Background: Studies on the influence of diabetes mellitus on the radiological presentation
of pulmonary tuberculosis performed so far yielded inconsistent results. We aimed to
summarize the relevant evidence on this topic systematically.
Methods: We systematically searched PubMed/MEDLINE (1980–2016) and the references of
related articles (English-language reports) for observational studies that compared the radiological
presentation of pulmonary tuberculosis in diabetes and non-diabetes patients. Results: A total of
fifteen studies that enrolled 2,020 diabetic patients and 5,280 controls were included in this
systematic review. None of the included studies showed any significant difference in the upper
lobe involvement and or in bilateral disease between diabetes and non-diabetes patients. However,
lower lung field cavitary disease was found to be more frequent (relative risks ranging from 2.76,
95% CI 2.28-3.35 to 4.47, 95% CI 2.62-7.62) in patients with poor glycemic control (HbA1C
>9%). Similarly, a significantly higher proportion of cavitary disease in diabetes patients was reported
by 7 out of 15 studies, the meta-analysis of cavities of any size/site also showed the
significantly higher risk of cavitary disease in diabetes patients (p-value = 0.0008). Three studies
stratified the presence of cavities by diabetes control status, finding a higher proportion of cavities
in uncontrolled diabetic patients (relative risks ranging from 1.85, 95%CI 1.34-2.55 to 3.59, 95%CI
2.53-5.11). One out of four studies found a significantly higher proportion of nodular infiltrations
in diabetes versus non-diabetes patients.
Conclusion: While there is no difference in localization of lung lesions between patients with diabetes
and non-diabetes, our review found that the risk of cavitary disease is relatively higher in
diabetes patients. It is essential for researchers to unify the criteria for diabetes diagnosis, patient
selection, and radiographic severity and stratify the results by the potentially confounding factors.