TY - JOUR AU - van Asten, Liselotte AU - van de Kassteele, Jan AU - van der Hoek, Wim PY - 2017/05/02 Y2 - 2024/03/28 TI - Respiratory and circulatory deaths attributable to influenza A & B JF - Online Journal of Public Health Informatics JA - OJPHI VL - 9 IS - 1 SE - Communicable Disease Surveillance Use Cases for Human, Animal, and Zoonotic Diseases DO - 10.5210/ojphi.v9i1.7704 UR - https://ojphi.org/ojs/index.php/ojphi/article/view/7704 SP - AB - <div style="left: 78.2727px; top: 278.962px; font-size: 12.3207px; font-family: sans-serif; transform: scaleX(1.0823);" data-canvas-width="55.467823232323234">Objective</div><div style="left: 91.3182px; top: 291.965px; font-size: 12.3207px; font-family: serif; transform: scaleX(1.03824);" data-canvas-width="330.1419704545454">To estimate mortality attributable to influenza adjusted for other</div><div style="left: 78.2727px; top: 306.46px; font-size: 12.3207px; font-family: serif; transform: scaleX(0.995983);" data-canvas-width="342.0536300505051">common respiratory pathogens, baseline seasonal trends and extreme</div><div style="left: 78.2727px; top: 320.955px; font-size: 12.3207px; font-family: serif; transform: scaleX(1.0015);" data-canvas-width="66.71662878787879">temperatures.</div><div style="left: 78.2727px; top: 348.538px; font-size: 12.3207px; font-family: sans-serif; transform: scaleX(1.11884);" data-canvas-width="71.86668434343434">Introduction</div><div style="left: 91.3182px; top: 361.541px; font-size: 12.3207px; font-family: serif; transform: scaleX(0.96112);" data-canvas-width="328.46265808080807">Assigning causes of deaths to seasonal infectious diseases is difficult</div><div style="left: 78.2727px; top: 376.036px; font-size: 12.3207px; font-family: serif; transform: scaleX(0.977853);" data-canvas-width="341.87374772727253">in part due to laboratory testing prior to death being uncommon. Since</div><div style="left: 78.2727px; top: 390.531px; font-size: 12.3207px; font-family: serif; transform: scaleX(0.978274);" data-canvas-width="343.73294242424254">influenza (and other common respiratory pathogens) are therefore</div><div style="left: 78.2727px; top: 405.026px; font-size: 12.3207px; font-family: serif; transform: scaleX(0.993517);" data-canvas-width="339.1866015151514">notoriously underreported as a (contributing) cause of death in death-</div><div style="left: 78.2727px; top: 419.521px; font-size: 12.3207px; font-family: serif; transform: scaleX(1.01736);" data-canvas-width="342.81504974747475">cause statistics modeling studies are commonly used to estimate the</div><div style="left: 78.2727px; top: 434.016px; font-size: 12.3207px; font-family: serif; transform: scaleX(1.01066);" data-canvas-width="162.54708838383843">impact of influenza on mortality.</div><div style="left: 78.2727px; top: 461.599px; font-size: 12.3207px; font-family: sans-serif; transform: scaleX(1.07424);" data-canvas-width="50.65042676767676">Methods</div><div style="left: 91.3182px; top: 474.602px; font-size: 12.3207px; font-family: serif; transform: scaleX(1.00026);" data-canvas-width="329.1846515151515">Using primary cause of death (Statistics Netherlands) we modeled</div><div style="left: 78.2727px; top: 489.097px; font-size: 12.3207px; font-family: serif; transform: scaleX(1.0013);" data-canvas-width="101.96617171717172">weekly timeseries of</div><div style="left: 91.3182px; top: 503.592px; font-size: 12.3207px; font-family: serif; transform: scaleX(1.00125);" data-canvas-width="239.51454545454536">1) respiratory deaths (ICD10 codes J00-J99) and</div><div style="left: 91.3182px; top: 518.086px; font-size: 12.3207px; font-family: serif; transform: scaleX(1.00126);" data-canvas-width="220.3435252525252">2) circulatory deaths (ICD10 codes I00-I99).</div><div style="left: 91.3182px; top: 532.581px; font-size: 12.3207px; font-family: serif; transform: scaleX(0.995205);" data-canvas-width="331.05493484848483">We used regression models with an identity link and Poisson</div><div style="left: 78.2727px; top: 547.076px; font-size: 12.3207px; font-family: serif; transform: scaleX(0.967457);" data-canvas-width="343.62452020202016">error to relate mortality to counts of influenza A &amp; B diagnoses.