Review: Race and age are not associated with the effectiveness of calcium antagonists for hypertension
ACP J Club. 1992 Mar-April;116:39. doi:10.7326/ACPJC-1992-116-2-039
Zing W, Ferguson RK, Vlasses PH. Calcium antagonists in elderly and black hypertensive patients. Therapeutic controversies. Arch Intern Med. 1991 Nov;151:2154-62.
To review the literature assessing the influence of race and age on the antihypertensive effect of calcium antagonists and to evaluate the effectiveness of these drugs in comparison with other antihypertensive agents. The review was done to assess the evidence for the 1988 observation of the Joint National Committee on the Detection, Evaluation, and Treatment of High Blood Pressure that black and elderly patients tend to respond better to calcium antagonists.
A computerized search of the National Library of Medicine's English-language holdings for studies evaluating calcium antagonists in elderly or black hypertensive patients.
Studies involving calcium antagonists alone had to examine race or age as a factor predicting outcome. Studies comparing calcium antagonists with other antihypertensive agents had to use random assignment and were usually double-blind.
Methods not described.
Data from individual studies were not combined quantitatively in this review. Most studies found no correlation between age and blood pressure reduction with calcium antagonists (11 studies, n = 531). 7 studies (n = 323) found a positive correlation between age and some measure of blood pressure reduction. One small study (n = 14) found an inverse relation between age and diastolic blood pressure reduction. Comparison studies showed that calcium antagonists were as effective in elderly patients as β-blockers, angiotensin-converting enzyme inhibitors, or diuretics. None of the studies found that black patients were more responsive to the antihypertensive effect of calcium antagonists than were white patients. Calcium antagonists were as effective as diuretics in black patients, but may be more effective than β-blockers. Comparisons of calcium antagonists and angiotensin-converting enzyme inhibitors were inconclusive.
Insufficient evidence exists to support the statement of the Joint National Committee that blacks and elderly patients tend to respond better to calcium antagonists than do whites and younger individuals. Black patients may respond better to calcium antagonists than to β-blockers.
Source of funding: No external funding.
Address for article reprint: Dr. W. Zing, Department of Pharmacy, Crozer-Chester Medical Center, 1 Medical Center Boulevard, Upland, PA 19013-3995, USA.
In recent years, clinicians have attempted to individualize treatment of hypertension by identifying subgroups of patients whose blood pressure is likely to respond to specific drugs. On pathophysiologic grounds, calcium antagonists appear to be ideal drugs for elderly or black hypertensive patients, who characteristically have low plasma renin activity and, in the elderly, impaired sympathetic vasoconstrictor responses to reductions in peripheral resistance. National guidelines for hypertension treatment have promoted calcium antagonists for use in these patient groups (1).
In the comprehensive review by Zing and colleagues, calcium antagonists were not consistently more effective in elderly or black hypertensive patients than in younger or white patients. Further, reductions in blood pressure produced by calcium antagonists were comparable with reductions by other antihypertensive drugs in elderly patients. The authors' conclusion that calcium antagonists are as good as, but no better than, other drugs in these patient groups must be interpreted cautiously. Only 8 of the 30 studies reviewed (27%) included 50 or more patients who received calcium antagonists. As a result, individual studies were generally too small to demonstrate the statistical significance of potentially important differences in blood pressure control among subgroups of patients, even if such differences were present. As the authors note, the problem of small sample size could be rectified either by new, larger studies or by a quantitative synthesis (meta-analysis) of the existing literature.
The authors correctly conclude that the weight of clinical evidence at this time does not support preferential use of calcium antagonists in elderly or black hypertensive patients. The last page of this story will not be written until a definitive study or analysis of existing studies is done.
John F. Steiner, MD, MPH
University of ColoradoDenver, Colorado, USA
John F. Steiner, MD, MPH
University of Colorado
Denver, Colorado, USA