Serum immunoglobulin G levels and peritonitis in peritoneal dialysis patients

Background Peritonitis is a frequent and serious complication of peritoneal dialysis (PD). Whether low immunoglobulin level is associated with PD-related peritonitis is unknown. Methods We conducted a prospective study to assess whether immunoglobulin levels at PD onset could predict the occurrence of peritonitis. All patients starting peritoneal dialysis between 01/2005 and 12/2010 at the University hospital of Besanc, on, France, were included in the study. Results Of 240 consecutive PD patients enrolled (mean follow-up 25 +/- 12 months), 76 (32 %) had at least one episode of peritonitis. Mean immunoglobulin (Ig)G level at PD start was lower in patients who subsequently experienced peritonitis (7.9 + 3.4 vs. 9.7 + 3.4 g/l, p = 0.005). An increased IgG level at PD onset was associated with a reduced risk of peritonitis [hazard ratio (HR) 0.88, 95 % confidence interval (CI) 0.80-0.97 for each increase of 1 g/l in IgG, p = 0.008]. IgG level <= 6.4 g/l ("low IgG") was the best predictive value for the occurrence of subsequent peritonitis: 52 patients (24 %) had low IgG levels. At multivariate analysis, both low IgG level (HR 2.49, 95 % CI 1.32-4.69, p = 0.005) and diabetes (HR 2.78, 95 % CI 1.49-5.20, p = 0.001) were predictive of the occurrence of peritonitis. Conclusion Low IgG levels predict the occurrence of PD-related peritonitis. Randomized studies should determine whether such patients could benefit from intravenous immunoglobulin administration.