Complications

Infectious Complications in Patients With Diabetes

Host defence of each diabetic, however, is compromised, and thus, diabetics are prone to all microbial colonisation, infection and invasion. With the dual jeopardy of a large diabetes pool especially in the elderly, the role of pneumococcal disease becomes relevant in the Indian context. Diabetics have a poor antibody response, with a host of cell-mediated immune abnormalities. They have decreased CD4/CD8 lymphocyte ratios, which lead to changes in natural killer cell function, reduced lymphocyte blastogenesis, defects in interleukin-2 function and reduced phagocytic function of monocytes. Diabetics have classically impaired leukocyte function and thus are predisposed to colonisation and pneumonia. Patients with diabetes have a high risk for microbiological infections (fungal, viral and bacterial), leading to complications with high morbidity and mortality. Clinically, the most important infections are fungal and bacterial infections of the skin, urinary tract and respiratory tract. Other factors associated with diabetes (age, renal disease and cardiovascular disease) have been shown to be significant comorbid factors that can increase the risk of sequel of certain infections.¹

People with diabetes are susceptible to pneumococcal infections and are at an increased risk for morbidity and mortality. Additional risk is associated with age ≥65 years and having chronic cardiovascular, pulmonary and renal diseases. Diabetes mellitus has been identified as an independent risk factor for developing respiratory tract infections. There are no data on the burden of lower respiratory infections in India. The WHO data from low- and middle-income countries suggest that lower respiratory tract infections remain the third leading cause of death. S. pneumoniae remains the major cause of pneumonia. Apart from pneumonia and its complications, viz., empyema and lung abscess, the pneumococcus also causes other clinical syndromes such as sinusitis, otitis media, trachea-bronchitis, bacteraemia, meningitis and peritonitis, some of which have high CFRs. Diabetes is a well-known risk factor for pneumococcal infections and predisposes individuals to nasopharyngeal colonisation with the pneumococcus which is associated with invasive infections. Pneumococcal pneumonia is the most common form of acute bacterial CAP. Bacteraemia is seen in nearly 30% (8%-50%) of individuals with pneumococcal infections, and of these, 15% to 20% are fatal despite treatment with antibiotics. Also, there are several studies which show that diabetes is one of the most common comorbidities in patients with pneumococcal infections.¹

CAP, community-acquired pneumonia; CD4, cluster of differentiation 4; CD8, cluster of differentiation 8; CFR, case fatality rate; WHO, World Health Organization.

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