Hospital and economic burden of influenza-like illness and lower respiratory tract infection in adults \u226550\u2009years-old

Cecilia Trucchi,Bruno Buonopane,Filippo Ansaldi,Domenico Gallo,Simona Simonetti,Chiara Paganino,Andrea Orsi,Giancarlo Icardi,Maria Francesca Piazza,Valentino Tisa,Daniela Amicizia

doi:10.1186/s12913-019-4412-7

Abstract

BackgroundInfluenza-like illnesses (ILIs) and lower respiratory tract infections (LRTIs) cause substantial morbidity and mortality worldwide.The study assessed the health and economic burden of ILI and LRTI according to age and comorbidities, since available evidence is limited and heterogeneous.MethodThe prevalence of comorbidities, the seasonal incidence rates and the mean and per capita direct costs of ED accesses for ILI/LRTI, whether followed by hospitalization or not, recorded in adults aged ≥50 years over the last 6 years, in the referral hospitals located in the Genoese metropolitan area (Liguria, Italy) where the syndromic surveillance system is active, were evaluated through a retrospective observational study. Comorbidities were estimated through the Chronic Condition Data Warehouse that integrates multiple Medicare data sources. A comparison with the administrative healthcare International Classification of Diseases-9th revision-Clinical Modification (ICD-9-CM)-based data was also conducted.ResultsThe prevalence of subjects with ≥1 comorbidity ranged from 23.49 to 59.92%. The most prevalent all-age comorbidities were cardiovascular diseases and cancer. The overall ILI/LRTI incidence rate was 6.73/1000 person-years, almost double the value derived from routine data, and increased with age. The highest rates were observed in patients with renal failure and bronchopneumopathies. The mean cost of ED accesses/hospitalization for ILI/LRTI was €3353 and was almost twice as high in the ≥85 years as in the youngest age-group. The highest mean costs were observed in patients with renal failure and cancer. The per capita costs increased from €4 to €71 with age, and were highest in patients with renal failure and bronchopneumopathy.ConclusionThe burden of ILIs/LRTIs in terms of ED accesses and hospitalizations in adults aged ≥50 years is heavy, and is related to increasing age and, especially, to specific comorbidities.These results could contribute to revising age- and risk-based anti-influenza and -pneumococcus immunization strategies.

Highlights

Influenza-like illnesses (ILIs) and lower respiratory tract infections (LRTIs) cause substantial morbidity and mortality worldwide
The Genoese metropolitan area (GMA), which contains the majority of the Ligurian population, is representative of the entire Ligurian region and no significant differences in terms of demographic structure and chronic diseases prevalence are found in Liguria
The highest ILIs/LRTIs incidence rates in the study population were observed in patients with renal failure, bronchopneumopathies, followed by neuropathies, cardiovascular diseases and transplants: 38.32 (36.19– 50.63), 37.41 (31.97–39.59), 21.43 (17.97–24.61), 20.63 (18.74–24.13) and 16.83 (4.87–25.89) per 1000 personyears, respectively

Summary

Introduction

Influenza-like illnesses (ILIs) and lower respiratory tract infections (LRTIs) cause substantial morbidity and mortality worldwide. Few data on the impact of ILIs and LRTIs on health systems according to age, comorbidities and risk factors are available. These data are crucial to calibrating the health system response, developing age- and risk-based preventive strategies - i.e. recommendations for influenza and pneumococcus vaccination or antiviral therapy - guiding the proactive management of at-risk patients in primary care, implementing educational initiatives, and conducting future research. Current Italian anti-influenza immunization strategies target subjects aged ≥65 years and those at risk of complications [1]. During the last six influenza seasons, Italian and Ligurian influenza vaccine coverage (VC) rates have been suboptimal in the elderly (62.7–52% and 55.5–47.3%, respectively) and very low in at-risk subjects aged < 65 years (12–8.5% and 15.2–7.1%, respectively). The incremental VC objectives for the recently introduced pneumococcal vaccination for the elderly are 55% in 2018 and 75% in 2019 [3]

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