Anis Rassi Hospital – Goiânia, GO
A medicina moderna passa por um momento de inquietação, em que a busca por novas ferramentas diagnósticas e por intervenções terapêuticas mais eficazes e seguras é uma constante. Nesse contexto, a introdução da intervenção coronariana percutânea (do balão aos
Há dois tipos principais de análises econômicas em saúde3,4: 1) análises de custo-efetividade, que habitualmente traduzem a diferença entre o custo de duas intervenções, expresso em valor monetário, dividido pela diferença entre suas efetividades, expressas em anos de vida ganhos (expectativa de vida) ou outros desfechos menos importantes, como complicações prevenidas e eventos não-fatais evitados, e 2) análises de custo-utilidade, em que a medida de efetividade é expressa em anos de vida salvos ajustados para a qualidade de vida (
Referem-se, portanto, ambas as análises, a uma razão incremental. Ou seja, ao comparar dois (ou mais) métodos alternativos de tratamento numa condição específica, elas expressam o custo adicional necessário para atingir uma unidade extra de benefício clínico. Exemplificando, se determinado tratamento custa US$ 10 mil e é compatível com expectativa de vida de 3,5 anos, com qualidade de vida de 0,8 ponto, e um competidor custa US$ 20 mil, gerando expectativa de vida de 5,0 anos, com qualidade de vida de 0,7 ponto, teremos as seguintes razões econômicas: análise de custo-efetividade = (20.000 – 10.000) / (5,0 – 3,5) = US$ 6.667,00 para cada ano de vida adicional com o tratamento competidor; análise de custo-utilidade = (20.000 – 10.000) / (5,0 x 0,7 – 3,5 x 0,8) = US$ 14.286 para cada ano de vida ganho ajustado para a qualidade de vida.
As informações utilizadas nas análises econômicas podem ser extraídas de ensaios clínicos randomizados ou, mais freqüentemente, advir de modelos matemáticos ou árvores de decisão clínica, baseados em dados da literatura. A maioria dos estudos de custo-efetividade, entretanto, é proveniente da literatura internacional (Estados Unidos, Canadá e países europeus). Ademais, existe uma série de limitações relacionadas à extrapolação de dados para outros países; daí a necessidade premente de se realizar análises econômicas no Brasil, refletindo melhor nossa realidade.
Nesse contexto, é bastante oportuno o trabalho de Polanczyk e cols.5, publicado nesta edição dos
A análise de efetividade foi expressa por meio de desfecho menos habitual (sobrevida livre de reestenose em um ano), em vez de sobrevida livre de nova revascularização do vaso-alvo, este mais freqüentemente utilizado. As probabilidades necessárias para inclusão no modelo matemático foram extraídas da literatura internacional. O cálculo da análise de custos relacionada ao procedimento índice, aos
Sob a perspectiva de convênios e particulares, o custo do tratamento no primeiro ano foi de R$ 17.840,00 com o uso de
Tendo como base referências internacionais6, que adotam valores de até US$ 50 mil para cada ano de vida ganho e de até US$ 10 mil para cada revascularização evitada (no caso específico de intervenções coronarianas percutâneas) como um emprego razoável dos recursos em saúde, as relações de custo-efetividade do
Entretanto, análises de sensibilidade demonstraram que esse perfil pode ser algo mais favorável para alguns subgrupos de pacientes, como os de alto risco de reestenose e aqueles com elevado custo no manejo de reestenose, principalmente sob a perspectiva não-pública. A redução do preço do
Infelizmente, dois outros fatores que poderiam ter influenciado (agora de maneira negativa) as análises de custo-efetividade, gerando custos ainda maiores para o
No cenário atual de competitividade entre diferentes procedimentos médicos de alta complexidade, outro aspecto a considerar é a exeqüibilidade de incorporação de novas tecnologias cardiovasculares pelo sistema de saúde (público ou privado), tomando por base o impacto financeiro que a adoção dessas medidas é capaz de gerar, principalmente em ambiente de escassez de recursos.
Em outro artigo desta edição dos
O preço do
Com base nesses dados, os autores calcularam que a substituição (parcial) do
Em resumo, pode-se afirmar que os dois estudos apresentam resultados convergentes, ou seja, do ponto de vista de custo-efetividade e de alocação de recursos financeiros em saúde, o uso de
1. Mehta NJ, Khan IA. Cardiology's 10 greatest discoveries of the 20th century. Tex Heart Inst J. 2002; 29: 164-71.
2. Braunwald E. The Simon Dack lecture: cardiology: the past, the present, and the future. J Am Coll Cardiol. 2003; 42: 2031-41.
3. Meltzer MI. Introduction to health economics for physicians. Lancet. 2001; 358: 993-8.
4. Mark DB, Hlatky MA. Medical economics and the assessment of value in cardiovascular medicine: Part I. Circulation. 2002; 106: 516-20.
