Association of Blood Pressure Patterns with Loss of Residual Uresis in Patients on Dialysis at the Valentín Gómez Farías Regional Hospital

Background: Residual kidney function is a key predictor of survival and quality of life in chronic kidney disease on dialysis therapy, and is associated with improved fluid management, nutrition, and cardiovascular control. Hypertension affects 60–90% of these patients. Circadian blood pressure patterns (dipping, nondipping, and reversal) are associated with organ damage and cardiovascular risk, although their association with loss of residual uresis is understudied. Methods: Ambispective cross-sectional, analytical study in elderly patients with Chronic Kidney Disease on dialysis and pre-dialysis, in whom a blood pressure pattern was documented by ABPM. The ANOVA test was used for analysis of variance of residual uresis over time, and the Tukey/Bonferroni test was used for comparisons between different blood pressure patterns. Statistical significance was considered at a p value <0.05. Results: Time showed a significant impact on the loss of residual urine output (p < 0.001), with a time-circadian pattern interaction (p = 0.019). Between-group differences: No significant differences at specific time points (ANOVA: p = 0.743 at baseline, 0.271 at 6 months, 0.102 at 12 months); progressive divergence was observed (Eta2: 0.016 → 0.075). The Reverse Dipper group showed greater absolute loss at 12 months (−586 ml/day), while the Reverse Dipper group showed relative stability (+42 ml/day at 6 months). Post hoc: Multiple comparisons (Tukey/Bonferroni) did not identify significant differences (p > 0.40). Conclusion: There is a significant impact on the loss of residual diuresis in dialysis patients, showing that the Reverse Dipper group presented greater absolute loss at 12 months compared to other patterns. The beneficial impact of preserving residual uresis is well known, so it is important to know all the factors that may impact its maintenance, one of them being the determination of the blood pressure profile and its association with the preservation of residual uresis.