| ObjectiveThis paper calculated acute myocardial infarction(AMI)mortality/incidence(M/I)ratio in Tianjin from 2007-2015 by using Disease Surveillance Point System(DSP)and incidence surveillance system(ISS)data(called Direct method),in addition,we calculated the adjusted M/I ratio by using mortality rate,incidence rate and remission rate of AMI through DisMod II software(called DisMod Method).Then,the AMI underreporting rate of incidence rate from ISS in Tianjin was assessed.Finally,AMI incidence trend of Tianjin was described after adjustment,which will provide basis for Tianjin ISS improvement,as well as a reference for AMI incidence rate estimation through AMI mortality rate in other cities.Materials and Methods1.Completeness Evaluation for Data from DSP and Adjustment:Death data from DSP and population data in Tianjin from 2007 to 2015 were collected.First,the completeness of population data was evaluated and adjusted by using the Generalized Growth Balance(GGB)method.Second,the Synthetic Extinct Generation(SEG)method was adopted to evaluate the completeness of death data,and to adjust it accordingly.2.Direct Calculation of Incidence Rate for People Aged above 35 from 2007 to 2015:Incidence data for AMI in Tianjin from 2007 to 2015 was collected from ISS.Incidence rate by gender,different age groups in each year was directly calculated.Age-standard incidence rate(ASIR)was computed using Tianjin’s 2010 censuse population structure to describe its trend.3.Estimation of Mortality/incidence Ratio of AMI:First,AMI M/I ratio in Tianjin from 2007 to 2015 by gender,different age groups in each year and each month was directly calculatd by using DSP and ISS data(called Direct method).Then,the above death rate and incidence rate,accompanyed with AMI remission data released by the Institute for Health Metrics and Evaluation(IHME)at the University of Washington were put into DisMod Ⅱ tool to caluculate adjusted M/I ratio(called DisMod Method).The two M/I raios were compared by t-test of paired design or Wilcoxon matched-pair sign-rank test.4.AMI Incidence Rate among People Aged above 35 from 2007 to 2015 in Tianjin adjusted by DisMod method:The incidence was reestimated by the death rate and adjusted M/I ratio from DisMod Ⅱ tool,then we can assess the underreporting rate of incidence from ISS,as well as desribed the incidence trend for Tianjin from 2007 to 2015.Results1.Completeness of DSP and AMI Mortality Trend in Tianjin from 2007 to 2015:The completeness of population and death data was 92.05%and 1.173,repectively.Among people aged above 35,in total,the mortality rate was between 130 per 100,000 populations and 180 per 100,000 populations,and for male in 150 per 100,000 populations to 200 per 100,000 populations,for female in 110 per 100,000 populations to 160 per 100,000 populations.Both male and female age-standard mortality rates(ASMRs)kept stable from 2007 to 2015.2.Incidence Rate of AMI for People aged above 35 Years Old in Tianjin from 2007 to 2015 by Using Direct Mothod:Among people aged above 35,the male and female incidence rates were between 140-220 per 100,000 populations and 80-160 per 100,000 populations,repectively.And for the total population,the inicidence rate was between 140 per 100,000 populations and 220 per 100,000 populations.The ASIRs from 2007 to 2015 showed decreased for male and female.3.The comparison of M/I ratios calculated in the two methods:The M/I ratio of AMI in Tianjin from 2007 to 2015 was directly calculated.The average yearly value of the ratio for males was 1.04(95%confidence interval:0.90,1.19),and that for females was 1.34(95%CI:1.11,1.56),totaling 1.16(95%CI:0.98,1.33);the average monthly value of the ratio of males was 1.10(95%CI:1.03,1.18),and that of females was 1.48(95%CI:1.39,1.56),totaling 1.24(95%CI:1.16,1.32).In view of the 95%confidence interval of monthly M/I ratio,there was no significant difference among monthly ratios.Upon the calibration of the DisMod II software,the average value of AMI M/I ratio of males in Tianjin from 2007 to 2015 was 0.79(95%CI:0.74,0.85)and that of females was 0.85(95%CI:0.77,0.92),and the total was 0.81(95%CI:0.76,0.87).The average monthly AMI ratio of males calculated by DisMod II was 0.84(95%CI:0.83,0.86),and that of females was 0.87(95%CI:0.85,0.89),totaling 0.85(95%CI:0.84,0.87).There was no significant difference among monthly AMI M/I ratios.The M/I ratio increased with the increase of age,and the AMI M/I of females was higher than that of males.There was no statistical difference in the ratios of people below 70 calculated by the DisMod Ⅱ software and calculated directly,and there was a statistical difference between the M/Ⅰ ratio of people above 70 calculated by using two different methods,in that the ratio calculated by the DisMod Ⅱ software was generally less than 1 in the old age group,while that calculated by the direct method was generally above 1.4.Estimation of AMI incidence rate in Tianjin through DisMoD:The missing report rate of incidence was between 2%and 44%.After correction,among people aged above 35,the crude incidence rate of AMI among men from 2007 to 2015 was between 181 per 100,000 populations and 255 per 100,000 populations,and the crude incidence rate of AMI among women was between 118 per 100,000 populations and 177 per 100,000 populations.The overall crude incidence rate of AMI was between 155 per 100,000 populations and 215 per 100,000 populations.According to the standardized AMI incidence of Tianjin from 2007 to 2015,the incidence rate of males,females and the total was showing a stable trend.ConclusionsThe evaluation of the completeness of AMI death surveillance data in Tianjin by using the GGB-SEG method shows that there was almost no underreporting of DSP,and that the death data were complete,therefore it is reasonable to estimate AMI incidence rate by AMI death data.The M/I ratio calculated by DisMod Ⅱ software was smaller and close to 1 in the old age group,which shows that though the case fatality rate of AMI patients in the old age group was high,their AMI mortality rate was still less than the incidence rate,meeting the morbidity and death law of chronic diseases;while the M/I ratio directly calculated was generally more than 1 in the old age group,which shows that mortality was more than incidence,inconsistent with the law of chronic diseases,showing that underreporting may exist in AMI incidence surveillance data.Therefore,it is more reasonable to estimate the AMI mortality incidence ratio by adopting the DisMod software.After correction,AMI incidence of people over 35 years old in Tianjin from 2007 to 2015 was between 155 per 100000 populations and 215 per 100000 populations,showing a stable trend.This article used the DisMod Ⅱ software to estimate the AMI incidence rate in Tianjin,which may be taken as a reference for the estimation of AMI incidence in other regions. |
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