[Interactive effect of hypoparathyroidism and type 2 diabetes mellitus on peritoneal dialysis related peritonitis]

Objective: To investigate the interactive effect of hypoparathyroidism (HPTH) and type 2 diabetes mellitus (T2DM) on peritonitis in patients on peritoneal dialysis (PD). Methods: In this retrospective cohort study, all PD patients who were firstly catheterized in the peritoneal dialysis center of Guizhou Provincial People's Hospital from January 1, 2012 to December 31, 2018 were included. The characteristics of demographics, baseline clinical and laboratory data were collected, and patients were followed up until December 31, 2020. Kaplan-Meier survival curve and Cox regression analysis were used to explore the associations between the interaction of HPTH+T2DM and peritonitis. Results: A total of 270 PD patients were enrolled in this study, aged (39.9±13.2) years, including 143 males and 24 T2DM patients. These serum levels of intact parathyroid hormone (iPTH) [M(Q₁, Q₃)] was 268.1 (121.7, 447.0)pg/ml. After a median follow-up of 29.5 (range from 4.0 to 75.0) months, peritonitis occurred in 69 (25.6%) PD patients for the first time. After controlling for confounding factors, the interaction analysis showed that the risk of peritonitis in T2DM patients with HPTH (n=12) was 3.48 times that of non-T2DM patients without HPTH (n=180) (HR=3.48, 95%CI: 1.04-3.87, P=0.034), which was also greater than the sum of the factors alone (HR=1.35, 95%CI: 0.78-2.31 and HR=0.82, 95%CI: 0.20-3.40). The synergy index between HPTH and T2DM was 1.95, the attributable proportion of interaction was 67.6%, and the relative excess risk of interaction was 2.35. The receiver operating characteristic (ROC) curve indicated that the area under the curve of combined diagnosis of HPTH and T2DM was 0.626 (95%CI: 0.550-0.703, P=0.039). Conclusion: The positive interaction between HPTH and T2DM is an independent risk factor for peritonitis in PD patients, both of which can significantly increase the risk of peritonitis.