and also collected information on duration, dose, and indi- cation for use. While some underreporting of aspirin use by self-report has been noted in other studies, reporting accuracy tends to improve with more frequent and regular use. 43,44 As information on aspirin use was obtained prospectively in this study, any misclassification of aspirin use due to inaccurate reporting is likely to be nondifferential, leading most likely to an attenuation of the effects of aspirin. 45 Although we relied on self-reported data on comorbidities, the validity of self-reported data has been shown to be generally good for heart disease, stroke, hypertension, diabetes, and other medi- cal conditions. 27–31 It is possible that the elevated mortality risks we observed were due to other conditions not captured in the questionnaires; however, the unidentified comorbidities would need to be strongly correlated with both aspirin use and mortality to have a substantial impact on our findings. Cardiovascular mortality risk estimates for individuals tak- ing aspirin more than once daily remained elevated even after excluding deaths in the first 5 years of follow-up, minimizing the likelihood that heavy aspirin users were treating symp- toms related to end-stage disease. In conclusion, our study confirms the potential utility of daily aspirin for the secondary prevention of cardiovas- cular mortality, but suggests caution for its use among those without a history of cardiovascular disease. Consistent find- ings across 2 large cohorts suggest that more than once daily use of aspirin does not provide a reduction in mortality and may be associated with an increased risk of death, particularly among individuals without a history of cardiovascular disease. Although further studies are needed to confirm these findings, our study highlights the need to evaluate important long-term health risks of aspirin across a broad range of common use patterns and to fully consider the risks and benefits before making public health recommendations. ACKNOWLEDGMENTS The authors thank the participants from the NIH-AARP and PLCO cohorts for their excellent cooperation in these studies. The authors also thank Mr. Adam Risch and Mr. John Commins, Information Management Services, Inc. for their assistance in the data analysis. The content of this publication does not necessarily reflect the views or policies of the Department of Health and Human Services nor does mention of trade names, commercial products, or organizations imply endorsement by the US Government. All statements in this report, including its findings and conclusions, are solely those of the authors and do not necessarily represent the views of the Patient-Centered Outcomes Research Institute (PCORI), its Board of Governors or Methodology Committee.
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- Fall '18
- Epidemiology, Randomized controlled trial, Wolters Kluwer Health