COVID-19 & Chronic Diseases: What Doctors and Patients Need to Know

6 min read

SAR-CoV-2 has a circular connection to chronic diseases: those who have them are more susceptible to COVID-19 while those who get a severe form of COVID-19 are left prone to acquiring chronic diseases. Some are left with long-term organ damage.

COVID-19 affects different people differently. Most develop mild to moderate illness with symptoms like fever, dry cough and tiredness, aches and pains, headache, diarrhoea, loss of taste and smell etc and don’t need hospitalization.

A very few will need hospitalization due to the seriousness of the same symptoms and others symptoms that include – shortness of breath, chest pain, impairment of physical movement etc. Those who survive and recover are at an increased risk of chronic diseases, even if they didn’t have any pre-existing conditions.

Some complications include diabetes, heart diseases, respiratory diseases, kidney and liver diseases, gastrointestinal complications and obesity.

Thus it is essential to understand the relationship between COVID-19 and chronic diseases to manage susceptible patients optimally.

Diabetes and COVID-19

Though the research is still ongoing, some patients who have recovered from COVID-19 seem to develop diabetes or their existing diabetes gets progressively serious.

Diabetes as one of the major complication after covid recovery

(Photo: iStock)

This could be for many reasons. Hyperglycaemia observed in COVID-19 patients is perhaps caused by impaired glucose disposal and diminished insulin secretion. An Inflammatory condition in any individual can cause insulin resistance and increase hepatic glucose production.

Diabetics affected with severe COVID-19 need special care with emphasis on controlling glycemic levels. Most Type 2 diabetic patients have other syndromes like hypertension and dyslipidemia and need careful selection of agents to lower these. Care should also be taken with glucose lowering agents considering the risk of lactic acidosis.

Potassium balance is also a key consideration for diabetic patients.

Cardiovascular Disease and COVID-19

Research suggests that the pathology and metabolism of hypertension predisposes patients to severe COVID-19. Individuals with heart failure have significantly high levels of ACE2 at mRNA and protein levels, perhaps the reason for severe COVID-19 in the first place.

Cardiac injury is also one of the severe complications arising from it. Patients with coronary artery diseases show risk of myocardial infarction via a buildup of plaque in coronary vessels that become unstable with high inflammation.

Though ACE inhibitors and ARBs are used in heart failure, hypertension and post-myocardial infarction, their use in COVID-19 patients have been controversial as it has been associated with higher mortality. Many clinical studies however, have not confirmed association.

Thus care providers have been warned against discontinuing them as it could aggravate the heart condition of patients. NSAIDs are also discouraged as they can cause kidney impairment and sodium retention thus worsening the problem.

Respiratory Diseases

The susceptibility of asthmatic patients to respiratory viral infections is well known. Despite this, though it was anticipated that asthmatics would be more vulnerable to COVID-19, proof of the same is not as widespread as was expected. Despite this, asthmatic patients often have weakened lungs and immunity and thus the said precautions they take to protect themselves should be strengthened.

COPD i.e. Chronic Obstructive Pulmonary Disease, a chronic inflammatory lung disease that causes obstructed airflow from the lungs caused mainly by cigarette smoking, suggested that such patients would be greatly susceptible to COVID-19.

However, observations across the world showed little correlation in the initial months of the pandemic. Yet, further studies and more research showed that COPD patients were indeed at a higher risk of a poor outcome due to COVID-19 than those without it.

The lung – as almost everyone knows – is the organ most affected by the SARS-CoV-2 virus. Cytokine storms cause acute lung damage. Excessive release of cytokines causes inflammation leading to complications like ARDS. Pulmonary thrombosis also causes lung damage in COVID-19 patients.

One of the major impacts seen in COVID-19 survivors is long term pulmonary impairment. Pulmonary fibrosis, caused by accumulation of fibroblasts and extracellular matrix components like collagen in lung tissues, progressively increases with patients suffering persistent decline in lung function and eventually respiratory failure. Antifibrotic therapy as a prophylactic measure against possible long-term effects of COVID-19 could be an important intervention in COVID survivors.