5. Polanczyk CA, Wainstein MV, Ribeiro JP. Custo-efetividade dos stents recobertos com rapamicina em procedimentos percutâneos coronarianos no Brasil. Arq Bras Cardiol. 2007; 88(4): 464-474.
6. Ryan J, Cohen DJ. Are drug-eluting stents cost-effective? It depends on whom you ask. Circulation. 2006; 114: 1736-43.
7. Grines CL, Bonow RO, Casey DE Jr, Gardner TJ, Lockhart PB, Moliterno DJ, et al. Prevention of premature discontinuation of dual antiplatelet therapy in patients with coronary artery stents: a science advisory from the American Heart Association, American College of Cardiology, Society for Cardiovascular Angiography and Interventions, American College of Surgeons, and American Dental Association, with representation from the American College of Physicians. J Am Coll Cardiol. 2007; 49: 734-9.
8. Araújo DV, Lima VC, Ferraz MB. Análise de impacto do stent farmacológico no orçamento do Sistema Único de Saúde. Arq Bras Cardiol. 2007; 88(4): 458-463.
Anis Rassi Jr. Anis Rassi Hospital Av. José Alves, 453 – Setor Oeste 74110-020 – Goiânia, GO E-mail:
Artigo recebido em 26/02/07; aceito em 26/02/07.
Anis Rassi Hospital – Goiânia, GO - Brazil
Modern medicine is going through a restless period, marked by a constant quest for safer, more effective diagnostic tools and therapeutic interventions. In this context, the introduction of percutaneous coronary intervention (from balloon to drug-eluting stents) is considered by many as one of the greatest advances ever made in cardiology1,2. Conversely, escalating health care costs have been a source of growing concern. For a given strategy to be considered optimal, it should be more effective and less costly. This binomial, however, is rare in medicine. The introduction of new diagnostic and therapeutic methods usually entails significant incremental costs. As health care resources are always scarce and finite, the need for studies addressing the economic impact of different strategies in the medical field has been heightened in recent years.
There are two major types of economic analyses used in health care3,4: 1) cost-effectiveness analysis, which usually translates the difference in costs between two interventions (expressed in monetary values) divided by the difference in their effectiveness and expressed in years of life saved (life expectancy) or other less important endpoints, such as prevented complications, non-fatal events avoided, and 2) cost-utility analysis, which uses quality-adjusted life years (QALY) saved as a measure of effectiveness; that is to say, utility weights ranging from 0 (equivalent to death) to 1 (perfect health) are attributed to survival time to express the number of years spent in good health.
Both analyses, therefore, refer to an incremental ratio. In other words, by comparing two (or more) alternative therapeutic methods in a specific condition, they express the incremental cost required to achieve a unit of additional clinical benefit. For example, if a particular treatment costs US$10,000 and is consistent with 3.5 years of life expectancy at a 0.8 score in quality of life and that of a competitor costs US$ 20,000 and generates 5.0 years of life expectancy at a 0.7 score in quality of life, the following economic ratios will be produced: cost-effectiveness analysis = (20,000 – 10,000) / (5.0 – 3.5) = US$ 6,667 per life-year gained using the competitor's treatment; cost-utility analysis = (20,000 – 10,000) / (5.0 x 0.7 – 3.5 x 0.8) = US$ 14,286 per QALY gained.
The information used in the economic analyses may be derived from randomized clinical trials or, more frequently, from mathematic models or clinical decision trees based on literature data. Most cost-effectiveness studies, however, have been published in the international literature (USA, Canada, and European countries). Moreover, there are a number of limitations to extrapolating data to other countries, hence the pressing need for economic analyses that reflect the Brazilian reality more accurately.
In this regard, the study by Polanczyk et al5, published in this issue, is very timely. The authors used a decision-analytic model to compare the cost-effectiveness ratios of sirolimus-eluting stents (SES) with bare-metal stents (BMS) in Brazil in single-vessel disease patients with stable angina under two perspectives: public (SUS) and nonpublic (health plans and private patients).
Effectiveness analysis was expressed by using less common endpoints (one-year restenosis-free survival), rather than the more frequently used survival free of repeat target-lesion revascularization. The probabilities needed for inclusion in the mathematical model were derived from international literature. As for cost analysis related to index procedures, stents, cardiovascular events, and repeat revascularization in one year of follow-up, this was based on the amounts paid directly to the hospitals by the SUS and health plans/private patients. Cost-utility analysis could not be performed due to the lack of information on the quality of life of patients with chronic coronary artery disease in the Brazilian population.
