Influenza-associated cardiovascular mortality in older adults in Beijing, China: a population-based time-series study

Abstract

ObjectiveThis study comprehensively estimated the excess cardiovascular disease (CVD) mortality attributable to influenza in an older (age ≥65 years) population.DesignEcological study.SettingAggregated data from administrative systems on CVD mortality, influenza surveillance and meteorological data in Beijing, China.Main outcome measureExcess overall CVD, and separately for ischaemic heart disease (IHD), ischaemic stroke, haemorrhagic stroke mortality attributable to influenza, adjusting for influenza activity, time trend, seasonality and ambient temperature.ResultsCVD (risk ratio (RR) 1.02, 95% CI 1.01, 1.02), IHD (RR 1.01, 95% CI 1.01, 1.02), ischaemic stroke (RR=1.03, 95% CI 1.02, 1.04), but not haemorrhagic stroke (RR=1.00, 95% CI 0.99, 1.01) mortality, were significantly associated with every 10% increase in influenza activity. An increase in circulating A(H1N1)09pdm, A(H3N2) and B type virus were all significantly associated with CVD and ischaemic stroke mortality, but only A(H3N2) and B type virus with IHD mortality. The strongest increase in disease mortality was in the same week as the increase in influenza activity. Annual excess CVD mortality rate attributable to influenza ranged from 54 to 96 per 100 000 population. The 3%–6% CVD mortality attributable to influenza activity was related to an annual excess of 916–1640 CVD deaths in Beijing, China.ConclusionsInfluenza activity has moderate to strong associations with CVD, IHD and ischaemic stroke mortality in older adults in China. Promoting influenza vaccination could have major health benefit in this population.BackgroundInfluenza may trigger serious CVD events. An estimation of excess CVD mortality attributable to influenza has particular relevance in China where vaccination is low and CVD burden is high.MethodsThis study analysed data at the population level (age ≥65 years) using linked aggregated data from administrative systems on CVD mortality, influenza surveillance and meteorological data during 2011 to 2018. Quasi-Poisson regression models were used to estimate the excess overall CVD, and separately for IHD, ischaemic stroke, haemorrhagic stroke mortality attributable to influenza, adjusting for influenza activity, time trend, seasonality and ambient temperature. Analyses were also undertaken for influenza subtypes (A(H1N1)09pdm, A(H3N2) and B viruses), and mortality risk with time lags of 1–5 weeks following influenza activity in the current week.

Trends and Inequalities in the Incidence of Acute Myocardial Infarction among Beijing Townships, 2007–2018

“…First, data analysis in most previous geographic studies has focused either on AMI hospital admissions or mortality, which may lead to underestimation of the total AMI burden [ 37 , 38 , 39 ]. We obtained data on AMI incidence that covered both hospitalized AMI cases and out-of-hospital deaths from the BCDSS [ 12 , 14 ], thus providing more accurate depictions of spatiotemporal patterns for the AMI burden. In addition, by borrowing statistical strength across space (neighboring townships), our Bayesian model produced more robust estimates of AMI incidence at the small area level [ 40 ].…”

“…AMI admissions were identified from the Beijing HDIS based on principal discharge diagnoses with codes I21–I22 of the International Classification of Diseases, Tenth Revision (ICD-10) [ 13 ]. The VRMS of the Beijing Center for Disease Control and Prevention covers all deaths in Beijing [ 14 ]. Deaths from AMI, which included those that occurred both in and out of hospital, were identified from the Beijing VRMS according to the underlying causes of death using the ICD-10 codes (I21–I22) [ 13 ].…”

Association between influenza vaccination, all-cause mortality and cardiovascular mortality: a protocol for a living systematic review and prospective meta-analysis

“…In China, the estimated influenza VCR for the entire population is 2% and is even lower (<1%) among high-risk groups 14 15. In a limited number of Chinese cities with a policy for free influenza vaccination among seniors, VCR in those older than 65 years is reported to be around 20% 16…”

The association between influenza vaccination, all-cause mortality and cardiovascular mortality: a protocol for a living systematic review and prospective meta-analysis

“…16,17 In a limited number of Chinese cities with a policy for free influenza vaccination among seniors, VCR in those older than 65 years is reported to be around 20%. 18 As evidence from ongoing RCTs are still emerging, it is appropriate to conduct a living systematic review (LSR), which will continually incorporate the latest research findings and keep the synthesized information updated. 19 Along with the LSR design, a prospective meta-analysis (PMA) will better address this evolving evidence.…”

“…16,17 In a limited number of Chinese cities with a policy for free influenza vaccination among seniors, VCR in those older than 65 years is reported to be around 20%. 18…”