Resistant or Difficult-to-Control Hypertension
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《新英格兰医药杂志》
To the Editor: In the article by Moser and Setaro (July 27 issue),1 the description of the Osler maneuver (to assess "pseudohypertension") should be clarified. A positive result is reflected by the continued palpability of the radial artery (not of the radial pulse) while the brachial artery is occluded with a blood-pressure cuff.
In recommending against the use of thiazide diuretics, the authors appear to equate a serum creatinine level of more than 1.5 mg per deciliter with a glomerular filtration rate (GFR) of less than 30 to 50 ml per minute. In a recent review in the Journal of the assessment of renal function, when the GFR was 60 ml per minute per 1.73 m2, the 95% confidence interval for the serum creatinine level was 1.3 to 1.5 mg per deciliter in white men, 1.4 to 1.8 mg per deciliter in black men, 1.0 to 1.2 mg per deciliter in white women, and 1.1 to 1.4 mg per deciliter in black women.2 Thiazides are often effective until the GFR is less than 20 ml per minute.3 Typically, the corresponding level of serum creatinine will thus be much higher than 1.5 mg per deciliter except in the elderly and persons with poor muscle mass or liver disease.
Prem Chandran, M.D.
University of Iowa
Des Moines, IA 50309
pkgchandran@juno.com
References
Moser M, Setaro JF. Resistant or difficult-to-control hypertension. N Engl J Med 2006;355:385-392.
Stevens LA, Coresh J, Greene T, Levey AS. Assessing kidney function -- measured and estimated glomerular filtration rate. N Engl J Med 2006;354:2473-2483.
Kaplan NM, Rose BD. Hypertension in renal disease. UpToDate 2006. (Accessed October 12, 2006, at http://www.patients.uptodate.com/topic.asp?file=hyperten/7248.)
The authors reply: We agree that a better description of the Osler maneuver would be that the radial artery itself remains palpable structurally, although pulsatility would not be detected.
With regard to Chandran's comments about the use of a thiazide diuretic, we stated that thiazides may not be very effective if the GFR is below 30 to 50 ml per minute (or the serum creatinine level is more than 1.5 mg per deciliter). Although this implies that a creatinine level of 1.5 mg per deciliter is equivalent to a GFR of about 30 to 50 ml per minute, the accuracy of the creatinine level as a measure of renal function depends on the patient's age, muscle mass, ethnicity, and other factors, and this level may correlate more closely with a GFR of 60 to 70 ml per minute, especially in men. Although thiazides may still be effective in a patient whose GFR is as low as 20 to 30 ml per minute, most patients will not have an adequate response at these levels. It is therefore reasonable to suggest that a loop diuretic or an agent that acts more proximately in the glomerulus is likely to be more effective than a thiazide in such patients.
Marvin Moser, M.D.
John Setaro, M.D.
Yale University School of Medicine
New Haven, CT 06520
In recommending against the use of thiazide diuretics, the authors appear to equate a serum creatinine level of more than 1.5 mg per deciliter with a glomerular filtration rate (GFR) of less than 30 to 50 ml per minute. In a recent review in the Journal of the assessment of renal function, when the GFR was 60 ml per minute per 1.73 m2, the 95% confidence interval for the serum creatinine level was 1.3 to 1.5 mg per deciliter in white men, 1.4 to 1.8 mg per deciliter in black men, 1.0 to 1.2 mg per deciliter in white women, and 1.1 to 1.4 mg per deciliter in black women.2 Thiazides are often effective until the GFR is less than 20 ml per minute.3 Typically, the corresponding level of serum creatinine will thus be much higher than 1.5 mg per deciliter except in the elderly and persons with poor muscle mass or liver disease.
Prem Chandran, M.D.
University of Iowa
Des Moines, IA 50309
pkgchandran@juno.com
References
Moser M, Setaro JF. Resistant or difficult-to-control hypertension. N Engl J Med 2006;355:385-392.
Stevens LA, Coresh J, Greene T, Levey AS. Assessing kidney function -- measured and estimated glomerular filtration rate. N Engl J Med 2006;354:2473-2483.
Kaplan NM, Rose BD. Hypertension in renal disease. UpToDate 2006. (Accessed October 12, 2006, at http://www.patients.uptodate.com/topic.asp?file=hyperten/7248.)
The authors reply: We agree that a better description of the Osler maneuver would be that the radial artery itself remains palpable structurally, although pulsatility would not be detected.
With regard to Chandran's comments about the use of a thiazide diuretic, we stated that thiazides may not be very effective if the GFR is below 30 to 50 ml per minute (or the serum creatinine level is more than 1.5 mg per deciliter). Although this implies that a creatinine level of 1.5 mg per deciliter is equivalent to a GFR of about 30 to 50 ml per minute, the accuracy of the creatinine level as a measure of renal function depends on the patient's age, muscle mass, ethnicity, and other factors, and this level may correlate more closely with a GFR of 60 to 70 ml per minute, especially in men. Although thiazides may still be effective in a patient whose GFR is as low as 20 to 30 ml per minute, most patients will not have an adequate response at these levels. It is therefore reasonable to suggest that a loop diuretic or an agent that acts more proximately in the glomerulus is likely to be more effective than a thiazide in such patients.
Marvin Moser, M.D.
John Setaro, M.D.
Yale University School of Medicine
New Haven, CT 06520