key: cord-0735010-qz1m2kc5
authors: Czernichow, Sebastien; Bain, Stephen C.; Capehorn, Matthew; Bøgelund, Mette; Madsen, Maria Elmegaard; Yssing, Cecilie; McMillan, Annabell Cajus; Cancino, Ana‐Paula; Panton, Ulrik Haagen
title: Costs of the COVID‐19 pandemic associated with obesity in Europe: A health‐care cost model
date: 2021-02-07
journal: Clin Obes
DOI: 10.1111/cob.12442
sha: df9a619be0446b1c9e39a136340df40d16fe2b07
doc_id: 735010
cord_uid: qz1m2kc5

Excess weight is associated with severe outcomes of coronavirus disease 2019 (COVID‐19). We aimed to estimate the total secondary care costs by body mass index (BMI, kg/m(2)) category when hospitalized due to COVID‐19 in Europe during the first wave of the pandemic from January to June 2020. Building a health‐care cost model, this study aimed to estimate the total costs of COVID‐19. Information on risk of hospitalization, admission to intensive care unit (ICU) and risk of ventilation were based on published data. Average cost per patient and in total were calculated based on risks of admission to ICU, risk of invasive mechanical ventilation and length of hospital stay when hospitalized and published costs associated with hospitalization. The total direct costs of secondary care during the first wave of COVID‐19 in Europe were estimated at EUR 13.9 billon, whereof 76% accounted for treating people with overweight and obesity. The average cost per hospital admission increased with BMI, from EUR 15831 for BMI <25 kg/m(2) to EUR 30982 for BMI ≥40 kg/m(2). This study reveals that excess weight contributes disproportionally to the costs of COVID‐19. This might reflect that overweight and obesity caused the COVID‐19 pandemic to result in more severe outcomes for citizens and higher secondary care costs throughout Europe.

The burden of coronavirus disease 2019 , caused by severe acute respiratory syndrome coronavirus 2 (SARS CoV-2), increased continuously during the first 6 months of 2020, referred to as the first wave of the COVID-19 pandemic. As of June 30, 2020, more than 2.4 million people in Europe had been tested and reported positive with the virus, and COVID-19 led to more than 190 000 deaths in this region, with presumably many more unconfirmed cases. 1, 2 Throughout Europe, the prevalence of obesity (defined as having a body mass index, or BMI, at or above 30 kg/m 2 ) in the adult population has risen during the past decade. 3 According to the World Obesity Federation, 58% of people over the age of 15 in Europe were overweight (corresponding to a BMI at or greater than 25 kg/m 2 for adults) and 21% had obesity in 2018. 4 These numbers are expected to increase further unless significant interventions are taken. 5 Recent studies from Europe, the United States and China have identified obesity as an independent risk factor for the most severe outcomes of COVID-19, including death. [6] [7] [8] [9] [10] [11] [12] [13] [14] A nationwide Danish study 6 of 11 122 individuals with a positive polymerase chain reaction test for SARS-CoV-2 found hospitalization rates of 20% among all patients and 29% among patients with overweight or obesity. A US study by Petrilli et al 10 that looked at 5279 people with found that an individual's risk of hospitalization increased with higher BMI. Furthermore, a French study by Simonnet et al 7 of 124 COVID-19 patients admitted to the intensive care unit (ICU) indicated that the risk of invasive mechanical ventilation (IMV) increased with higher BMI, and that the age-and sex-adjusted odds ratio (OR) for IMV in hospitalized patients with BMI >35 kg/m 2 was 7.36 (1.63-33.14) compared with hospitalized patients with BMI <25 kg/m 2 .

Although the underlying mechanisms of the increased risk of severe outcomes of COVID-19 among people with overweight and obesity are poorly understood, potential mechanisms have been hypothesised. Among these, it has been proposed that insulin resistance, and not fat mass, is the link between obesity and severe COVID -19 outcomes. Another explanation is that low circulating levels of adiponectin predispose to aggressive pulmonary inflammation. 15 However, no hypotheses have yet been confirmed.

Because people with obesity experience more severe outcomes due to COVID-19, the purpose of this study was to investigate the total treatment cost per patient with overweight or obesity when hospitalized due to COVID-19 in European countries.

