Table 2.

Baseline clinical characteristics of quartile subgroups stratified according to the levels of urinary potassium excretion

VariableQuartiles of Urinary Potassium Excretion (g/d)P Valuea
Q1 (<1.72)Q2 (1.72–2.32)Q3 (2.33–2.90)Q4 (>2.90)
n156156156155
Male (%)46.251.364.169.7<0.001
Age (yr)59±1259±1159±1059±80.98
Body mass index (kg/m2)23.4±3.523.6±3.623.2±3.023.7±3.10.58
Duration of diabetes (yr)9 (4–16)10 (6–16)11 (5–18)10 (5–17)0.52
Diet/OHA/insulin (%)24/50/2621/58/2120/56/2425/54/210.25
HbA1c (%)7.7±1.37.6±1.07.6±1.27.4±1.00.29
Total cholesterol (mg/dl)211±34219±32216±38209±340.04
HDL-cholesterol (mg/dl)55 (47–65)54 (47–64)56 (46–66)54 (45–66)0.88
LDL-cholesterol (mg/dl)129±30137±30134±35129±290.07
Triglycerides (mg/dl)106 (73–153)103 (78–147)101 (75–160)93 (66–144)0.41
Systolic BP (mmHg)138±19135±18130±18132±180.001
Diastolic BP (mmHg)78±1077±1075±1177±100.07
Hypertension (%)58.351.937.240.0<0.001
Using RAS inhibitors (%)20.017.311.519.90.15
Current smoking (%)26.928.230.127.70.94
Urinary AER (μg/min)11 (5–28)11 (6–24)12 (6–35)13 (7–37)0.17
eGFR (ml/min per 1.73 m2)89±2289±1987±1687±160.44
Urinary sodium excretion (g/d)3.7±1.65.0±1.75.7±1.86.9±2.3<0.001
Urinary potassium excretion (g/d)1.4±0.32.0±0.22.6±0.23.6±0.6<0.001
Urinary sodium to potassium ratio4.8±2.14.2±1.53.8±1.23.3±1.1<0.001
Serum sodium (mEq/L)141±2141±2141±2140±20.54
Serum potassium (mEq/L)4.3±0.44.3±0.34.4±0.34.4±0.40.001
  • Data are expressed as mean±SD for normally distributed continuous variables, median (interquartile range) for skewed continuous variables, or as otherwise indicated. Q1, first quartile; Q2, second quartile; Q3, third quartile; Q4, fourth quartile; OHA, oral hypoglycemic agent; HbA1c, hemoglobin A1c; RAS, renin-angiotensin system; AER, albumin excretion rate.

  • a Differences between quartile subgroups were compared with a chi-squared test for categorical variables and ANOVA for continuous variables.