</div><div style="left: 78.2727px; top: 561.571px; font-size: 12.3207px; font-family: serif; transform: scaleX(1.03237);" data-canvas-width="342.97152272727254">We adjusted for other common respiratory pathogens (all pathogen</div><div style="left: 78.2727px; top: 576.066px; font-size: 12.3207px; font-family: serif; transform: scaleX(0.971081);" data-canvas-width="341.480717171717">data was at population level from the national laboratory surveillance),</div><div style="left: 78.2727px; top: 590.561px; font-size: 12.3207px; font-family: serif; transform: scaleX(0.978389);" data-canvas-width="343.4471020202019">temperature (from the Dutch Royal Meteorological Institute), and</div><div style="left: 78.2727px; top: 605.056px; font-size: 12.3207px; font-family: serif; transform: scaleX(0.984011);" data-canvas-width="343.89557575757567">baseline linear and cyclical (i.e. seasonal) trends. To account for</div><div style="left: 78.2727px; top: 619.551px; font-size: 12.3207px; font-family: serif; transform: scaleX(1.02503);" data-canvas-width="342.95673787878786">the yearly variation in the severity of the main circulating influenza</div><div style="left: 78.2727px; top: 634.046px; font-size: 12.3207px; font-family: serif; transform: scaleX(0.96863);" data-canvas-width="343.7021406565654">A strain we used time dependent variables for influenza A (fixed</div><div style="left: 78.2727px; top: 648.541px; font-size: 12.3207px; font-family: serif; transform: scaleX(0.974141);" data-canvas-width="343.8068666666666">at lag 0 – assuming a direct effect of influenza. For influenza B</div><div style="left: 78.2727px; top: 663.036px; font-size: 12.3207px; font-family: serif; transform: scaleX(0.977387);" data-canvas-width="344.1543106060605">and the confoundig pathogens we considered a 0 tot -4 time lag</div><div style="left: 78.2727px; top: 677.531px; font-size: 12.3207px; font-family: serif; transform: scaleX(1.03343);" data-canvas-width="345.1498237373738">(thus allowing infection to precede death for up to 4 weeks).</div><div style="left: 78.2727px; top: 692.026px; font-size: 12.3207px; font-family: serif; transform: scaleX(1.01902);" data-canvas-width="342.73126893939394">We performed the analyses separately per death cause group and by</div><div style="left: 78.2727px; top: 706.521px; font-size: 12.3207px; font-family: serif; transform: scaleX(1.02367);" data-canvas-width="339.2100108585858">3 different age groups (0-64, 65-74,75+ years) over a 14-year time-</div><div style="left: 78.2727px; top: 721.016px; font-size: 12.3207px; font-family: serif; transform: scaleX(1.00144);" data-canvas-width="309.36063383838365">period (mid 1999-mid 2013, thus 14 complete winter seasons).</div><div style="left: 78.2727px; top: 748.599px; font-size: 12.3207px; font-family: sans-serif; transform: scaleX(1.08542);" data-canvas-width="44.50239393939395">Results</div><div style="left: 91.3182px; top: 761.602px; font-size: 12.3207px; font-family: serif; transform: scaleX(1.02836);" data-canvas-width="332.1946002525252">In the Netherlands on average 2,636 all cause deaths occur</div><div style="left: 78.2727px; top: 776.097px; font-size: 12.3207px; font-family: serif; transform: scaleX(1.00039);" data-canvas-width="342.23228030303017">per week varying by season (lower in summer min: 2,219 and higher</div><div style="left: 78.2727px; top: 790.592px; font-size: 12.3207px; font-family: serif; transform: scaleX(1.01059);" data-canvas-width="342.58958080808077">in winter max: 3,564) with yearly incidence ranging from 20/10,000</div><div style="left: 78.2727px; top: 805.086px; font-size: 12.3207px; font-family: serif; transform: scaleX(1.0014);" data-canvas-width="258.3775479797979">in 0-64 year olds to 885/10,000 in 75-plus year olds.</div><div style="left: 91.3182px; top: 819.581px; font-size: 12.3207px; font-family: serif; transform: scaleX(1.02846);" data-canvas-width="331.8681015151514">Circulatory mortality (31% of total deaths) was higher than</div><div style="left: 78.2727px; top: 834.076px; font-size: 12.3207px; font-family: serif; transform: scaleX(0.966734);" data-canvas-width="343.67380303030296">respiratory mortality (10% of total deaths) and both showed clear</div><div style="left: 78.2727px; top: 848.571px; font-size: 12.3207px; font-family: serif; transform: scaleX(0.996858);" data-canvas-width="344.4808093434343">seasonality in all age-groups. Overall, 0.14% of all deaths were</div><div style="left: 78.2727px; top: 863.066px; font-size: 12.3207px; font-family: serif; transform: scaleX(1.00529);" data-canvas-width="171.41799747474752">actually coded as influenza deaths.