Epidemiologic and Economic Burden of Influenza in the Outpatient Setting: A Prospective Study in a Subtropical Area of China

Abstract

ObjectivesTo understand the incidence of outpatient influenza cases in a subtropical area of China and the associated economic burden on patients' families.MethodsA hospital-based prospective study was conducted in Zhuhai City during 2008–2009. All outpatient influenza-like illness (ILI) cases were identified in 28 sentinel hospitals. A representative sample of throat swabs from ILI cases were collected for virus isolation using Madin-Darby canine kidney cells. The incidence of outpatient influenza cases in Zhuhai was estimated on the basis of the number of influenza patients detected by the sentinel sites. A telephone survey on the direct costs associated with illness was conducted as a follow-up.ResultsThe incidence of influenza was estimated to be 4.1 per 1,000 population in 2008 and 19.2 per 1,000 population in 2009. Children aged <5 years were the most-affected population, suffering from influenza at the highest rates (34.3 per 1,000 population in 2008 and 95.3 per 1,000 population in 2009). A high incidence of 29.2–40.9 per 1000 population was also seen in young people aged 5–24 years in 2009. ILI activity and influenza virus isolations adopted a consistent seasonal pattern, with a summer peak in July 2008 and the longest epidemic period lasting from July–December 2009. The medical costs per episode of influenza among urban patients were higher than those for rural patients. A total of $1.1 million in direct economic losses were estimated to be associated with outpatient influenza during 2008–2009 in Zhuhai community.ConclusionsInfluenza attacks children aged <5 years in greater proportions than children in other age groups. Seasonal influenza 2008 and Pandemic influenza A (H1N1) 2009 had different epidemiological and etiological characteristics. Direct costs (mostly medical costs) impose an enormous burden on the patient family. Vaccination strategies for high-risk groups need to be further strengthened.

Socio-Economic Burden of Influenza among Children Younger than 5 Years in the Outpatient Setting in Suzhou, China

“…It was found in our study that the average direct medical cost per episode of influenza was $63.1, which was much higher than Guo [27] reported ($22.8) in a study of all age groups in Zhuhai City in South China. However, our results from two medical settings were much lower than those from the US, $167 per influenza-associated outpatient visit in 2003 [13] and $512 per influenza-associated ED visit in 2003–2006 [28].…”

Impact of Influenza on Outpatient Visits, Hospitalizations, and Deaths by Using a Time Series Poisson Generalized Additive Model

“…Our study group helped evaluate the large influence of influenza and influenza-like illness (ILI) on outpatient visits in view of morbidity and direct economic burden [18,19]; however, the impact of influenza on hospitalizations and deaths has never been examined in southern China, an area once considered by experts as the "epicenter of influenza pandemic" [20] and the origin or high-risk location of multiple emerging infectious diseases such as severe acute respiratory syndrome [21] and human infection with avian influenza H7N9 [22].…”

Technical guidelines for the application of seasonal influenza vaccine in China (2014–2015)

“…It is estimated that about 10-15% of children who need to see a doctor is due to influenza infection each year. 62,63 The risk of serious complications after influenza infection in children < 5 y old is higher, with hospitalization rate of influenza-related diseases up to 921/100,000 person-year. In general, the admission rate is highest in infants <2 y old.…”

“…Studies on the economic burden by influenza in China are mostly conducted in the economically developed areas, and only one unpublished study covered 29 provinces across mainland China (except provinces of Tibet and Liaoning). 63,69,70,[110][111][112] Studies suggested that the direct medical cost of influenza outpatients was 156-398 RMB/person, and indirect cost was 198-244 RMB/person. 63,69,70,110 The economic burden of hospitalized influenza cases was obviously higher than that of outpatient cases.…”

“…63,69,70,[110][111][112] Studies suggested that the direct medical cost of influenza outpatients was 156-398 RMB/person, and indirect cost was 198-244 RMB/person. 63,69,70,110 The economic burden of hospitalized influenza cases was obviously higher than that of outpatient cases. The survey in 29 provinces showed that the direct medical cost was 4783 RMB/person (IQR: 2949-7286), direct non-medical cost was 1307 RMB/person (IQR: 706-2193), and indirect cost was 626 RMB/person (IQR: 322-1053).…”