Table 1.
Risk factors for poor outcome in COVID-19.
| Risk factors | Association with COVID-19 |
|---|---|
| Demographic characteristics | |
| Age | Children and younger people generally exhibit more asymptomatic or mild cases, whereas older patients are at higher risk for severe cases and death (136–138). |
| Sex | The male sex is associated with higher infection rates and worse outcomes compared with the female sex (138, 143–145). |
| Socioeconomic status | People with lower income are at increased risk of COVID-19 infection and higher mortality compared to those with higher income (146, 147). |
| Comorbidities | |
| Hypertension | Most common comorbidity among COVID-19 patients, increases risk for poor outcome (138–140, 143) |
| Heart disease | Increases risk for poor outcome (138–141, 143) |
| Diabetes mellitus | Type 1 and type 2 diabetes as well as uncontrolled hyperglycemia increase the risk for poor COVID-19 outcome (139, 140, 143, 148–150). The association between high HbA1c and increased mortality remains controversial (151–154). Especially for type 2 diabetes, use of insulin is linked to higher mortality (153, 155). |
| COPD | Increases risk for poor outcome (139, 140, 143, 156) |
| Chronic kidney disease | Increases risk for poor outcome (141, 157) |
| Obesity | Increases risk for poor outcome (140–143) |
| Cancer | Increases risk for poor outcome (139, 141, 158) |
| Chronic liver disease | Increases risk for poor outcome (159, 160) |
| Genetic factors | |
| ACE2 (Angiotensin-converting enzyme 2) | Some polymorphisms increase susceptibility to SARS-CoV-2 (e.g., S19P, K26R, E23K), others hinder interactions between the spike protein and ACE2 (e.g., K31R, N33I, E329G) (161, 162). |
| TMPRSS2 (Transmembrane serine protease 2) | Some variants are linked to increased TMPRSS2 expression and higher susceptibility to SARS-CoV-2 (e.g., rs12329760) (163). |
| HLA (Human leukocyte antigen) | Variants encoding proteins with low binding affinity to SARS-CoV-2 (e.g., B*46:01, C*14:02) increase vulnerability, whereas variants encoding proteins with high binding affinity to SARS-CoV-2 (e.g., B*15:03, A*02:02) encourage immunity (164, 165). |
| ABO (blood groups) | Higher risk of infection for blood type A, lower risk for blood type O (166, 167). |
| Lifestyle | |
| Smoking | Increases risk for poor outcome (156, 168) |
| Alcohol abuse | Uncertain, likely increases risk for poor outcome (169, 170) |
| Physical activity | Decreases risk for poor outcome (171, 172) |
*
indicates Nomenclature of HLA alleles.