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

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.

Predictors of time to sputum smear conversion in patients with pulmonary tuberculosis under treatment

Sputum acid-fast bacilli smear conversion is a fundamental index of treatment response and reduced infectivity in patients with pulmonary tuberculosis (P-TB). To date, there are no models to predict the time to sputum conversion based on patient characteristics. This study aims to ascertain the time to sputum conversion in patients with smear-positive P-TB under treatment, and the variables associated with time to smear conversion. We retrospectively evaluated the time to sputum smear conversion of 89 patients with smear-positive P-TB undergoing treatment at the S. Orsola-Malpighi University Hospital, Bologna (Italy), a referral centre for the diagnosis of TB. Multivariate Cox regression analysis was performed to document variables independently associated with time to conversion. Median time to sputum smear conversion was 24 days (IQR 12-54); the sputum smear converted within the first 2 months of treatment in 78.7% patients. Multivariate Cox regression analysis showed that older age, high baseline mycobacterial load detected by Xpert MTB/RIF, and severity of lung involvement are predictors of persistent smear positivity. The identification of risk factors delaying smear conversion allowed us to develop predictive models that may greatly facilitate the management of smear-positive patients in terms of the duration of respiratory isolation and treatment.

Chest X ray score (Timika score): an useful adjunct to predict treatment outcome in tuberculosis

INTRODUCTION

Chest X-ray (CXR) has been used since long as an aid in the diagnosis of pulmonary tuberculosis (PTB) and also to determine the extent of the disease. The present study was conducted to evaluate the correlation of disease extent on CXR basing on the Timika CXR score with clinical and microbiological parameters at baseline, in sputum positive cases of pulmonary tuberculosis.

MATERIAL AND METHODS

The study was conducted at a tertiary referral centre for chest diseases in Bangalore, Karnataka from January 2017 to January 2018. This is a prospective study of new sputum smear positive pulmonary tuberculosis cases diagnosed in the department of Pulmonary Medicine. At baseline, patients' symptoms and signs on chest auscultation were recorded. The clinical scoring was done by the Karfosky performance score (KPS) and TB score I (Bandim TB score) and II. Baseline CXR- PA view of each patient was assessed independently by two chest physicians and evaluated by the Timika CXR scoring method. Routine blood investigations and sputum smear for acid fast bacilli were done. The correlation between the CXR score and other disease severity parameters was analysed.

RESULTS

Clinical scores such as the KPS and TB score I (Bandim TB score) and II, did not correlate with the presence of cavitary disease on CXR (p > 0.05). 48.6% of patients with cavitary disease had higher baseline AFB density in sputum (i.e. sputum smear microscopy grade 3+) as compared to 40% of patients with non cavitary disease, which was not statistically significant. CXR score > 71 was significantly associated with longer duration of symptoms, higher clinical scores (KPS and TB score I, II) and lower Body Mass Index (BMI) at diagnosis of PTB (p < 0.05). 65.2% of the patients with CXR score ≤ 71 had significantly higher baseline AFB density as compared to only 32.4% with CXR result > 71 (p 0.04). CXR score > 71 also had significant association with higher ESR.

CONCLUSION

Cavitary disease on CXR is associated with a higher mycobacterial load at baseline. The Timika CXR score is a simple, standard scoring system which can be used by a chest physician in a clinical setting. The CXR score significantly correlates with a broad range of clinical and microbiological measures of disease severity in PTB patients. Thus, it has a role in risk stratification, especially in patients not producing sputum or sputum negative PTB at diagnosis.