Using data from the period of omicron dominance in England, the COVID-19 risk prediction algorithm QCOVID4 more accurately identified individuals at the highest levels of absolute risk for targeted interventions than the approach adopted by NHS Digital, a study shows. The algorithm, which now includes vaccination dose and previous SARS-CoV-2 infections, predicted COVID-19–related deaths.
The cohort study data for 1.3 million adults in the derivation cohort and 150,000 adults in the validation cohort came from the QResearch database linked to English national data on COVID-19 vaccinations, SARS-CoV-2 test results, hospital admissions, and cancer and mortality data for the Dec. 2021 to Mar. 2022 period, with follow-up through June 2022. Based on a primary outcome of COVID-19–related death, the study showed: “Of 1,297,922 people with a positive test result for SARS-CoV-2 infection in the derivation cohort, 18,756 (1.5%) had a covid-19 related hospital admission and 3,878 (0.3%) had a covid-19 related death during follow-up. The final QCOVID4 models included age, deprivation score and a range of health and sociodemographic factors, number of covid-19 vaccinations, and previous SARS-CoV-2 infection. The risk of death related to covid-19 was lower among those who had received a covid-19 vaccine, with evidence of a dose-response relation (42% risk reduction associated with one vaccine dose and 92% reduction with four or more doses in men). Previous SARS-CoV-2 infection was associated with a reduction in the risk of covid-19 related death (49% reduction in men). The QCOVID4 algorithm for covid-19 explained 76.0% (95% confidence interval 73.9% to 78.2%) of the variation in time to covid-19 related death in men with a D statistic of 3.65 (3.43 to 3.86) and Harrell’s C statistic of 0.970 (0.962 to 0.979). Results were similar for women. QCOVID4 was well calibrated. QCOVID4 was substantially more efficient than the NHS Digital algorithm for correctly identifying patients at high risk of covid-19 related death. Of the 461 covid-19 related deaths in the validation cohort, 333 (72.2%) were in the QCOVID4 high risk group and 95 (20.6%) in the NHS Digital high risk group.”