Circadian blood pressure abnormalities in patients with primary nephrotic syndrome

Background: Only a few studies have evaluated the abnormalities of ambulatory blood pressure (ABP) in patients with nephrotic syndrome (NS). Methods: The 24-h ABPs were measured in primary NS patients with acute onset of disease and analyzed in relation to the clinical variables. Results: Our subjects comprised 21 patients: 17 with minimal change disease and 4 with focal segmental glomerulosclerosis. Of these patients, 8 (38%) had daytime hypertension, 13 (62%) had nighttime hypertension, and 13 (62%) were non-dippers (nighttime-to-daytime ratio of ABP: NDR > 0.9). The serum sodium level was correlated with the average 24-h ABP and NDR, after adjustment for other clinical variables, such as the increase in body weight, serum albumin level, and urinary protein excretion. The data from repeated ABP measurements, before and after the achievement of remission, showed a marked decrease in the average 24-h ABP after remission. Furthermore, change in the serum sodium level was significantly correlated with the change in NDR. Conclusion: These results suggest that alteration in renal handling of sodium and water, which might be reflected in serum sodium level, is involved in the abnormality of circadian blood pressure in primary NS patients.