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Changes in Diabetes Complications Over Three Decades

May 29, 2021
 
Editor: Steve Freed, R.PH., CDE

Author: Macrina Ghali, PharmD Candidate 2021, Florida A&M University, College of Pharmacy and Pharmaceutical Sciences

Researchers sought to assess the prevalence and trend of diabetes complications in adult patients over thirty years. 

Diabetic complications increase the disease burden of patients with type 2 diabetes. Studies have shown that hyperglycemia and increased cardiovascular risk are present in patients before a type 2 diabetes diagnosis. Increases in asymptomatic screening and more stringent guidelines for diagnosis have led to greater diagnoses over the past three decades. Prior studies have shown that from 1997 to 2003, obesity prevalence increased among newly diagnosed patients while cardiovascular disease and hypertension prevalence remained the same. Researchers analyzed thirty years of data from the National Health and Nutrition Examination Survey (NHANES) to determine the trend in micro and macrovascular diabetic complications.  

 

Researchers included 1,486 nonpregnant patients at least 20 years of age and with newly diagnosed type 2 diabetes within the past two years in the study. Microvascular complications were chronic kidney disease, microalbuminuria, retinopathy, and neuropathy. Neuropathy was identified as a history of foot or leg ulcers or a diagnosis of peripheral artery disease. In contrast, macrovascular complications or cardiovascular disease included congestive heart failure, stroke, or heart attack. Researchers took survey years from three data sets divided into 1988 to 1994, 1999 to 2008, and 2009 to 2018. Researchers performed statistical analysis with logistic, linear, or quantile regression models, and the change over time according to risk factors was analyzed with Chi-square tests.  

Although patients’ sex and age distribution with a new type 2 diabetes diagnosis did not change over the thirty years, there was an increased incidence among non-White, college-educated, or obesity patients. Furthermore, more patients had good glycemic control, defined as an HbA1c less than 7%, from 1988 to 2018. Similarly, the percentage of insulin therapy patients decreased from 12.8% to 7.5% (p=0.03), which further confirms glucose control improvements. Furthermore, among newly diagnosed patients, there was greater blood pressure and cholesterol control. Over the three-decade period, more patients achieved a blood pressure controlled < 140/90 mmHg (P = 0.02) and <130/80 mmHg (p < 0.001), depending on the hypertensive goal used. Similarly, an increased number of patients achieved a total cholesterol level less than 240 mg/dL (p<0.001) or less than 200 mg/dL (p < 0.001). The prevalence of chronic kidney disease and albuminuria significantly declined from 40.4% to 25.5% (p = 0.003) and 38.9% to 18.7% (p < 0.001), respectively. Retinopathy was unchanged during the twenty years from 13.2% in 1988 to 12.1% in 2008. The prevalence of lower-extremity diseases (peripheral neuropathy, peripheral arterial disease, or ulcers) in the 1999–2004 period was ∼24%, 15%, 9%, and 6%, respectively; since the availability of this data was limited to 1999-2004, it precluded trend analyses of lower-extremity diseases.  

Macrovascular complications did not change significantly in the thirty years, with 19% in 1988 and 16.5% in 2018. There was a higher prevalence of complications among patients with a lower income, less education, former or current smoking status, obesity, and older age at diabetes diagnosis.  

A limitation of this study includes the reliance on patient self-reporting for a diabetes diagnosis. Furthermore, the study had a small sample size and only tested for retinopathy and neuropathy in patients greater than 40 years old, limiting generalizability to younger patients. In contrast, a strength of this study was the long duration of follow-up which spanned thirty years. Altogether, from 1988 to 2018, there were significant improvements in glycemic control, blood pressure, and cholesterol. Furthermore, there were considerable declines in albuminuria prevalence, with no substantial changes in the majority of cardiovascular diseases, retinopathy, or neuropathy. The significant decrease of albuminuria may be attributed to more stringent glycemic control, increased use of renin-angiotensin blockers, and improved early detection and awareness of diabetes. The lack of improvement in cardiovascular disease and retinopathy may be related to the changes in retinopathy diagnosis methods and self-reported nature, respectively.  

Practice Pearls 

  • The burden of diabetic complications remains elevated in patients with type 2 diabetes despite albuminuria and risk factor control improvements. 
  • Increased screening of groups at greater risk for diabetic complications, such as the low-income population, is essential in decreasing complication prevalence.  
  • As diabetic complication awareness and strategies for reduction are implemented, further analysis can be conducted to determine such interventions’ impact.  

 

Fang M, Selvin E. Thirty-year Trends in Complications in U.S. Adults With Newly Diagnosed Type 2 Diabetes. Diabetes Care. 2021.  

Geiss LS, Pan L, Cadwell B, Gregg EW, Benjamin SM, Engelgau MM. Changes in incidence of diabetes in U.S. adults, 1997-2003. Am J Prev Med. 2006 May;30(5):371-7.  

Macrina Ghali, PharmD Candidate 2021, Florida A&M University, College of Pharmacy and Pharmaceutical Sciences