Effects of salt loading and potassium supplement on the circadian blood pressure profile in salt-sensitive Chinese patients

BACKGROUND AND OBJECTIVE: Salt-sensitive (SS) patients more frequently showed a nondipper blood pressure pattern and were associated with more serious target organ damage than non-SS patients. We aimed to investigate whether potassium supplement can improve the blunted nocturnal blood pressure fall in SS patients exposed to a high-salt diet. PATIENTS AND METHODS: Approximately 49 normotensive and mildly hypertensive Chinese patients received a study protocol of a 3 days of baseline examination, 7 days of a low-salt diet (3 g NaCl/day), 7 days of a high-salt diet (18 g NaCl/day), and 7 days of a high-salt diet with a potassium supplement (18 g NaCl and 4.5 g KCl/day). The 24 h ambulatory blood pressure was determined at the end of each period. RESULTS: A total of 14 patients were classified as SS according to the at least 10% increase in their 24-h mean arterial pressure after high-salt loading. The night-to-day blood pressure ratio was significantly higher in SS patients than in non-SS patients during the high-salt loading period (systolic 0.96±0.01 vs. 0.89±0.01, P<0.01; diastolic 0.96±0.01 vs. 0.92±0.01, P<0.05). Compared with the high-salt loading period, the night-to-day blood pressure ratio was significantly reversed by potassium supplement in SS patients (systolic 0.91±0.01 vs. 0.96±0.01, P<0.05; diastolic 0.91±0.01 vs. 0.96±0.01, P<0.05). CONCLUSION: Potassium supplement can improve the blunted nocturnal blood pressure fall in SS patients exposed to a high-salt diet, but the related mechanism needs to be studied further.