Table 4.
Rate of major adverse cardiovascular events according to serum potassium by eGFR stratum
| Variable | Serum K+ Level | P Value | ||||||
|---|---|---|---|---|---|---|---|---|
| <3.5 mEq/L | 3.5–3.9 mEq/L | 4.0–4.4 mEq/L | 4.5–4.9 mEq/L | 5.0–5.4 mEq/L | 5.5–5.9 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) | Ref | 1.01 (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) | Ref | 1.02 (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) | Ref | 1.07 (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) | Ref | 0.97 (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.
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.
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.