Just over 20% of our hospitalised COVID-19 patients were immigrants and, excluding the early days of the study period (when the patients were mainly Italians from the first epidemic hotspots in Lombardy) [1, 13], the percentage was similar during the first and second waves of the epidemic in early spring and autumn 2020. This is slightly higher than the percentage of immigrants living in the metropolitan area of Milan (14.1%) or in the inner-city (18.2%) [19], and included a much higher proportion of Latin Americans (38.4%) than the proportion of Latin Americans in the city’s immigrant population as a whole (16.5%) [20]. This suggests a greater spread of SARS-CoV-2 infection among Latin Americans than in the other immigrant communities.
The immigrants in our cohort were significantly younger and less frequently affected by age-related co-morbidities than the Italians, which reflects the demographic differences between the two groups in northern Italy [21]. An older age and age-related co-morbidities are known to be associated with COVID-19-related mortality [3, 13, 14], and so it is not surprising that in-hospital mortality was greater among the Italians than among the immigrants as a whole. However, it was worryingly unexpected to find that, after adjusting for age, gender, and baseline clinical characteristics, Latin Americans were at higher risk of dying than the immigrants from other regions.
The findings of two previous studies of Spanish and immigrant COVID-19 patients hospitalised in Spain (including a majority of immigrants from Latin America) are different: one did not find any significant difference in mortality between patients of European and non-European origin [12], and the other found that mortality was actually lower among the immigrants [11]. The foreign-born patients in these studies had similar demographic characteristics to those of our immigrant patients, but the lack of additional information concerning the clinical drivers of COVID-19 outcomes (such disease severity or the prevalence of obesity) makes it difficult to make a more detailed comparison. It is also worth remembering that, although Italy and Spain are the main European destinations of Latin American migrants [22], it is likely that those settling in Spain are more integrated, not least because of their common language and cultural proximity.
It is possible that the Latin Americans in our study experienced severe/critical disease more frequently than immigrants from other regions because they knew less about or underestimated the early signs of COVID-19 and were therefore less likely to seek medical advice promptly, or they may have been afraid of losing wages or their often precarious and unregistered jobs. These factors were found to be common in a qualitative study of Latin Americans with COVID-19 hospitalised in San Francisco [23], and may explain the excess burden of morbidity and mortality among Latin Americans in the USA, particularly in more recent immigrants [24, 25].
Government policies limiting the access of uninsured or undocumented immigrants to healthcare services can also affect the care seeking behaviour of immigrants and, although Italy guarantees free emergency healthcare regardless of legal status, undocumented immigrants are highly vulnerable and may be unaware of their rights [26].
Another striking characteristic of our Latin American patients is the high (30%) prevalence of obesity, which substantially increases the risk of COVID-related death [13, 14]. The rates of obesity have markedly increased in Latin America over the last 10–15 years, and it is now considered a public health problem in most countries [27–29]. In addition, there is evidence that the change in dietary habits associated with immigration and integration increases susceptibility to obesity [28].
The greater frequency of severe COVID-19 and disease-related mortality among the Latin American immigrants hospitalised in two clinical centres in Milan is alarming, and there is a real need to clarify if it is due to a higher incidence of SARS-CoV-2 infection in the Latin American community, or to cultural, behavioural and socio-economic reasons preventing them from promptly seeking healthcare, or to other factors that have not yet been identified.
Study limitations
This study has a number of limitations. First of all, its design means that our findings may not apply to different settings and, although the study centres were located in different parts of Milan, it is possible that the study population did not reflect the demographics of the entire metropolitan area. Secondly, the relatively small number of immigrants in our cohort may have limited our characterisation of the differences between groups of immigrants of different origin. Finally, we were unable to collect data regarding the patients' education level or health literacy, their occupations, the length of time they had been in Italy, or their legal status, all of which would have allowed a more precise analysis of the possible association between socio-economic factors and COVID-19 outcomes.