Seasonal influenza is a cause of hospitalization, especially in people with underlying disease or extreme age, and its severity may differ depending on the types and subtypes of circulating viruses. We investigated the factors associated with ICU admission or death in hospitalized patients with severe laboratory-confirmed influenza according to the viral type and subtype. An observational epidemiological study was carried out in patients aged ≥18 years from 12 Catalan hospitals between 2010 and 2016. For each reported case we collected demographic, virological and clinical characteristics. A mixed-effects logistic regression model was used to estimate crude and adjusted ORs. 1726 hospitalized patients were included: 595 (34.5%) were admitted to the ICU and 224 (13.0%) died. Lower ICU admission was associated with age ≥75 years in all influenza types and subtypes and with age 65–74 years for type A. In contrast, the 65–74 and ≥75 years age groups were associated with an increased risk of death in all types and subtypes, especially for type B (aOR 27.42, 95% CI: 4.95–151.93 and 15.96; 95% CI: 3.01–84.68). The comorbidity most closely associated with severe outcomes was immune deficiency, which was associated with death for type B (aOR 9.02, 95% CI: 3.05–26.69) and subtype A(H1N1)pdm09 (aOR 3.16, 95% CI: 1.77–5.66). Older age was a differential factor for ICU admission and death: it was associated with lower ICU admission but a risk factor for death. The comorbidity with the closest association with death was immune deficiency, mainly in influenza type B patients.

Background. In most seasons, the influenza vaccine is effective in preventing influenza, but it is not clear whether it is equally effective in preventing mild and severe cases. We designed a case-control study to compare the effectiveness of the influenza vaccine in preventing outpatient, inpatient, and severe or fatal cases of laboratory-confirmed influenza. Methods. Hospitalized patients (n = 691) with laboratory-confirmed influenza in the 2010–2011 season recruited in 29 Spanish hospitals were individually matched by age, admission/visit date, and province with an outpatient with laboratory-confirmed influenza and an outpatient control. Severe cases were considered those patients admitted to intensive care units or who died in the hospital (n = 177). We compared the influenza vaccine status of controls and outpatient cases, inpatient cases, and severe cases using conditional logistic regression adjusted for potential confounding factors. Severe and nonsevere inpatient influenza cases were compared using unconditional logistic regression. Vaccine effectiveness was (1 – odds ratio) × 100. Results. Vaccine effectiveness was 75% (adjusted odds ratio [AOR], 0.25; 95% confidence interval [CI], .16–.39) in preventing influenza outpatient cases, 60% (AOR, 0.40; 95% CI, .25–.63) in preventing influenza-associated hospitalizations, and 89% (AOR, 0.11; 95% CI, .04–.37) in preventing severe cases. In inpatients, influenza vaccination was associated with a lower risk of severe influenza (AOR, 0.42; 95% CI, .22–.80). Conclusions. Influenza vaccination prevented influenza cases and hospitalizations and was associated with a better prognosis in inpatients with influenza. The combined effect of these 2 mechanisms would explain the high effectiveness of the vaccine in preventing severe cases due to influenza.

Volume 2, Number 2—April 1996 - Emerging Infectious Disease journal - CDC

Through its effects on the immune system, smoking may facilitate influenza virus infection, its severity and its most frequent complications. The objective was to investigate the smoking history as a risk factor for influenza hospitalization and influenza vaccine effectiveness in elderly smokers/ex-smokers and non-smokers. We carried out a multicenter case–control study in the 2013–2014 and 2014–2015 influenza seasons. Cases aged ≥65 years and age-, sex-matched controls were selected from 20 Spanish hospitals. We collected epidemiological variables, comorbidities, vaccination history and the smoking history. The risk of hospitalization due to smoking (current smokers and ex-smokers) was determined using the adjusted odds ratio (aOR) with conditional logistic regression models. Vaccine effectiveness (VE) was calculated using the formula: VE = (1 – aOR) × 100. We studied 728 cases and 1826 controls. Cases had a higher frequency of smoking (47.4% vs 42.1%). Smoking was associated with an increased risk of influenza hospitalization (aOR = 1.32, 95% CI: 1.04–1.68). Influenza vaccine effectiveness in preventing hospitalization was 21% (95% CI: -2 to 39) in current/ex-smokers and 39% in non-smokers (95% CI: 22–52). A history of smoking may increase the risk of hospitalization in smokers and ex-smokers. Preventing smoking could reduce hospitalizations due to influenza. Smokers and ex-smokers should be informed of the risk of hospitalization due to influenza infection, and encouraged to stop smoking. Smokers should be considered an at-risk group to be aggressively targeted for routine influenza vaccination.

Background: Type 2 diabetes comorbidity is common in patients with COPD. One of the most frequent causes of hospital admission in patients with COPD are exacerbations. Methods: Prospective cohort study, which included 512 patients with COPD recruited in a primary care centre in Mollerussa (Lleida, Spain). Inclusion criteria were: patients >40 years of age with COPD according to the Global Initiative for Chronic Obstructive Lung Disease. Variables collected were as follows: age, gender, civil status, education level, smoking habit, severity (Global Initiative for Chronic Obstructive Lung Disease), comorbidities (Charlson), history of severe exacerbations, dyspnoea (mMRC), BODEx, EuroQol 5 D and depression (HAD). Logistic regression was used to determine the association of diabetes with risk of hospital admission and death. Results: Prevalence of diabetes was 25.8%. During the second year of follow up, 18.2% of patients with COPD and diabetes were admitted for exacerbation, in comparison with 8.9% non-diabetic COPD patients. The variables associated with hospital admission were diabetes (ORa=1.54); gender (men, ORa=1.93); age (ORa=1.02); number of hospital admissions during the previous year: 1 (ORa=2.83) or more than one admission (ORa=4.08); EuroQol 5 D (ORa=0.76) and BODEx (ORa=1.24). With the exclusion of BODEx, all these variables were associated with a higher risk of death. Conclusion: Prevalence of diabetes is high in patients suffering from COPD. COPD patients with diabetes are at higher risk of severe exacerbation and death. The suggested predictive model could identify patients at higher risk so that adequate preventive and therapeutic measures can be implemented.