People living with chronic conditions are more susceptible to infection for a variety of reasons.

What is a Chronic Condition?

The term chronic condition refers to a broad spectrum of chronic and complex health conditions (both communicable and non-communicable), including mental illness, trauma, disability and genetic disorders (Australian Health Ministers’ Advisory Council 2017).

More specifically, chronic conditions can be defined as conditions that:

• Have several and complex causes
• Can occur as a standalone condition or comorbidity
• Generally have a gradual onset
• Can occur at any age but are more prevalent with older age
• Can adversely affect quality of life and cause limitations or disability
• Are long-term and persistent, often causing gradual deterioration of health and loss of independence, and
• May contribute to premature mortality, even if not immediately life-threatening.

(Australian Health Ministers’ Advisory Council 2017; DoHaAC 2020)

Chronic conditions are common, with half of all Australians experiencing at least one of the following:

• Arthritis
• Asthma
• Back pain
• Cancer
• Cardiovascular disease
• Chronic obstructive pulmonary disease (COPD)
• Diabetes
• Mental illness.

(DoHaAC 2020)

Chronic Conditions and Infection

Clients living with chronic conditions may be more susceptible to infectious illnesses for a number of reasons, including:

• Having a compromised immune system
• The use of certain medications (e.g. antibiotics, steroids, certain cancer medications)
• Treatments and procedures that provide additional pathways for pathogens to enter the body (e.g. catheters and drain tubes)
• Exposure to healthcare environments
• Poor nutrition due to loss of appetite or decreased access (due to limited mobility, money or time)
• Weight gain or loss.

(CDC 2016; Dobner & Kaser 2017)

Healthcare-Associated Infections

People who are immunocompromised or have certain conditions such as diabetes are more susceptible to developing healthcare-associated infections (HAIs) (Better Health Channel 2019). Accessing healthcare services and spending time in healthcare environments may also increase the risk of HAIs for people with chronic conditions.

Specific risk factors for HAIs include:

• Long hospital stays
• Surgical procedures, with the length and type of surgery potentially increasing the risk
• Inadequate hand hygiene by clients and staff
• Invasive procedures such as catheter or cannula insertion
• Having wounds, incisions, burns, ulcers and other areas of non-intact skin
• Antibiotic use, which can cause antimicrobial resistance
• Having several chronic conditions
• Frequent exposure to healthcare environments
• Admission to critical care.

(Better Health Channel 2019; Monegro et al. 2023)

Reducing the Risk of Healthcare-Associated Infections

In order to reduce the risk of clients living with chronic conditions developing HAIs, health service organisations should:

• Implement infection prevention and control procedures including:
  • Hand hygiene
  • Surface, environment and equipment cleaning
  • Aseptic technique
• Ensure appropriate use of antibiotics
• Undertake HAI surveillance.

(Better Health Channel 2019)

Clients Taking Medicines for Chronic Illness

The prevalence of chronic conditions increases with age, and many older adults live with multimorbidity (several chronic conditions). This, in turn, means that polypharmacy is common among older adults. Two-thirds of older Australians aged over 75 are taking five or more medicines (ACSQHC 2021).

The use of certain medicines may increase the risk or severity of infection (CDC 2016).

Antibiotics

Read: Appropriate Antibiotic use in Aged Care

Immunosuppressants

Some chronic autoimmune conditions may require the client to take immunosuppressant medicines. These conditions include:

• Psoriasis
• Lupus
• Rheumatoid arthritis
• Crohn’s disease
• Multiple sclerosis
• Alopecia areata.

(Giorgi 2019)

Immunosuppressants may also be used for organ transplant recipients to prevent organ rejection (Jones 2020).

As immunosuppressants work by weakening the immune system, they increase the risk of infection, potentially leading to morbidity or mortality (Giorgi 2019; Ponzo & Hong 2017).

Clients taking immunosuppressants may als be susceptible to opportunistic infections such as cytomegalovirus (CMV) and Epstein-Barr virus (EBV), or reactivated latent infections such as varicella-zoster virus (VZV) and herpes simplex virus (HSV) (Loechelt et. al 2014).

