Patients with diabetes diagnosed with tuberculosis are more likely to present with advanced disease and cavitation in the lungs vs. those with TB who do not have diabetes, according to findings from a cross-sectional study published in the Journal of the Endocrine Society.
Several large-scale studies have demonstrated a higher TB incidence rate in patients with diabetes vs. those without diabetes, whereas the radiographic presentation of TB has been shown to be more severe in patients with diabetes, Charles F. Kreisel, MD, of the New Jersey Medical School at Rutgers University, and colleagues wrote in the study background. However, due to the larger TB burden abroad, most studies examining TB and diabetes have been conducted internationally, they added.
“As a result, there is need for further studying the relationships between tuberculosis and diabetes clinically in the United States,” the researchers wrote. “Of primary concern is that the relationship between tuberculosis and diabetes may be underappreciated, and as a result, the population of patients with both tuberculosis and diabetes may be undermanaged.”
Kreisel and colleagues analyzed chart data from all HIV-negative patients with TB who had diabetes at the time of TB diagnosis (n = 33) or had TB without diabetes (n = 40) receiving care at the Lattimore Clinic at New Jersey Medical School between 2009 and 2014. Researchers assessed demographic and clinical characteristics and chest X-ray data. The extent of disease on chest X-rays was graded using a scale from A to C, with A defined as limited disease (< 25% involvement), B defined as moderate disease (25% to 50% involvement) and C defined as severe disease (> 50% involvement).
Researchers found significant between-group differences for the extent of TB disease and for cavitation on the initial chest X-ray in patients with and without diabetes. Patients with both type 2 diabetes and TB were more likely to have initial chest X-rays characterized as grades B or C vs. those with TB but without diabetes (55% vs. 29%).
“Notably, all members of the [diabetes] group had evidence of disease on chest X-ray, whereas six members of the [diabetes negative] group showed no evidence of pulmonary disease on chest X-ray,” the researchers wrote.
Presence of cavitation was further grouped into presence or absence due to the small sample size, according to the researchers. Presence of cavitation was higher in the diabetes group vs. the TB-only group (24% vs. 5%). Initial sputum culture results were marginally different between groups, according to researchers, with 81% positive in the diabetes group vs. 62% positive in the TB-alone group (P = .07). Smear grade at the time of initial presentation was not different between groups, and there were no differences observed by diabetes status for BMI at time of diagnosis, type of TB or multidrug-resistant status, according to the researchers.
“These findings support recommendations to screen for and consider TB among diabetics with a high likelihood for infection,” they wrote. “Ultimately, the TB/[diabetes] population must be further studied within the United States to better determine proper management of this unique and increasing population.”