Mary K. Rhee

Patient adherence improves glycemic control

Purpose The purpose of this study was to assess the influence of appointment keeping and medication adherence on HbA1c. Methods A retrospective evaluation was performed in 1560 patients with type 2 diabetes who presented for a new visit to the Grady Diabetes Clinic between 1991 and 2001 and returned for a follow-up visit and HbA1c after 1 year of care. Appointment keeping was assessed by the number of scheduled intervening visits that were kept, and medication adherence was assessed by the percentage of visits in which self-reported diabetes medication use was as recommended at the preceding visit. Results The patients had an average age of 55 years, body mass index (BMI) of 32 kg/m2, diabetes duration of 4.6 years, and baseline HbA1c of 9.1%. Ninety percent were African American, and 63% were female. Those who kept more intervening appointments had lower HbA1c levels after 12 months of care (7.6% with 6-7 intervening visits vs 9.7% with 0 intervening visits). Better medication adherence was also associated with lower HbA1c levels after 12 months of care (7.8% with 76%-100% adherence). After adjusting for age, gender, race, BMI, diabetes duration, and diabetes therapy in multivariate linear regression analysis, the benefits of appointment keeping and medication adherence remained significant and contributed independently; the HbA1c was 0.12% lower for every additional intervening appointment that was kept (P= .0001) and 0.34% lower for each quartile of better medication adherence (P= .0009). Conclusion Keeping more appointments and taking diabetes medications as directed were associated with substantial improvements in HbA1c. Efforts to enhance glycemic outcomes should include emphasis on these simple but critically important aspects of patient adherence.

Glucose-Independent, Black–White Differences in Hemoglobin A1c Levels: A Cross-sectional Analysis of 2 Studies

BACKGROUND A previous study of participants with prediabetes found that hemoglobin A(1c) (HbA(1c)) levels differed between black and white participants with no differences in glucose concentration. OBJECTIVE To determine whether black-white differences in HbA(1c) level are present in other populations and across the full spectrum of glycemia. DESIGN Cross-sectional, retrospective. SETTING Outpatient. PARTICIPANTS 1581 non-Hispanic black and white participants between 18 and 87 years of age without known diabetes in the SIGT (Screening for Impaired Glucose Tolerance) study and 1967 non-Hispanic black and white participants older than 40 years without known diabetes in the NHANES III (Third National Health and Nutrition Examination Survey). MEASUREMENTS HbA(1c) levels, anthropometry, and plasma glucose levels during oral glucose tolerance testing. RESULTS Hemoglobin A(1c) levels were higher in black than in white participants with normal glucose tolerance (0.13 percentage point [P < 0.001] in the SIGT sample and 0.21 percentage point [P < 0.001] in the NHANES III sample), prediabetes (0.26 percentage point [P < 0.001] and 0.30 percentage point [P < 0.001], respectively), or diabetes (0.47 percentage point [P < 0.020] and 0.47 percentage point [P < 0.013], respectively) after adjustment for plasma glucose levels and other characteristics known to correlate with HbA(1c) levels. LIMITATION The mechanism for the differences is unknown. CONCLUSION Black persons have higher HbA(1c) levels than white persons across the full spectrum of glycemia, and the differences increase as glucose intolerance worsens. These findings could limit the use of HbA(1c) to screen for glucose intolerance, indicate the risk for complications, measure quality of care, and evaluate disparities in health.

Clinical Inertia Contributes to Poor Diabetes Control in a Primary Care Setting

Purpose The purpose of this study was to determine whether “clinical inertia”—inadequate intensification of therapy by the provider—could contribute to high A1C levels in patients with type 2 diabetes managed in a primary care site. Methods In a prospective observational study, management was compared in the Medical Clinic, a primary care site supervised by general internal medicine faculty, and the Diabetes Clinic, a specialty site supervised by endocrinologists. These municipal hospital clinics serve a common population that is largely African American, poor, and uninsured. Results Four hundred thirty-eight African American patients in the Medical Clinic and 2157 in the Diabetes Clinic were similar in average age, diabetes duration, body mass index, and gender, but A1C averaged 8.6% in the Medical Clinic versus 7.7% in the Diabetes Clinic (P < .0001). Use of pharmacotherapy was less intensive in the Medical Clinic (less use of insulin), and when patients had elevated glucose levels during clinic visits, therapy was less than half as likely to be advanced in the Medical Clinic compared to the Diabetes Clinic (P < .0001). Intensification rates were lower in the Medical Clinic regardless of type of therapy (P < .0001), and intensification of therapy was independently associated with improvement in A1C (P < .001). Conclusions Medical Clinic patients had worse glycemic control, were less likely to be treated with insulin, and were less likely to have their therapy intensified if glucose levels were elevated. To improve diabetes management and glycemic control nationwide, physicians in training and generalists must learn to overcome clinical inertia, to intensify therapy when appropriate, and to use insulin when clinically indicated.