Kidney Diseases

Kidney diseases severely impact COVID-19 prognosis and early detection of the same has been key to treating COVID patients. ACE2 has been known to aid viral entry to kidney tissues and thus play a key role in COVID induced kidney injury. Cytokine storms also have a direct role in causing renal tissue damage and acute tubular necrosis.

Even after recovery from COVID, a patient’s creatinine and urine output levels should be constantly monitored to prevent acute kidney injury in the long term.

Gastrointestinal Diseases

There’s evidence to suggest that gastrointestinal symptoms like diarrhoea, abdominal pain and loss of appetite, may precede respiratory symptoms in some COVID patients. Some evidence also suggests that patients with both COVID-19 AND gastrointestinal issues are more prone to complications like ARDS, liver injury and higher mortality.


The management of gastrointestinal complication is symptomatic both during COVID-19 and after recovery. Besides the requisite medication, hydration is critical for maintaining electrolyte balance. Monitoring potassium levels has also been suggested for such patients. Probiotics to replenish gut microbiota is also an effective strategy.

Liver Diseases

COVID-19 patients show elevated levels of crucial liver enzymes like ALT and AST and studies have shown this to be associated with the severity of COVID-19. Since liver is rich in ACE2, like the lungs, the liver seems to be a target of SARS-CoV-2.

liver is one of the main targets of SARS-CoV-2

(Photo: iStock)

Additionally, respiratory failure in COVID-19 patients induces anoxia that can affect liver function via an emerging hypoxic hepatitis. Cytokine storm and severe inflammation caused by COVID-19 also cause liver damage both in the short and long term.

Treatment of patients with many hepatotoxic agents like antibiotics, antivirals and steroids can itself initiate liver damage. Thus, management of liver both while one is suffering from COVID-19 and post their recovery, is of utmost importance.

Autoimmune Diseases

Those with autoimmune diseases are more susceptible to developing serious infections because of their weakened immunity caused by use of immunomodulatory drugs. COVID-19 has also shown to induce autoimmune and auto-inflamatory complications.


Blood Disorders

People with blood disorders like sickle cell disease, leukaemia, thalassemia, lymphocytopenia, thrombocytopenia, leukopenia etc. are immunodeficient and thus carry not just an excess risk for viral infections like SARS-CoV-2 but also developing severe form of it. In such patients, detection and close monitoring of haemoglobin levels is a must. Even post recovery, patients should take care of this.

The treatment varies depending on the type of blood disorder. Increased blood viscosity caused in either blood disorders or by COVID, require anticoagulation. Some may even require regular blood transfusion therapy.

In many cases it is advised that their platelet count, prothrombin time, activated partial thromboplastin time, D-dimer, and fibrinogen are monitored specifically during SARS-CoV-2 infection and some of them even after recovery.

Obesity and COVID-19

Link between obesity and viral respiratory infections like H1N1 has been long established. Data suggest similar risk for COVID-19 as well. The other issue is that even after one recovers from COVID-19, the long days of immobility could cause obesity in some recovered patients and lead to associated risks. Thus it is extremely important to watch BMI of recovered patients.

COVID-19 baffles because at times people over 100 survive it, while those in their 30s succumb. One hypothesis corroborated by some data and popularised by Nir Barzilai differentiates chronological age and biological age. A young person with comorbidities i.e. presence of more than one disease, is biologically older and at a higher risk of mortality from COVID-19 than an older person with no comorbidity.


This could also explain India’s high death rate despite a younger population. Its citizens might be chronologically young but in terms of underlying metabolic health, many suffering from – besides detected diseases – a string of undetected illnesses of heart, blood, lungs, kidney and liver.

Besides keeping track of other factors, a government making decisions about COVID-19 would do well to not miss this important factor as well.

(Dr Marcus Ranney is a medical doctor and Champion of Wellbeing. A global thought leader, he is currently engaged in efforts to advocate towards a better understanding of the relationship with the climate crisis and our health. He is also the author of the book At the Human Edge.)

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