Risk factors and outcomes of culture-negative peritonitis in peritoneal dialysis: 10 years’ insight from a large center in northern China

Peritoneal dialysis-associated peritonitis is the primary cause of technical failure and infection-related mortality in PD patients. Culture-negative peritonitis poses unique management challenges. The reported incidence of culture-negative peritonitis varies substantially across regions and centers, likely reflecting differences in patient characteristics, microbiological practices, and treatment protocols. In this study, we aimed to investigate the risk factors, treatment strategies, and clinical outcomes of culture-negative peritonitis in a large peritoneal dialysis center in northern China. In this single-center retrospective cohort study, we included consecutive peritonitis episodes from January 2013 to December 2023. We assessed patient demographics, medical history, peritonitis presentation, antibiotic use, and treatment pathways. The primary outcomes were culture-negativity and outcomes of medical cure. Logistic regression was used to identify independent risk factors for culture negativity and failure to achieve a medical cure. The overall incidence of peritonitis during the study period was 0.15 episodes per patient-year and the culture-negative peritonitis rate was 25.5%. Patients with culture-negative peritonitis were more likely to have a smoking history (P = 0.026) and to have used antibiotics before culture collection (47.6% vs. 9.2%, P < 0.0001). A higher proportion of culture-negative cases experienced a delay of over a day from hospital presentation to obtaining a culture (27.0% vs. 8.7%, P = 0.0009). Multivariate analysis revealed that only antibiotic use before culture independently predicted culture negativity (OR = 12.40, 95% CI = 3.80 to 40.20, P < 0.0001). Culture-negative peritonitis had a medical cure rate of 76.2%, similar to Gram-positive infections (76.2% vs. 67.3%, P = 0.229) and better than Gram-negative, polymicrobial, fungal, or tuberculosis-related peritonitis. In multivariate analysis, longer dialysis vintage, culture positivity, and higher post-peritonitis hsCRP levels were associated with a failure to achieve a medical cure. Culture-negative peritonitis had favorable outcomes compared to Gram-negative and polymicrobial peritonitis. Increased patient awareness and an optimized treatment pathway can enhance a timely and standardized culture collection and reduce the culture-negative rate.