Systemic and local complement activation in peritoneal dialysis patients via conceivably distinct pathways

BACKGROUND

Despite several advantages compared to haemodialysis (HD), peritoneal dialysis (PD) remains an underused dialysis technique due to its high technique failure rate related to membrane fibrosis and peritonitis events. Previous work has suggested a harmful role for the complement system in these processes, highlighting the need for a more comprehensive examination in PD.

METHODS

Plasma levels of C1q, mannose-binding lectin (MBL), Properdin, Factor D, C3d/C3-ratio and soluble membrane attack complex (sC5b-9) were determined in PD patients (n = 55), HD patients (n = 41), non-dialysis chronic kidney disease (CKD) patients (n = 15) and healthy controls (n = 14). Additionally, C1q, MBL, Properdin, Factor D and sC5b-9 levels were assessed in the peritoneal dialysis fluid (PDF). In a subgroup, interleukin-6, matrix metalloproteinase-2 (MMP-2), myeloperoxidase (MPO) and elastase were measured in the PDF.

RESULTS

PD patients had significantly higher systemic levels of sC5b-9 compared to healthy controls, CKD and HD patients (p < 0.001). Plasma levels of C1q and C3d/C3-ratios were significantly associated with systemic sC5b-9 levels (p < 0.001). Locally, sC5b-9 was detected in the PDF of all PD patients, and levels were approximately 33% of those in matched plasma, but they did not correlate. In the PDF, only Properdin levels remained significantly associated with PDF sC5b-9 levels in multivariate analysis (p < 0.001). Additionally, PDF levels of sC5b-9 positively correlated with elastase, MPO and MMP-2 levels in the PDF (p < 0.01).

CONCLUSIONS

Our data reveal both systemic and local complement activation in PD patients. Furthermore, these two processes seem independent considering the involvement of different pathways and the lack of correlation.

P1132EXIT-SITE CARE PROTOCOLS IN PORTUGAL AND ITS ASSOCIATION WITH CATHETER-RELATED INFECTIONS RATE

Background and Aims

Exit-site infections (ESi) are frequent complications in peritoneal dialysis (PD) patients and their prevention and treatment are key aspects to lower peritonitis’ risk.

The aim of this study was to evaluate the annual incidence rate of ESi and peritonitis in Portugal and to study possible associations between exit-site (ES) care protocols in each Portuguese unit and the number / rate of ESi and peritonitis.

Method

We performed a national study using two questionnaires at each Portuguese PD Unit: one about the incidence of catheter-related infections, the other characterizing patients’ education and ES care protocols. ESi and peritonitis were defined according to ISPD guidelines. Associations between variables were performed using T-student test or pairwise correlation test. STATA software was used.

Results

Of the 23 Portuguese PD Units, 14 units answered both questionnaires. In the last two years (2017 & 2018), those units followed 1453 patients. Portuguese ESi incidence rate was 0.41 episodes per year [1 episode per 29.2 months (MSSA incidence rate 0.13; MRSA incidence rate 0.03; Pseudomonas incidence rate 0.07)] and the peritonites incidence rate was 0.37 (1 episode per 32.5 months). We found a trend between the absolute number of ESi episodes and the number of peritonites in each unit (r=0.5, p=0.05).

Although ESi prevention guidelines were known by 100% of the Portuguese units, only three out of 5 of the selected guidelines for this study were followed by 100% of the units: monitoring catheter-related infections on a yearly basis; using antibiotic prophylaxis at time of catheter placement and treating nasal carriage of S. aureus. The other 2 guidelines have variable implementation: 12 out of 14 units (86%) perform screening of nasal carriage of S. aureus and only 6 out of 14 (43%) of the units recommend daily topic antibiotic cream at the ES. We didn’t find associations between those differences and ESi incidence.

Whenever S. aureus carriage is detected, 100% of the units proceed treating with mupirocine using different posology (twice or three times a day, 5 or 7 or 21 days, with/out chlorexidine). Also, the screening of nasal carriage of S. aureus is different: only pre catheter implantation (n=4); annually (n=4); semi annually (n=3); bimonthly (n=2). Oral antibiotics are prescribed after catheter placement in 4 units. We didn’t find statistical differences in ESi / peritonitis, comparing those practices.

Regarding to ES care protocols, ESi rate was lower with non-occlusive dressing (0.38 vs. 0.57) immediately after catheter insertion. ESi and peritonitis rate were lower in units where bathing without ES dressing is advocated (n=9, 0.58 & 0.37 vs. 0.32 & 0.34). The use of bath sponge is associated with higher ESi rate (0.57 vs. 0.34). The use of colostomy bags in beach baths was associated with lower incidence rate of ESi compared to regular dressing or waterproof dressing (o.32 vs. 0.54).

100% of units use two different empirical antibiotics for initial ESi treatment. In the presence of chronic ESi, 3 units don’t perform shaving of external cuff and peritonitis rate is higher in those who do not apply this procedure (0.38 vs. 0.31).

Conclusion

in Portuguese PD units there is a wide variability in ISPD guidelines implementation and ES care protocols. We found that using non-occlusive dressing immediately after catheter insertion, removing ES dressing before shower, bathing not using a sponge and using colostomy bags at beach baths were associated with lower incidence rate of ESi. Shaving of the external cuff was associated with lower incidence rate of peritonitis. A regular national audit of PD Units is an important tool of quality improvement to clarify the best procedures for reduction of catheter-related infections in PD.