Association of Bariatric Surgery With Risk of Infectious Diseases: A Self-Controlled Case Series Analysis

Although emerging data demonstrate that obesity is a risk factor for infectious diseases, no study has investigated the relationship of bariatric surgery with the risk of infectious diseases among obese adults.

We conducted a self-controlled case series analysis using data from the State Emergency Department Database and State Inpatient Database of 3 US states (California, Florida, and Nebraska) from 2005 through 2011. We included obese adults who underwent bariatric surgery as an instrument of weight reduction. Primary outcomes were emergency department (ED) visit or hospitalization for skin and soft-tissue infection (SSTI), respiratory infection, intra-abdominal infection, or urinary tract infection (UTI).

Among 56277 obese adults who underwent bariatric surgery, compared to presurgery months 13-24 as the reference period, the risk of ED visit or hospitalization in the 0- to 12-month postsurgery period decreased significantly for SSTI (aOR, 0.85 [95% confidence interval {CI}, .76-.95]) and respiratory infection (aOR, 0.82 [95% CI, .75-.90]) and remained significantly low in the 13- to 24-month postsurgery period (aORs, 0.77 [95% CI, .68-.86] and 0.75 [95% CI, .68-.82], respectively). By contrast, the risk increased significantly in the 0- to 12-month postsurgery period for intra-abdominal infection (aOR, 2.09 [95% CI, 1.78-2.46]) and UTI (aOR, 1.93 [95% CI, 1.74-2.15]) and remained high in the 13- to 24-month postsurgery period (aORs, 1.29 [95% CI, 1.09-1.54] and 1.31 [95% CI, 1.17-1.47], respectively).

We found a divergent risk pattern in the risk of 4 common infectious diseases after bariatric surgery. The risk of SSTI and respiratory infection decreased after bariatric surgery whereas that of intra-abdominal infection and UTI increased.