Higher frequency of hospitalization but lower relative mortality for pandemic influenza in people with type 2 diabetes

P L D Ruiz; I J Bakken; S E Håberg; G Tapia; S H Hauge; K I Birkeland; H L Gulseth; L C Stene

doi:10.1111/joim.12984

Higher frequency of hospitalization but lower relative mortality for pandemic influenza in people with type 2 diabetes

J Intern Med. 2020 Jan;287(1):78-86. doi: 10.1111/joim.12984. Epub 2019 Oct 28.

Authors

P L D Ruiz^{1

2

3}, I J Bakken⁴, S E Håberg⁴, G Tapia¹, S H Hauge⁵, K I Birkeland^{3

6}, H L Gulseth^{1

2}, L C Stene¹

Affiliations

¹ From the, Department of Chronic Diseases and Ageing, Norwegian Institute of Public Health, Oslo, Norway.
² Department of Endocrinology, Morbid Obesity and Preventive Medicine, Oslo University Hospital, Oslo, Norway.
³ Institute of Clinical Medicine, University of Oslo, Oslo, Norway.
⁴ Centre for Fertility and Health, Norwegian Institute of Public Health, Oslo, Norway.
⁵ Department of Influenza, Norwegian Institute of Public Health, Oslo, Norway.
⁶ Department of Transplantation Medicine, Oslo University Hospital, Oslo, Norway.

PMID: 31587396
DOI: 10.1111/joim.12984

Abstract

Background: There is limited evidence linking type 2 diabetes (T2D) to influenza-related complications.

Objectives: To test a set of research questions relating to pandemic influenza vaccination, hospitalization and mortality in people with and without T2D.

Methods: In this population-based cohort study, we linked individual-level data from several national registers for all Norwegian residents aged 30 years or more as of January 2009. People with or without T2D at baseline (n = 2 992 228) were followed until December 2013. We used Cox regression to estimate adjusted hazard ratios (aHRs).

Results: Pandemic influenza hospitalization was more common in individuals with T2D (aHR = 2.46, 95% CI 2.04-2.98). The mortality hazard ratio associated with hospitalization for pandemic influenza was lower in people with T2D (aHR = 1.82, 95% CI 1.21-2.74) than in those without T2D (aHR = 3.89, 95% CI 3.27-4.62). The same pattern was observed when restricting to 90-day mortality (aHR = 3.89, 95% CI 1.25-12.06 amongst those with T2D and aHR = 10.79, 95% CI 7.23-16.10 amongst those without T2D). The rate of hospitalization for pandemic influenza was 78% lower in those vaccinated compared to nonvaccinated amongst people with T2D (aHR = 0.22, 95% CI 0.11-0.39), whilst the corresponding estimate for those without T2D was 59% lower (aHR = 0.41, 95% CI 0.33-0.52). Mortality was 25% lower in those vaccinated compared to nonvaccinated amongst people with T2D (aHR = 0.75, 95% CI 0.73-0.77), whilst the corresponding estimate for those without T2D was 9% (aHR = 0.91, 95% CI 0.90-0.92).

Conclusions: There may have been a lower threshold for pandemic influenza hospitalization for people with T2D, rather than more severe influenza infection. Our combined results support the importance of influenza vaccination amongst people with T2D, especially during pandemics.

Keywords: diabetes mellitus, type 2; human; influenza; mortality; vaccination.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Adult
Age Distribution
Aged
Aged, 80 and over
Cohort Studies
Diabetes Mellitus, Type 2 / epidemiology*
Female
Hospitalization / statistics & numerical data*
Humans
Influenza A Virus, H1N1 Subtype*
Influenza Vaccines
Influenza, Human / mortality*
Male
Middle Aged
Norway / epidemiology
Pandemics
Registries
Sex Distribution
Vaccination / statistics & numerical data

Substances

Influenza Vaccines