TABLE 1.
Reasons of increased severity of covid‐19 in diabetes and obesity based on various studies
| Impact of diabetes on covid‐19 | Evidence | References |
|---|---|---|
| Aggravated inflammatory storm | Postulated | 24‐32 |
| Higher NLR, hsCRP and procalcitonin | ||
| Higher interleukin (IL)‐6, ferritin, fibrinogen and D‐dimer | ||
| Immune system dysfunction | Established | 33‐55 |
| Impaired innate immune defences | ||
| Impaired adaptive immune defences | ||
| Lung injury associated with diabetes | Postulated | 56‐60 |
| Physiological and structural abnormalities in lung | ||
| Pulmonary microangiopathy | ||
| Increased infectivity and virulence of virus | Postulated |
61, 62, 66‐71, 75, 76 |
| Abnormal expression of ACE2 | ||
| Increased plasmin | ||
| Increased furin | ||
| Diabetes‐related comorbidities | Established | 3–6, 16–19 |
| Obesity | ||
| Cardiovascular disease | ||
| Renal damage | ||
| Psychiatric disease | ||
| Impact of obesity on covid‐19 | ||
| Immune system dysfunction | Established | 114‐144 |
| Chronic inflammation state | ||
| Interferes with cellular responses | ||
| Imbalanced crosstalk between immune and metabolic system | ||
| Complement system overactivation | Postulated | 145, 146 |
| Altered lung mechanics and physiology | Postulated | 147‐150 |
| Increased airway resistance | ||
| Abnormal topographical distribution of ventilation | ||
| Reduced lung volumes and decreased lung compliance | ||
| Ventilation‐perfusion mismatching | ||
| Respiratory muscle inefficiency | ||
| High risk of pulmonary embolism | ||
| Increased infectivity and virulence of virus | Postulated |
66‐68, 154‐158 |
| High ACE2 expression | ||
| Elevated viral titers | ||
| Prolonged viral shed | ||
| Delayed clearance | ||
| Increased viral evolution and diversity | ||
| Obesity‐related comorbidities | Established | 3–6, 16–19 |
| Diabetes | ||
| Cardiovascular disease | ||
| Atherosclerosis | ||
| Psychiatric disease |
Abbreviations: ACE 2, angiotensin‐converting enzyme 2; COVID‐19: coronavirus disease 2019; NLR, neutrophil‐to‐lymphocyte ratio; hsCRP, high‐sensitivity C reaction protein.