Impact of Diabetes Mellitus on Radiological Presentation of Pulmonary Tuberculosis in Otherwise Non-Immunocompromised Patients: A Systematic Review

Abstract

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.