Table 2.
GRADE summary of findings table showing quality of evidence for effect of higher potassium intake on selected health outcomes in adults
| Outcomes | Effect (95% CI) | No of participants (studies) | Quality of evidence (GRADE) | Comments |
|---|---|---|---|---|
| Resting systolic blood pressure* (follow-up 1-36 months; units mm Hg; better indicated by lower values) | MD 3.49 lower (5.15 to 1.82 lower) | 1892 (21) | High | None |
| Cardiovascular disease† (directly assessed; RR<1 indicates decreased risk with increased potassium intake) | RR 0.88 (0.70 to 1.11) | 29067 (4) | Very low | Data from cohort studies begin with GRADE of low; downgraded owing to imprecision |
| Cardiovascular disease†‡ (assessed by change in blood pressure (mm Hg); better indicated by lower values) | MD 3.49 lower (5.15 to 1.82 lower) | 1892 (21) | Moderate | Data downgraded owing to indirectness |
| Stroke (directly assessed; RR<1 indicates decreased risk with increased potassium intake) | RR 0.79 (0.68 to 0.93) | 97 152 (9) | Low | Data from cohort studies begin with GRADE of low |
| Stroke‡ (assessed by change in blood pressure (mm Hg); better indicated by lower values) | MD 3.49 lower (5.15 to 1.82 lower) | 1892 (21) | Moderate | Data downgraded owing to indirectness |
| Coronary heart disease (directly assessed; RR<1 indicates decreased risk with increased potassium intake) | RR 0.97 (0.77 to 1.24) | 31 162 (3) | Very low | Data from cohort studies begin with GRADE of low; downgraded owing to imprecision |
| Coronary heart disease‡ (assessed by change in blood pressure (mm Hg); better indicated by lower values) | MD 3.49 lower (5.15 to 1.82 lower) | 1892 (21) | Moderate | Data downgraded owing to indirectness |
| All cause mortality (directly assessed; RR<1 indicates decreased risk with increased potassium intake) | RR 1.08 (0.91 to 1.29) | 1766 (1) | Very low | Only one study reported this outcome; downgraded owing to imprecision |
| Total cholesterol§ (follow-up 1-2 months; units mmol/L; better indicated by lower values) | MD 0.12 lower (0.33 lower to 0.09 higher) | 208 (3) | High | – |
| Plasma noradrenaline¶ (follow-up 1-2.5 months; units pg/mL; better indicated by lower values) | MD 4.32 lower (23.78 lower to 15.13 higher) | 152 (3) | High | – |
| Serum creatinine (follow-up mean 1.5 months; units ng/mL filtrate; better indicated by lower values) | MD 4.86 lower (13.59 lower to 3.87 higher) | 147 (3) | High | – |
| Minor side effects (better indicated by lower values) | – | – | – | No studies reported this outcome |
MD=mean difference; RR=risk ratio.
*Additional evidence from meta-analysis of 20 randomised controlled trials with 20 comparisons reporting resting diastolic blood pressure is supportive of benefit of increased potassium on blood pressure (MD 1.96 mm Hg lower, 3.06 to 0.86 lower) (quality of evidence high); meta-analysis of 4 randomised controlled studies with 4 comparisons reporting ambulatory systolic blood pressure is supportive of benefit of increased potassium on blood pressure (MD 3.04 mm Hg lower, 5.42 to 0.66 lower) (quality of evidence moderate); meta-analysis of 4 randomised controlled trials with 4 comparisons reporting ambulatory diastolic blood pressure is consistent with benefit of increased potassium on blood pressure (MD 1.24 mm Hg lower, 3.13 lower to 0.66 higher) (quality of evidence moderate).
†Composite cardiovascular disease as reported by original study authors. This variable included some or all of fatal and non-fatal stroke; coronary heart disease; myocardial infarction; congestive cardiac failure; or episode of coronary revascularisation, bypass grafting, or angioplasty.
‡Data from systolic blood pressure used as evidence for effect of potassium intake on risk of cardiovascular disease, stroke, and coronary heart because blood pressure is good proxy indicator for risk of these outcomes.45-47
§Additional evidence on relation between potassium intake and blood lipids comes from meta-analysis of 2 randomised controlled trials with 2 comparisons reporting high density lipoprotein cholesterol concentration supportive of no effect of increased potassium in blood lipids (MD 0.01 mmol/L lower, 0.13 lower to 0.11 higher) (quality of evidence high) and meta-analysis of 2 randomised controlled trials with 2 comparisons reporting triglyceride concentration supportive of no effect of increased potassium on blood lipids (MD 0.11 mmol/L lower, 0.48 lower to 0.26 higher) (quality of evidence high). Only one randomised controlled trial in literature reported low density lipoprotein concentration; it was consistent with no effect of increased potassium on blood lipids (MD 0.10 mmol/L lower, 0.38 lower to 0.18 higher).
¶Meta-analysis of 3 randomised controlled trials with 3 comparisons reporting plasma adrenaline concentration is supportive of no effect of increased potassium on catecholamine concentrations (MD 3.94 pg/mL lower, 9.22 lower to 1.34 higher) (quality of evidence high). No studies reporting urinary catecholamine concentrations were found.