Supplementary Material for: Higher Platelet Count Mostly in Normal Range is Associated with First Episode of Peritonitis Risk in Incident Peritoneal Dialysis Patients

Background. Platelets play parts in infection and immune processes. However, the association between platelet count and the risk of peritoneal dialysis-associated peritonitis is unclear.
Methods. This was a retrospective, observational, single-center cohort study. A Cox regression analysis was used to evaluate the independent association of platelet count with the occurrence of first PD-associated peritonitis. Models were adjusted for gender, age, BMI, cardiovascular disease, diabetes mellitus, white blood cell count, neutrophil-lymphocyte ratio, hemoglobin level, albumin level, potassium level, and anti-platelet medication usage.
Results. A total of 2374 patients were enrolled in this study (59% men; mean age 47.40 ± 12.12). The average platelet count was 229.30±82.12 x 109/L. 467 (20%) patients suffered from PD-associated peritonitis at least once. In the multivariable model, the adjusted hazard ratios (HRs) for quartiles 2, 3 and 4 versus quartile 1 were 1.428 (95% CI 1.060-1.924, P=0.019), 1.663 (95% CI 1.240-2.229, P<0.001) and 1.843 (95% CI 1.363-2.492, P<0.001) with baseline data. A nonlinear relationship between platelet count and first PD-associated peritonitis was observed. Further, the association between platelet and first PD-associated peritonitis was significant in the patients with hypokalemia (P for interaction=0.040).
Conclusion. In PD patients, elevated platelet counts were significantly associated with an increased risk of the first onset of PD-associated peritonitis.