Objective: To identify predictors of 30-day survival in elderly patients with coronavirus disease 2019 (COVID-19).

Methods: Retrospective cohort study including patients with COVID-19 aged ≥65 years hospitalized in six European sites (January 2020 to May 2021). Data on demographics, comorbidities, clinical characteristics, and outcomes were collected. A predictive score (FLAMINCOV) was developed using logistic regression. Regression coefficients were used to calculate the score. External validation was performed in a cohort including elderly patients from a major COVID-19 centre in Israel. Discrimination was evaluated using the area under the receiver operating characteristic curve (AUC) in the derivation and validation cohorts. Survival risk groups based on the score were derived and applied to the validation cohort.

Results: Among 3010 patients included in the derivation cohort, 30-day survival was 74.5% (2242/3010). The intensive care unit admission rate was 7.6% (228/3010). The model predicting survival included independent functional status (OR, 4.87; 95% CI, 3.93-6.03), a oxygen saturation to fraction of inspired oxygen (SpO₂/FiO₂₎ratio of >235 (OR, 3.75; 95% CI, 3.04-4.63), a C-reactive protein level of <14 mg/dL (OR, 2.41; 95% CI, 1.91-3.04), a creatinine level of <1.3 (OR, 2.02; 95% CI, 1.62-2.52) mg/dL, and absence of fever (OR, 1.34; 95% CI, 1.09-1.66). The score was validated in 1174 patients. The FLAMINCOV score ranges from 0 to 15 and showed good discrimination in the derivation (AUC, 0.79; 95% CI, 0.77-0.81; p < 0.001) and validation cohorts (AUC, 0.79; 95% CI, 0.76-0.81; p < 0.001). Thirty-day survival ranged from 39.4% (203/515) to 95.3% (634/665) across four risk groups according to score quartiles in the derivation cohort. Similar proportions were observed in the validation set.

Discussion: The FLAMINCOV score identifying elderly with higher or lower chances of survival may allow better triage and management, including intensive care unit admission/exclusion.