Aldosterone [KLH]

Aims The associations between potassium level and outcomes, the effect of sacubitril-valsartan on potassium level, and whether potassium level modified the effect of sacubitril-valsartan in patients with heart failure and a reduced ejection fraction were studied in PARADIGM-HF. Several outcomes, including cardiovascular death, sudden death, pump failure death, non-cardiovascular death and heart failure hospitalization, were examined. Methods and results A total of 8399 patients were randomized to either enalapril or sacubitril-valsartan. Potassium level at randomization and follow-up was examined as a continuous and categorical variable (<= 3.5, 3.6-4.0, 4.1-4.9, 5.0-5.4 and >= 5.5 mmol/L) in various statistical models. Hyperkalaemia was defined as K+ >= 5.5 mmol/L and hypokalaemia as K+ <= 3.5 mmol/L. Compared with potassium 4.1-4.9 mmol/L, both hypokalaemia [hazard ratio (HR) 2.40, 95% confidence interval (CI) 1.84-3.14] and hyperkalaemia (HR 1.42, 95% CI 1.10-1.83) were associated with a higher risk for cardiovascular death. However, potassium abnormalities were similarly associated with sudden death and pump failure death, as well as non-cardiovascular death and heart failure hospitalization. Sacubitril-valsartan had no effect on potassium overall. The benefit of sacubitril-valsartan over enalapril was consistent across the range of baseline potassium levels. Conclusions Although both higher and lower potassium levels were independent predictors of cardiovascular death, potassium abnormalities may mainly be markers rather than mediators of risk for death.

Background: Clinical practice guidelines recommend routine kidney function and serum potassium testing within 30 days of initiating ACE (angiotensin-converting enzyme) inhibitor or angiotensin II receptor blocker therapy. However, evidence is lacking about whether follow-up testing reduces therapy-related adverse outcomes. Methods and Results: We conducted 2 population-based retrospective cohort studies in Kaiser Permanente Northern California and Ontario, Canada. Patients with outpatient serum creatinine and potassium tests in the 30 days after starting ACE inhibitor or angiotensin II receptor blocker therapy were matched 1:1 to patients without follow-up tests. We evaluated the association of follow-up testing with 30-day all-cause mortality and hospitalization with acute kidney injury or hyperkalemia using Cox regression. We also developed and externally validated a risk score to identify patients at risk of having abnormally high serum creatinine and potassium values in follow-up. We identified 75 251 matched pairs initiating ACE inhibitor or angiotensin II receptor blocker therapy between January 1, 2007, and December 31, 2017, in Kaiser Permanente Northern California. Follow-up testing was not significantly associated with 30-day all-cause mortality in Kaiser Permanente Northern California (hazard ratio, 0.75 [95% CI, 0.54-1.06]) and was associated with higher mortality in 84 905 matched pairs in Ontario (hazard ratio, 1.32 [95% CI, 1.07-1.62]). In Kaiser Permanente Northern California, follow-up testing was significantly associated with higher rates of hospitalization with acute kidney injury (hazard ratio, 1.66 [95% CI, 1.10-2.22]) and hyperkalemia (hazard ratio, 3.36 [95% CI, 1.08-10.41]), as was observed in Ontario. The risk score for abnormal potassium provided good discrimination (area under the curve [AUC], 0.75) and excellent calibration of predicted risks, while the risk score for abnormal serum creatinine provided moderate discrimination (AUC, 0.62) but excellent calibration. Conclusions: Routine laboratory monitoring after ACE inhibitor or angiotensin II receptor blocker initiation was not associated with a lower risk of 30-day mortality. We identified patient subgroups in which targeted testing may be effective in identifying therapy-related changes in serum potassium or kidney function.