Immunosuppressants have the potential to alter the clinical properties of infections (for example, the client may not display the classic symptoms of an infection), making them more difficult to recognise. Infections may be severe and progress rapidly and may become recurrent (Jones 2020; St. Jude Children's Research Hospital 2014).

Therefore, before commencing any immunosuppressants, it is essential to:

• Screen the client for infection risk factors such as:
  • Comorbidity
  • Age
  • Occupation
  • History of travel to areas where there is an endemic disease
  • History of high-risk sexual activity or drug abuse
  • Exposure to tuberculosis
  • History of blood transfusion
• Screen the client for active or latent infections including Epstein-Barr virus, cytomegalovirus (CMV), herpes simplex virus, varicella-zoster virus (VZV), human immunodeficiency virus (HIV), hepatitis B and hepatitis C
• Ensure the client has received all recommended vaccines, as immunosuppressants reduce their effectiveness (live vaccines must be avoided after commencing immunosuppressants)
• Provide client education in regards to hand hygiene, infection prevention, signs of infection to look out for and when to seek medical advice.

(Ponzo & Hong 2017; Loechelt et. al 2014)

If a client develops an infection while taking immunosuppressants, the immunosuppressants may need to be reduced, replaced or stopped, depending on the severity of the infection (Jones 2020). This will be determined by a medical practitioner.

Corticosteroids and Tumour Necrosis Factor Inhibitors

Corticosteroids and tumour necrosis factor (TNF) inhibitors are used to treat some chronic conditions. They may weaken the immune system and increase the risk of fungal infection (CDC 2020).

• Corticosteroids are used to treat arthritis, asthma, allergic reactions and some autoimmune diseases (e.g. lupus. Inflammatory bowel disease).
• TNF inhibitors are used to treat autoimmune diseases including rheumatoid arthritis, psoriasis and inflammatory bowel disease.

(CDC 2020)

While some fungal infections such as oral candidiasis are generally mild, others may be serious and even life-threatening (CDC 2020).

Generally, the risk of fungal infection depends on the length of treatment, dosage and country where the client resides (as some pathogenic fungi are more prevalent in certain places) (CDC 2020).

Clients Living With Specific Chronic Conditions

Cancer

Clients with cancer are more susceptible to infection.

Cancer can lead to poor nutrition, reduced white blood cells, internal blockages due to tumours and an overall weakened immune system, all of which increase the risk of infection (ACS 2020).

Some particular types of cancer, including those that affect the bone marrow (e.g. lymphoma, leukemia and multiple myeloma) and those that spread to the bone are more likely to lead to infection (ACS 2020; Cancer.Net 2020).

Furthermore, cancer treatments can cause short (e.g. chemotherapy) or long-term (e.g. splenectomy) interference with the immune system, leaving clients more susceptible (ACS 2020).

Cancer treatments that may weaken the immune system include:

• Surgery
• Chemotherapy
• Radiation therapy
• Targeted therapy
• Immunotherapy
• Stem cell transplant.

(ACS 2020)

The presence of comorbidity also increases the risk (Cancer.Net 2020).

Chronic Obstructive Pulmonary Disease

Clients with COPD are more susceptible to developing respiratory infections (Sepsis Alliance 2023).

Furthermore, respiratory infections often worsen the symptoms of COPD, which increases the risk of the client experiencing more severe respiratory infections (DispatchHealth 2019).

Diabetes

Clients with diabetes may have a compromised immune system due to high blood glucose, which impairs the white blood cells’ ability to travel to infected areas and kill pathogens. Diabetes can also cause plaque to concentrate in the blood vessels, reducing blood supply to areas of infection. This further compromises the body’s ability to fight infections and heal (Healthwise 2023).

Common infection sites include the bladder, kidneys, vagina, gums, feet and skin (WebMD 2023).

Conclusion

Clients with chronic conditions are more susceptible to infection for several reasons, with the type of chronic condition(s), exposure to healthcare settings, and medicines and treatments all contributing to this risk.

While specific risk factors and management options will depend on the nature of the client’s chronic condition(s), the most effective way for healthcare staff to universally reduce the risk of infection is to practice correct infection control and prevention procedures.