INTRODUCTION

The pandemic by COVID-19 initiated towards the end of 2019 in the city of Wuhan in China¹. This disease has a wide range of clinical symptoms that range from asymptomatic infection, mild deses of upper respiratory tract to a serious viral pneumonia with respiratory distress^2,3. However, few research exists that evaluate the correlation between sociodemographic and economic aspects of the populations with mortality by COVID-19.

In international studies, they reference the deaths by COVID-19 are comparable and sometimes superior to the total of deaths by opioids and HIV/AIDS⁴. In the United States, monetary income inequality is reflected in a greater number of deaths, and this could generate differences found in the different states⁵. Other studies that have assessed the effect of sociodemographic indicators in rural and urban communities have found an association between socioeconomic status (relative risks [RR] of 1.42 and 1.71) and housing and transportation domains (RR 1.52 and 1.32) with a major risk of COVID-19 diagnosis and death⁶. Another reported consequence of inequalities is associated with the diagnostic test availability for the entire population. In the beginning of the pandemic, there were more diagnosis in the most unfavorable locations, but this changed over time, a greater number of positive cases in wealthier places began to be reported. The inequalities associated to racial factors have also played a role. For example, a double risk for COVID-19 hospitalizations among the African American population in the United States has been reported⁷.

A Peruvian study analyzed mortality by non-violent causes and district quintiles, showing a relation between human development index (HDI) and mortality due to COVID-19, with a greater number of deaths due to COVID-19 in quintiles with lower HDI. Although this study did not find a significant association between poverty and mortality, their findings are limited due to short observation time⁸.

Our study seeks to find a correlation between mortality due to COVID-19, poverty percentage, HDI, and population density in districts within Metropolitan Lima during 2020.

METHODS

RESULTS

We analyzed the data of 13,154 people who died due to COVID-19 in Lima from March 18th to September 30th, 2020. 70,9% (9325) of the deceased were males. The districts with greater number of deaths were San Juan de Lurigancho with 11.4% (1,499), Lima with 8.3% (1,096) and San Martin de Porres with 7.0% (919). The districts with fewer number of deaths were the districts of Punta Hermosa (9 deceased), San Bartolo (9 deceased), Punta Negra (2 deceased), Santa María del Mar (1 deceased). The districts with greater fatalities due to COVID-19 were Villa El Salvador (6.04%), La Victoria (5.12%), Chorrillos (5.07%) and San Juan de Lurigancho (4.99%). The districts with lower fatalities due to COVID-19 were Santa María del Mar (1.54%), Jesús María (1.72%) and Punta Negra (2.0%). The total number of deceased per districts are shown inTable 1. Mortality and fatality due to COVID-19 in the same period are shown inTable 2.

Table 3shows the poverty rate and human development index of each district of Lima during 2020. The poverty rate of the districts varied from 0.2% in the district of Miraflores, San Isidro up to 41.1% in the district of Pachacamac and 40.7% in Puente Piedra. With regards to the district HDI, we observe that San Isidro and Miraflores have the highest indexes with 0.809 and 0.790, respectively. The districts with lowest HDI were the districts of Puente Piedra (0.673) and Pachacamac (0.669.Table 3shows a population density of the districts in Lima according to the last census carried out by INEI. We observe that the districts of Punta Negra and Punta Hermosa have the lowest population density with 64 and 67 Inhab/Km², respectively, while the districts of Surquillo a²the highest levels of population density with 2 6438 and 2 3202 Inhab/Km .

Mortality due to COVID-19 and its correlation with poverty, HDI, and population density

No significant correlation was found between mortality and poverty rate (rho= -0.2230; p=0.150) (Figure 1). A significant correlation was found between mortality due to COVID-19 and HDI (rho= 0.4466; p=0.002) (Figure 1). A significant correlation was found between mortality due to COVID-19 and population density (rho=0.7616; p=<0.001) (Figure 1).

Fatality due to COVID-19 and its correlation with poverty, HDI, and population density

A statistically significant correlation was found between fatality due to COVID-19 and district poverty rate (rho=0.319; p=0.037) (Figure 1). No significant correlation was found between fatality due to COVID-19 and district HDI (rho=-0.106; p=0.501) (Figure 1). A significant correlation was found between fatality due to COVID-19 and population density (rho=0.7616; p=<0.001) (Figure 1).

Additionally, a significant correlation was found between poverty rate and district HDI (rho= -0.8871; p<0,001) (Figure 1).

