Influenza-Associated Morbidity and Mortality in Young and Middle-Aged Women

Working-age adults with diabetes experience greater susceptibility to seasonal influenza: a population-based cohort study

“…Finally, Neuzil et al reported a fivefold (unadjusted) higher rate of influenza-attributable cardiopulmonary hospitalisations or deaths in working-age women with diabetes [12]. The limitations of these studies include potential bias from the use of hospital-based comparison groups [11], lack of adjustment for comorbidities and vaccination status [11][12][13] and inadequate adjustment for seasonality [12], as mentioned earlier. Additionally, several studies have examined the effects of diabetes on pH1N1 influenza.…”

“…Bouter et al found that diabetes increased the risk of both pneumonia hospitalisations and subsequent mortality to a greater extent during years with significant influenza activity Counts and rates for adults without diabetes were estimated for the matched comparison group of non-diabetic subjects, and therefore do not represent the actual numbers of influenza-attributable outcomes in adults in Manitoba without diabetes a 'Projected' minus 'counterfactual' [11]. Finally, Neuzil et al reported a fivefold (unadjusted) higher rate of influenza-attributable cardiopulmonary hospitalisations or deaths in working-age women with diabetes [12]. The limitations of these studies include potential bias from the use of hospital-based comparison groups [11], lack of adjustment for comorbidities and vaccination status [11][12][13] and inadequate adjustment for seasonality [12], as mentioned earlier.…”

“…We divided calendar time into years from 1 July to 30 June [12]. Influenza season was defined as a continuous period between the first and last occurrences of at least two consecutive weeks with two or more isolates positive for influenza, according to provincial surveillance data [17][18][19].…”

“…Consequently, influenza infections are rarely suspected or laboratory-confirmed, making direct measurement of infection difficult. As the circulation of influenza is minimal outside the influenza season, the burden of influenza can instead be estimated by comparing health outcomes during influenza season to those during the off-season [12]. However, this approach may be confounded by cyclic trends, since respiratory outcomes rise and fall each year even in the absence of significant influenza activity [27][28][29]).…”

“…To our knowledge, only three studies have compared the burden of seasonal influenza in adults with and without diabetes. These studies have several limitations, including potential bias from the use of hospital-based comparison groups [11], lack of adjustment for comorbidities and vaccination status [11][12][13] and inadequate adjustment for seasonality [12]. More recently, studies of pandemic H1N1 (pH1N1) influenza have drawn varying conclusions regarding the extent to which diabetes increases the risk of severe outcomes.…”