A low-salt diet increases the estimated net endogenous acid production in nondiabetic chronic kidney disease patients treated with angiotensin receptor blockade.

Background/aims: An acid-base imbalance precedes renal disease progression in patients with chronic kidney disease (CKD). Little is known about the effects of a low-salt diet (LSD) on net endogenous acid production (NEAP) levels in CKD patients using angiotensin receptor blockade.

Methods: We enrolled a total of 202 nondiabetic CKD patients who underwent an 8-week treatment with olmesartan from the original trial [Effects of Low Sodium Intake on the Antiproteinuric Efficacy of Olmesartan in Hypertensive Patients with Albuminuria (ESPECIAL) trial: NCT01552954]. The patients were divided into good- and poor-LSD-compliance groups.

Results: During the interventional 8 weeks, the NEAP in the good-compliance group increased compared to the control group (12.9 ± 32.0 vs. -2.0 ± 35.0 mmol/day, p = 0.002). NEAP was positively associated with the good-LSD-compliance group in the fully adjusted analyses (r = 0.135, p = 0.016). The additional reduction of 2.39 g/day of protein intake with a reduction of 1 g/day of salt intake did not increase the NEAP under angiotensin II receptor blockade (ARB) treatment with an LSD (r = 0.546, p < 0.001).

Conclusion: We found that an LSD may increase the NEAP in nondiabetic CKD patients using ARB, which suggests that additional acid producing-protein restriction should be required to prevent the NEAP from rising.