Development of influenza-associated disease burden pyramid in Shanghai, China, 2010–2017: a Bayesian modelling study

Abstract

ObjectivesNegative estimates can be produced when statistical modelling techniques are applied to estimate morbidity and mortality attributable to influenza. Based on the prior knowledge that influenza viruses are hazardous pathogens and have adverse health outcomes of respiratory and circulatory disease (R&C), we developed an improved model incorporating Bayes’ theorem to estimate the disease burden of influenza in Shanghai, China, from 2010 to 2017.DesignA modelling study using aggregated data from administrative systems on weekly R&C mortality and hospitalisation, influenza surveillance and meteorological data. We constrained the regression coefficients for influenza activity to be positive by truncating the prior distributions at zero.SettingShanghai, China.ParticipantsPeople registered with R&C deaths (450 298) and hospitalisations (2621 787, from 1 July 2013), and with influenza-like illness (ILI) outpatient visits (342 149) between 4 January 2010 and 31 December 2017.Primary outcome measuresInfluenza-associated disease burden (mortality, hospitalisation and outpatient visit rates) and clinical severity (outpatient–mortality, outpatient–hospitalisation and hospitalisation–mortality risks).ResultsInfluenza was associated with an annual average of 15.49 (95% credibility interval (CrI) 9.06–22.06) excess R&C deaths, 100.65 (95% CrI 48.79–156.78) excess R&C hospitalisations and 914.95 (95% CrI 798.51–1023.66) excess ILI outpatient visits per 100 000 population in Shanghai. 97.23% and 80.24% excess R&C deaths and hospitalisations occurred in people aged ≥65 years. More than half of excess morbidity and mortality were associated with influenza A(H3N2) virus, and its severities were 1.65-fold to 3.54-fold and 1.47-fold to 2.16-fold higher than that for influenza A(H1N1) and B viruses, respectively.ConclusionsThe proposed Bayesian approach with reasonable prior information improved estimates of influenza-associated disease burden. Influenza A(H3N2) virus was generally associated with higher morbidity and mortality, and was relatively more severe compared with influenza A(H1N1) and B viruses. Targeted influenza prevention and control strategies for the elderly in Shanghai may substantially reduce the disease burden.

Age-dependent and sex-dependent differences in mortality from influenza-associated cardiovascular diseases among older adults in Shanghai, China: a population-based study

“… 5 The ageing population in Shanghai is on the rise, which is an important factor contributing to the persistently high influenza-associated mortality. 24 In 2019, about 4.7 million adults>60 years were registered in Shanghai, an increase of 48.51% compared with 2010, accounting for 32.05% of the total population. CVD had been the leading COD in older adults during this period.…”

“…A study from Singapore found that the burden of influenza on CVD increased with age and was significantly associated with excess hospitalisations for CVD, mainly in people≥80 years old 5. The ageing population in Shanghai is on the rise, which is an important factor contributing to the persistently high influenza-associated mortality 24. In 2019, about 4.7 million adults>60 years were registered in Shanghai, an increase of 48.51% compared with 2010, accounting for 32.05% of the total population.…”

Recent Increases in Influenza-Related Hospitalizations, Critical Care Resource Use, and In-Hospital Mortality: A 10-Year Population-Based Study in South Korea

“…Therefore, some cases of hospitalization or mortality from the 2009/2010 season may have been missed in our study. However, studies from U.S., the United Kingdom, and China (Shanghai) indicate that since the decline of the 2009 H1N1 pandemic outbreak, the rates of hospitalization have increased again, with a peak during the 2017/2018 season [ 7 , 8 , 9 , 26 ]. These data are consistent with our results.…”

Estimating mortality associated with seasonal influenza among adults aged 65 years and above in China from 2011 to 2016: A systematic review and model analysis

“…The comparison was aimed to evaluate the accuracy of our estimates of influenza‐associated mortality. Furthermore, to externally validate our estimates, we compared the annual average influenza‐associated excess mortality among older adults aged 65 years and above after 2010 in two municipalities (Chongqing and Shanghai) 16,17,36 with that of corresponding cities from 2011 to 2016 in the main analysis and sensitivity analyses. Finally, we compared the provincial‐level variation trend of our estimated influenza‐associated excess R&C and AC mortality with that of influenza‐associated excess respiratory mortality published previously 3 .…”

“…To our knowledge, Li et al estimated the national and provincial influenza‐associated excess respiratory mortality in older adults after the 2009 influenza pandemic in mainland China. 3 For influenza‐associated excess R&C or AC mortality, a few studies estimated mortality at the national or regional level before the 2009 influenza pandemic 4 , 10 or at the city level, such as Beijing, 15 Shanghai, 16 , 17 and Shenzhen. 18 To better understand the post‐pandemic influenza‐associated mortality burden among elderly individuals aged 65 years and above in mainland China, we used a systematic review and model method to estimate influenza‐associated excess R&C and AC mortality by province and nationwide from 2011 to 2016.…”