BMJ：高钾摄入降低高血压患者的血压

血压升高和高血压病是心血管疾病，特别是冠心病、中风、心衰以及肾衰的主要危险因素。钾是维持总体液量、酸和电解质平衡，以及正常细胞功能需要的必需营养素。为了填补钾摄入和健康的知识空白，来自世界卫生组织健康发展营养部的Nancy J Aburto研究院及其团队进行了一项系统性的文献回顾和荟萃分析，该研究发现钾摄入增加降低高血压患者的血压，较高的钾摄入与卒中风险的降低相关。该研究结果发表在2013年4月5日的《英国医学期刊》（British medical journal）上。

该研究的数据来源于临床对照试验中心注册数据库、Medline、Embase、世界卫生组织国际临床试验注册平台、拉美及加勒比地区健康科学文献数据库，以及上述综述的参考文献。该研究中，入选的研究包括钾摄入对血压、肾功能、血脂、儿茶酚胺浓度、全因死亡率、心血管疾病、卒中以及冠心病影响的随机对照试验和队列研究。潜在的研究被独立筛选两次，并且提取他们的特征和结果。可能时，采用反向方差法及随机效应模型荟萃分析，评估高钾摄入的影响（平均差或风险比的95%可信区间）。

该研究结果表明，荟萃分析共纳入22项随机对照试验（包含1606例受试者），涉及血压、血脂、儿茶酚胺浓度和肾功能，以及11项队列研究（包含127038例受试者），涉及成人患者全因死亡率、心血管疾病、卒中或冠心病。钾摄入增加使成人的收缩压降低3.49（95%CI 1.82–5.15）mmHg，舒张压降低1.96（95%CI 0.86–3.06）mmHg，在高血压患者中观察到此效应，但在非高血压患者中没有。高钾摄入达90–120 mmol/天时，患者收缩压下将7.16(1.91–12.41)mmHg，不伴有任何剂量反应。钾摄入的增加对成人的肾功能、血脂和儿茶酚胺浓度没有显著的不良反应。钾摄入与卒中发生风险之间呈统计学显著负相关（风险比0.76，0.66–0.89）。钾摄入与心血管疾病（风险比0.88，0.70–1.11）或冠心病（风险比0.96，0.78–1.19）发生之间的相关性无统计学意义。在儿童，3项对照试验和1项队列研究提示，钾摄入增加使收缩压下降0.28（–0.49–1.05）mmHg，降幅没有意义。

该研究发现，高质量证据显示，钾摄入增加降低高血压患者的血压，且对成人的血脂浓度、儿茶酚胺浓度或肾脏功能无不良反应。高钾摄入与卒中的风险降低24%相关（中等质量证据）。这些结果提示，钾摄入增加对于大多数无肾脏排钾功能受损的人有潜在的益处，对于其血压升高和卒中具有预防和控制作用。

与高血压相关的拓展阅读：

• JAMA Neurol:高血压协同致AD病理蛋白沉积
• Hypertension：靶向交感神经消融可降低遗传盐敏感性高血压
• 摄钠过量，幼儿也患高血压
• Diabetologia:血钾低的高血压患者易患糖尿病
• Diabetes Care：糖尿病患者高血压越早治疗越好
• Hypertension：非吸烟者中血清可替宁水平与高血压相关
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Effect of increased potassium intake on cardiovascular risk factors and disease: systematic review and meta-analyses.
OBJECTIVE
To conduct a systematic review of the literature and meta-analyses to fill the gaps in knowledge on potassium intake and health.
DATA SOURCES
Cochrane Central Register of Controlled Trials, Medline, Embase, WHO International Clinical Trials Registry Platform, Latin American and Caribbean Health Science Literature Database, and the reference lists of previous reviews.
STUDY SELECTION
Randomised controlled trials and cohort studies reporting the effects of potassium intake on blood pressure, renal function, blood lipids, catecholamine concentrations, all cause mortality, cardiovascular disease, stroke, and coronary heart disease were included.
DATA EXTRACTION AND SYNTHESIS
Potential studies were independently screened in duplicate, and their characteristics and outcomes were extracted. When possible, meta-analysis was done to estimate the effects (mean difference or risk ratio with 95% confidence interval) of higher potassium intake by using the inverse variance method and a random effect model.
RESULTS
22 randomised controlled trials (including 1606 participants) reporting blood pressure, blood lipids, catecholamine concentrations, and renal function and 11 cohort studies (127 038 participants) reporting all cause mortality, cardiovascular disease, stroke, or coronary heart disease in adults were included in the meta-analyses. Increased potassium intake reduced systolic blood pressure by 3.49 (95% confidence interval 1.82 to 5.15) mm Hg and diastolic blood pressure by 1.96 (0.86 to 3.06) mm Hg in adults, an effect seen in people with hypertension but not in those without hypertension. Systolic blood pressure was reduced by 7.16 (1.91 to 12.41) mm Hg when the higher potassium intake was 90-120 mmol/day, without any dose response. Increased potassium intake had no significant adverse effect on renal function, blood lipids, or catecholamine concentrations in adults. An inverse statistically significant association was seen between potassium intake and risk of incident stroke (risk ratio 0.76, 0.66 to 0.89). Associations between potassium intake and incident cardiovascular disease (risk ratio 0.88, 0.70 to 1.11) or coronary heart disease (0.96, 0.78 to 1.19) were not statistically significant. In children, three controlled trials and one cohort study suggested that increased potassium intake reduced systolic blood pressure by a non-significant 0.28 (-0.49 to 1.05) mm Hg.
CONCLUSIONS
High quality evidence shows that increased potassium intake reduces blood pressure in people with hypertension and has no adverse effect on blood lipid concentrations, catecholamine concentrations, or renal function in adults. Higher potassium intake was associated with a 24% lower risk of stroke (moderate quality evidence). These results suggest that increased potassium intake is potentially beneficial to most people without impaired renal handling of potassium for the prevention and control of elevated blood pressure and stroke.