Personalized Medicine Essential, says Mario Ehlers, CSO of Pacific Biomedics

One-size-fits-all therapies no longer work, Dr. Ehlers argues. in the essay below MANAGING DIABETES “ RACIAL FACTORS APPEAR TO PLAY A ROLE Why do African-Americans suffer from disproportionately higher rates of death and complications from diabetes?  A recent study Wake Forest Report that analyzed a combination of 11 other research studies concluded that African-Americans with diabetes have a lower level of control of blood sugar than Caucasians. The lead author of that study was Julienne Kirk, PharmD, it was conducted at Wake Forest University School of Medicine, and results were published in Diabetes Care. This was the first meta-analysis of racial and ethnic differences in blood sugar control among patients with diabetes. Dr. Kirks research team analyzed studies that measured sugar control among blacks and whites over age 50 with type 2-diabetes.  The blood test used was  for glycosylated hemoglobin, the hemoglobin that has been linked with glucose, or blood sugar. The lower the amounts of glycosylated hemoglobin, also called A1C, in the blood, the better the body is controlling blood sugar. By combining the data from the 11 studies into a meta-analysis involving a total of 42,273 white and 14,670 black patients, the researchers were able to detect differences that may not have shown up in each individual study. Kirk and the team said the findings point to a need to determine why the differences exist and the importance of identifying ways to prevent or reduce the resulting health problems. Poor blood sugar control can result in long-term complications such as blindness, amputation and end-stage kidney failure. Previous studies have suggested that blood sugar control may be poorer among minority populations. The researchers were not able to examine the factors responsible for the difference in their study, and said additional research is needed.  Dr. Kirk also emphasized that although A1C control among blacks likely contributes to their elevated risk of complications, it accounts for only a portion of the risk.   To me this is another example of why we need to think in terms of targeted therapies and, eventually, the widespread use of personalized medicine. Although this study by J.K. Kirk et al. did not determine the causes for the disparity, there are several possible reasons.  Those possibilities include differences in quality of care, including the intensity of treatment; socioeconomic differences, such as the African American population at large being less likely to have prescription drug coverage; and also genetic differences.  It is important to exclude socioeconomic factors that may contribute to reduced access to post-diagnosis medical care by African-Americans or lead to differences in lifestyle, including diet and exercise. The authors do note that two of the largest studies contributing to this meta-analysis took place in managed care settings, where all subjects had access to health care.  Other studies show that African Americans and non-Hispanic whites had similar health insurance coverage, indicating perhaps that the disparity in glycemic metabolism may be due to genetic rather than socioeconomic differences.   This report is not the first time diseases and responses to treatment have been shown to differ between population groups in the US.  The recent approval of the heart drug BiDil caused controversy because it was approved specifically for African Americans with heart failure.  Yet, it is well known that the prevalence of high blood pressure and heart failure is significantly higher in blacks than in whites, as referenced in the 2006 update of the Heart Disease and Stroke statistics put out by the American Heart Association.  It has also been documented that blacks do not respond as well as whites to certain classes of blood pressure medications, such as beta-blockers and ACE inhibitors.  While race is clearly a blunt tool for stratifying patients for optimal pharmacological care, it is a starting point for understanding fundamental inter-individual differences that govern disease patterns and responses to medical care. The study by Kirk et al. is, similarly, a starting point for further research to understand differences between population groups and individuals in the severity of diabetes and responses to medical care.  We must, in my opinion, move away from the one-size-fits-all model of medical care to one that is targeted to specific population groups and, ultimately, to specific individuals in the form of personalized medicine.  And, in fact, these advances are being enabled by the post-genome revolution in our understanding of human biology and disease, and the increasing use of disease-specific biomarkers for diagnosis, treatment stratification, and treatment monitoring.