Matrix Metalloproteinase-7 Associated with Congestive Heart Failure in Peritoneal Dialysis Patients: A Prospective Cohort Study.

Background: Matrix metalloproteinase-7 (MMP7) is markedly expressed in patients with chronic kidney disease; its expression in dialysate and role in patients undergoing peritoneal dialysis (PD) have not been well established. Methods: Participants undergoing PD from June 1st, 2015, to June 30th, 2020, were involved and were followed up every 3 months for the first year and every 6 months thereafter until death, PD withdrawal, or the end of the study. Data at each follow-up point were collected and analyzed for the association with congestive heart failure (CHF), PD withdrawal, and combined endpoint. Results: A total of 283 participants were included in this study. During a median follow-up of 21 months, 20 (7%) participants died, 93 (33%) withdrew from PD, and 105 (37%) developed CHF. A significantly increased level of serum and dialysate MMP7 was observed at baseline. Dialysate MMP7 presented a good linearity with serum MMP7. Baseline serum and dialysate MMP7 levels were associated with CHF in multivariable Cox proportional hazards regression models. After categorization, participants with high baseline MMP7 levels had a higher incidence of CHF (42%), and the hazard ratios (95% confidence intervals) were 1.595 (1.023-2.488). Interestingly, participants with higher serum MMP7 levels were trended to use dialysate with higher glucose concentration. However, the ultrafiltration volumes were not significantly increased. Higher MMP7 levels were also positively associated with PD withdrawal and combined endpoint. Conclusions: The expression of MMP7 in serum and dialysate was markedly increased and was tightly associated with the risk of CHF in PD patients. This finding suggests that the measurement of MMP7 may inform strategies for managing CHF at an earlier stage.

Degree and duration of hypokalemia associated with peritonitis in patients undergoing peritoneal dialysis.

BACKGROUND: Hypokalemia (LK) was associated with peritonitis in peritoneal dialysis (PD) patients, while the role of its degree and duration have not been fully established. Here, we conducted a retrospective cohort study to identify the relationships of LK degree and duration with peritonitis in PD patients. METHODS: A total of 602 PD patients in our department from Jan 1st, 2009 to Dec 31st, 2019 entered the last analysis. Data were collected from their medical records. Serum potassium (SK) levels, degree of hypokalemia, and duration of hypokalemia were analysed with peritonitis. The time association of hypokalemia and peritonitis was also analysed. RESULTS: There were totally 320 (53.7%) and 123 (20.7%) patients who had ever suffered from LK and serious hypokalemia (SLK) in the cohort. Only 6.82% and 0.5% of patients had LK and SLK at baseline, while the incidence increased and kept in 25%-32% and 5.5%-8.2% after PD. Both LK (HR 1.437, 95% CI 1.014-2.038, P = .042) and SLK (HR 2.021, 95% CI 1.429-2.857, P < .001) did correlate to peritonitis after adjusted analyses, while only SLK remained the significance at each follow-up point. The LK/SLK durations were 6 (3-12) and 6 (3-6) months, and only longer SLK duration correlated with peritonitis after adjusted analyses. After categorised, those LK durations more than 6 months and SLK durations more than 3 months presented a significant association with peritonitis. Of the patients who suffered from both hypokalemia and peritonitis, 70.4% patients' LK times were earlier than peritonitis time, while most SLK times (62.7%) were later. SLK also correlated with combined endpoint. CONCLUSIONS: Hypokalemia degree and duration were tightly associated with peritonitis. Hypokalemia might be a causal factor of peritonitis, while peritonitis might also aggravate hypokalemia. We should manage SK as much as possible and avoid hypokalemia, especially serious hypokalemia in clinic practice.

Automated peritoneal dialysis could rapidly improve left heart failure by increasing peritoneal dialysis ultrafiltration: a single-center observational clinical study
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Ultrafiltration failure (UFF) is a major cause of water retention, left heart failure (LHF), and peritoneal dialysis (PD) failure. Automated peritoneal dialysis (APD) might have better ultrafiltration (UF) than continuous ambulatory peritoneal dialysis (CAPD). Here, we have studied whether short-term APD could increase UF and improve LHF. 47 patients were included in this study from December 1, 2015, to January 1, 2017. All patients had been treated with CAPD before they came to our center and were treated with APD in the hospital. 24-hour peritoneal UF volume, 24-hour urine volume, body weight, blood pressure, LHF class, serum creatinine, blood urea nitrogen, albumin, potassium, hemoglobin, and glucose were collected and compared before and after receiving short-time APD. A total of 47 patients (31 men, mean age 46.8 ± 16.2 years, mean duration 26 months (2 - 195 months)) were enrolled in this study. Of the 47 patients, peritoneal dialysis UF was significantly increased when receiving short-term APD compared to CAPD (1,261.9 ± 329.6 mL vs. 706.2 ± 222.3 mL, p < 0.001), and body weights had significantly decreased 3 days after treatment with APD (57.73 ± 10.5 vs. 59.81 ± 10.8, p < 0.001). LHF class was significantly decreased 3 days after receiving APD (1.7 ± 0.8 vs. 2.4 ± 1.0, p < 0.001). Blood pressure was well controlled 3 days after treatment with APD (146.6 ± 14.4 vs. 162.5 ± 23.8 of SBP, p = 0.007, and 85.6 ± 11.1 vs. 95.6 ± 14.7 of DBP, p = 0.001). In conclusion, short-term APD could significantly increase ultrafiltration, rapidly alleviate edema and improve LHF, and might be an effective method to treat UFF and LHF in PD patients.
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Hypokalemia Duration in the First Year Associated with Subsequent Peritoneal Dialysis-Associated Peritonitis: A Multicenter Retrospective Cohort Study.

