Performance status: A key factor in predicting mortality in the first wave of COVID-19 in South-East Scotland

Abstract

Background: COVID-19 mortality risk factors have been established in large cohort studies; long-term mortality outcomes are less documented.

Methods: We performed multivariable logistic regression to identify factors associated with in-patient mortality and intensive care unit (ICU) admission in symptomatic COVID-19 patients admitted to hospitals in South-East Scotland from 1st March to 30th June 2020. One-year mortality was reviewed.

Results: Of 726 patients (median age 72; interquartile range: 58-83 years, 55% male), 104 (14%) required ICU admission and 199 (27%) died in hospital. A further 64 died between discharge and 30th June 2021 (36% overall 1-year mortality). Stepwise logistic regression identified age >79 (odds ratio (OR), 4.77 (95% confidence interval (CI), 1.96-12.75)), male sex (OR, 1.83 (95% CI, 1.21-2.80)) and higher European Cooperative Oncology Group/World Health Organization performance status as associated with higher mortality risk.

Discussion: Poor functional baseline was the predominant independent risk factor for mortality in COVID-19. More than one-third of individuals had died by 1 year following admission.

Keywords: COVID-19; SARS-CoV2; clinical scores; frailty; mortality.

Figure 1.

Consort diagram of study population. RT-PCR: reverse transcription polymerase chain reaction. *Hospital acquired COVID-19 defined as new symptoms and a SARS-CoV-2 RT-PCR positive ⩾8 days following admission.

Figure 2.

Alluvial plot illustrating patients’ ECOG performance status stratified by ICU admission and all-cause mortality. Colours represent patient’s ECOG performance status ranging from 0 – fully active, 1 – restricted in strenuous activity, 2 – able to self-care, 3 – limited self-care and 4 – bedbound. All patients for whom complete data were available for their performance status, ICU admission and mortality outcome were included in this plot (99.5% (723/726)). ECOG: Eastern Cooperative Oncology Group; ICU: intensive care unit.

Figure 3.

Forest plot demonstrating predictors of all cause inpatient mortality and ICU admission in patients with COVID-19. Multivariate stepwise regression modelling examined the association of clinical characteristics with all cause inpatient mortality and ICU admission as the response variables. COPD: chronic obstructive pulmonary disease; ECOG: Eastern Cooperative Oncology Group; ICU: intensive care unit; CRP: C-reactive protein; SaO₂: oxygen saturations. Unit of measurement: age years, respiratory rate breaths per minute, oxygen saturations percentage, creatinine µmol/L, CRP mg/L, admission pulse beats per minute, haemoglobin g/L, neutrophil count 10⁹/L, lymphocyte count 10⁹/L. Definition: ECOG performance status; 0 – fully active, 1 – restricted in strenuous activity, 2 – able to self-care, 3 – limited self-care and 4 – bedbound.