Putting Prevention into Practice
An Evidence-Based Approach
Screening for High Blood Pressure
Am Fam Physician. 2009 Jun 15;79(12):1093-1094.
A.R. is a healthy 30-year-old man who recently obtained health insurance through his new job. His last physical examination was more than 10 years ago. Because you are a friend and a family physician, he asks you whether he should have his blood pressure checked.
Case Study Questions
1. Which one of the following statements accurately reflects the U.S. Preventive Services Task Force (USPSTF) recommendations on screening for high blood pressure?
A. There is insufficient evidence to recommend for or against screening for high blood pressure in adults.
B. Routine screening for high blood pressure is not recommended for patients younger than 35 years.
C. High blood pressure is usually defined in adults as a systolic blood pressure higher than 120 mm Hg or a diastolic blood pressure higher than 80 mm Hg.
D. High blood pressure should be diagnosed after two or more elevated blood pressure measurements over the course of one to several weeks.
E. There is poor evidence that blood pressure measurement identifies adults at increased risk of cardiovascular disease.
2. A.R.'s blood pressure is found to be 135/79 mm Hg. Based on recommendations from the USPSTF, which one of the following conclusions may be made?
A. The optimal rescreening interval is not known.
B. He should be screened again in one year.
C. He should be screened again in two years.
D. The actual level of A.R.'s blood pressure elevation is the only factor that should be used to determine treatment.
E. He should begin treatment with a thiazide diuretic.
3. Two years later, A.R.'s blood pressure is 124/68 mm Hg. Which of the following factors could account for the improvement in his blood pressure?
A. He has reduced the amount of salt in his diet.
B. He has reduced the amount of potassium in his diet.
C. He has increased his physical activity by taking a brisk, 30-minute walk four times per week.
D. He has been working to reduce his stress.
1. The correct answer is D. High blood pressure should be diagnosed after two or more elevated readings are obtained on at least two visits over a period of one to several weeks. High blood pressure is usually defined in adults as a systolic blood pressure of 140 mm Hg or higher, or a diastolic blood pressure of 90 mm Hg or higher. The USPSTF recommends blood pressure screening in adults 18 years and older because there is good evidence that it can identify adults at increased risk of cardiovascular disease from high blood pressure. There is also good evidence that treatment of high blood pressure in adults substantially decreases the incidence of cardiovascular events and causes few major harms.
2. The correct answer is A. The optimal screening interval is not known. Although most physicians would screen A.R. again based on his increased risk of developing high blood pressure, the USPSTF found no evidence to recommend a specific screening interval. Based on expert opinion, the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure has recommended screening every two years in persons with blood pressure below 120/80 mm Hg, and screening every year in persons with systolic blood pressures of 120 to 139 mm Hg or diastolic blood pressure of 80 to 89 mm Hg.
When making treatment decisions, physicians should consider the patient's overall cardiovascular risk profile, including smoking, diabetes, abnormal blood lipid values, age, sex, sedentary lifestyle, and obesity, in addition to the level of blood pressure elevation. Because A.R. has not been diagnosed with high blood pressure, it is inappropriate to begin treatment with a thiazide diuretic.
3. The correct answers are A, C, and D. Nonpharmacologic interventions to reduce blood pressure include dietary sodium reduction, exercise, and stress management. Reducing dietary sodium intake and practicing stress management techniques are associated with reductions in blood pressure. Increasing physical activity, including a brisk walk for at least 30 minutes every other day, is also associated with reductions in blood pressure. Increasing potassium consumption, rather than decreasing consumption, is associated with reduced blood pressure.
US Preventive Services Task Force. Screening for high blood pressure: US Preventive Services Task Force reaffirmation recommendation statement. Agency for Healthcare Research and Quality 2007http://www.ahrq.gov/clinic/uspstf07/hbp/hbprs.htm. Accessed April 7, 2009.
Wolff T, Miller T. Evidence for the reaffirmation of the U.S. Preventive Services Task Force recommendation on screening for high blood pressure. Ann Intern Med. 2007;147(11):787–791.
The case study and answers to the following questions on screening for high blood pressure 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, the evidence synthesis, and the systematic evidence review 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/uspshype.htm.
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