Table 1.

Table summarizing the findings of the studies used in this review

First author	Year of publication	Study design and sample size	Main exposure(s) of interest	Main outcome(s) of interest	Main results and Remarks
Peleg AY	2007	Literature review	Glycaemic control	Risk of common community acquired infections	Further research is needed to improve understanding of the role of diabetes and glycaemic control in the pathogenesis and management of community and hospital acquired infections
Leung CC	2008	Cohort study 42,116 clients aged 65 years or more,	Diabetes mellitus	TB	Among diabetic subjects, higher risks of active, culture-confirmed, and pulmonary but not extrapulmonary tuberculosis were observed, with baseline hemoglobin A1c ≥7 % (vs. <7 %)
Dick Menzies	2011	Review article	LTBI	TB	LTBI therapy should be given only to those with positive tests for LTBI. Underutilized, particularly in LMIC
Matthew J. Magee	2014	cohort of 1366 adult patients	DM	MDR TB	DM did not impact culture conversion rates in a clinically meaningful way, but smoking did.
Holt PR	2001	Review/Perspective	Elderly population	Malabsorption	Nutrition may be compromised rapidly by the reduction in food intake or malabsorption that accompanies many of the conditions that cause diarrhea in the elderly
Cruz-Hervert LP	2012	Cross sectional study of 893 65 years of age or older.	65 years of age or older	Clinical and epidemiological consequences of pulmonary tuberculosis	Untimely and difficult diagnosis and a higher risk of poor outcomes even after treatment completion emphasize the need for specific strategies in this vulnerable group.
J. Peter Cegielski	2012	Cohort 1982–1992 of 14,189 adults	BMI	TB	Population's nutritional profile is an important determinant of TB incidence.
Nyadzayo	2014 (still in press)	Cohort study 410 adults	TB	Recovery from moderate malnutrition	Moderately malnourished adults are less likely to recover their nutritional status compared to non-TB patients when under supplementary treatment
Kurbatova, E. V	2012	Cohort study of 1416 adults in 5 countries	predictors of initial sputum culture conversion in MDR TB treatment		Lower but not significant unadjusted rate of sputum culture conversion among patients with DM
Matthew J. Magee	2014	Cohort study of 1,366 adult patients in Georgia	MDR TB treatment in DM patients	culture conversion among patients with multidrug-resistant (MDR)-TB	In adjusted analyses, DM did not impact culture conversion rates in a clinically meaningful way
María Eugenia Jiménez-Corona	2013	Cohort study of 1262 patients with pulmonary TB in Mexico	Patients with DM	clinical consequences of pulmonary tuberculosis	Patients with DM and pulmonary TB had more severe clinical manifestations, delayed sputum conversion, a higher probability of treatment failure and recurrence
Meghan A Baker	2011	Systematic review and meta-analysis.	quantitative summary evidence for the impact of diabetes on tuberculosis outcomes		DM increases the risk of treatment failure and death combined, death and relapse among patients with tuberculosis.
Christie Y Jeon	2008	13 observational studies (n = 1,786,212 participants) with 17,698 TB cases	Patients with DM	Active TB disease	Meta-analysis shows that DM increases the risk of TB, regardless of different study designs, background TB incidence or geographic region of the study.
Stevenson CR	2007	Review	Patients with DM	Active TB disease	All studies identified statistically significant associations, with a 1.5- and 7.8-fold increase in risk or odds of TB in diabetic patients. Inadequate adjustment of potential major confounders.
Nijland HM	2006	1 prospective pharmacokinetic study (n = 17 adult patients	Patients with TB-DM comorbidity	Effect on plasma rifampicin levels	Study showed 53 % lower rifampicin exposure (AUC0–6 h) in TB-DM patients, compared to TB only patients.
Meghan A Baker	2012	Prospective study	Patients with DM	Active TB and severe TB	The risk of developing tuberculosis increased among those with increasing diabetes severity.
Brendan K. Podell,	2012	60 guinea pigs were randomly assigned to Mtb infected and sucrose-fed (n  =  20), Mtb infected and water-fed (n  =  20), uninfected and sucrose-fed (sucrose control, n  =  10) and uninfected and water-fed (uninfected control, n  =  10).	Hyperglycaemia	Severity of tuberculosis infection in non-diabetic guinea pigs	The exacerbation of insulin resistance and hyperglycaemia by Mtb infection alone may explain why TB is more severe in diabetics with poorly controlled hyperglycaemia compared to non-diabetics and patients with properly controlled blood glucose levels.
J. Peter Cegielski	2012	A prospective study of 13,419 adults from 25 to 72 years of age	different levels of nutritional status	Incident cases of TB	Population's nutritional profile is an important determinant of TB incidence, after controlling for socio-economic factors, excess alcohol consumption, smoking, and DM
Yung-Feng Yen	2016	Population-Based Follow-Up Study of 1608 patients	(<18.5), normal (18.5–24.9), and overweight (≥25).	TB treatment outcome	Insufficient body weight was associated with higher risks of TB-specific and non-TB-specific mortality during TB treatment, particularly in male patients.