Mortality Trend of Severe COVID-19 in Under-Vaccinated Population Admitted to ICU in French Amazonia

Abstract

(1) Background: Until December 2021, French Guiana (FG), located in South America, faced four consecutive COVID-19 epidemic waves. This study sought to analyze the mortality trend of severe COVID-19 patients admitted to the referral ICU of FG. (2) Methods: We conducted a prospective, observational, and non-interventional study in ICU at Cayenne Hospital. We included 383 patients older than 18 admitted with SARS-CoV-2-related pneumonia hospitalized from May 2020 to December 2021. The study covers three periods. Period 1 (Waves 1 and 2, original variant), period 2 (Wave 3, Gamma variant), and period 3 (Wave 4, Delta variant). (3) Results: The median age was 63 years (52-70). Frailty was diagnosed in 36 patients over 70 (32.4%). Only 4.8% of patients were vaccinated. The median ICU LOS was 10 days (6-19). Hospital mortality was 37.3%. It was 30.9% in period 1, 36.6% in period 2 (p = 0.329 vs. period 1), and 47.1% in period 3 (0.015 vs. period 1). In multivariate analysis, independent factors associated with hospital mortality included age greater than 40 years (]40-60 years] OR = 5.2, 95%CI: 1.4-19.5; (]60-70 years] OR = 8.5, 95%CI: 2.2-32; (]70+ years] OR = 17.9, 95%CI: 4.5-70.9), frailty (OR = 5.6, 95%CI: 2.2-17.2), immunosuppression (OR = 2.6, 95%CI: 1.05-6.7), and MV use (OR = 11, 95%CI: 6.1-19.9). This model had an overall sensitivity of 72%, a specificity of 80.4%, a positive predictive value of 68.7%, and a negative predictive value of 82.8%. (4) Conclusions: The mortality of severe COVID-19 patients in French Amazonia was higher during the Delta variant wave. This over-death could be explained by the virulence of the responsible SARS-CoV-2 variant and the under-vaccination coverage of the studied population.

Keywords: COVID-19; Delta variant; French Guiana; Gamma variant; mortality.

Figure 1

The flow-chart of the study.

Figure 2

ICU-bed capacity (in red line) and occupancy rate (in bars) during the study period.

Figure 3

The vaccination rate during the study periods. In bar: number of patients in whom the vaccination status was available. Red mark: the vaccination rate (at least one dose). Green mark: the vaccination rate (two doses).

Figure 4

Sixty-day mortality according to the period of analysis. Period 1 vs. period 2 (Log Rank = 0.176), Period 1 vs. period 3 (Log Rank = 0.005).

Figure 5

Hospital mortality according to age groups (r = 0.939, p < 0.001). Bars indicate the number of patients in each age group, the red line represents the hospital mortality rate, and the black line represents the tendency line of hospital mortality according to age groups.