Underlying Medical Conditions Associated with Higher Risk for Severe COVID-19: Information for Healthcare Professionals

This page summarizes data from published reports, scientific articles in press, unreviewed pre-prints, and internal data that were included in literature reviews conducted by subject matter experts. Evidence used to inform the list of underlying conditions was determined by CDC reviewers based on available literature about COVID-19 at time of review. The information reflects evidence regarding underlying medical conditions and is intended to help healthcare professionals make informed decisions about patient care and to increase the awareness of risk among their patients.

The methods used to assess the conditions have changed during the pandemic as the amount of literature and types of studies increased. For instance, preliminary versions of this list focused on providing the latest information based on descriptive data. As the literature grew, CDC investigators categorized the literature by study design.

Since May 2021, the process has been updated to include a CDC-led review process that uses rigorous systematic review methods. To learn more about the process of CDC’s systematic reviews, see CDC systematic review process.

Age is the strongest risk factor for severe COVID-19 outcomes. Patients with one or multiple of certain underlying medical conditions are also at higher risk.^(1–3)

Additionally, being unvaccinated or not being up to date on COVID-19 vaccinations also increases the risk of severe COVID-19 outcomes.

Providers should consider the patient’s age, presence of underlying medical conditions and other risk factors, and vaccination status in determining the risk of severe COVID-19-associated outcomes for any patient.

Studies have shown that COVID-19 does not affect all population groups equally. Three important factors are age, race, and ethnicity.

Age remains the strongest risk factor for severe COVID-19 outcomes, with risk of severe outcomes increasing markedly with increasing age. Based on data from the National Vital Statistics System (NVSS) at NCHS (Risk for COVID-19 Infection, Hospitalization, and Death By Age Group), compared with ages 18–29 years, the risk of death is 25 times higher in those ages 50–64 years, 60 times higher in those ages 65–74 years, 140 times higher in those ages 75–84 years, and 340 times higher in those ages 85+ years. Notably, these data include all deaths in the United States that occurred throughout the pandemic, from February 2020 to July 1, 2022, including deaths among unvaccinated individuals.

Risk of severe outcomes is increased in people of all ages with certain underlying medical conditions and in people who are 50 years and older, with risk increasing substantially at ages >65 years.^4,5 Residents of long-term care facilities are also at increased risk, making up less than 1% of the U.S. population but accounting for more than 35% of all COVID-19 deaths.^6-10

The COVID-19 pandemic has highlighted racial, ethnic, and socioeconomic disparities in COVID-19 illnesses, hospitalizations, and deaths.^11-13 Some racial and ethnic minority groups are also more likely to face multiple barriers to accessing health care including lack of insurance, transportation, child care, or ability to take time off from work.

Studies have identified racial and ethnic differences in at-home COVID-19 test use, vaccination coverage, and access to outpatient therapeutics.14-16 Data has shown that compared to non-Hispanic White people, people from racial and ethnic minority groups are more likely to be infected with SARS-CoV-2 (the virus that causes COVID-19). Once infected, people from racial and ethnic minority groups are more likely to be hospitalized, be admitted to the ICU, and die from COVID-19 at younger ages.¹⁷

We are still learning about how the environments where people live, learn, and work can influence the risk for infection and severe COVID-19 outcomes.

Evidence used to inform the list of underlying medical conditions that increase a person’s risk of severe illness from COVID-19 is presented in alphabetical order by study design section. Conditions are categorized as higher risk, suggestive higher risk, and mixed evidence.

Higher risk is defined as an underlying medical condition or risk factor that has a published meta-analysis or systematic review or underwent the CDC systematic review process. The meta-analysis or systematic review demonstrates a conclusive increase in risk for at least one severe COVID-19 outcome.

Suggestive higher risk is defined as an underlying medical condition or risk factor that did not have a published meta-analysis or systematic review or did not undergo the CDC systematic review process. The evidence is supported by mostly cohort, case-control, or cross-sectional studies. (Systematic reviews are available for some conditions for children with underlying conditions.)

Mixed evidence is defined as an underlying medical condition or risk factor that has a published meta-analysis or systematic review or underwent the CDC systematic review process. The meta-analysis or systematic review is inconclusive, either because the aggregated data on the association between an underlying condition and severe COVID-19 outcomes are inconsistent in direction or there are insufficient (or limited) data on the association between an underlying condition and severe COVID-19 outcomes.

• Limited: The evidence consists of one study, or several small studies with no comparison group, limiting the conclusions that can be drawn.
• Inconsistent: The evidence suggests no clear direction of association, meaning no firm conclusions can be drawn.

Footnotes:
* Indicates presence of evidence for pregnant and non-pregnant people

‡ Underlying conditions for which there is evidence in pediatric patients

^ Risk may be further increased for people receiving dialysis

• Ask patients about their concerns about vaccines and therapy. Consider using an evidence-based and culturally sensitive approach, such as motivational interviewing. Try to provide trusted sources of information and other resources.
• Encourage testing, as well as early treatment, for patients who are eligible.
• Facilitate access to culturally and linguistically appropriate resources.
• Reduce barriers to accessing current outpatient treatments.

Underlying Medical Conditions and Severe Illness Among 540,667 Adults Hospitalized With COVID-19, March 2020–March 2021

This study used data from the Premier Healthcare Database, which represents approximately 20% of all inpatient admissions in the United States since 2000. This cross-sectional study of 540,667 adults hospitalized with COVID-19 included both inpatients and hospital-based outpatients with laboratory-diagnosed COVID-19 from March 1, 2020, through March 31, 2021. The database included reports from 592 acute care hospitals in the United States. The study was designed to examine risk factors associated with severe outcomes of COVID-19 including admission to an ICU or stepdown unit, invasive mechanical ventilation, and death.

Main Findings:

• Certain underlying medical conditions were associated with an increased risk for severe COVID-19 illness in adults.
• Having multiple conditions was also associated with severe COVID-19 illness.
• Obesity, diabetes with complications, and anxiety and fear-related disorders had the strongest association with death.
• The number of frequent underlying medical conditions (present in ≥10.0% of patients) increased with age.²⁰⁷

Adapted from Sources:

• Kompaniyets L, Pennington AF, Goodman AB, Rosenblum HG, Belay B, Ko JY, et al. Underlying Medical Conditions and Severe Illness Among 540,667 Adults Hospitalized With COVID-19, March 2020–March 2021. To learn more, visit the Preventing Chronic Disease article: https://www.cdc.gov/pcd/issues/2021/21_0123.htm
• Pennington AF, Kompaniyets L, Summers AD, Danielson ML, Goodman AB, Chevinsky JR, Preston LE, Schieber LZ, Namulanda G, Courtney J, Strosnider HM, Boehmer TB, Mac Kenzie WR, Baggs J, Gundlapalli AV, Risk of Clinical Severity by Age and Race/Ethnicity Among Adults Hospitalized for COVID-19—United States, March–September 2020, Open Forum Infectious Diseases, Volume 8, Issue 2, February 2021. To learn more, visit: https://doi.org/10.1093/ofid/ofaa638

Source: Kompaniyets L, Pennington AF, Goodman AB, Rosenblum HG, Belay B, Ko JY, et al. Underlying Medical Conditions and Severe Illness Among 540,667 Adults Hospitalized With COVID-19, March 2020–March 2021. To learn more, visit the Preventing Chronic Disease article: https://www.cdc.gov/pcd/issues/2021/21_0123.htm