In the robust regression model used, only population density was a factor associated with mortality due to COVID-19 (Beta coefficient:0.06 CI95%:0.03-0.08; p<0.001). Population density was also associated with fatality due to COVID-19 (Beta coefficient: 0.06 CI95%:0.03-0.08; p<0.001). The results are shown inTable 4, therefore, it is assumed that robust regression associates much more population density with mortality and lethality, being poverty and HDI, nonsignificant variables.

Figure 1: A: Scatter plot: mortality by Covid-19 and district poverty rate. B: Scatter plot: mortality by COVID-19 and district human development index. C: Scatter plot: mortality by COVID-19 and district population density. D: Scatter plot: mortality by COVID-19 and district poverty rate. E: Scatter plot: fatality by COVID-19 and Human Development Index. F: Scatter plot: fatality by COVID-19 and district population density. G: Scatter plot: Dispersion diagram: human development index and percentage of district poverty 

DISCUSSION

The results from this study show that mortality due to COVID-19 in the districts of Lima were greater mostly in older adults over 60 years of age and of masculine gender. In addition to this, we were able to determine that from the beginning of the pandemic until the month of September there was a positive correlation (at district level) between fatality due to COVID-19 and poverty rate at the district level. Population density was the factor associated more consistently to mortality and fatality due to COVID-19. For every increase in population density (in one thousand inhabitants), the fatality and mortality from district COVID-19 infection would increase 6%. Poverty was associated with greater fatality, but not with greater mortality.

Deaths due to COVID-19 mostly in older adults of male gender with comorbidities such as hypertension, obesity, diabetes^(31-34). Prior studies such Hernández-Vásquez et al.⁸describe that there is an excess of mortality of 20,093 non-violent deaths and 2,979 COVID-19 confirmed deaths in the department of Metropolitan Lima during the first 24 weeks of the year 2020, where older adults, males, and in poverty were the ones who died most from this disease⁸.

The main results from this study show that the greater the district poverty, the greater COVID-19 fatality. This resembles prior research such as those of Ogedegbe et al., Gadson et al. and Hernández-Vásquez et al.⁸among others^(14,15). Ogedegbe et al. showed in his study the existence of a substantial variation of COVID-19 fatality in the districts of New York city, determining that zones with greater number of people living in poverty and lower educational levels had higher rates of deaths related to COVID-19⁹. In this same manner, Hernández-Vásquez et al. describe that the excess of deaths due to COVID-19 were greater in the districts with extreme poverty⁸. The study of these relationships demonstrates the importance of accessibility of district monetary resources facing the fatality of this pandemic, given that districts with less accessibility of economic resources have greater chance of counting on less infrastructure resources and human resources, reporting in turn a greater number of deaths^14,15.

This study has evaluated the correlation between fatality and poverty rate at the district level. This study evaluated a smaller population compared to other studies such as Achoki et al. which evaluated countries that showed a similar situation^16-18. Achoki et al. Demonstrated that fatality due to COVID-19 (in the beginning of the pandemic) was greater in impoverished countries in continents, such as Africa, and that this too could replicate in countries in Latin America, as we can observe through results from this study^18,19.

The main implications in this research were the possibility to determine population groups with greater risk, where the state and health ministry can intervene and target prevention actions such as early detection of cases, of patients with greater risk of infection and mortality, as well as early referral to health establishments with greater complexity, mainly in those districts with higher poverty levels.

The main limitations from this research were related to the data base quality. It is possible that an underreporting of patients who died in the beginning of the pandemic exist, due to lack of knowledge of diagnostic criteria and delay in molecular test results, among others. Since it is an ecological study, the results should be interpreted at a district level and not necessarily at an individual level. However, we consider that the risk of ecological fallacy is highly unlikely.

CONCLUSION

COVID-19 is transmitted directly from person to person, being the cause of many complications such as a trigger of pneumonia, the transmission is among people that keep little distance from each other, this disease will travel through respiratory droplets, this disease spreads when the infected person coughs, this is why the association between mortality and fatality with population density is important, since once there is contact between people the spread is greater. This is shown in the results of robust regression, that when population density in a thousand inhabitants increases, the district fatality due to COVID-19 increased by 6%, and we can also observe that the districts with less population density had less deaths in a bivariate analysis, and it is much more associated in a robust regression, therefore we show that population density is a very relevant factor, with poverty and HDI not having any association.

The prevention of the agglomeration of people is very important in enclosed places or those with poor ventilation, since this would make the spread easier.