Glycemic, BP, Lipid Control in T2D Declining, Upping Risk for Related Disease, Complications

A new analysis of data from the National Health and Nutrition Examination Survey (NHANES) points to a deterioration in glycemic and blood pressure (BP) control in the US in recent years and to stalled improvement in lipid control.

The authors, writing in the June 10, 2021, issue of the New England Journal of Medicine, say that tight control of hyperglycemia, blood pressure, and lipids, when attained simultaneously, lowers the risk of diabetes-related illnesses and mortality. Senior author Elizabeth Selvin, PhD, MPH, codirector, Cardiovascular Disease Epidemiology Training Program, Johns Hopkins Bloomberg School of Public Health with a joint appointment in medicine, and colleagues emphasize that “…multifactorial risk-factor control forms the foundation of clinical care” for diabetes patients.

Between 1999 and 2010 control of all 3 risk factors improved in adults with diabetes, according to the researchers, but analyses tracking progress since 2010 suggest that improvement has not only stalled but may have reversed, creating the potential for a “population-level increase in diabetes related illness moving forward,” they wrote.

To update understanding of US trends in risk factor control in adults with diabetes, evaluate trends in treatment, and identify populations most likely undertreated for risk factors, investigators analyzed data from NHANES surveys between 1999 through 2018 for adults aged ≥20 years who had ever received a diabetes diagnosis by a physician (total = 6653).

RISK FACTOR CONTROL

For all measures, as noted above, the year 2010 appeared to be a turning point.

A1c: In 1999-2002, 44% of participants achieved A1c <7%; that rose to 57.4% in the 2007-2010 survey but then dropped to 50.5% in 2015-2018. Trends were similar for BP controlled to <130/80 m Hg.

BP: Blood pressure <140/90 mm Hg was reached by 64% (1999-2002), then 74.2% (2007-2010), followed by a decline to 70.4% (2015-2018). 

Lipids: non-HDL-C <130 mg/dL increased from 25.3% (1999-2002) to 52.3% (2007-2010) and then plateaued at 55.7% (2015-2018).

When all years were modeled, the annual rate of change in diabetes control decreased for all outcomes, according to investigators.

MEDICATION USE

Looking at trends in medication use paralleling risk factor control, investigators found that use of any glucose-lowering medication increased by 8.6% from 1999 to 2010, and then leveled off. Missing behind this pattern appears to be any impact reflecting increases between 1999 and 2018 in use of metformin, insulin, and newer classes of antihyperglycemic agents and a decline in use of sulfonylureas and thiazolidinediones, the more traditional medications.

Use of any BP-lowering medication increased by 15.9% and then stabilized in 2010; between 1999 and 2018, use of diuretics and calcium channel blockers remained constant while beta-blocker and ACE or ARBs rose. Statin use plateaued in 2014 after a rise of 27.6% since 1999.

INTENSIVE TREATMENT QUESTIONED

Selvin and colleagues point to results from several landmark clinical trials published between 2008 and 2010 that could potentially have influenced attitudes toward aggressive risk factor control in clinical practice.

The ADVANCE, ACCORD, and VADT trials demonstrated that intensive glucose control (ie, to A1c <6% or <6.5%) conferred no cardiovascular benefit and increased risk for hypoglycemia; in addition, ACCORD results showed that systolic BP control to <120 mm Hg (vs 140 mm Hg) offered no CV benefit and raised the risk of significant harm.

The erosion in both glycemic and BP control, the authors note, began soon after these trials reported results, telegraphing an overall shift “toward more conservative treatment.”

The researchers also point to recent and troubling trends linked to poor glycemic control in patients with diabetes, such as an increase in rates of hyperglycemic emergences and amputations of the feet or limbs both of which had been in steady decline from 1995 to 2010.

These and other trends that signal undertreatment of risk factors, the authors say, “highlight the urgent need for interventions and strategies that safely resume progress in diabetes risk-factor control.”

Populations the study found to be at particular risk as a result of suboptimal diabetes treatment (eg, medication access and uptake) include younger adults, Mexican Americans, and persons without health insurance. The gaps are the more egregious for the increased vulnerability of these groups to complications, say the authors.

Limitations mentioned by the researchers include the relatively small sample size which could have impacted the power to detect more subtle changes in diabetes control or treatment; the dwindling response rate to NHANES over time; and changes in clinical guidelines during the study period that may have affected risk-factor control targets used in the analyses.

Reference: Fang M, Wang, D, Coresh J, Selvin E. Trends in diabetes treatment and control in US adults, 1999–2018. N Enlg J Med. 2021;384:2219-2228. doi/full/10.1056/NEJMsa2032271