Effects of the blood urea nitrogen to creatinine ratio on haemorrhagic transformation in AIS patients with diabetes mellitus

Background: The effect of the blood urea nitrogen (BUN) to creatinine (Cr) ratio (henceforth BUN/Cr) on haemorrhagic transformation (HT) of acute ischaemic stroke (AIS) patients is unclear. Methods: AIS patients in the West China Hospital, Sichuan University, Chengdu, China, admitted within seven days from stroke onset (2012-2016) were included in the study. Baseline data, including BUN and Cr levels, were collected. The outcome was defined as HT during hospitalization. Results: In this study, 1738 participants with an average age of 62.7 +/- 14.0 years were included. After adjusting potential confounders (age, blood platelet, albumin, stroke severity, triglycerides and low-density lipoprotein [LDL]), multivariate logistic regression analyses indicated that BUN/Cr is independently associated with HT. The nonlinear relation between BUN/Cr and HT was explored in a dose-dependent manner, with an apparent inflection point of 30.71. On the left and right sides of the inflection point, the odds ratio (OR) and 95% confidence interval (CI) were 1.05 (1.02-1.08) and 0.96 (0.88-1.05), respectively. Interaction between BUN/Cr and diabetes mellitus (DM) and HT (P for interaction = 0.0395) was noted. BUN/Cr showed positive correlation with HT in DM patients (OR = 1.07; 95% CI: [1.02, 1.12]) but no significant relationship with HT in patients without DM. Conclusion: BUN/Cr is significantly associated with HT in AIS patients in a linear fashion, with an apparent cut point demarcating the HT difference. When the patients have DM, BUN/Cr is positively correlated with HT. These results support a revision in how we anticipate the prognosis for AIS patients.