Table 2.

Factors associated with low serum bicarbonate and high serum bicarbonate at CKD diagnosis

EffectModel 1 (n = 37,346)Model 2 (n = 32,623)
Low Bicarbonate (<23 mmol/L) OR (95% CI)PHigh Bicarbonate (>32 mmol/L) OR (95% CI)P
Age quintiles<0.010.09
    62.4 to 70.1 versus 18 to 62.40.72 (0.66, 0.79)0.79 (0.61, 1.02)
    70.2 to 76.4 2 versus 18 to 62.40.63 (0.58, 0.70)0.71 (0.55, 0.93)
    76.4 to 82.3 versus 18 to 62.40.57 (0.52, 0.63)0.82 (0.63, 1.06)
    82.3 to 104 versus 18 to 62.40.50 (0.45, 0.55)0.73 (0.56, 0.96)
Male gender1.32 (1.23, 1.40)<0.010.94 (0.79, 1.11)0.46
African-American race versus others1.24 (1.14, 1.35)<0.011.09 (0.86, 1.37)0.49
BMI group (kg/m2)0.17<0.01
     <18.5 versus 18.5 to 24.91.28 (1.00, 1.63)0.82 (0.40, 1.68)
    25 to 29.9 versus 18.5 to 24.90.96 (0.89, 1.04)0.71 (0.57, 0.88)
    30 to 34.9 versus 18.5 to 24.90.96 (0.87, 1.05)0.67 (0.51, 0.86)
    35 to 39.9 versus 18.5 to 24.90.94 (0.84, 1.07)1.17 (0.88, 1.56)
    40+ versus 18.5 to 24.90.88 (0.77, 1.02)1.16 (0.83, 1.62)
    missing versus 18.5 to 24.91.03 (0.87, 1.21)0.97 (0.65, 1.46)
eGFR (per 10-ml/min per 1.73 m2 increase)0.66 (0.64, 0.67)<0.010.92 (0.85, 0.998)0.046
Diabetes1.20 (1.11, 1.29)<0.010.79 (0.64, 0.98)0.03
Hypertension1.03 (0.93, 1.14)0.540.71 (0.56, 0.90)0.04
Hyperlipidemia0.79 (0.73, 0.85)<0.010.84 (0.69, 1.03)0.10
Coronary artery disease0.94 (0.87, 1.02)0.121.13 (0.92, 1.38)0.25
Congestive heart failure0.82 (0.73, 0.91)<0.012.57 (2.08, 3.16)<0.01
COPD0.88 (0.78, 0.98)0.0192.52 (2.05, 3.09)<0.01
Smoking<0.010.77
    yes versus no1.38 (1.24, 1.54)0.92 (0.67, 1.27)
    missing versus no1.28 (1.12, 1.47)1.10 (0.75, 1.60)
Hb per 1 g/dl increase0.83 (0.82, 0.85)<0.011.01 (0.96, 1.06)0.83
Albumin per 1 mg/dl increase0.79 (0.74, 0.84)<0.010.71 (0.59, 0.86)<0.01
  • Model was additionally adjusted for the year of inclusion in the registry. CKD, chronic kidney disease; OR, odds ratio; CI, confidence interval; BMI, body mass index; eGFR, estimated glomerular filtration rate; COPD, chronic obstructive pulmonary disease.