Disease burden of serious infections, including opportunistic infections, skin and soft tissue infections (SSTIs), urinary tract infections (UTIs), pneumonia, and sepsis/bacteremia, was found to be increased in patients with Sjögren syndrome, according to a study results published in Clinical and Experimental Rheumatology.
Using the 1998 to 2016 United States National Inpatient Sample (NIS), the study authors analyzed the data of patients who were hospitalized and had International Classification of Disease, Ninth Revision, Clinical Modification (ICD-9-CM) or International Classification of Disease, Tenth Revision, Clinical Modification (ICD-10-CM) codes for serious infection as the primary diagnosis and the main reason for hospitalization.
Records of patients with Sjögren syndrome (N=69,239) were compared with those of patients in the general population (N=49,897,331) for outcomes and epidemiologic trends. Summary statistics, including means and proportions, were compared, and the rates of infections were calculated per 100,000 NIS claims. Multivariable logistic regression analyses were performed for each study, adjusting for covariates based on clinical importance.
The most common serious infections during the study period were pneumonia and sepsis (37% and 34%, respectively). The frequency of all serious infections were found to be increased in the Sjögren syndrome population, compared with those, except opportunistic infections and pneumonia, in the general population. From 1998 to 2000 to 2015 to 2016, the rates of each serious infection per 100,000 NIS claims increased from 0.16 to 0.46 in opportunistic infections, from 0.55 to 2.90 in SSTIs, from 0.25 to 1.96 in UTIs, from 2.78 to 5.43 in pneumonia, from 0.63 to 10.71 in sepsis, and from 4.38 to 21.47 in composite infection. During the study period, unadjusted length of hospital stay and in-hospital mortality decreased, and total hospital charges increased for serious infections.
Overall, the study authors determined that the rate of serious infections among patients with Sjögren syndrome increased from 1998 to 2000 to 2015 to 2016 for all the 5 serious infections studied, with the rate of sepsis accounting for the highest rates of serious infections in this population.
This study was limited by the nature of NIS data, which did not provide disease severity, organ manifestations of Sjögren syndrome, or the type of treatment used. Primary vs secondary Sjögren syndrome could not be differentiated; therefore, the study authors were unable to evaluate the effects of disease type, severity, or treatment on the burden of serious infections and associated outcomes. The use of ICD-9-CM codes may have led to misclassification bias, and study findings may not be generalizable to countries other than the United States.
“Despite the increase in the rates of serious infections over time, the crude mortality decreased over time, which indicates an earlier recognition and treatment of serious infections, a lower threshold for hospitalization, and/or better therapeutics in the more recent years,” the study authors concluded. “Future studies can examine whether interventions, targeting systems of individuals can reduce mortality and improve utilization outcomes in [Sjögren syndrome] admitted with serious infections.”
Singh JA, Cleveland JD. Serious infections in Sjögren’s syndrome patients: a national U.S. study. Clin Exp Rheumatol. 2020;38(126):47-52.