Study Overview
Objective. To update national trends in the treatment and risk factor control of diabetic patients from 1999 through 2018 in the US using data from the National Health and Nutrition Examination Survey (NHANES) with the goal of identifying population subgroups with the highest probability of having untreated risk factors.
Design. The authors conducted a cross-sectional analysis of data from NHANES focusing on adults with diabetes. They examined patient characteristics and medication use over time and estimated the prevalence of risk factor control and medication use. To minimize the effects of a small sample size, the survey years were pooled into 4-year intervals. The variables studied included glycated hemoglobin (HbA1c), blood pressure, serum cholesterol, medication use, sociodemographic characteristics, and weight status. For statistical analysis, logistic and multinomial logistic regression models were used to examine factors associated with treatment in participants who did not achieve targets for glycemic, blood pressure, and lipid control. Temporal trends were estimated using 2-piece linear spline models with 1 knot at inflection points.
Setting and participants. The NHANES program began in the early 1960s to monitor the health of the US population. In 1999, the survey became a continuous program combining interviews and physical examinations. The survey examines a nationally representative sample of about 5000 persons each year. This study included 6653 participants who were nonpregnant, aged older than 20 years, reported a diagnosis of diabetes from a physician, and participated in NHANES from 1999 through 2018.
Main outcome measures. The main outcome measures were temporal trends in risk factor control (glycemic, blood pressure, or lipid levels) and medication use (glucose lowering, blood pressure lowering, or lipid lowering medications), and number as well as class of drug used, from 1999 through 2018 in diabetic adults from the US participating in NHANES.
Results. Sociodemographic characteristics of the studied diabetes population—The age and racial or ethnic distribution of participants with diabetes were stable from 1999 through 2018, whereas participants with a college degree, higher income, health insurance, obesity, or long-standing diabetes increased during the same period.
Trends in diabetes risk factor control—The trends for glycemic, blood pressure, and lipid control were nonlinear, with an inflection point around 2010. Glycemic control was defined as HbA1c less than 7%, blood pressure was considered controlled if less than 140/90 mmHg, and lipid was controlled if non-HDL cholesterol level was less than 130 mg/dL. Although these chosen targets were based on the most recent clinical guidelines, the authors declared that they observed similar trends when alternative targets were used. The level of risk factor control improved in all diabetic patients from 1999 through 2010. However, the percentage of adult diabetic participants for whom glycemic control was achieved declined from 57.4% (95% CI, 52.9-61.8) in 2007-2010 to 50.5% (95% CI, 45.8-55.3) in 2015-2018. Blood pressure control was achieved in 74.2% of participants (95% CI, 70.7-77.4) in 2011-2014 but declined to 70.4% (95% CI, 66.7-73.8) in 2015-2018. Control in lipid levels improved during the entire study period; however, the rate of improvement heavily declined after 2007 with lipid target levels attained in 52.3% of participants (95% CI, 49.2-55.3) in 2007-2014 and 55.7% (95% CI, 50.8-60.5) in 2015-2018. Finally, the percentage of participants in whom targets for all 3 risk factors were simultaneously achieved plateaued after 2010 and was 22.2% (95% CI, 17.9-27.3) in 2015-2018.
Trends in diabetes treatment—The use of glucose lowering drugs increased from 74.1% in 1999-2002 to 82.7% in 2007-2010 and then stabilized. A shift toward a safer glucose lowering treatment choice was observed with a decline in the use of older glucose lowering medications such as sulfonylureas, which increases the risk of hypoglycemia, and an increase in the use of metformin, insulin, and newer agents such as sodium-glucose cotransporter 2 inhibitors.