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Abstract: FR-PO635

Alkalinization by Urologists and Nephrologists (AlcalUN): Does Oral Sodium Bicarbonate (NaHCO3) Affect Extracellular Volume?

Session Information

Category: Fluid and Electrolytes

  • 902 Fluid and Electrolytes: Clinical


  • Bertocchio, Jean-philippe, Club des Jeunes Néphrologues, Paris, France
  • Figueres, Lucile, Nantes University Hospital, Nantes, France
  • De laforcade, Louis, Centre Hospitalier Pierre Oudot, Bourgoin-Jallieu, France
  • Ayari, Hamza, AP-HP, European Georges Pompidou Hospital, Paris, France
  • Dolley-Hitze, Thibault, AUB Santé, Saint-Malo, France
  • Gueutin, Victor, CHU Caen, Caen, France
  • Golbin, Leonard, CHU Pontchaillou, Rennes, France
  • Overs, Camille, Grenoble University Hospital, La Tronche, France
  • Moriniere beaume, Julie, AVODD, Toulon, France

Oral alkalinization with NaHCO3 or citrate is widely prescribed in numerous situations from metabolic acidosis to nephrolithiasis. Most of nephrologists/urologists use it on a regular basis, while extracellular volume (ECV) increase is the main feared adverse event for NaHCO3. To date, no clinical trial has specifically studied this aspect in clinical routine.


AlcalUN (NCT03035812) is a French multicentric prospective open trial aiming at determining the impact on ECV of a chronic oral alkalinization by NaHCO3 during nephrologists or urologists use. Patients receiving oral alkalinization without NaHCO3 composed a control group. The main criterion was the ECV increase as judged on body weight (BW), blood pressure (BP), and edema at first visit.


From 01/2017 to 12/2018, 20 investigators included 122 patients whom 92 (75%) had at least one follow-up and 74 (61%) received NaHCO3. If both groups were comparable as judged on demographic data, patients in the NaHCO3-group had more chronic kidney diseases (74 vs. 28%, p<0.001) where patients in the non NaHCO3-group (citrate) had more nephrolithiasis (23 vs. 94%, p<0.001). At baseline (inclusion), BW, BP, and presence of edema were comparable in both groups. After a mean of 98±48 days of follow-up, 70 patients (76%) had an ECV increase but the repartition was highly similar in both groups (77 vs. 72%, p=0.76), especially BW did not differ (cf. Figure 1).


Oral alkalinization with NaHCO3 does not increase ECV more than citrate while it is used in a more risky population. These results should be confirmed in a widest population (recruitment continues) and now in a randomized controlled trial.

Figure 1. Evolution of body weight between inclusion (V0) and first follow-up (V1).