Impact of influenza vaccination on mortality risk among the elderly
ABSTRACT Estimates of influenza vaccine effectiveness have mostly been derived from nonrandomised studies and therefore are potentially confounded. The aim of the current study was to estimate influenza vaccine effectiveness in preventing mortality among the elderly, taking both measured and unmeasured confounding into account. Information on patients aged o65 yrs from the computerised Utrecht General Practitioner database on eight influenza epidemic periods and summer periods was pooled to estimate influenza vaccine effectiveness in preventing mortality. Summer periods (during which no effect of vaccination was expected) were used as a reference to control for unmeasured confounding in epidemic periods. After adjustment for measured confounders using multivariable regression analysis, propensity score matching and propensity score regression analysis, influenza vaccination reduced mortality risk (odds ratios (ORs) 0.58 (95% confidence interval (CI) 0.46–0.72), 0.56 (95% CI 0.44–0.71) and 0.56 (95% CI 0.45–0.69), respectively). After additional adjustment for unmeasured confounding (as observed during summer periods), the association between influenza vaccination and mortality risk decreased (OR 0.69 (95% CI 0.52–0.92)). We conclude that after state-of-the-art adjustment for typical confounders such as age, sex and comorbidity status, unmeasured confounding still biased estimates of influenza vaccine effectiveness. After taking unmeasured confounding into account, influenza vaccination is still associated with substantial reduction in mortality risk.
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ABSTRACT: Pneumonia is a major cause of morbidity and mortality among nursing home residents. The approach to managing these patients has lacked uniformity because of the paucity of clinical trials, complexity of underlying comorbid diseases, and heterogeneity of administrative structures. The decision to hospitalize nursing home patients with pneumonia varies among institutions depending on staffing level, availability of diagnostic testing, and laboratory support. In the absence of comparative studies, choice of empirical antibiotic therapy continues to be based on expert opinion. Validated prognostic scoring models are needed for risk stratification. Pneumococcal and influenza vaccination are the primary prevention measures. As of January 2010, Medicare no longer pays for consultation codes; thus, practitioners must instead use existing evaluation and management service codes when providing these services.Chest 12/2010; 138(6):1480-5. DOI:10.1378/chest.10-1135 · 7.13 Impact Factor
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ABSTRACT: Pneumococcal, influenza and herpes zoster infections cause significant morbidity and mortality in the aging population. Effective vaccines are available in Canada to prevent and minimize illnesses caused by these infections. The purpose of this review is to provide an overview of the epidemiology of pneumococcal, influenza and herpes zoster infections in older adults, as well as available vaccines and recommended immunization schedules. In addition, the benefits of these vaccines on patient outcomes and the role of pharmacists in improving immunization rates are highlighted.Canadian Pharmacists Journal 05/2011; 144(3):132-141. DOI:10.3821/1913-701X-144.3.132
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ABSTRACT: Influenza is a common respiratory disease occurring in seasonal patterns, and may lead to severe complications in frail populations such as the elderly. In Poland, influenza vaccination is recommended for people aged ≥65 years; however the vaccine coverage rate in the elderly is very low. The fact that influenza vaccine is neither reimbursed by the National Health Insurance (Narodowy Fundusz Zdrowia [NFZ]) nor financed via a National Immunization Program (NIP) could be a reason for the low coverage rate. This study assessed the cost effectiveness of the full reimbursement of an influenza vaccination programme in Poland for people aged ≥65 years. A decision-analytic model was developed to compare costs and outcomes associated with the current situation in which influenza vaccination is not reimbursed and a new situation in which it would be fully covered by the NFZ. The model was parameterized to Poland using data from the literature and from the Central Statistic Office of Poland. Within the elderly population, 50% were considered to be at high risk of influenza complications. An influenza attack rate of 3.5% was used for calculation purposes. Influenza-associated hospitalizations and death rates were estimated at 439.9 per 100 000 person-years and 79.1 per 100 000 person-years, respectively. Cost estimates were derived from a cost study conducted in Poland. Costs are presented in Polish Zloty (PLN) [2009 mean exchange rate: 1 PLN = €0.232]. Only direct medical costs were included to fit to the NFZ perspective. To reflect the seasonality of influenza, a time horizon of 1 year was chosen. Life-years and quality-adjusted life-years (QALYs) accumulated over future years were discounted at a rate of 5% as recommended by Polish guidelines. Deterministic and probabilistic sensitivity analyses were conducted. In Poland, the introduction of the public funding of influenza vaccination for people aged ≥65 years would cost PLN 79 million when an increase in coverage rate from 13.5% to 40% is assumed. 23 900 cases of influenza, 1777 hospitalizations and 548 premature deaths would be averted each year due to the influenza vaccination programme. Fifty-seven persons would need to be vaccinated to prevent one case of influenza. To prevent one hospitalization and one death due to influenza, 842 and 2809 individuals would need to be vaccinated, respectively. The new strategy would be very cost effective compared with the current situation with an incremental cost-effectiveness ratio (ICER) of PLN26 118/QALY, which is below the 2009 yearly gross domestic product (GDP) per capita. Deterministic sensitivity analyses demonstrated that the most influential variables for the ICER were vaccine efficacy against death, excess hospitalization rate, utility norms, influenza attack rate, vaccine efficacy against hospitalization, and discount rates. All ICERs computed were below the threshold of 3 GDP per capita. From the probabilistic analysis, the proposed new influenza vaccination programme, if implemented, was predicted to be cost effective from the NFZ perspective with a probability of 100%, given the same threshold. Implementing a vaccination programme in Poland in which influenza vaccination would be fully reimbursed by the NFZ for people aged ≥65 years would be a very cost-effective strategy.Clinical Drug Investigation 12/2011; 32(2):73-85. DOI:10.2165/11594030-000000000-00000 · 1.70 Impact Factor