Approximation of bicarbonate concentration using serum total carbon dioxide concentration in patients with non-dialysis chronic kidney disease
- Author:
Keiji HIRAI
1
;
Saori MINATO
;
Shohei KANEKO
;
Katsunori YANAI
;
Hiroki ISHII
;
Taisuke KITANO
;
Mitsutoshi SHINDO
;
Haruhisa MIYAZAWA
;
Kiyonori ITO
;
Yuichirou UEDA
;
Yoshio KAKU
;
Taro HOSHINO
;
Tatsuro WATANO
;
Shinji FUJINO
;
Susumu OOKAWARA
;
Kiyoka OMOTO
;
Yoshiyuki MORISHITA
Author Information
- Publication Type:Original Article
- Keywords: Acid base balance; Bicarbonates; Carbon dioxide; Chronic kidney disease
- MeSH: Acid-Base Equilibrium; Bicarbonates; Carbon Dioxide; Carbon; Glomerular Filtration Rate; Humans; Linear Models; Renal Insufficiency, Chronic; ROC Curve
- From:Kidney Research and Clinical Practice 2019;38(3):326-335
- CountryRepublic of Korea
- Language:English
- Abstract: BACKGROUND: We investigated the relationship between serum total carbon dioxide (CO₂) and bicarbonate ion (HCO₃⁻) concentrations in pre-dialysis chronic kidney disease (CKD) patients and devised a formula for predicting low bicarbonate (HCO₃⁻< 24 mmol/L) and high bicarbonate (HCO₃⁻ ≥ 24 mmol/L) using clinical parameters. METHODS: In total, 305 samples of venous blood collected from 207 pre-dialysis patients assessed by CKD stage (G1 + G2, 46; G3, 50; G4, 51; G5, 60) were investigated. The relationship between serum total CO₂ and HCO₃⁻ concentrations was analyzed using Pearson’s correlation coefficient. An approximation formula was developed using clinical parameters correlated independently with HCO₃⁻ concentration. Diagnostic accuracy of serum total CO₂ and the approximation formula was evaluated by receiver operating characteristic curve analysis and a 2 × 2 table. RESULTS: Serum total CO₂ correlated strongly with HCO₃⁻ concentration (r = 0.91; P < 0.001). The following approximation formula was obtained by a multiple linear regression analysis: HCO₃⁻ (mmol/L) = total CO₂ − 0.5 × albumin − 0.1 × chloride − 0.01 × (estimated glomerular filtration rate + blood glucose) + 15. The areas under the curves of serum total CO₂ and the approximation formula for detection of low bicarbonate and high bicarbonate were 0.981, 0.996, 0.993, and 1.000, respectively. This formula had superior diagnostic accuracy compared with that of serum total CO₂ (86.6% vs. 81.3%). CONCLUSION: Serum total CO₂ correlated strongly with HCO₃⁻ concentration in pre-dialysis CKD patients. An approximation formula including serum total CO₂ showed superior diagnostic accuracy for low and high bicarbonate compared with serum total CO₂.
