Brancati F L, Appel L J, Seidler A J, Whelton P K
Welch Center for Prevention, Epidemiology, & Clinical Research, Johns Hopkins Medical Institutions, Baltimore, Md., USA.
Arch Intern Med. 1996 Jan 8;156(1):61-7.
To determine the effect of potassium supplementation on blood pressure in African Americans consuming a low-potassium diet.
Randomized, double-blind, placebo-controlled trial with two parallel arms.
Community-based research site.
Eighty-seven healthy African Americans aged 27 to 65 years with a systolic blood pressure between 100 and 159 mm Hg and a diastolic blood pressure between 70 and 94 mm Hg.
During the 21-day intervention period, all participants were provided with a low-potassium diet (32 to 35 mmol/d). In addition to this diet, they were randomly assigned to receive either potassium supplements (80 mmol/d) or placebo.
Change in blood pressure in the potassium vs the placebo group, based on a total of nine blood pressure readings at three visits. Blood pressures were taken before and during the intervention by means of random-zero sphygmomanometry.
At baseline, the placebo and potassium groups were similar for mean blood pressure (127/78 vs 125/77 mm Hg), 24-hour urinary potassium excretion (50 vs 44 mmol), and all other variables measured (all P > .05). During the intervention, the net difference in 24-hour urinary potassium excretion between groups was 70 mmol. Compared with the placebo group, the potassium supplementation group experienced a net decline in systolic blood pressure of 6.9 mm Hg (95% confidence interval, -9.3 to -4.4 mm Hg; P < .001) and a decline in diastolic blood pressure of 2.5 mm Hg (95% confidence interval, -4.3 to -0.8 mm Hg; P = .004). Simultaneous adjustment for differences in baseline characteristics only strengthened these estimates.
Potassium supplementation reduces blood pressure substantially in African Americans consuming a diet low in potassium. Increased potassium intake may play an important role in reducing blood pressure in this population at high risk for hypertension.
确定补钾对食用低钾饮食的非裔美国人血压的影响。
随机、双盲、安慰剂对照试验，分为两个平行组。
基于社区的研究场所。
87名年龄在27至65岁之间的健康非裔美国人，收缩压在100至159毫米汞柱之间，舒张压在70至94毫米汞柱之间。
在为期21天的干预期内，所有参与者均食用低钾饮食（32至35毫摩尔/天）。除此之外，他们被随机分配接受补钾（80毫摩尔/天）或安慰剂。
根据三次就诊时共九次的血压读数，比较补钾组与安慰剂组的血压变化。在干预前和干预期间，通过随机零位血压计测量血压。
在基线时，安慰剂组和补钾组的平均血压（127/78对125/77毫米汞柱）、24小时尿钾排泄量（50对44毫摩尔）以及所有其他测量变量均相似（所有P>.05）。在干预期间，两组之间24小时尿钾排泄量的净差异为70毫摩尔。与安慰剂组相比，补钾组的收缩压净下降6.9毫米汞柱（95%置信区间，-9.3至-4.4毫米汞柱；P<.001），舒张压下降2.5毫米汞柱（95%置信区间，-4.3至-0.8毫米汞柱；P=.004）。仅对基线特征差异进行同时调整会强化这些估计值。
补钾可使食用低钾饮食的非裔美国人血压大幅降低。增加钾摄入量可能在降低该高血压高危人群的血压方面发挥重要作用。
