Putting Prevention into Practice
An Evidence-Based Approach
Screening for Type 2 Diabetes Mellitus in Adults
Am Fam Physician. 2009 Nov 15;80(10):1141-1142.
A 50-year-old woman with a history of hyperlipidemia visits your office for a physical examination. Her blood pressure is 140/82 mm Hg, and her body mass index is 30 kg per m2. She reports no symptoms of polydipsia, polyphagia, or polyuria. Her blood pressure has been less than 130/80 mm Hg at previous visits.
Case Study Questions
Based on recommendations from the U.S. Preventive Services Task Force (USPSTF), which one of the following actions regarding screening and prevention of type 2 diabetes mellitus is appropriate for this patient?
A. Obtain a fasting plasma glucose level because of her history of hyperlipidemia.
B. Obtain a fasting plasma glucose level because of her elevated blood pressure at this office visit.
C. Obtain an A1C measurement because of her elevated blood pressure at this visit.
D. Obtain a random blood glucose level because of her history of hyperlipidemia.
E. Repeat blood pressure measurement at a subsequent visit.
Which of the following statements about early identification and treatment of type 2 diabetes and their effects on long-term complications is/are correct?
A. Aggressive blood pressure control in persons with type 2 diabetes reduces total cardiovascular events by 50 percent.
B. Tight glycemic control before clinical detection of type 2 diabetes reduces total cardiovascular events by 30 percent.
C. Implementation of foot care programs before clinical detection of type 2 diabetes decreases patients' risk of lower-limb amputation.
D. Tight glycemic and blood pressure control in persons with type 2 diabetes decreases development and progression of albuminuria, but it is unclear whether initiating control earlier has an important impact on chronic renal failure.
1. The correct answer is E. The USPSTF recommends screening for type 2 diabetes in asymptomatic persons with sustained elevated blood pressure greater than or equal to 135/80 mm Hg. A single elevated measurement does not constitute hypertension.
Recent randomized controlled studies have demonstrated that aggressive control of blood pressure in patients with diabetes significantly decreases cardiovascular events. Treatment of isolated systolic hypertension in persons older than 60 years with diabetes also decreases cardiovascular events.
The USPSTF no longer recommends routine screening for type 2 diabetes in normotensive adults with hyperlipidemia.
The American Diabetes Association recommends screening for type 2 diabetes with fasting plasma glucose measurement. There are no widely accepted criteria for using A1C or random blood sugar levels as screening tests for type 2 diabetes.
2. The correct answers are A and D. Blood pressure control in patients with diabetes reduces cardiovascular events by 50 percent. In addition, treatment of isolated systolic hypertension among persons older than 60 years with diabetes reduces cardiovascular events by 34 to 69 percent.
There is inadequate evidence that tight glycemic control reduces macrovascular complications, such as myocardial infarction (MI) and stroke. No randomized, controlled trial has demonstrated a statistically significant reduction in total cardiovascular events from tight glycemic control. In the U.K. Prospective Diabetes Study, patients assigned to tight glycemic control had non-significantly lower rates of MI and sudden death. However, there were no reductions in strokes, heart failure, angina, or all-cause mortality compared with patients receiving conventional management after 10 years of follow-up.
Although evidence shows a decrease in development of and progression to albuminuria in patients with diabetes who have tight glycemic and blood pressure control and who use angiotensin-converting enzyme inhibitors and angiotensin receptor blockers, it cannot be determined whether initiating these treatments earlier as a result of screening would have an important impact on chronic renal failure.
Early initiation of foot care programs, tight glycemic control, and blood pressure control in the preclinical phase does not appear to affect the long-term outcome of lower-limb amputation.
U.S. Preventive Services Task Force. Screening for type 2 diabetes mellitus in adults: U.S. Preventive Services Task Force recommendation statement [published correction appears in Ann Intern Med. 2008;149(2):147]. Ann Intern Med. 2008;148(11):846–854.
Norris SL, Kansagara D, Bougatsos C, Fu R. Screening adults for type 2 diabetes: a review of the evidence for the U.S. Preventive Services Task Force. Rockville, Md.: Agency for Healthcare Research and Quality; 2008. http://www.ahrq.gov/clinic/uspstf08/type2/type2art.htm. Accessed September 14, 2009.
The case study and answers to the following questions on screening for type 2 diabetes mellitus in adults are based on the recommendations of the U.S. Preventive Services Task Force (USPSTF), an independent panel of experts in primary care and prevention that systematically reviews the evidence of effectiveness and develops recommendations for clinical preventive services. More detailed information on this subject is available in the USPSTF Recommendation Statement and the evidence synthesis on the USPSTF Web site (http://www.ahrq.gov/clinic/uspstfix.htm). The practice recommendations in this activity are available at http://www.ahrq.gov/clinic/uspstf/uspsdiab.htm.
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