Screening for Diabetes and Pre-Diabetes With Proposed A1C-Based Diagnostic Criteria

OBJECTIVE An International Expert Committee (IEC) and the American Diabetes Association (ADA) proposed diagnostic criteria for diabetes and pre-diabetes based on A1C levels. We hypothesized that screening for diabetes and pre-diabetes with A1C measurements would differ from using oral glucose tolerance tests (OGTT). RESEARCH DESIGN AND METHODS We compared pre-diabetes, dysglycemia (diabetes or pre-diabetes), and diabetes identified by the proposed criteria (A1C ≥6.5% for diabetes and 6.0–6.4% [IEC] or 5.7–6.4% [ADA] for high risk/pre-diabetes) with standard OGTT diagnoses in three datasets. Non-Hispanic white or black adults without known diabetes who had A1C and 75-g OGTT measurements were included from the prospective Screening for Impaired Glucose Tolerance study (n = 1,581), and from the National Health and Nutrition Examination Survey (NHANES) III (n = 2014), and NHANES 2005–2006 (n = 1,111). RESULTS OGTTs revealed pre-diabetes in 35.8% and diabetes in 5.2% of combined study subjects. A1C provided receiver operating characteristic (ROC) curve areas for diabetes of 0.79–0.83, but ROC curve areas were ≤0.70 for dysglycemia or pre-diabetes. The proposed criteria missed 70% of individuals with diabetes, 71–84% with dysglycemia, and 82–94% with pre-diabetes. Compared with the IEC criteria, the ADA criteria for pre-diabetes resulted in fewer false-negative and more false-positive result. There were also racial differences, with false-positive results being more common in black subjects and false-negative results being more common in white subjects. With use of NHANES 2005–2006 data, ∼5.9 million non-Hispanic U.S. adults with unrecognized diabetes and 43–52 million with pre-diabetes would be missed by screening with A1C. CONCLUSIONS The proposed A1C diagnostic criteria are insensitive and racially discrepant for screening, missing most Americans with undiagnosed diabetes and pre-diabetes.

Hyperglycemia during total parenteral nutrition: an important marker of poor outcome and mortality in hospitalized patients.

OBJECTIVE To determine the effect of total parenteral nutrition (TPN)-induced hyperglycemia on hospital outcome. RESEARCH DESIGN AND METHODS The study determined whether blood glucose values before, within 24 h, and during days 2–10 of TPN are predictive of hospital complications and mortality. RESULTS Subjects included a total of 276 patients receiving TPN for a mean duration of 15 ± 24 days (±SD). In multiple regression models adjusted for age, sex, and diabetes status, mortality was independently predicted by pre-TPN blood glucose of 121–150 mg/dl (odds ratio [OR] 2.2, 95% CI 1.1–4.4, P = 0.030), 151–180 mg/dl (3.41, 1.3–8.7, P = 0.01), and >180 mg/dl (2.2, 0.9–5.2, P = 0.077) and by blood glucose within 24 h of >180 mg/dl (2.8, 1.2–6.8, P = 0.020). A blood glucose within 24 h of >180 mg/dl was associated with increased risk of pneumonia (OR 3.1, 95% CI 1.4–7.1) and acute renal failure (2.3, 1.1–5.0). CONCLUSIONS Hyperglycemia is associated with increased hospital complications and mortality in patients receiving TPN.

Exercise preferences and barriers in urban African Americans with type 2 diabetes.

PURPOSE The purpose of this study was to determine physical activity preferences and barriers to exercise in an urban diabetes clinic population. METHODS A survey was conducted of all patients attending the clinic for the first time. Evaluation measures were type and frequency of favorite leisure-time physical activity, prevalence and types of reported barriers to exercise, and analysis of patient characteristics associated with reporting an obstacle to exercise. RESULTS For 605 patients (44% male, 89% African American, mean age = 50 years, mean duration of diabetes = 5.6 years), the average frequency of leisure activity was 3.5 days per week (mean time = 45 minutes per session). Walking outdoors was preferred, but 52% reported an exercise barrier (predominantly pain). Patients who cited an impediment to physical activity exercised fewer days per week and less time each session compared with persons without a barrier. Increasing age, body mass index, college education, and being a smoker increased the odds of reporting a barrier; being male decreased the chances. Men reported more leisure-time physical activity than women. Exercise preferences and types of barriers changed with age. CONCLUSIONS Recognition of patient exercise preferences and barriers should help in developing exercise strategies for improving glycemic control.

