Influenza-Like-Illness and Clinically Diagnosed Flu: Disease Burden, Costs and Quality of Life for Patients Seeking Ambulatory Care or No Professional Care at All

Abstract

This is one of the first studies to (1) describe the out-of-hospital burden of influenza-like-illness (ILI) and clinically diagnosed flu, also for patients not seeking professional medical care, (2) assess influential background characteristics, and (3) formally compare the burden of ILI in patients with and without a clinical diagnosis of flu. A general population sample with recent ILI experience was recruited during the 2011–2012 influenza season in Belgium. Half of the 2250 respondents sought professional medical care, reported more symptoms (especially more often fever), a longer duration of illness, more use of medication (especially antibiotics) and a higher direct medical cost than patients not seeking medical care. The disease and economic burden were similar for ambulatory ILI patients, irrespective of whether they received a clinical diagnosis of flu. On average, they experienced 5–6 symptoms over a 6-day period; required 1.6 physician visits and 86–91% took medication. An average episode amounted to €51–€53 in direct medical costs, 4 days of absence from work or school and the loss of 0.005 quality-adjusted life-years. Underlying illness led to greater costs and lower quality-of-life. The costs of ILI patients with clinically diagnosed flu tended to increase, while those of ILI patients without clinically diagnosed flu tended to decrease with age. Recently vaccinated persons experienced lower costs and a higher quality-of-life, but this was only the case for patients not seeking professional medical care. This information can be used directly to evaluate the implementation of cost-effective prevention and control measures for influenza. In particular to inform the evaluation of more widespread seasonal influenza vaccination, including in children, which is currently considered by many countries.

Burden of medically attended influenza in Norway 2008‐2017

“…In addition to medically attended influenza, there will be a large number of influenza patients who never seek medical care. A Belgian study found that around half of those experiencing influenza‐like illness seeks medical counselling . Simulation studies from the pandemic in Norway support this finding, as an estimated 30% of the population was infected with the pandemic influenza virus, while less than 5% of the population consulted a doctor .…”

“…A Belgian study found that around half of those experiencing influenza-like illness seeks medical counselling. 45 Simulation studies from the pandemic in Norway support this finding, as an estimated 30% of the population was infected with the pandemic influenza virus, while less than 5% of the population consulted a doctor. 46 Considering this, the impact on society caused by influenza infections is higher than observed in our study.…”

Social and economic burden of patients with influenza-like illness and clinically diagnosed flu treated at various health facilities in Vietnam

“…In the USA, medical costs totaled US$3,990 in 2012 for inpatients and US$730 for emergency department patients 7. In Belgium, the average direct medical cost per case in 2014 was €51–53 8. From a societal viewpoint, the total average mean cost for physician-diagnosed influenza and ILI at primary care level in Germany in 2015 was €514 for adults and €105 for children 9.…”

An Under-Recognized Influenza Epidemic Identified by Rapid Influenza Testing, Southern Sri Lanka, 2013

“…17 Children with influenza were more likely to report pain with breathing, headache, fatigue, arthralgias, and myalgias, whereas adults with influenza were more likely to report pain with breathing, vomiting, and arthralgias. Pleuritic chest pain, although not universally reported in ILI, has previously been described in patients with pandemic H1N1.…”