Author: Jonathan Brown
Position: Senior Investigator
Institution: Kaiser Permanente Center for Health Research; Chair of the International Diabetes Federation Task Force on Diabetes Health Economics
E-mail: jonathan.brown@kpchr.org
Submitted Date: November 15, 2005
Published Date: November 15, 2005
This comment was originally posted as a “Reader Response” on the publication date indicated above. All Reader Responses are now available as comments.

The importance of prophylactic aspirin use in both industrialized and developing countries can hardly be overemphasized. I am troubled, however, by Stafford and colleagues' failure to cite and discuss US studies that show much higher rates of antithrombotic use than they report. Using a cross-sectional postal survey of 2500 Kaiser Permanente members with atherosclerotic cardiovascular disease, Brown et al.[1] found that 84% were currently taking prophylactic aspirin (72%) or a prescription agent (12%, usually warfarin) in 1999. In an earlier study of another integrated non-profit US medical care system, Health Partners, O'Connor et al.[2] similarly found that 71% of members with clinically diagnosed coronary heart disease were taking aspirin. These results are almost triple the ~25% that Stafford et al. now report for the 1999-2000 time period (the low point in their time series) and about double that 34% that Stafford[4] previously reported from NAMCS for patients with coronary heart disease.

Two factors probably account for these differences. First, Stafford et al.'s federal surveys of ambulatory care encounters miss a significant proportion of aspirin use. This is shown by other US studies not involving integrated medical care programs that used direct patient surveys and other methods. These studies, some of which are cited in Brown et al.,[1] found higher rates of aspirin use than Stafford has reported over the years. Second, non-profit integrated medical care programs emphasize and promote aspirin aggressively and effectively. Their members probably have higher rates of aspirin use than the US as a whole.

The latter point is important because it calls into question Stafford et al.'s suggestion, emphasized in PLOS's accompanying synopsis, that direct to consumer advertising of statins explains the 1997-2000 dip in aspirin use in their NAMCS/NHAMCS data. Kaiser Permanente and HealthPartners members were equally exposed to direct advertising but maintained high aspirin use during this period--despite probably also using statins (and ACE inhibitors) at higher-than-US rates, as well.

Nevertheless, the US non-profit HMO experience reinforces the authors' main conclusion that "aggressive and targeted interventions are needed to enhance provider and patient adherence to consensus guidelines for CVD risk reduction." This experience also gives some hope that it can be more broadly accomplished in the US. Major structural factors such as lack of universal health insurance, a fee-for-service rather than population-based orientation, and failure to use comprehensive electronic medical record systems will continue to hamper us, however. Direct to consumer advertising, although symptomatic, pales in importance against these other problems.