In this study we observed good TB treatment outcome at 72.5% of the study patients [95% CI: 69% − 76%], the good TB treatment outcome for DM free TB patients was at 95.4%, only 48.8% of the DM and TB patients have good treatment outcome; The odds of good TB treatment outcome were 75% lower in the presence of DM. This finding agrees with the research conducted in Indonesia . This is due to the high Mycobacterium burden leading to a longer time for culture conversion. Additionally, DM affects the pharmacokinetics of anti-TB drugs by reducing their plasma concentration .
The proportion of pulmonary TB was lower in the presence of DM, only 24.1% of the TB cases were pulmonary and 55.11% of them were extra-pulmonary TB which was found to be very severe. This finding was in-line with the findings in Georgia . This is due to the effects of DM on the smear production and excretion that affects the detection of TB, indicating that a significant number of pulmonary TB was not detected in DM patients .
Atypical TB was common in DM patients reaching 40% of the TB patients. This finding is consistent with the findings in Brazil . This indicates that the TB diagnostic algorithm should be revised in the case of DM as reported with the study in India .
In this study, 15.5% of the DM patients manifested with adverse TB reaction compared to 8.3% of the adverse drug reaction in TB patients without DM. The reason might be due to the high pills burden of TB-DM patients that finally predisposed the patients for the adverse drug reactions .
In this study, the median time of clinical response in TB and DM patients was 45 days, interquartile range (IQR) of 8 days; the median time of clinical response in DM free TB patients was 9 days [IQR 2 days]. This is consistent with the previous report in Ethiopia , suggesting that the treatment algorithm should be revised in TB-DM patients in Ethiopia.
In our study, we observed that TB increased the HbA1c level of DM patients by 1.22%. The mean HbA1c level of the patients was at 7.56% [SD ± 1.12%]. The mean HbA1c level of TB free DM patient was 6.81% [SD ± 0.38%]; the mean HbA1c level of DM patients with TB was 8.31% [SD ± 1.12%]. The glycemic control was good in 40.8% [95% CI: 37.15% − 44.35%] of the patients. Glycemic control was good in 64% [95% CI: 58.97% − 68.96%] of TB free DM patients; the glycemic control was good in 17.7% [95% CI: 13.77% − 21.69%] of DM patients with TB infection. This finding agrees with the findings in India . This is due to the reason that TB induces glucose intolerance worsening the glycemic control of DM patients .
In our study, we observed that excess episode of acute DM complications in DM and TB patients; in the 6 months period, 60% of the TB and DM patients which had found to be 3 episodes of acute complications compared to 15% of cumulative complications in TB free DM patients. This finding is comparable with the finding in Mexico . This is be due to the effects of infection on inducing the stress hormones that disturbs insulin metabolism [35, 36].
After DOTS completion, Vitamin A increased by 2.65 µg/dl for DM and TB patients, as compared to 7 µg/dl increment for DM free TB patients. This strengthens the justification that, higher complications rate of DM among TB patients was attributed to low vitamin A level.
The baseline serum zinc level of DM and TB patients was 88.23 µg/dl, while the baseline serum zinc level of DM free TB patients was 90.87 µg/dl. This finding agrees with findings from India . This will strengthen the necessity of zinc supplementation for DM patients .
In this study, vitamin D increased by 1.1 ng/dl for DM and TB patients, and its values increased by 7.46 ng/dl for DM free TB patients. This finding agrees with the finding in Korea . This finding implies that the critical role of vitamin D was limited in TB-DM patients.
The study indicated that the baseline Ferritin level of DM and TB patients was 14.88 ng/ml whereas the baseline Ferritin level of DM free TB patients was 18.88 ng/ml. The finding was consistent with previously available literature regarding the association between DM and Ferritin. This is due to the high burden of anemia in our study areas .
In our study we observed that the HDL level of DM and TB patients was at 34.17 mg/dl, the baseline HDL level of DM free TB patients was at 43.49 mg/dl. The finding was in line with the finding in Netherland , suggesting high malnutrition burdens in the study area .
In DM and TB group, the basic activity of daily living was improved by 11.6% for the good zone, 44.5% increment for the good zone was observed in DM free TB patients. This finding is in agreement with the findings in Netherland . This urgently calls great attention of decision-makers to revise the management of the two morbidities during co-existence.
The main limitation of this research work was a failure to identify the effects of TB on the chronic complications of DM and the effect of DM on the relapse of TB.