key: cord-314737-2fun90ze
authors: Cardoso, Filipe S.; Papoila, Ana L.; Machado, Rita Sá; Fidalgo, Pedro
title: Age, sex, and comorbidities predict ICU admission or mortality in cases with SARS-CoV2 infection: a population-based cohort study
date: 2020-07-28
journal: Crit Care
DOI: 10.1186/s13054-020-03173-1
sha: 
doc_id: 314737
cord_uid: 2fun90ze

nan

Previous studies have identified risk factors for severe acute respiratory syndrome coronavirus 2 (SARS-CoV2) severe outcomes preferentially among hospitalized patients; therefore, they may have understated the denominator of such estimations [1, 2] . We aimed to determine pre-hospital risk factors and estimate individual probabilities of SARS-CoV2 severe outcomes among a nationwide cohort of cases of SARS-CoV2 infection, including those with and without hospitalization.

This was a retrospective analysis from a nationwide prospective registry, including confirmed (nasal/pharynx swab real-time polymerase chain reaction) cases of SARS-CoV2 infection notified to the Directorate-General of Health from March 02 until April 21, 2020, in Portugal. Primary endpoint was a composite of ICU admission or all-cause mortality until April 21. Multivariable analysis was performed with logistic regression. Internal validation was performed with bootstrapping. Models' performance was studied with calibration plots, c-statistic, and Brier score [3, 4] . Significance level was α = 0.05. Informed consent was waived due to the use of anonymized data and the current state of public health emergency.

Overall, 18,647 cases were included in our analyses, following exclusion of 1623 (8.0%) cases without hospital admission status and 23 (0.1%) cases without outcome status.

Among all cases, median (IQR) age was 50 (36-66) years ( There were 687 (3.7%) cases admitted to the ICU or deceased (Table 1) . Cases with ICU admission or nonsurvivors had higher median age (80 vs. 49 years; P < 0.001) and were more frequently men (54.7% vs. 40.8%; P < 0.001) than those that were not admitted to the ICU and survived.

Cases with ICU admission or non-survivors had more frequently any comorbidity than those that were not admitted to the ICU and survived (56.6% vs. 14.5%; P < 0.001). All types of comorbidities were more frequently reported in cases with ICU admission or non-survivors than those that were not admitted to the ICU and survived.

In multivariable analysis with logistic regression, higher age (aOR 1.065), male sex (aOR 1.896), or higher number of comorbidities (aOR 2.953 if one vs. aOR 3.568 if 2 vs. aOR 6.002 if ≥ 3; P < 0.001 for all comparisons) were associated with higher risk of ICU admission or all-cause mortality ( Table 2) .

The model's calibration plot showed a very good predictive performance up to estimated probabilities of Among cases with SARS-CoV2 infection at an early phase of the epidemic in Portugal, pre-hospital characteristics like age, sex, and the number of comorbidities were useful to predict ICU admission or all-cause mortality [5] . These findings may inform health policies designed to protect specific subgroups of the population and project allocation of health resources, especially while measures of containment are being eased in many countries. 

Comorbidity and its impact on 1590 patients with COVID-19 in China: a nationwide analysis

Prevalence of comorbidities and its effects in cases infected with SARS-CoV-2: a systematic review and meta-analysis

Regression modelling strategies: with applications to linear models, logistic regression, and survival analysis

Bias reduction of maximum likelihood estimates

Estimating excess 1-year mortality associated with the COVID-19 pandemic according to underlying conditions and age: a population-based cohort study

Publisher's Note

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The authors would like to acknowledge the Portuguese Directorate-General of Health and all staff of the Portuguese National Health System. 

Dr. Cardoso is the guarantor of the paper, taking responsibility for the integrity of the content of the manuscript as a whole, from inception to published article. Dr. Cardoso conceived and designed the study, performed statistical and data analyses, drafted the manuscript, revised the manuscript, and provided final approval. Prof Papoila provided significant contribution to data analyses and interpretation, revised the manuscript, and provided final approval. Dr. Machado provided significant contribution to data acquisition, contributed to the data analysis and interpretation, revised the manuscript, and provided final approval. Dr. Fidalgo contributed to the conception and design of the study and data analysis and interpretation, contributed to drafting and revision of the manuscript, and provided final approval. The manuscript has been reviewed and approved by all authors.

The authors received no funding at all pertaining to this study.

The datasets generated and/or analyzed during the current study are not publicly available due to confidentiality but are available from the corresponding author on reasonable request.

This study was approved by the Ethics Committee at Curry Cabral Hospital, Central Lisbon University Hospital Center, Lisbon, Portugal. Informed consent was waived due to the use of anonymized data and the current public health state of emergency.

Not applicable.

The authors declare that they have no competing interests.Author details 1 Intensive Care Unit, Curry Cabral Hospital, Central Lisbon University Hospital Center, Nova Medical School, Nova University, Lisbon, Portugal.