Barriers to Diabetes Education in Urban Patients Perceptions, Patterns, and Associated Factors

Purpose This study explored patients’ perceptions of barriers to diabetes education among a mostly African American population of adults with diabetes. Methods A survey was conducted among 605 new patients attending an urban outpatient diabetes clinic. The questionnaire gathered information on issues patients believed would adversely affect their ability to learn about diabetes. The type and frequency of education barriers were evaluated, and variables associated with reporting an obstacle were analyzed. Results Average patient age was 50 years, diabetes duration was 5.6 years, body mass index was 32 kg/m2, and hemoglobin A1C was 9.1%. The majority (56%) were women, 89% were African American, and 95% had type 2 diabetes. Most respondents (96%) had received some prior instruction in diabetes care; however, 53% anticipated future difficulties learning about diabetes. The most commonly cited concerns were poor vision (74%) and reading problems (29%). Patients with a perceived barrier to diabetes education were older (P < .001) than were persons without a barrier, and they differed in both employment and educational status (both P < .001). In adjusted analyses, older age, male gender, being disabled, and having an elementary education or less were associated with a significantly increased likelihood of having a barrier to diabetes education, whereas having a college education decreased the odds. Higher hemoglobin A1C levels also tended to be associated with a greater chance of reporting an education barrier (P = .05). Conclusions A substantial number of persons anticipated a barrier to diabetes education. Interventions at multiple levels that address the demographic and socioeconomic obstacles to diabetes education are needed to ensure successful self-management training.

Many Americans have pre-diabetes and should be considered for metformin therapy.

OBJECTIVE To determine the proportion of the American population who would merit metformin treatment, according to recent American Diabetes Association (ADA) consensus panel recommendations to prevent or delay the development of diabetes. RESEARCH DESIGN AND METHODS Risk factors were evaluated in 1,581 Screening for Impaired Glucose Tolerance (SIGT), 2,014 Third National Health and Nutrition Examination Survey (NHANES III), and 1,111 National Health and Nutrition Examination Survey 2005–2006 (NHANES 2005–2006) subjects, who were non-Hispanic white and black, without known diabetes. Criteria for consideration of metformin included the presence of both impaired fasting glucose (IFG) and impaired glucose tolerance (IGT), with ≥1 additional diabetes risk factor: age <60 years, BMI ≥35 kg/m2, family history of diabetes, elevated triglycerides, reduced HDL cholesterol, hypertension, or A1C >6.0%. RESULTS Isolated IFG, isolated IGT, and IFG and IGT were found in 18.0, 7.2, and 8.2% of SIGT; 22.3, 6.4, and 9.4% of NHANES III; and 21.8, 5.0, and 9.0% of NHANES 2005–2006 subjects, respectively. In SIGT, NHANES III, and NHANES 2005–2006, criteria for metformin consideration were met in 99, 96, and 96% of those with IFG and IGT; 31, 29, and 28% of all those with IFG; and 53, 57, and 62% of all those with IGT (8.1, 9.1, and 8.7% of all subjects), respectively. CONCLUSIONS More than 96% of individuals with both IFG and IGT are likely to meet ADA consensus criteria for consideration of metformin. Because >28% of all those with IFG met the criteria, providers should perform oral glucose tolerance tests to find concomitant IGT in all patients with IFG. To the extent that our findings are representative of the U.S. population, ∼1 in 12 adults has a combination of pre-diabetes and risk factors that may justify consideration of metformin treatment for diabetes prevention.

Aging is associated with increased HbA1c levels, independently of glucose levels and insulin resistance, and also with decreased HbA1c diagnostic specificity.

To determine whether using HbA1c for screening and management could be confounded by age differences, whether age effects can be explained by unrecognized diabetes and prediabetes, insulin resistance or postprandial hyperglycaemia, and whether the effects of aging have an impact on diagnostic accuracy.

Safety and efficacy of continuous insulin infusion in noncritical care settings

BACKGROUND Continuous insulin infusion (CII) to manage hyperglycemia is the accepted standard of care in the intensive care unit (ICU); however, the safety and efficacy of CII in the non-ICU setting has not been determined. RESEARCH DESIGN AND METHODS This is a retrospective analysis of 200 consecutive patients receiving CII while admitted to general medical-surgical units at Emory University Hospital. We evaluated clinical outcomes and rates of hyperglycemia (blood glucose [BG] >200 mg/dL) and hypoglycemia (BG <60 mg/dL) events during CII. RESULTS A total of 200 patients (age 52 +/- 16 years; male/female [M/F] 108/92) were admitted to general medicine (45%) or surgery (55%) services, 88.5% with history of diabetes and 41% treated with corticosteroids. The mean BG prior to and during the CII was 323 mg/dL and 170 mg/dL, respectively. Blood glucose of <or=150 mg/dL was the targeted goal in 85% of patients and 67% achieved a BG <or=150 mg/dL by hospital day 2. Hypoglycemia (BG <60 mg/dL) occurred at least once in 22% of patients, and severe hypoglycemia (BG <40 mg/dL) occurred in 5% of patients. Multivariate regression analyses showed that nutrition status during CII was associated with increased frequency of hyperglycemia and hypoglycemia. Compared to patients kept nil per os (NPO), oral intake during CII increased rates of hyperglycemic (P = 0.012) and hypoglycemic events (P = 0.035). CONCLUSIONS CII resulted in rapid and sustained glycemic control and a rate of hypoglycemic events similar to that reported in recent ICU trials. The rates of hypoglycemic and hyperglycemic events are significantly higher in patients allowed to eat during CII.