In the perspective of health plans and private patients, treatment cost in the first year was R$17,840 using sirolimus-eluting stent and R$14,024 using bare-metal stent (difference of R$3,816 favoring BMS). In the perspective of SUS these costs were R$12,708 and R$5,788, respectively (a difference of R$ 6,620 favoring BMS). On the other hand, one-year restenosis-free survival was 92.7% with sirolimus-eluting stent and 78.8% with bare-metal stent (a difference of about 14% favoring SES). As a result, the cost per restenosis avoided in one year was R$27,403 (R$3,816/~0.14) for health plans/private patients and R$47,529 (R$6,620/~0.14) for the SUS.
Based on international references6, which adopt values up to US$ 50,000 per year of life saved and up to US$10,000 per revascularization avoided, (in this specific case, percutaneous coronary interventions) using a reasonable amount of health resources, the cost-effectiveness ratios of sirolimus-eluting stent may be considered elevated for the Brazilian reality, according to the model proposed by the authors. It should be noted that with the dollar standing at R$2,10 (on February 22, 2007), the cost-effectiveness threshold would be R$21,000 per event avoided.
However, sensitivity analyses have shown that this profile may be somewhat more favorable to certain subgroups of patients, such as those at high risk of restenosis and those presenting high cost of restenosis management, particularly under the nonpublic perspective. A decrease in the cost of drug-eluting stents would improve this cost-effectiveness ratio. Incidentally, the use of the market price for sirolimus-eluting stents in the SUS model (R$10,320, indeed higher than that specified in its reimbursement table) may have contributed to the more unfavorable results in this health system.
Unfortunately, two other factors might have influenced (this time negatively) the cost-effectiveness analyses, yielding costs even higher for drug-eluting stents, were not taken into account in this study: the need for dual antiplatelet therapy for at least one year (more recently recommended ), rather than only the three months assumed, and the greater number of stents per patient, since it seems that a single stent was used per procedure.
Given the current competition among highly complex medical procedures, another aspect that should be taken into account is how feasible it is for the health care system (public and nonpublic) to incorporate new cardiovascular technologies, considering their economic impact, especially in a setting with scant resources.
In another article published in this issue, Araújo
The price of bare-metal stent adopted in the analysis was R$2,580, equivalent to the amount reimbursed by the SUS to its hospital network at that time. For drug-eluting stent, the amount reimbursed by Medicare (USA) was used, that is, R$5,166 (dollar at R$2,87 in June 30, 2003), far lower, therefore, than that used in the study by Polanczyk
Based on these data, the authors calculated that the (partial) replacement of bare-metal stent with drug-eluting stent (with a one-year follow-up) would incur an approximate additional cost of $24 million, R$37 million, and R$44 million in the first, second and third scenarios, corresponding to a 12.8%, 20.1% and 24.4% increase, respectively, in the SUS budget allocated for that purpose. A non-negligible increase, in my opinion, at least in absolute values. Once more, it stands to reason that these costs would be even higher if clopidogrel was used for a longer period.
In sum, both studies provide converging results, that is to say, not only from the cost-effectiveness standpoint but also in terms of allocation of funds to health care, the use of drug-eluting stents should be restricted to selected cases.
1. Mehta NJ, Khan IA. Cardiology's 10 greatest discoveries of the 20th century. Tex Heart Inst J. 2002; 29: 164-71.
2. Braunwald E. The Simon Dack lecture: cardiology: the past, the present, and the future. J Am Coll Cardiol. 2003; 42: 2031-41.
3. Meltzer MI. Introduction to health economics for physicians. Lancet. 2001; 358: 993-8.
4. Mark DB, Hlatky MA. Medical economics and the assessment of value in cardiovascular medicine: Part I. Circulation. 2002; 106: 516-20.
5. Polanczyk CA, Wainstein MV, Ribeiro JP. Custo-efetividade dos stents recobertos com rapamicina em procedimentos percutâneos coronarianos no Brasil. Arq Bras Cardiol. 2007; 88 (4): 464-474.
6. Ryan J, Cohen DJ. Are drug-eluting stents cost-effective? It depends on whom you ask. Circulation. 2006; 114: 1736-43.
7. Grines CL, Bonow RO, Casey DE Jr, Gardner TJ, Lockhart PB, Moliterno DJ, et al. Prevention of premature discontinuation of dual antiplatelet therapy in patients with coronary artery stents: a science advisory from the American Heart Association, American College of Cardiology, Society for Cardiovascular Angiography and Interventions, American College of Surgeons, and American Dental Association, with representation from the American College of Physicians. J Am Coll Cardiol. 2007; 49: 734-9.
8. Araújo DV, Lima VC, Ferraz MB. Análise de impacto do stent farmacológico no orçamento do Sistema Único de Saúde. Arq Bras Cardiol. 2007; 88 (4): 458-463.
Anis Rassi Jr. Anis Rassi Hospital Av. José Alves, 453 – Setor Oeste 74110-020 – Goiânia, GO - Brazil E-mail:
Manuscript received February 26, 2007; accepted February 26, 2007