Clinical features and treatment of small intestinal bacterial overgrowth in elderly patients hospitalized in gastroenterology department

Objective To investigate the prevalence and clinical features of small intestinal bacterial overgrowth （SIBO） in elderly patients hospitalized in gastroenterology department,and study the effect of drug therapy. Methods Patients over 60 years old hospitalized in the department of gastroenterology of the second medical center in Chinese PLA General Hospital were enrolled from September 2016 to June 2019.A11 patients had undergone lactulose breath test （LBT） to detect the prevalence of SIBO.The clinical and LBT features of SIBO were analyzed.The effects of bifidobacterium triple viable capsules （420 mg,thrice per day） with bacillus licheniformis capsule （0.5 g,thrice per day）,rifaximin tablet （0.4 g,thrice per day） or metronidazole tablet （0.4 g,thrice per day） for 2 weeks on SIBO were evaluated by comparing changes in clinical features and LBT results after treatment. Results Totally 272 patients were enrolled in our study,and the prevalence of SIBO was 62.50% （170/272）.Common symptoms of SIBO included increased flatus,abdominal distension,borborygmus,belching,bad breath,abdominal pain,fecal urgency,incomplete evacuation,hard stool,etc.The breath hydrogen and methane concentrations in SIBO positive group were significantly higher than those of SIBO negative group （P<0.05）.Multivariate logistic regression analysis showed that abdominal surgery history was an independent risk factor for SIBO.Totally 86 patients received drug therapy,and the symptom improvement rate was 65.12% （56/86）.After treatment,the symptoms of abdominal pain,abdominal bloating,belching,increased flatus,borborygmus,defecation increase,fecal urgency,incomplete evacuation,bad breath and hard stool significantly improved （P<0.05）;however,the symptom of loose stool did not changed （P>0.05）.After treatment,43.02% （37/86） of SIBO patients presented negative LBT results with lower hydrogen concentration at all time points,especially at 120 min (67.77±52.26×10^-6 vs 46.94±55.19×10^-6,P<0.05),and lower methane concentration especially at 80 min (17.85±23.65×10^-6 vs 12.48±11.42×10^-6,P<0.05). Conclusion The prevalence of SIBO in the elderly is 62.50%.History of abdominal surgery is an independent risk factor for SIBO.Drug therapy can improve the symptoms of elderly SIBO patients,and reduce the concentration of hydrogen and methane in breath.