 For those found to have WCH, long-term surveillance using ABPM has been recommended,12,40 but no specific strategies have been fully explored. The results presented here provide a rationale for the use of annual ABPM to search for WCH in recent clinic hypertension as the basis for initial diagnosis and subsequent surveillance. It is predicted that overall cost of treatment for hypertension and years of drug treatment will be reduced. Additional studies are much needed to explore these estimates in community practice.
Received July 25, 2005; first decision August 16, 2005; accepted November 7, 2005.
| References |
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2. Verdecchia P, Porcellati C, Schillaci G, Borgioni C, Ciucci A, Battistelli M, Guerrieri M, Gatteschi C, Zampi I, Santucci A, Santucci C, Reboldi G. Ambulatory blood pressure: an independent predictor of prognosis in essential hypertension. Hypertension. 1994; 24: 793801.
3. Clement D, De Buyzere M, De Bacqer DA, de Leeuw PW, Duprez DA, Fagard RH, Gheeraert PJ, Missault LH, Braun JJ, Six RO, Van der Niepen P, OBrien E, for the Office versus Ambulatory Pressure Study Investigators. Prognostic value of ambulatory blood-pressure recordings in patients with treated hypertension. N Engl J Med. 2003; 348: 24072415.
4. Hansen TW, Jeppesen J, Rasmussen S, Ibsen H, Torp-Pedersen C. Ambulatory blood pressure and mortality. Hypertension. 2005; 45: 499504.
5. Fagard RH, Staessen JA, Thijs L, Bulpitt CJ, Clement D, de Leeuw PW, Jaaskivi M, Mancia G, OBrien E, Palatini P, Tuomilehto J, Webster J. Relationship between ambulatory blood pressure and follow-up clinic blood pressure in elderly patients with systolic hypertension. J Hypertens. 2004; 22: 8187.[CrossRef][Medline] [Order article via Infotrieve]
6. Dolan E, Stanton A, Thijs L, Hinedi K, Atkins N, McClory S, Den HE, McCormack P, Staessen JA, OBrien E. Superiority of ambulatory over clinic blood pressure measurement in predicting mortality: the Dublin outcome study. Hypertension. 2005; 461: 156161.
7. Pickering TG. White coat hypertension. Curr Op Nephrol Hypert. 2002; 5: 192198.
8. Verdecchia P, Reboldi GP, Angeli F, Schillaci G, Schwartz JE, Pickering TG, Imai Y, Ohkubo T, Kario K. Short- and long-term incidence of stroke in white-coat hypertension. Hypertension. 2005; 45: 203208.
9. Bjorklund K, Lind L, Vessby B, Andren B, Lithell H. Different metabolic predictors of white-coat and sustained hypertension over a 20-year follow-up period: a population-based study of elderly men. Circulation. 2002; 106: 6368.
10. Chobanian AV, Bakris GL, Black HR, Green L, Izzo JL Jr, Jones DW, Materson BJ, Oparil S, Wright JT, Roccella EJ. The seventh report of the Joint National Committee on Prevention, Detection, Evaluation and Treatment of High Blood Pressure: The JNC 7 Report. JAMA. 2003; 289: 25602572.
11. Guidlines Committee. 2003 European Society of Hypertension- European Society of Cardiology guidelines for the management of arterial hypertension*. J Hypertens. 2003; 21: 10111053.[CrossRef][Medline] [Order article via Infotrieve]
12. Pickering TG, Hall JE, Appel LJ, Falkner BE, Graves J, Hill MN, Jones DW, Kurtz T, Sheps SG, Roccella EJ. Recommendations for blood pressure measurement in humans and experimental animals: Part 1: blood pressure measurement in humans: a statement for professionals from the Subcommittee of Professional and Public Education of the Am Heart Association Council on High Blood Pressure Research. Hypertension. 2005; 45: 142161.
13. Ernst ME, Bergus GR. Favorable patient acceptance of ambulatory blood pressure monitoring in a primary care setting in the United States: a cross-sectional survey. BMC Fam Pract. 2003; 4: 15.[CrossRef][Medline] [Order article via Infotrieve]
14. Krakoff LR, Eison H, Phillips RH, Leiman S, Lev S. Effect of ambulatory blood pressure monitoring on the diagnosis and cost of treatment for mild hypertension. Am Heart J. 1988; 116: 11521154.[CrossRef][Medline] [Order article via Infotrieve]
15. Krakoff LR, Schechter C, Fahs M, Andre M. Ambulatory blood pressure monitoring: is it cost-effective? J Hypertens. 1991; 9: S28S30.
16. Polonia JJ, Gama GM, Silva JA, Amaral C, Martins LR, Bertoquini SE. Sequential follow-up clinic and ambulatory blood pressure evaluation in a low risk population of white-coat hypertensives and normotensives. Blood Pressure Monitoring. 2005; 10: 5764.[Medline] [Order article via Infotrieve]
17. Odell TW, Gregory MC. Cost of hypertension treatment. J Gen Intern Med. 1995; 10: 686688.[Medline] [Order article via Infotrieve]
18. Ramsey SD, Neil N, Sullivan SD, Perfetto E. An economic evaluation of the JNC hypertension guidelines using data from a randomized controlled trial. Joint National Committee. J Am Board Fam Pract. 1999; 12: 105114.[Abstract]
19. Fischer MA, Avorn J. Economic implications of evidence-based prescribing for hypertension: Can better care cost less? JAMA. 2004; 291: 18501856.
