Incidence And Risk Factors Analysis Of Small Intestinal Bacterial Overgrowth In Patients With Chronic Kidney Disease

ObjectivesTo investigate the incidence and possible risk factors of small intestinal bacterial overgrowth（SIBO）in patients with chronic kidney disease（CKD）.And to explore the correlation between SIBO and gastrointestinal symptoms,as well as that between SIBO and cardiovascular complications in CKD patients.MethodsPatients with CKD,who were hospitalized in the Department of Nephropathy of our hospital between June 2019 to June 2021,were selected as subjects,and were divided into early stage CKD group（n=17）,moderate and advanced stage CKD group（n=34）and PD group（n=31）,according to CKD stage and whether they were treated with peritoneal dialysis or not.SIBO was assessed by lactulose hydrogen-methane breath test（LHMBT）,gastrointestinal symptoms were evaluated by gastrointestinal symptom rating scale（GSRS）,body composition parameters including fat tissue index（FTI）were determined using multifrequency bioelectrical impedance analysis,cardiac function and hemodynamic changes were measured by non-invasive hemodynamic monitoring system.According to the results of LHMBT,the patients were divided into SIBO group and non-SIBO group.The demographic data,laboratory and clinical indicators,gastrointestinal symptoms and other differences between these two groups were compared.Binomial logistic stepwise regression was used to analyze the possible risk factors of SIBO in CKD patients.Result（1）The incidence of SIBO in these 92 patients was 47.83%.The positive rates of SIBO in early stage CKD,moderate and advanced stage CKD,PD groups were 62.96%,38.24%and 45.16%respectively,and there was no significant difference among these three groups（χ~2=3.821,P=0.148）.In PD group,the incidences of SIBO in total Kt/V<1.7 group and total Kt/V≥1.7 group were 50.00%and 41.18%.Besides,the incidences of SIBO in low transport group,low average transport group,high average transport group and high transport group were 66.67%,37.50%,43.75%and 50.00%,respectively.There was no significant difference in the incidence of SIBO among the above groups（P>0.05）.（2）Compared with non-SIBO group,the GSRS score of SIBO group was higher（23.27±3.97 VS 21.13±4.39,t=-2.451,P=0.016）.There was significant difference in the incidence of dyspepsia-related symptoms between these two groups（χ~2=4.611,P=0.032）,but the difference in the incidence of abdominal pain,reflux,constipation and diarrhea was not statistically significant（P>0.05）.（3）In terms of body composition parameters,FTI and body mass index（BMI）in SIBO group were significantly higher than those in non-SIBO group,but there was no significant difference in parameters reflecting volume load state between these two groups.（4）In terms of hemodynamic parameters,the stroke volume（SV）in the SIBO group was higher than that in the non-SIBO group,and the systemic vascular resistance（SVR）was lower than that in the non-SIBO group,the difference was statistically significant（P<0.05）.（5）Univariate analysis indicated that serum potassium,blood urea nitrogen,e GFR,FTI,BMI,SV and SVR were related factors of SIBO in patients with CKD.Multivariate logistic stepwise regression analysis showed that low potassium（OR=0.396,95%CI0.176～0.893,P=0.025）and high FTI（OR=1.182,95%CI 1.037～1.348,P=0.013）were independent risk factors for SIBO in patients with CKD.Conclusion（1）The incidence of SIBO was high in CKD patients,but there was no significant difference in the incidence of SIBO among early stage CKD group,moderate and advanced stage CKD group,PD group,adequate and inadequate dialysis group,and among different peritoneal transport types.（2）Symptoms of dyspepsia were more prominent in SIBO positive patients.Decreased renal function and SIBO may jointly lead to non-specific gastrointestinal symptoms in patients with CKD.（3）Patients with moderate and advanced CKD were more likely to have decreased body weight and fat content.CKD patients with SIBO had higher FTI and BMI than those without SIBO,but there were no significant differences in volume loading status.（4）With the progression of CKD,the renal function decreased,cardiac afterload increased and pump function were impaired more easily.On this basis,SIBO may further cause hemodynamic changes in CKD patients.（5）Low serum potassium and high FTI were found to be independent risk factors for SIBO in patients with CKD.CKD patients should avoid hypokalemia and obesity.