Table 4.

Rate of major adverse cardiovascular events according to serum potassium by eGFR stratum

VariableSerum K+ Level P Value
<3.5 mEq/L3.5–3.9 mEq/L4.0–4.4 mEq/L4.5–4.9 mEq/L5.0–5.4 mEq/L5.5–5.9 mEq/L≥6.0 mEq/L
eGFR<30 ml/min per 1.73 m2
 Crude ratea (95% CI)12.75 (12.14 to 13.39)8.45 (8.24 to 8.66)6.08 (5.98 to 6.18)5.65 (5.57 to 5.74)5.16 (5.06 to 5.26)5.49 (5.31 to 5.67)9.02 (8.57 to 9.49)
 Adjusted IRRb (95% CI)1.63 (1.25 to 2.14)1.50 (1.25 to 1.80)1.12 (1.00 to 1.26)Ref1.01 (0.88 to 1.15)1.14 (0.98 to 1.33)2.11 (1.68 to 2.65)<0.001
eGFR 30–39 ml/min per 1.73 m2
 Crude ratea (95% CI)9.65 (9.25 to 10.07)5.91 (5.79 to 6.03)4.56 (4.50 to 4.61)4.20 (4.15 to 4.25)4.07 (4.01 to 4.14)4.51 (4.38 to 4.66)6.85 (6.42 to 7.30)
 Adjusted IRRb (95% CI)1.69 (1.29 to 2.22)1.25 (1.08 to 1.44)1.06 (0.97 to 1.16)Ref1.02 (0.93 to 1.12)1.16 (1.00 to 1.35)1.44 (1.12 to 1.84)<0.001
eGFR 40–49 ml/min per 1.73 m2
 Crude ratea (95% CI)5.30 (5.09 to 5.50)4.19 (4.12 to 4.25)3.49 (3.46 to 3.52)3.10 (3.07 to 3.13)3.27 (3.22 to 3.32)3.54 (3.43 to 3.66)4.09 (3.76 to 4.46)
 Adjusted IRRb (95% CI)1.73 (1.30 to 2.29)1.19 (1.07 to 1.32)1.06 (0.99 to 1.14)Ref1.07 (0.98 to 1.17)1.14 (0.98 to 1.33)1.56 (1.11 to 2.17)<0.001
eGFR 50–59 ml/min per 1.73 m2
 Crude ratea (95% CI)3.99 (3.86 to 4.11)3.07 (3.03 to 3.10)2.50 (2.49 to 2.52)2.53 (2.52 to 2.55)2.54 (2.50 to 2.57)2.56 (2.47 to 2.65)3.27 (2.96 to 3.61)
 Adjusted IRRb (95% CI)1.44 (1.19 to 1.75)1.13 (1.03 to 1.23)1.00 (0.94 to 1.07)Ref0.97 (0.88 to 1.06)1.12 (0.96 to 1.30)2.11 (1.53 to 2.89)<0.001
  • Reference group for comparison is 4.5–4.9 mEq/L. P value interaction between eGFR stratum and K=0.94 in the pooled study population. K+, potassium; 95% CI, 95% confidence interval; IRR, incidence rate ratio; Ref, reference.

  • a The 95% CIs for crude rates are based on a Poisson model that has no additional covariates except serum K+ levels for each of the eGFR categories. Crude rates are expressed as events per patient-year.

  • b Rates were adjusted for hospitalization within the preceding 30 days, age, sex, race, diabetes, congestive heart failure, coronary artery disease, cerebrovascular accident, loop diuretic use, thiazide diuretic use, renin-angiotensin-aldosterone system blocker use, β-blocker use, and nondihydropyridine calcium channel blocker use based on the generalized estimating equation with a negative binomial distribution and a log link specified.