Microvascular complications in diabetes patients with heart failure and reduced ejection fraction-insights from the Beta-blocker Evaluation of Survival Trial : Diabetes with complications in HFrEF

The role of cardiac glycosides in treating patients with chronic heart failure and normal sinus rhythm remains controversial. We studied the effect of digoxin on mortality and hospitalization in a randomized, double-blind clinical trial. In the main trial, patients with a left ventricular ejection fraction of 0.45 or less were randomly assigned to digoxin (3397 patients) or placebo (3403 patients) in addition to diuretics and angiotensin-converting-enzyme inhibitors (median dose of digoxin, 0.25 mg per day; average follow-up, 37 months). In an ancillary trial of patients with ejection fractions greater than 0.45, 492 patients were randomly assigned to digoxin and 496 to placebo. In the main trial, mortality was unaffected. There were 1181 deaths (34.8 percent) with digoxin and 1194 deaths (35.1 percent) with placebo (risk ratio when digoxin was compared with placebo, 0.99; 95 percent confidence interval, 0.91 to 1.07; P=0.80). In the digoxin group, there was a trend toward a decrease in the risk of death attributed to worsening heart failure (risk ratio, 0.88; 95 percent confidence interval, 0.77 to 1.01; P=0.06). There were 6 percent fewer hospitalizations overall in that group than in the placebo group, and fewer patients were hospitalized for worsening heart failure (26.8 percent vs. 34.7 percent; risk ratio, 0.72; 95 percent confidence interval, 0.66 to 0.79; P<0.001). In the ancillary trial, the findings regarding the primary combined outcome of death or hospitalization due to worsening heart failure were consistent with the results of the main trial. Digoxin did not reduce overall mortality, but it reduced the rate of hospitalization both overall and for worsening heart failure. These findings define more precisely the role of digoxin in the management of chronic heart failure.

Higher rates of microvascular complications have been reported for minorities. Disparate access to quality health care is a common explanation for ethnic disparities in diabetic complication rates in the US population. Examining an ethnically diverse population with uniform health care coverage may be useful. To assess ethnic disparities in the incidence of diabetic complications within a nonprofit prepaid health care organization. Longitudinal observational study conducted January 1, 1995, through December 31, 1998, at Kaiser Permanente Medical Care Program in northern California. A total of 62 432 diabetic patients, including Asians (12%), blacks (14%), Latinos (10%), and whites (64%). Incident myocardial infarction (MI), stroke, congestive heart failure (CHF), and nontraumatic lower extremity amputation (LEA), defined by primary hospitalization discharge diagnosis, procedures, or underlying cause of death; and end-stage renal disease (ESRD), defined as renal insufficiency requiring renal replacement therapy or transplantation for survival or by underlying cause of death. Patterns of ethnic differences were not consistent across complications and frequently persisted despite adjustment for a wide range of demographic, socioeconomic, behavioral, and clinical factors. Adjusted hazard ratios (relative to that of whites) were 0.56, 0.68, and 0.68 for blacks, Asians, and Latinos, respectively (P<.001), for MI; 0.76 and 0.72 for Asians and Latinos, respectively (P<.01), for stroke; 0.70 and 0.61 for Asians and Latinos, respectively (P<.01), for CHF; 0.40 for Asians (P<.001) for LEA; and 2.03, 1.85, and 1.46 for blacks, Asians, and Latinos, respectively (P<.01), for ESRD. There were no statistically significant black-white differences for stroke, CHF, or LEA and no Latino-white differences for LEA. This study confirms previous reports of elevated incidence of ESRD among ethnic minorities, despite uniform medical care coverage, and provides new evidence that rates of other complications are similar or lower relative to those of whites. The persistence of ethnic disparities after adjustment suggests a possible genetic origin, the contribution of unmeasured environmental factors, or a combination of these factors.

Both type 1 and type 2 diabetes adversely affect the microvasculature in multiple organs. Our understanding of the genesis of this injury and of potential interventions to prevent, limit, or reverse injury/dysfunction is continuously evolving. This statement reviews biochemical/cellular pathways involved in facilitating and abrogating microvascular injury. The statement summarizes the types of injury/dysfunction that occur in the three classical diabetes microvascular target tissues, the eye, the kidney, and the peripheral nervous system; the statement also reviews information on the effects of diabetes and insulin resistance on the microvasculature of skin, brain, adipose tissue, and cardiac and skeletal muscle. Despite extensive and intensive research, it is disappointing that microvascular complications of diabetes continue to compromise the quantity and quality of life for patients with diabetes. Hopefully, by understanding and building on current research findings, we will discover new approaches for prevention and treatment that will be effective for future generations.