Diabetes and the Severity of Pandemic Influenza A (H1N1) Infection

OBJECTIVE To confirm the existence of an increased risk of complications from influenza A (H1N1)p among patients with diabetes. RESEARCH DESIGN AND METHODS Using data from an enhanced influenza surveillance project in Montreal, Canada, and age/sex-specific population estimates of diabetes prevalence, we estimated the risk of hospitalization among persons with diabetes. Comparing hospitalized patients admitted or not to an intensive care unit (ICU), we estimated the risk of ICU admission associated with diabetes, controlling for other patient characteristics. RESULTS Among 239 hospitalized patients with PCR-confirmed influenza A (H1N1)p, 162 (68%) were interviewed, of whom 22 had diabetes, when 7.1 were expected (prevalence ratio 3.10 [95% CI 2.04-4.71]). The odds ratio for ICU admission was 4.29 (95% CI 1.29-14.3) among hospitalized patients with diabetes compared to those without. CONCLUSIONS Diabetes triples the risk of hospitalization after influenza A (H1N1)p and quadruples the risk of ICU admission once hospitalized.