In a recent study published in the Annals of Family Medicine, researchers estimated the post-coronavirus disease 2019 (COVID-19) conditions (PCC) or long COVID prevalence among United States (US) adults infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).

​​​​​​​Study: Post-COVID Conditions in US Primary Care: A PRIME Registry Comparison of Patients With COVID-19, Influenza-Like Illness, and Wellness Visits. Image Credit: Photoroyalty/Shutterstock.com

Background

COVID-19 considerably influences United States health, resulting in chronic illnesses typically detected in primary care settings.

The secondary COVID-19 wave of chronic symptoms may increase the COVID-19 burden on US residents. While severe COVID-19 disease and hospital admission may raise the likelihood of PCC, people with mild-moderate SARS-CoV-2 infection may also experience chronic symptoms.

Existing research on PCC symptoms is expanding; however, there are constraints, especially concerning healthcare delivery in the US. Issues include low generalizability owing to patient identification criteria, a lack of variety in patient features, inadequate follow-up time, and unpredictability in outcome measurements.

Existing studies are prospective and estimate the prevalence rates of preselected symptoms, which may not require general population healthcare or a diagnosis due to low severity.

About the study

In the present study, researchers evaluated the PCC burden and determined the cumulative morbidity rate for COVID-19 patients pre- and post-infection in primary care settings.

The researchers analyzed the American Family Cohort (AFC) national primary care registry data to identify study patients between January 2017 and March 2022, including 3.90 million US residents having 32 million healthcare visits.

Eligible participants visited primary care practices at least once in 12 or more months before COVID-19 and one or more visits two weeks to one year before diagnosis, excluding those who turned inactive within three months of their diagnosis.

The researchers performed propensity score matching to assess the individual and cumulative prevalence of 17 PCC categories.

They compared individuals infected with SARS-CoV-2 in 2020-2021 with (i) historical control individuals having influenza-like illness (ILI) in 2018 and (ii) contemporaneous controls seen for preventive or wellness visits in 2020-2021.

The researchers identified COVID-19 patients using the International Classification of Diseases, tenth revision, and clinical modification (ICD-10-CM) codes, diagnosed between April 2020 and October 2021. Historical controls were diagnosed with ILI between January and December 2018 using the Systematized Nomenclature of Medicine (SNOMED), ICD-9-CM, and ICD-10-CM codes.

The team identified contemporaneous controls for 2020 (between April and December) and 2021 (between January and October) using current procedural terminology (CPT) codes.

The researchers used multivariable logistic regressions for analysis, controlling for age, gender, race, ethnicity, socioeconomic deprivation, pre-diagnosis or pre-inclusion healthcare use, and pre-diagnosis or pre-inclusion morbidity in the diagnostic categories, month, and year of diagnosis or inclusion.

They performed secondary analyses, restricting the sample population to ILI and COVID-19 patients visiting primary care clinics at least once, three or more months after diagnosis.

Results

The researchers identified 28,215 individuals infected with SARS-CoV-2 and 235,953 ILI patients. COVID-19 patients had higher prevalences of diabetes mellitus type 2 (12% versus 10%), breathing difficulties (4.2% versus 1.9%), sleep disturbances (3.5% versus 2.4%), and fatigue (3.9% versus 2.2%).

However, the team found no differences in the postdiagnosis monthly trend in cumulative morbidity between ILI and COVID-19 patients. Relative to contemporaneous wellness controls, COVID-19 patients had higher prevalence rates for type 2 diabetes and breathing difficulties.

The secondary analysis revealed that COVID-19 and ILI patients had similar cumulative morbidity at diagnosis, but there was a higher divergence after six months. The average number of problems grew from 0.5 at diagnosis to 0.7 after six months, while ILI patients had a reduction from 0.5 to 0.6.

COVID-19 patients exhibited higher monthly increases in cumulative morbidity, whereas ILI patients had a 0.006 lower rise.

The study showed that COVID-19 patients and wellness controls had comparable rates of different diagnoses. In 2020, patients had a greater morbidity rate for respiratory issues and type 2 diabetes mellitus than controls. In 2021, patients had higher rates of these disorders.

Conclusion

The study found a modest prevalence of post-COVID symptoms in primary care practices, such as exhaustion, sleep disruptions, and breathing difficulties. These situations are less severe than those encountered in hospitals and specialist settings.

The study underlines the significance of ongoing PCC monitoring to assess their epidemiology, morbidity, and longevity.

The team detected PCC symptoms in 12% of individuals following SARS-CoV-2 infection, with prevalence below 12% for 17 diagnostic categories at six months. Future studies should investigate PCC in various patient situations, considering changes in clinical care capability.