Risk of Severe Infection in Patients With Biopsy-proven Nonalcoholic Fatty Liver Disease - A Population-based Cohort Study

BACKGROUND & AIMS: It has been suggested that patients with nonalcoholic fatty liver disease (NAFLD) might be at increased risk of severe infections, but large-scale data from cohorts with biopsy-proven NAFLD are lacking.METHODS: Population-based cohort study including all Swedish adults with histologically confirmed NAFLD (n = 12,133) from 1969 to 2017. NAFLD was defined as simple steatosis (n = 8232), nonfibrotic steatohepatitis (n = 1378), noncirrhotic fibrosis (n = 1845), and cirrhosis (n = 678). Patients were matched to 5 pound population comparators (n = 57,516) by age, sex, calendar year, and county. Swedish national registers were used to ascertain incident severe infections requiring hospital admission. Multivariable adjusted Cox regression was used to estimate hazard ratios in NAFLD and histopathological subgroups.RESULTS: Over a median of 14.1 years, 4517 (37.2%) patients with NAFLD vs 15,075 (26.2%) comparators were hospitalized for severe infections. Patients with NAFLD had higher incidence of severe infections than comparators (32.3 vs. 17.0/1000 person-years; adjusted hazard ratio [aHR], 1.71; 95% confidence interval, 1.63L1.79). The most frequent infections were respiratory (13.8/1000 person-years) and urinary tract infections (11.4/1000 person-years). The absolute risk difference at 20 years after NAFLD diagnosis was 17.3%, equal to one extra severe infection in every 6 patients with NAFLD. Risk of infection increased with worsening histological severity of NAFLD (simple steatosis [aHR, 1.64], nonfibrotic steatohepatitis [aHR, 1.84], noncirrhotic fibrosis [aHR, 1.77], and cirrhosis [aHR, 2.32]. Also compared with their full siblings, patients with NAFLD were at increased risk of severe infections (aHR, 1.54; 95% confidence interval, 1.40-1.70).CONCLUSIONS: Patients with biopsy-proven NAFLD were at significantly higher risk of incident severe infection requiring hospitalization both compared with the general population and compared with siblings. Excess risk was evident across all stages of NAFLD and increased with worsening disease severity.