</div><div style="left: 91.3182px; top: 877.561px; font-size: 12.3207px; font-family: serif; transform: scaleX(1.04876);" data-canvas-width="332.66771540404034">Preliminary model estimates showed that the proportion of</div><div style="left: 78.2727px; top: 892.056px; font-size: 12.3207px; font-family: serif; transform: scaleX(0.954273);" data-canvas-width="341.45484368686857">respiratory deaths attributable to influenza A were quite similar for 0-64</div><div style="left: 78.2727px; top: 906.551px; font-size: 12.3207px; font-family: serif; transform: scaleX(0.972042);" data-canvas-width="341.89962121212113">and 65-74 year olds but higher in 75+ (5.1%, 5.7%, 7.0% respectively)</div><div style="left: 78.2727px; top: 921.046px; font-size: 12.3207px; font-family: serif; transform: scaleX(0.972369);" data-canvas-width="343.6676426767677">while this proportion was stable across age-groups for circulatory</div><div style="left: 78.2727px; top: 935.541px; font-size: 12.3207px; font-family: serif; transform: scaleX(1.02831);" data-canvas-width="345.15228787878783">deaths (approximately 1.5% in all agegroups for influenza A).</div><div style="left: 78.2727px; top: 950.036px; font-size: 12.3207px; font-family: serif; transform: scaleX(1.01122);" data-canvas-width="344.25410833333353">Influenza B was significantly associated with respiratory deaths</div><div style="left: 78.2727px; top: 964.531px; font-size: 12.3207px; font-family: serif; transform: scaleX(1.06215);" data-canvas-width="345.78187601010086">and circulatory deaths in the oldest age group of 75+ years</div><div style="left: 78.2727px; top: 979.026px; font-size: 12.3207px; font-family: serif; transform: scaleX(1.01767);" data-canvas-width="345.0758994949497">(with proportions of 0.7% and 0.2% respectively) while in the</div><div style="left: 78.2727px; top: 993.521px; font-size: 12.3207px; font-family: serif; transform: scaleX(0.987466);" data-canvas-width="341.84417803030294">65-74 year olds it was associated only with circulatory deaths (0.2%).</div><div style="left: 78.2727px; top: 1008.02px; font-size: 12.3207px; font-family: serif; transform: scaleX(0.992264);" data-canvas-width="341.81830454545457">Influenza B was not significantly associated with either respiratory or</div><div style="left: 78.2727px; top: 1022.51px; font-size: 12.3207px; font-family: serif; transform: scaleX(1.00128);" data-canvas-width="237.4693080808081">circulatory mortality in the 0-64 year age group.</div><div style="left: 91.3182px; top: 1037.01px; font-size: 12.3207px; font-family: serif; transform: scaleX(0.969367);" data-canvas-width="330.78018308080794">On average, yearly in the 75+ age group 70/10,000 respiratory</div><div style="left: 78.2727px; top: 1051.5px; font-size: 12.3207px; font-family: serif; transform: scaleX(0.988586);" data-canvas-width="341.88606843434354">deaths and 39/10,000 circulatory deaths were attributable to influenza</div><div style="left: 443.545px; top: 277.47px; font-size: 12.3207px; font-family: serif; transform: scaleX(1.01794);" data-canvas-width="342.67089747474745">A. For influenza B the incidences were 7 to 10 fold lower (7/10,000</div><div style="left: 443.545px; top: 291.965px; font-size: 12.3207px; font-family: serif; transform: scaleX(1.00151);" data-canvas-width="134.1355378787879">and 6/10,000 respectively).</div><div style="left: 443.545px; top: 319.548px; font-size: 12.3207px; font-family: sans-serif; transform: scaleX(1.10408);" data-canvas-width="73.93656313131314">Conclusions</div><div style="left: 456.591px; top: 332.551px; font-size: 12.3207px; font-family: serif; transform: scaleX(1.01277);" data-canvas-width="331.63031186868676">Influenza A was significantly associated with respiratory and</div><div style="left: 443.545px; top: 347.046px; font-size: 12.3207px; font-family: serif; transform: scaleX(1.04005);" data-canvas-width="345.57242398989894">circulatory mortality in all age groups while influenza B was</div><div style="left: 443.545px; top: 361.541px; font-size: 12.3207px; font-family: serif; transform: scaleX(1.01758);" data-canvas-width="342.872957070707">significantly associated with respiratory and circulatory mortality in</div><div style="left: 443.545px; top: 376.036px; font-size: 12.3207px; font-family: serif; transform: scaleX(1.01154);" data-canvas-width="80.41725505050506">the elderly only.</div> ER -