Impact of comorbidities on mortality in hospitalized influenza patients with diabetes – Analysis of the Austrian Health Insurance

Faisal Aziz,Felix Aberer,Othmar Moser,Caren Sourij,Dirk Von Lewinski,Susanne Kaser,Berthold Reichardt,Harald Sourij

doi:10.1016/j.diabres.2021.108758

Abstract

AimsTo assess the impact of characteristics and comorbidities on the hospitalization rate and 30- and 90-days all-cause mortality after hospitalization for influenza-related illness (IRI) in individuals with diabetes. MethodsData of 507,184 individuals with diabetes enrolled in the national Austrian Health Insurance database during 2013–2017 were analyzed. Hospitalization for IRI was defined as per International Classification of Disease 10 codes (J09, J10, J11). All-cause mortality was calculated for 30- and 90-days post-hospitalization. ResultsOf the total diabetes population, 1994 (0.4%) were hospitalized for IRI during 2013–2017. The rate of comorbidities was higher in individiuals who were hospitalized due to IRI as compared with the general diabetes population. Overall 30-days cumulative mortality following hospitalization for IRI was 7.9% and 90-days mortality was 10.3%. The risk (adjusted Hazard Ratio, 95% Confidence Interval) of IRI related 90-days mortality increased with age (50–59: 3.00, 0.65–13.94; 60–69: 4.16, 0.99–17.55; 70–79: 4.79, 1.16–19.76; 80+: 7.15, 1.74–29.46), heart failure (1.97, 1.31–2.98), renal disease (1.50, 1.05–2.14), and Charlson comorbidity index (1.14, 1.08–1.19). ConclusionsOlder age, heart failure, renal disease, and Charlson comorbidity index were significant predictors of mortality following hospitalization for IRI in individuals with diabetes. These findings could help in improving the clinical management and performance of surveillance and health systems concerning IRI in Austria.

Highlights

Individuals with diabetes face an elevated overall risk of infections that can be attributed to impaired phagocytosis by neutrophils, macrophages, and monocytes, impaired neutrophil chemotaxis, and bactericidal activity as well as impaired innate cell-mediated immunity [1,2]
The database for individuals with diabetes only contains pseudo-anonymized information on demographic characteristics, primary and secondary medical diagnosis provided as International Classification of Disease (ICD) codes along with discharge dates from hospitals, prescribed medications coded as Anatomical Therapeutic Classification (ATC) system introduced by the World Health Organization, along with their dosage, volume, start dates, and end dates, medical procedures stored as MEL codes, and all-cause mortality along with the date of death
The accumulation of comorbidities expressed by the adjusted Charlson Comorbidity Index (ACCI) was associated with increased adjusted odds for influenza-related hospitalizations

Summary

Introduction

Individuals with diabetes face an elevated overall risk of infections that can be attributed to impaired phagocytosis by neutrophils, macrophages, and monocytes, impaired neutrophil chemotaxis, and bactericidal activity as well as impaired innate cell-mediated immunity [1,2]. Chronic hyperglycemia per se has been shown to promote immune dysfunction [1,2], micro- and macro-angiopathies [3], neuropathic disorders [4], inhibits antibacterial activity [5], and impairs gastrointestinal and urinary motility [6]. It increases the risk for diabetes related hospitalizations [7] and the necessity for medical interventions, which altogether make them more susceptible to nosocomial and communityacquired infections [8]. Older age (!65 years), as well as geographical and socioeconomic diversity, have been announced as the most prominent predictors of influenzarelated mortality [12]

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