Higher HbA1c Levels Increase the Risk of Cellulitis

Patients with diabetes who have higher HbA1c / worse glucose control may have a higher risk of infections like cellulitis.

Diabetes affects many complications, including nephropathy, retinopathy, and stroke. Hux and Shaw’s study shows a higher risk of infections and death from infection in patients with diabetes. A previous observational study demonstrated that patients with better glucose control could lower the risk of these complications. However, it is uncertain if there is a correlation between infection and diabetes control because studies have been inconsistent. A few studies have revealed an increased risk of pneumonia and urinary tract infection in patients with worse glucose control. However, Gorter et al. showed that glucose control was not linked to the risk of urinary tract infections in women with diabetes.

This prospective cohort study investigates infections related to the level of glucose control in people with diabetes. Using the Meuhedet database, 56,626 participants with diabetes born before 1964 were identified. The study was done between 2014 to 2017 in Israel. Participants with low hemoglobin, cancer, deficiency of G6PD, and on dialysis were excluded. A total of 33,637 were included in this study after meeting the exclusion criteria. Cellulitis, upper respiratory tract infection (URTI), urinary tract infection (UTI), and pneumonia were a few infections that were evaluated. The average age included was 65.9 years, and 47% of the participants were women; 21% of participants were on insulin. The study utilized multivariate logistic regression analysis to establish the chance of developing an infection based on the HbA1c level.

The results showed that 4,806 participants had an infection two months after the first HbA1c test was taken. The study recognized 407 participants with cellulitis, 3,161 participants with an upper respiratory tract infection,1,004 participants with a urinary tract infection, and 441 participants with pneumonia. The average HbA1c level after developing an infection was 7.2%. The highest average HbA1c level was 7.6% for participants following the diagnosis of cellulitis, and the lowest was 7.1% following urinary tract infection diagnosis.

After comparing the HbA1c level with those with, versus without, an infection, there was an increased risk of cellulitis for patients with a level greater than 7.5% (x2 [1] =14.99; P < 0.001). Using the multivariate logistic regression, patients with an HbA1c greater than 7.5% had a 1.4 times higher likelihood of cellulitis (OR 1.4; CI 1.1–1.7). Patients with a BMI greater than 35 had a 2.6 times higher chance of developing cellulitis (OR 2.6; CI 1.7–3.9). Also, participants with Parkinson’s disease had a higher chance of developing cellulitis (OR 2.0; CI 1.3–3.3). Participants with the peripheral vascular disease had a three times higher chance of cellulitis (OR 3.0; CI 2.4–3.8). The prednisone was associated with an increased risk (OR 2.3; CI 1.3–4.0). The risk of cellulitis increases by 12% when the HbA1c was higher by 1%.

Patients with uncontrolled diabetes had a higher risk of a cellulitis diagnosis. There was a significant increase risk of cellulitis among participants with an HbA1c level greater than 7.5%. Any 1% increase in HbA1c was associated with a higher risk of cellulitis. From all the infections evaluated in the study, only cellulitis had significantly increased risk. Due to the increased risk for patients who used prednisone, further evaluations should explore the link between steroids and the risk of infections.  

Practice Pearls:

• The risk of cellulitis may decrease with improved HbA1c levels.
• Participants had a higher risk of cellulitis if they had obesity, were previously treated with prednisone, had peripheral vascular disease or Parkinson’s disease.
• The odds of having cellulitis are 40% higher when HbA1c levels are more significant than 7.5%.

Zacay, Galia, et al. “Glycemic Control and Risk of Cellulitis.” Diabetes Care, vol. 44, no. 2, American Diabetes Association, Feb. 2021, pp. 367–72, doi:10.2337/dc19-1393.

 “Poor Glycemic Control Raises Risk of Infections in Diabetes Patients.” U.S. Pharmacist – The Leading Journal in Pharmacy, Jan 27, 2021.

Alexis Dunn, PharmD. Candidate, Florida Agricultural & Mechanical University, College of Pharmacy and Pharmaceutical Sciences