This study applied a healthcare cost model to estimate the total direct costs to secondary care of COVID-19 in the first 6 months of 2020 in Europe, defined as the EU 27, the European Free Trade Association (Iceland, Norway, Switzerland and Lichtenstein) and the United Kingdom. Total direct costs of secondary care in Europe were defined as publicly funded hospital service usage within the healthcare system, including hospital admissions, admissions to ICU and support by IMV during ICU stays (henceforth known as ICU + IMV). Primary care costs, that is, visits to a general practitioner or an associated healthcare professional with associated treatments, and indirect costs, for example, lost productivity during illness, were not included in the analysis. The healthcare cost model applied in this study is based on a parallel methodology as a healthcare cost model estimating the direct costs of secondary care according to diabetes categories. The manuscript for this article is currently in press. 16 

As the number of people testing positive for COVID-19 throughout Europe depended heavily on the testing strategy applied in each country, we used modelled country-specific data on number of hospitalizations from January 1, 2020 to June 30, 2020 as a starting point for the healthcare cost model. 17 To obtain knowledge on the severe disease course of COVID-19 among people with overweight and obesity to be used in the healthcare cost model, a rapid literature review was performed. We searched PubMed up until July 1, 2020 using the key terms "COVID-19" or "coronavirus infection" or "SARS-CoV-2" and "obesity" and identified relevant studies published from January 1, 2020 to June 30, 2020 estimating risks of severe outcomes associated with COVID-19 among people with overweight and obesity. Specifically, studies estimating risk of general hospitalization, risk of admission to ICU, risk of admission to ICU + IMV regarding COVID-19 and length of hospital stay among people with overweight and obesity were of interest.

The literature was screened using predefined inclusion criteria. Initially, the literature search identified 334 articles published in the specified date range. European or US publications estimating severe outcomes of COVID-19 written in English were included (Figure 1 ). In total, 19 of the 334 publications were selected for potential full-text review. Articles that did not estimate outcomes of interest or were not peer-reviewed were excluded, leaving 15 publications included in the review. people with BMI <30 kg/m 2 required 13 days' hospital stay. 19 An overview of the inputs to the economic model is presented in Table 1 . Where estimates were presented as OR in the literature, we recalculated these as risk ratios (RR) by RR = OR/([1-prevalence in ref-

erence group] + [prevalence in reference group*OR]), in order to estimate the prevalence of the three outcomes within BMI categories. 21 To minimize confounding risk, we preferred estimates already adjusted for sex and age, when available. If adjusted estimates were not identified, unadjusted estimates were used.

Estimates of costs of general hospitalization, admission to ICU and admission to ICU + IMV were based on publicly available costs from Denmark, France, Spain and the United Kingdom. [22] [23] [24] [25] [26] [27] [28] We assumed that unit costs are evenly distributed within the examined population.

All results are presented in euros (EUR) (2020 price level). Cost estimates were converted to EUR using exchange rates (as of June 18, 2020) of 1.11 for GBP and 0.13 for DKK. Subsequently, costs for the remaining 28 European countries were estimated using a relative cost index derived from Eurostat (the statistical office of the European Union). 29 

The elements and methodology of the economic model are presented in Figure 2 . patients across countries and BMI categories (j) was estimated by multiplying per-country admissions (a), relative risk of admission per BMI category (b) and distribution of population by BMI category (c). All risk ratios for hospitalization, admission to ICU and ICU + IMV are presented as relative risks compared with BMI <25 kg/m 2 . The distribution of admitted COVID-19 patients was therefore standardized; this ensured that the estimated patients reflected the total number of admissions. Note: Numbers have been rounded. BMI distribution in the European population was based on data from the World Obesity Federation. 4 RRs were calculated based on data from Petrilli et al, 10 Reilev et al 6 The total cost per BMI category (m) was estimated for each country by multiplying the cost per patient, per country per BMI category (l) and the estimated number of patients in each country and BMI category (j). Adding the country-specific costs across BMI groups gives the total estimated secondary care costs of COVID-19 in Europe.

In Europe, more than 720 547 people were admitted to hospital for COVID-19 between 1 January 2020 and 30 June 2020. 17 Table 1 summarizes the BMI distribution of the European population, the 

We estimated the total direct costs of secondary care of COVID-19 in Europe to be EUR 13.9 billion ( 10 Simonnet et al. 7 and Reilev et al. 6 Abbreviations: ICU, intensive care unit; BMI, body mass index; IMV, invasive mechanical ventilation; RRs, risk ratio. a (h) in Figure 2 . The rate of admission to ICU was obtained from Reilev et al. 6 for BMI <25.

costs related to obesity accounted for 44% of the total direct costs of secondary care.

In comparison, the estimated prevalence of overweight including obesity in Europe is 58%, and the prevalence of obesity in Europe is estimated at 21%. The country-specific total direct costs of secondary care are presented in Supplementary Table 3 . Note: The differences in costs among BMI categories were calculated based on increased risk of admission to ICU and ICU + IMV among people with obesity. (l) in Figure 2 . Abbreviations: ICU, intensive care unit; BMI, body mass index; IMV, invasive mechanical ventilation. 

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SUPPORTING INFORMATION Additional supporting information may be found online in the Supporting Information section at the end of this article. How to cite this article