Predictors of nirmatrelvir–ritonavir receipt among COVID-19 patients in a large US health system

A clear understanding of real-world uptake of nirmatrelvir-ritonavir for treatment of SARS-CoV-2 can inform treatment allocation strategies and improve interpretation of effectiveness studies. We used data from a large US healthcare system to describe nirmatrelvir-ritonavir dispenses among all SARS-CoV-2 positive patients aged ≥ 12 years meeting recommended National Institutes of Health treatment eligibility criteria for the study period between 1 January and 31 December, 2022. Overall, 10.9% (N = 34,791/319,900) of treatment eligible patients with SARS-CoV-2 infections received nirmatrelvir-ritonavir over the study period. Although uptake of nirmatrelvir-ritonavir increased over time, by the end of 2022, less than a quarter of treatment eligible patients with SARS-CoV-2 infections had received nirmatrelvir-ritonavir. Across patient demographics, treatment was generally consistent with tiered treatment guidelines, with dispenses concentrated among patients aged ≥ 65 years (14,706/63,921; 23.0%), and with multiple comorbidities (10,989/54,431; 20.1%). However, neighborhoods of lower socioeconomic status (upper third of neighborhood deprivation index [NDI]) had between 12% (95% CI: 7-18%) and 28% (25-32%) lower odds of treatment dispense over the time periods studied compared to the lower third of NDI distribution, even after accounting for demographic and clinical characteristics. A limited chart review (N = 40) confirmed that in some cases a decision not to treat was appropriate and aligned with national guidelines to use clinical judgement on a case-by-case basis. There is a need to enhance patient and provider awareness on the availability and benefits of nirmatrelvir-ritonavir for the treatment of COVID-19 illness. Nirmatrelvir is an oral antiviral that, when co-administered with ritonavir within 5 days of symptom onset, is highly effective at reducing the risk of hospitalization and death among patients with mild-to-moderate COVID-19 who are at risk for progression to severe disease 1-6 . Accordingly, nirmatrelvir-ritonavir received Emergency Use Authorization (EUA) from the Food and Drug Administration (FDA) in December 2021. Nirmatrelvir-ritonavir treatment eligibility depends on the presence of underlying risk factors for progression to severe COVID-19 including age and vaccination status, weight, renal and hepatic function, and current use of select medications known to interact with nirmatrelvir-ritonavir. In the United States, initial guidelines recommended a tiered prioritization approach to treatment based on clinical risk 7 . As knowledge and treatment availability expanded throughout 2022, recommendations adapted to widen treatment eligibility criteria, eventually including all persons aged 65 years and older or aged 12 years and older with one or more clinical risk factors for progression to severe COVID-19. More recently (i.e., after our study period), treatment eligibility criteria have expanded further to include all adults aged..