Table 1 shows the mortality indicators for the Metropolitan Region. An increase in absolute PYLL for all causes in the last 4 years is observed, with the largest change occurring with the advent of COVID-19, growing 13.6% between 2019 and 2020; this rise is 4.5 times greater than the observed in the previous year. In fact, during the first pandemic year there were 409,086 PYLL of which 90,734 were due to confirmed or suspected COVID-19, i.e, one-fifth of all absolute PYLL (22.2%). Similarly, to what was observed for the PYLL, the crude mortality for all causes experienced an increase during the four years: the rate in 2020 (6.3 deaths per 1,000 inhabitants) represents an increase of 19.8% with respect to the previous year (5.3 deaths per 1,000 inhabitants). It should be noted that despite the decrease in total crude mortality in 2021, the values of the mortality measures studied are still higher than pre-pandemic levels. Continuing with the annual analysis, a decrease in both absolute PYLL and crude mortality can be observed when all causes of death excluding COVID-19 are considered. This does not necessarily mean an improvement in the other causes of death, as it is reasonable to consider other hypotheses, such as that excess deaths from COVID-19 would produce deaths in the population that would be expected in the short term, reducing the number of deaths in other causes.
To compare the different waves of COVID-19, the mortality measures were divided by weeks of duration of each wave, which are presented in parentheses in Table 1. Considering the weekly values of absolute PYLL for all causes, the first two waves are the most severe with 11,081.5 and 9,103.6 absolute PYLL per week, for which two-fifths (43.6%) and one-third (33.9%) are explained by COVID-19. It should be noted that with the evolution of the pandemic in Chile, the contribution of PYLL by COVID-19 in each wave is, in general, decreasing.
The advantage of analyzing both mortality rates and PYLL after the arrival of COVID-19 is that by considering the last one it is possible to differentiate whether different age groups were affected differently by the disease. Thus, due to the marked increase observed in both mortality measures in 2020, it is possible to mention that the population exhibited a higher number of deaths, and a large part of them correspond to young people (behavior similar to the first waves of COVID-19).
Table 1: Summary of mortality indicators by periods in the Metropolitan Region.
Considering the previous analysis, it is interesting to observe the behavior of these variables at the municipal level. Figure 1 shows the standardized PYLL and mortality rates for COVID-19 confirmed in the first year of the pandemic (2020). As can be seen, the burden of the disease is unequal between municipalities, with the greatest differences for PYLL. Although the causes of inequity are multiple, we observe that municipalities with higher incomes—such as Vitacura, Lo Barnechea, and Las Condes—have lower values in mortality measures. On the other hand, the municipalities with the worst health outcomes are those with lower average income per household.
Specifically, the confirmed COVID-19 standardized PYLL rate ranged from 0.166 in the least impacted municipality (Vitacura) to 2.222 in the most affected (San Ramón), which represents a ratio of 13.4. On the other hand, the standardized mortality rate ranged from 0.070 (Vitacura) to 0.313 (La Pintana), which represents a ratio of 4.5. This behavior is also observed considering all causes of death (see Appendix 1).
Figure 1: PYLL and mortality rate by COVID-19 confirmed (2020) in the municipalities of the Greater Santiago.
The spatial relationship between PYLL and income is presented in Fig. 2. The figure on the left shows the spatial distribution of the PYLL rate for the first year of the confirmed COVID-19 pandemic, while the figure on the right shows the average income per household for each municipality. From them, it can be noted that there is an inverse relationship between years of life prematurely lost and income (this relationship can also be observed in Appendix 2).
Figure 2: Spatial distribution of confirmed COVID-19 PYLL (2020) and average income per household.
To quantify the inequality visualized in Figs. 1 and 2, the concentration index is calculated for all causes of death and, specifically, for COVID-19. The results are shown in Table 2. It is noteworthy that all values are negative, indicating that the burden of the rates is concentrated in the most economically disadvantaged municipalities. In addition, it should be noted that the inequities shown are more pronounced when estimating the burden of disease using PYLL, suggesting greater inequality in younger age groups.
As can be observed, with the arrival of COVID-19 the PYLL and death rates indexes show an increase in inequality compared to the previous two years. It should be noted that whether or not we consider COVID-19 as the cause of death in 2020, it is possible to observe this rise. Where, the PYLL concentration index goes from − 0.112 (2019) to -0.149 (2020) if all causes of death are considered or to -0.138 without considering COVID-19 deaths. Comparing the concentration indexes in the first year of the pandemic, more inequity is detected in COVID-19 deaths than in the remaining causes. On the other hand, in the second year of the pandemic a decrease in inequity is observed compared to the first year for all causes of death, returning to levels closer to those seen in pre-pandemic years; this decrease in inequity is also observed for COVID-19 deaths.
Table 2: Concentration indexes for mortalities and PYLL according to cause of death and period.