Mortality, Burden of Disease, Life Expectancy, and Methodology

Letters to the Editor Years of Life Lost to Death A Comprehensive Analysis of Mortality in Germany Conducted as Part of the BURDEN 2020 Project by Dr. rer. pol. Annelene Wengler, Dr. rer. med. Alexander Rommel, Dr. PH Dietrich Plaß, Heike Gruhl, Janko Leddin, Dr. med. Thomas Ziese, and Dr. rer. pol. Elena von der Lippe and The COVID-19 Disease Burden in Germany in 2020 Years of Life Lost to Death and Disease Over the Course of the Pandemic by Dr. rer. med. Alexander Rommel, Dr. rer. pol. Elena von der Lippe, Dr. PH Dietrich Plaß, Dr. med. Thomas Ziese, Michaela Diercke M.Sc., Dr. rer. nat. Matthias an der Heiden, Dr. med. Sebastian Haller, and Dr. rer. pol. Annelene Wengler in issue 9/2021

To the important work by Rommel et al. (1), I would like to add a methodological aspect and place the results in an broader context.

The loss of life span determined using the YLL formula in the article (1) is only valid if the number of attributable premature deaths is measured (2). However, this number must not be less than the number of attributable excess deaths (2): “in times of especially increased mortality [. . .], the excess mortality exceeded the reported deaths from COVID-19” (1).

Despite this potential underestimation of the YLL, the results of Rommel et al. (1) show that SARS-CoV-2 in Germany has so far had a small impact on life expectancy. At the beginning of 2020, there were around 83 million people in Germany with an average residual life expectancy of around 37 years. The YLL = 303 608 ascribed by the authors to COVID-19 means a loss of life expectancy of around 0.01% for these people, corresponding to around 1.5 days. According to Figure 2 of the article (1), the loss for men between the ages of 60 and 69 is approximately 750 years/100 000, i.e., approximately 3 days.

Such context (i.e., ~1.5 days and ~3 days) is important to explicitly reiterate to prevent misinterpretation of the larger numbers reported by the authors. They report: “On average, each patient who died [of COVID-19] lost 9.6 years of life” (1). This “residual life expectancy by age of death” (1) is only to be interpreted as an intermediate calculation step, since the deceased have no residual life expectancy.

According to ongoing analyses (3), an increase in the number of deaths in Germany by 5% in 2020 and the influence of SARS-CoV-2 on mortality are statistically confirmed despite massive countermeasures. The YLL associated with this undisputed SARS-CoV-2 effect should be better used—as the authors themselves suggest—for “effects [. . .] on public health” (1), i.e. with respect to a population at risk, rather than to deaths.

DOI: 10.3238/arztebl.m2021.0240

PD Dr. rer. medic. Peter Morfeld
Institut und Poliklinik für Arbeitsmedizin, Umweltmedizin und Präventionsforschung, Universität zu Köln, Cologne, Germany

References

1. Rommel A, von der Lippe E, Plaß D, et al.: The COVID-19 disease burden in Germany in 2020—years of life lost to death and disease over the course of the pandemic. Dtsch Arztebl Int 2021; 118: 145–51

2. Hammitt JK, Morfeld P, Tuomisto JT, Erren T: Premature deaths, statistical lives, and years of life lost: identification, quantification, and valuation of mortality risks. Risk Anal 2020; 40: 674–95

3. Morfeld P, Timmermann B, Groß JV, et al.: [COVID-19: How did mortality change?—Mortality of women and men in Germany and its federal states until October 2020]. Dtsch Med Wochenschr 2021; 146: 129–31