Mean A1C Levels Research Articles

FreeStyle Navigator Continuous Glucose Monitoring System Use in Children With Type 1 Diabetes Using Glargine-Based Multiple Daily Dose Regimens

In a previous pilot study of the FreeStyle Navigator Continuous Glucose Monitoring System, hereafter referred to as “Navigator,” in 30 children and adolescents with type 1 diabetes using insulin pumps, we found that Navigator use averaged >130 h per week over 13 weeks and mean A1C level dropped from 7.1 ± 0.6 to 6.8 ± 0.7% ( P = 0.02) (1). The current study evaluated whether the Navigator was similarly tolerated over 13 weeks in 27 children aged 4–17 years with type 1 diabetes using glargine-based, multiple daily injection(MDI) insulin regimens. Subjects averaged >100 h/week of Navigator use. Mean A1C level fell from 7.9 ± 1.0% at baseline to 7.3 ± 0.9% at 13 weeks ( P = 0.004). High satisfaction with the Navigator was reported on the Continuous Glucose Monitor Satisfaction Scale. These encouraging pilot study results support the inclusion of MDI users in longer-term randomized clinical trials of continuous glucose monitors. Institutional review boards at each of the Diabetes Research in Children Network (DirecNet) centers approved the study protocol and consent/assent forms. Research methods were virtually identical to those employed in our previous Navigator (Abbott Diabetes Care; Alameda, CA) study (1) except that all subjects were treated with glargine-based MDI treatment. Other eligibility requirements were as follows: subjects must 1 ) be aged 3–17 years, 2 ) have type 1 diabetes for a duration ≥1 year, 3 ) have access to a home computer equipped with E-mail, and 4 ) have a parent/older subject who comprehended English. Subjects were excluded for asthma, cystic fibrosis, psychiatric disorder, and use of glucocorticoids. Subjects were selected for participation from the existing patient population at each center. There was a 1-week run-in period during which Navigator use was blinded to collect baseline glucose data, followed by unblinded home use for 3 months. To blind subjects to the results …

Is Glycemic Control Improving in U.S. Adults?

The purpose of this study was to examine whether glycemic control has improved in recent years among individuals with diagnosed diabetes. We examined trends in A1C levels for adults with diagnosed diabetes using three consecutive waves of the National Health and Nutrition Examination Survey (NHANES): 1999-2000, 2001-2002, and 2003-2004. We estimated mean A1C levels and the proportion with A1C <7.0, <8.0, and <9.0%. We used multivariate regression to test whether A1C levels differed by NHANES wave after controlling for other factors. Multivariate dichotomous logistic regression and predictive margins were used to test whether the percentages of individuals with diabetes in selected A1C intervals differed by NHANES wave. Mean A1C levels among individuals with diagnosed diabetes declined from 7.82% in 1999-2000 to 7.47 and 7.18% in 2001-2002 and 2003-2004, respectively. After controlling for demographics and diabetes duration, A1C levels were 0.308 (P = 0.20) and 0.511 (P = 0.03) percentage points lower in 2001-2002 and 2003-2004, respectively, than in 1999-2000. The logistic results indicated corresponding improvements over time: the predictive margin for having A1C <7.0% increased from 37.0% in 1999-2000 to 49.7% in 2001-2002 and to 55.7% in 2003-2004. Glycemic control improved between 1999 and 2004. This trend may represent an important improvement in diabetes care and is encouraging for future reduction of diabetes-related complications.

Differences in A1C by Race and Ethnicity Among Patients With Impaired Glucose Tolerance in the Diabetes Prevention Program

We sought to examine racial and ethnic differences in A1C in individuals with impaired glucose tolerance (IGT). We studied 3,819 individuals aged > or = 25 years with IGT who were found to be eligible to participant in the Diabetes Prevention Program. A1C was compared among five racial and ethnic groups before and after adjustment for factors that differed among groups or might affect glycemia including age, sex, education, marital status, blood pressure, adiposity (BMI and waist circumference), hematocrit, fasting and post-glucose load glucose levels, glucose area under the curve (AUC), beta-cell function, and insulin resistance. Mean +/- SD A1C was 5.91 +/- 0.50%. Among whites, A1C was 5.80 +/- 0.44%, among Hispanics 5.89 +/- 0.46%, among Asian 5.96 +/- 0.45%, among American Indians 5.96 +/- 0.46%, and among blacks 6.19 +/- 0.59%. Age, sex, systolic blood pressure, diastolic blood pressure, BMI, fasting glucose, glucose AUC, corrected insulin response, and insulin resistance were each independent predictors of A1C. Adjusting for these and other factors, mean A1C levels were 5.78% for whites, 5.93% for Hispanics, 6.00% for Asians, 6.12% for American Indians, and 6.18% for blacks (P < 0.001). A1C levels are higher among U.S. racial and ethnic minority groups with IGT after adjustment for factors likely to affect glycemia. Among patients with IGT, A1C may not be valid for assessing and comparing glycemic control across racial and ethnic groups or as an indicator of health care disparities.

Management of Hyperglycemia in Type 2 Diabetes: A Consensus Algorithm for the Initiation and Adjustment of Therapy: A Consensus Statement From the American Diabetes Association and the European Association for the Study of Diabetes

Jellinger, Lebovitz, and Davidson (1), writing on behalf of the American College of Endocrinology/American Association of Clinical Endocrinologists (ACE/AACE) Outpatient Glycemic Control Implementation Task Force, challenge the consensus treatment algorithm of the American Diabetes Association (ADA) and the European Association for the Study of Diabetes (2). I will attempt to answer each of their objections. First, I will address the statement that the therapeutic A1C target should be <6.5% rather than <7.0%. The discussion of this point needs to be separated into microvascular and macrovascular outcomes. Regarding microvascular disease, there have been five studies in over 2,000 type 1 (3–5) and type 2 (6,7) diabetic patients demonstrating that there was virtually no development or progression of retinopathy and nephropathy over 6–9 years if mean A1C levels are maintained at <7.0%. In two of these studies (3,6), an intervention that lowered glycemia resulted in much less retinopathy and neuropathy, proving a causative relationship between control and improved outcomes. Regarding macrovascular disease, there is an association with glycemia defined by oral glucose tolerance testing that extends down into the midnormal range (8). Regarding glycemia at more than one point in time, there are significant ∼2.5-fold increases in clinical cardiac events in individuals with A1C levels >5.0% in one study (9) or 4.6% in another (10) over 4 or 8–10 years, respectively. However, in addition to the impossibility of reducing A1C levels to these values, association must not be confused with causation. One of the only things I remember from the biostatistics course in the first year of medical …