| [Background]The influenza A (H1N1) virus led to the first influenza pandemic of this century. Given the previous influenza pandemics brought heavy blows to the human health and social economy, countries around the world attached great importance to the unexpectedly2009influenza A(H1N1), and promptly took various interventions to respond at the beginning of this pandemic, and kept monitoring closely to observe its epidemic situation and features at all times. As influenza occurred in different regions often shows different epidemic features, it is very important to ascertain epidemiological features of influenza A(H1N1) for further influenza prevention and control work. At present, so many researches have been carried out in domestic and foreign regions, which mostly study on the etiology, epidemiology, clinical medicine, effectiveness evaluation of control measures about the influenza A (H1N1), but few study on economic burden. Therefore, we sought to investigate economic burden caused by influenza A(H1N1) in a certain point, with practical significance for the allocation of medical resources and emergency treatment in future pandemics or outbreaks.To determine the epidemiological characteristics and trend of influenza A(H1N1) in Shandong Province, descriptive epidemiological method was used to analyze the influenza A(H1N1) epidemic situation systematically. Through investigating cases hospitalized in Jinan, Linyi and Zibo retrospectively, we estimated their economic burden quantitatively by the economic burden evaluation method, and explored possible influencing factors of the influenza A (H1N1) hospitalization costs.[Objectives]1. To analyze the epidemiological characteristics and trend of influenza A(H1N1) in Shandong Province, in order to provide a scientific basis for the future influenza surveillance and prevention and control strategies.2. To evaluate the direct economic burden and indirect economic burden of influenza A(H1N1) hospitalized cases quantitatively, and explore possible influencing factors of the influenza A(H1N1) hospitalization costs.[Methods]The epidemic situation data of4382lab-confirmed influenza A(H1N1) patients reported in2009～2011were collected from the influenza A(H1N1) information system, and epidemiological characteristics of each epidemic stage was analyzed by descriptive epidemiological method. Through the hospital and interview investigation, we collected medical costs and working day lost data of lab-confirmed patients hospitalized in Jinan, Linyi and Zibo, then calculated direct economic burden with hospitalization costs and other related costs, and converted life lost and working time lost into the indirect economic burden. Possible influencing factors of the influenza A (H1N1) hospitalization costs were analyzed by generalized linear regression model for multivariate analysis. All above description and analysis were carried out by Excel2007and SPSS17.0software.[Results]1. Influenza A(H1N1) epidemic distribution characteristics in ShandongFrom May13,2009to December31,2011, a total of4382lab-confirmed influenza A(H1N1) cases were accumulatively reported in Shandong Province, including2416male and1966female. The reported cases are mainly concentrated in school-age children, adolescents, young adults under the age of35, accounted for80.90%of all cases. The number of student cases (2301) is reported the highest, accounting for57.7%of the total cases, followed by449farmer cases (10.25%) and324worker cases (7.39%). The reported incidence rate in2009,2010,2011were4.05/100,000,0.22/100,000,0.35/100,000respectively. Confirmed cases were reported in17cities; Qingdao, Jinan, Yantai, Taian and Linyi were the top five regions of the number of cases, accounting for57.7%of the total cases.397severe cases were reported, including61deaths. The severe ratio among all reported lab-confirmed cases was9.06%(397/4832), and the reported case fatality rate was1.39%(61/4832). Female cases with the reported severe ratio and case fatality rate were significantly higher than males (P<0.05). In elder age groups, especially in people over the age of55, rates of severe cases and dead cases were significantly increased. In farmer patients, rate of severe cases and fatality rate were36.53%and4.68%, while in student cases were the lowest, with1.91%and0.22%separately.78pregnant women were reported as severe cases, accounting for19.6%of all severe cases (78/397), of which20cases were dead, accounted for32.8%of all deaths reported (20/61).The influenza A(H1N1) epidemic distribution showed four phases obviously. In the initial phase of this pandemic during May-August2009, most cases in Shandong were imported ones from other countries, which mainly occurred in Qingdao and Jinan. The epidemic is maintained at a lower level. In the second phase during September-November2009, the outbreaks began to occur in schools with rapid increase of the cases. The epidemic spread rapidly to all cities, occurred more in urban areas. Severe cases and deaths occurred and gradually increased. In the third period, the epidemic spread from urban area to surrounding rural area, resulting in the shift of mostly affected population from students to farmers, which came down quickly in early December, and gradually subsided since February2010. The number of severe cases and deaths was the highest in this period. During the fourth phase from August2010to December2011, influenza A(H1N1) was a province-wide seasonal epidemics. The severe ratios and case fatality rates reported in different epidemic phase had significant difference (P=0.030), with the highest in early fall period.2. Economic burden evaluation of the hospitalized casesThere were reported422hospitalized cases in Jinan, Linyi and Zibo, including243mild cases,157severe but cured cases and22deaths. We collected the hospitalized cost data of299patients from hospital, including136mild cases,144severe survival cases and19dead. Other medical costs and work day lost information of74mild cases and89severe survival cases were collected in the interview survey.Per capita direct costs of mild cases, severe survival cases and deaths were4,281.68,19,738.95,50,954.7respectively. Their total direct economic burden were estimated1.0404million RMB,3.099million RMB,1.121million RMB respectively. Hospital costs held the highest proportion in the total direct burden, followed by nutrition fees and accommodation fees. The indirect losses caused by work day lost of mild cases and severe cases were440.3thousand RMB,878.6thousand RMB respectively. Dead cases were mainly concentrated on young people (median age25years), and the total years of potential life lost was1091.18years, accordingly estimated the total indirect losses amounted to23.7872RMB. Cases in the15-44age group had the largest number and heaviest indirect losses due to working day lost and death.The total economic burden of422cases was30.3665million RMB, with direct burden and indirect burden5.2604million RMB and25.1061million RMB respectively.The total economic burden of1147cases in Shandong was roughly estimated to be78.08～88.12million RMB, with direct burden and indirect burden9.92～17.3million RMB and68.16～70.82million RMB respectively.3. The influencing factors of hospitalized costs in generalized linear regression analysisMultiple factors analysis showed that the factors that hospitalized days, age, illness severity, complications, hospital level, admitted to ICU, pregnancy, death and regions, had a significant influence on hospitalization costs. Both per capita costs and average daily costs increased significantly with prolonged days of hospitalization, older, severe symptoms and signs, more complications, lower hospital level, admitted to ICU, pregnant and dead. The average hospitalization costs in Ji’nan and Zibo were significantly higher than those in Linyi, but no significant differences in average daily expenses.[Conclusions]1. School-age children, adolescents, and young adults under the age of35were high-risk population of influenza A (H1N1). People aged55years old and above, female (especially pregnant women), and farmers had a higher ratio of severe cases and death. Students played an important role in the spread process of Influenza A and were the key to control the epidemic.2. Influenza A(H1N1) pandemic showed an obvious staged characteristics. Each stage had different affected area and population, severe cases and death rate was also different. So, we need to take different prevention and control measures in different popular stage.3. The direct economic burden was higher than the indirect burden for survival cases, but far lower than the indirect burden for the deaths. The working-age population suffered the heaviest indirect economic burden due to working day lost and death, and the loss caused by premature death is much higher than the working day lost of survival cases. For Influenza A(H1N1), reducing case fatality rate, especially the deaths of young cases, is the key to reducing the indirect economic burden of hospitalized patients.4. The main factors that influenced the hospitalized costs of influenza A(H1N1) cases are length of hospital stay, age, in pregnancy, illness severity, prognosis, complications, admitted to ICU and hospital level. |
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