20. Vasan RS, Larson MG, Leip E, Kannel WB, Levy D. Assessment of frequency of progression to hypertension in non-hypertensive participants in the Framingham Heart Study. Lancet. 2001; 358: 16821686.[CrossRef][Medline] [Order article via Infotrieve]
21. Vasan RS, Beiser A, Seshadri S, Larson MG, DAgostino RB, Levy D. Residual lifetime risk for developing hypertension in middle-aged women and men: The Framingham Heart Study. JAMA. 2002; 287: 10031010.
22. Vasan RS, Levy D. Rates of progression to hypertension among non-hypertensive subjects: implications for blood pressure screening. Euro Heart J. 2004; 23: 10671070.
23. Sesso HD, Buring JE, Rifai N, Blake GJ, Gaziano JM, Ridker PM. C-reactive protein and the risk of developing hypertension. JAMA. 2003; 290: 29452951.
24. Bidlingmeyer I, Burnier M, Bidlingmeyer M, Waeber B, Brunner HR. Isolated office hypertension: a prehypertensive state? J Hypertens. 1996; 3: 327332.
25. The ALLHAT Officers and Coordinators for the ALLHAT Collaborative Research Group. Major outcomes in high-risk hypertensive patients randomized to angiotensin-converting enzyme inhibitor or calcium channel blocker vs diuretic. The Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial (ALLHAT). JAMA. 2002; 288: 29812997.
26. Wing LMH, Reid CM, Ryan P, Beilin LJ, Brown MA, Jennings GLR, Johnston C, McNeil JJ, Macdonald G, Marley JE, Morgan TO, West MJ, for the Second Australian National Blood Pressure Study Group. A comparison of outcomes with angiotensin-converting enzyme inhibitors and diuretics for hypertension in the elderly. N Engl J Med. 2003; 348: 583592.
27. Ewald B, Pekarsky B. Cost analysis of ambulatory blood pressure monitoring in initiating antihypertensive drug treatment in Australian general practice. Med J Aust. 2002; 176: 580583.[Medline] [Order article via Infotrieve]
28. Mena-Martin FJ, Martin-Escudero JC, Simal-Blanco F, Carretero-Ares JL, rzua-Mouronte D, Herreros-Fernandez V. Health-related quality of life of subjects with known and unknown hypertension: results from the population-based Hortega study. J Hypertens. 2003; : 12831289.
29. Grin JM, McCabe EJ, White WB. Management of hypertension after ambulatory blood pressure monitoring. Ann Int Med. 1993; 118: 833837.
30. Richards C, Sutherland M, Gough K, Padfield PL. Direct access ambulatory BP monitoring- the Edinburgh experience. Blood Pressure Monitoring. 2005; 9: 287291.
31. Little P, Barnett J, Barnsley L, Marjoram J, Fitzgerald-Barron A, Mant D. Comparison of acceptability of and preferences for different methods of measuring blood pressure in primary care. BMJ. 2002; 325: 258259.
32. Redon J, Campos C, Rodicio JL, Pascual JM, Ruilope LM. Prognostic value of ambulatory blood pressure monitoring in refractory hypertension: a prospective study. Hypertension. 2001; 31: 712718.
33. Staessen JA, Byttebier G, Buntinx F, Celis H, OBrien DE, Fagard R, for the Ambulatory Blood Pressure Monitoring and Treatment of Hypertension Investigators. Antihypertensive treatment based on conventional or ambulatory blood pressure measurement. JAMA. 1997; 278: 10651072.
34. Lorgelly P, Siatis I, Brooks A, Slinn B, Millar-Craig MW, Donnelly R, Manning G. Is ambulatory blood pressure monitoring cost-effective in the routine surveillance of treated hypertensive patients in primary care? Br J Gen Pract. 2003; 53: 794796.[Medline] [Order article via Infotrieve]
35. Liu JE, Roman MJ, Pini R, Schwartz JE, Pickering TG, Devereux RB. Cardiac and arterial target organ damage in adults with elevated ambulatory and normal office blood pressure. Ann Intern Med. 1999; 131: 564572.
36. Ohkubo T, Kikuya M, Metoki H, Asayama K, Obara T, Hashimoto J, Totsune K, Hoshi H, Satoh H, Imai Y. Prognosis of "masked" hypertension and "white-coat" hypertension detected by 24-h ambulatory blood pressure monitoring 10-year follow-up from the Ohasama study. J Am Coll Cardiol. 2005; 46: 508515.
37. Bombelli M, Sega R, Facchetti R, Corrao G, Friz HP, Vertemati AM, Sanvito R, Banfi E, Carugo S, Primitz L, Mancia G. Prevalence and clinical significance of a greater ambulatory versus office blood pressure (reversed white coat condition) in a general population. J Hypertens. 2005; 23: 513520.[Medline] [Order article via Infotrieve]
38. Palatini P. Masked hypertension: how can the condition be detected? Blood Press Monit. 2004; 9: 297299.[CrossRef][Medline] [Order article via Infotrieve]
39. Pickering TG, Davidson K, Gerin W, Schwartz JE. Masked hypertension. Hypertension. 2002; 40: 795796.
40. Mcgrath BP. Ambulatory blood pressure monitoring. Med J Aust. 2002; 176: 588592.[Medline] [Order article via Infotrieve]
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