The potential role of socio-economic status (SES) in COVID-19 remains unknown. The highest excess mortality rate in France linked to COVID-19 is reported in the Seine-Saint-Denis (SSD) district, which is the poorest district of the Greater Paris Area. Our objective was to compare patient characteristics between two districts of Greater Paris and determine whether precarity is a risk factor for severe COVID-19 respiratory disease at hospital admission. We selected patients hospitalized for COVID-19 from three academic hospitals, one located in SSD, and two in the Hauts-de-Seine (HDS) district, a rich district of Greater Paris. All selected patients were prospectively screened on the same day (April 20, 2020). Patients were asked about their SES via a questionnaire and information on smoking habits, comorbidities, and respiratory severity at admission was collected.

112 patients were included (58.6% (65/112) men, age: 66.7±16.3 years old, 11.0% (12/109) Africans or Afro-Caribbeans, and 7.7% (8/104) current smokers). COVID-19 was severe in most cases 59.8% (67/112). The distribution of initial severity was similar in both districts, although SSD patients were approximately 10 years younger than HDS patients (61.8±14.0 versus 71.0±17.1 years old, P=0.002). The proportion of comorbidities was higher in SSD patients, including overweight (29.6±6.08 versus 25.2±5.67, P<0.001) and diabetes (40.0% (20/110) versus 21.7% (13/110) P=0.041), than in HDS patients. SSD patients had lower incomes (monthly income under 800€, 37.8% (17/97) versus 19.6% (9/97), P=0.004), less private insurance coverage (55.8% (29/110) versus 75.9% (44/110) P=0.043), a lower educational level (High school graduate 24.0% (12/103) 56.6% (30/103)versus P=0.002) and a higher housing population density (23.7±22.1 versus 37.3±40.4 m2 per 1 habitant, P=0.027). Although no factor was found to be associated with initial severity in the overall population, age and deprivation index were associated with an increased risk of initial severity in patients under 70 years-old, with an odds ratios of 1.099 (95% CI: 1.038 to 1.178, P=0.003), and 1.029 per deprivation score point (95% CI:1.003 to 1.059, P=0.033), respectively.

Precarity seems to be associated with the initial severity of COVID-19 in hospitalized patients under the age of 70. Low SES and comorbidities may contribute to the excess mortality observed in SSD, the poorest district of Greater Paris with the youngest population.