Long-term Mortality for Older Diabetics Hospitalized with Acute Myocardial Infarction

LONG-TERM MORTALITY FOR OLDER DIABETICS HOSPITALIZED WITH ACUTE MYOCARDIAL INFARCTION” Marwah Abdalla, Barbara Gulanski, Yun Wang, Edward Havranek, Frederick Masoudi, Harlan Krumholz, JoAnne Micale Foody. Yale University School of Medicine-New Haven, CT & University of Colorado Health Sciences-Denver, CO Diabetics have higher mortality after myocardial infarction (MI), yet little is known regarding the impact of quality of care on long-term survival in older post-MI diabetics. Using data from the Cooperative Cardiovascular Project (CCP), a national cohort of 234,769 Medicare patients aged 65 or older hospitalized with confirmed AMI between 1994-1995, we assessed differences in 10-year mortality outcomes between diabetics and non-diabetics using Cox proportional regression. To account for quality of care, a composite measure among ideal candidates was constructed and entered into the final model adjusting for use of aspirin & beta-blocker on admission/discharge, angiotensin-converting enzyme inhibitors at discharge, reperfusion within 6 hours of admission, and smoking counseling at discharge. We also assessed the relationship between insulin use, sulfonylureas/biguanides, and statin therapy and longterm mortality within the diabetic cohort. The final study sample included 203,658 cases: 32% were diabetics. Compared to non-diabetics, diabetics were younger (75 vs. 76, p<0.001), female (53% vs. 47%, p<0.001), had more comorbidities, and unlikely to receive evidence-based care (59% vs. 64%, p<0.001). The unadjusted HR for mortality among diabetics vs. non-diabetics was 1.38 (95% CI: 1.37-1.40). After adjusting for demographics, past medical history, procedures during hospitalization, medications on admission/discharge, and quality of care, the HR was 1.29 (95% CI: 1.27-1.31). Among diabetics, those on insulin or oral hypoglycemic therapy during the initial hospitalization for AMI had the highest risk of mortality during the last 7 years, after adjustment for demographics, clinical characteristics, and quality of care (HR insulin=1.30, 95% CI: 1.25-1.35; HR oral hypoglycemics=1.11, 95% CI: 1.08-1.15) whereas those on statin therapy were not at increased risk (HR statin=0.95, 95% CI: 0.90-1.02). As compared to non-diabetics, older diabetics had a 29% increase in mortality even after adjusting for demographics, clinical variables during hospitalization, and quality of care (HR=1.29, 95% CI: 1.271.31). Additionally, within the diabetic cohort, the risk of long-term mortality was highest among those on insulin or oral hypoglycemic therapy during initial hospitalization for AMI. Our study demonstrates that neither patient characteristics nor quality of care fully account for the poor outcomes among diabetics suggesting that metabolic risk factors associated with diabetes ultimately require therapies beyond those currently recommended for post-MI patients. 3 A portion of this abstract was presented at the American Heart Association’s Scientific Sessions, November 2005. Publication reference: Marwah Abdalla, Barbara Gulanski, Yun Wang, Edward Havranek, Frederick Masoudi, Harlan Krumholz, JoAnne Foody. “Ten-Year Mortality for Older Diabetics Hospitalized With Acute Myocardial Infarction. ” Circulation, Vol 112, Suppl, October 2005. (abstr.) Acknowledgements First and foremost, I would like to thank my family. Throughout all my endeavors, your love, support, guidance, and endless patience have been truly inspirational—“thanks” will never suffice. The completion of this thesis would not have been possible without the direct support of two incredible mentors: Dr. Barbara Gulanski and Dr. JoAnne Foody. Their advice not only about research but life in general is unparalleled. I will always be eternally grateful for their “open-door policy,” patience, support, encouragement, wisdom, and of course, amazing sense of humor. No question was ever left unanswered. Thank you for being such wonderful teachers throughout the years, both in and outside the classroom. Others to whom I am extremely indebted: Yun Wang, Ph.D. for his superb statistical analyses without which this thesis truly could not have existed. Thank you for being such an excellent and patient teacher. I also owe much gratitude to Marlynn Wei, MD/JD ’07 for her support throughout the writing process, her excellent editing skills, and her amazing friendship. Many thanks to Sameera Fazili, JD ’06 for helping with the final revisions but more importantly for always keeping me sane. And to Hala Imam, MPH ’07 and Dr. Sumaira Aasi whose encouraging words and mere presence during those last crucial moments were essential. I would also like to acknowledge Dr. Harlan Krumholz, Dr. Frederick Masoudi, and Dr. Edward Havranek for their valuable insights during various stages of this research. Thank you to both the Office of Student Research and the Graduate Professional Student Senate (GPSS) whose funding allowed portions of this thesis to be presented at both the American Diabetes Association’s Scientific Sessions (San Diego, California, June 2005) and the American Heart Association’s Scientific Sessions (Dallas, Texas, November 2005). Last, but certainly not least, I am indebted to the patients whose lives and longterm outcomes are represented within this data and to the countless individuals who developed and implemented the Cooperative Cardiovascular Project.