BACKGROUND: The association of hypokalemia (LK) with peritoneal dialysis-associated peritonitis (PDAP) risk remains uncertain. Here, we calculated LK duration in the first PD year and evaluated its association with PDAP. METHODS: A multicenter, retrospective, incident cohort study of 1633 participants was conducted from January 2008 to October 2020 in China. The duration of LK and severe hypokalemia (SLK) was calculated as the total number of months that a patient's serum potassium (SK) level was less than 3.5 or 3.0 mEq/L during the first PD year. The study outcome was the risk of subsequent PDAP started in the second year and later. Cox proportional hazards models and competing risk models were used to assess the association. RESULTS: The subsequent PDAP occurred in 420 (25.7%) participants during a median of 28 months of follow-up. Overall, LK duration in the first year was positively associated with a subsequent PDAP risk (per 3-month increments, adjusted HR, 1.13; 95%CI: 1.05-1.23). After categorization, patients with LK duration longer than 6 months had the highest adjusted HR of 1.53 (p = 0.005 vs. those without LK) for subsequent PDAP risk. A similar trend was also found for SLK duration. In a competing risk model, a similar trend was also observed. None of the variables, including demographic and PD characteristics, diabetes history, and several clinical measurements, significantly modified this association. The causative organisms of PDAP were similar to those previously reported. CONCLUSIONS: PD patients with longer LK duration in the first year had a higher subsequent PDAP risk.

High-Salt Diet Accelerated the Decline of Residual Renal Function in Patients With Peritoneal Dialysis.

Objective: This study aims to investigate the relationship between dietary salt intake and residual renal function in peritoneal dialysis (PD) patients. Methods: The daily salt intake of the patients was calculated based on a 3 day dietary record. Sixty-two patients were divided into three groups: 33 patients in the low salt intake group (salt intake <6.0 g/day), 17 in the medium salt intake group (salt intake 6.0 to <8.0 g/day), and 12 in the high salt intake group (salt intake ≥8.0 g/day). Regular follow-up was conducted every 3 months. Urine volume, peritoneal ultrafiltration volume, and other clinical indicators were recorded. Biochemical indexes were detected to evaluate the changes in residual renal function and peritoneal function during follow-up. Results: A positive correlation between dietary sodium intake and sodium excretion was found. During 12-month follow-up, a decrease of residual renal function showed a significant difference among the three groups (p = 0.041) (15.3 ± 27.5 vs. 12.5 ± 11.5 vs. 32.9 ± 18.4 L/W/1.73 m2 in the low-, medium-, and high salt intake groups, respectively). Consistently, a higher decline of residual renal function (adjusted ß, 20.37; 95% CI, 2.83, 37.91) was found in participants with high salt intake (salt intake ≥8 g/day) compared with those in non-high salt intake. Conclusion: Our study showed that the sodium excretion by peritoneal dialysis was positively correlated with dietary sodium intake in PD patients. The high salt intake diet (salt intake ≥8 g/day) may lead to a faster decline of residual renal function in PD patients.

Duration of Serum Phosphorus Control Associated with Overall Mortality in Patients Undergoing Peritoneal Dialysis.

BACKGROUND: Serum phosphorus (SP) level is closely associated with overall mortality and cardiovascular events, while the role of SP controlled duration is not fully recognized. Here, we conducted a retrospective cohort study in our department to identify the relationship of SP controlled duration with clinical outcomes in patients undergoing peritoneal dialysis (PD). METHODS: PD patients in our center from January 1, 2009, to June 30, 2019, were followed up at 2-month (the first year) or 5-month (the next follow-up period) intervals, and until death, until PD withdrawal, or until June 30, 2019. Data at each follow-up point were collected from their medical records. SP levels, changed degree of SP over baseline, and SP controlled duration were analyzed with overall mortality, PD withdrawal (including death, transferred to hemodialysis, and received renal transplantation), and combined endpoint (including death, acute heart failure, cardiovascular event, and stroke). RESULTS: A total of 530 patients entered the analysis. Of them, 456 (86.0%) had hyperphosphatemia before dialysis, and the SP levels decreased soon after dialysis. The degree of SP change over baseline was the maximum at the 3rd month after dialysis (-31.0%), and lower degree was associated with higher overall mortality (hazard ratio [HR], 1.012; 95% CI, 1.004-1.020; p = 0.003). The median SP controlled duration was 13 (5-28) months, and longer duration was significantly associated with lower overall mortality (HR, 0.968; 95% CI, 0.956-0.981; p < 0.001). After categorization, duration more than 12 months greatly improved overall mortality with a HR of 0.197 (0.082-0.458; p < 0.001 vs. SP never controlled group) and 0.329 (0.150-0.724; p = 0.006 vs. duration <12 months group). Longer SP controlled duration also improved PD withdrawal and combined endpoint. CONCLUSIONS: In summary, both degree and duration of SP control were tightly associated with overall mortality. We should control SP levels as early, as possible, and as long as we could.