Characterization of Tuberculosis among Newly Diagnosed Tuberculosis and Comorbid Tuberculosis- Diabetes Patients Residing in Nairobi and Kiambu Counties, Kenya

Abstract

The double burden of diabetes mellitus (DM) and pulmonary tuberculosis (TB) is a global health challenge. Its management differs from that of either disease alone. Tuberculosis treatment regimens (Rifampicin and Isoniazid) interact with oral anti-diabetic drugs resulting in suboptimal glycemic control. Also, the suboptimal control of diabetes predisposes the patient to tuberculosis and poor response to anti-TB treatment. Diabetes Mellitus and Tuberculosis, therefore, interact with each other at multiple levels, each exacerbating the other. The objective of this study are to determine the burden of diabetes mellitus among newly diagnosed tuberculosis patients. The study was carried out in Kiambu and Nairobi counties in Kenya between February 2014 and August 2015. Patients above 15 yeas who tested positive for Mycobacterium Tuberculosis complex on sputum smear microscopy at the time of diagnosis were eligible to participate. We obtained clinical and social demographic data from a semi-structured questionnaire by abstracting patients' medical records from the National TB program database at 2, 3, 5, and 6 months of treatment therapy monitoring. The study enrolled 347 patients. We dropped 7/347 patients that had Mycobacterium Bovis from the analysis. The remaining 340 patients: 84% were cured, 7% completed therapy, and 9% had unfavourable outcomes, out of which 4% (n= 32) had a microbiologic failure. DM prevalence (HbA1c > 6%) among TB infected patients was 37.2%. The number of cigarettes smoked per day, and the value of the BUN were significant risk factors for developing DM among TB patients (P values = 0.045). Of the seven identified TB strains within the two counties, East Asia, Beijing, Euro America, and Indo Oceanic were dominant, accounting for 92.4% of infections. DM was not a significant factor in increasing the likelihood of PTB patients to cluster according to the genotype of the infecting M. tuberculosis bacillus. The Classification and Regression Tree (CART) identified the three HbAIc cut off levels depicting the U shaped pattern that interacted with both weight and BMI. The entire cohort revealed that 8/11 (73%) of the patient with >2.95%, 111/114 (97%) with HbA1c 2.95-4.55%, and >4.55% containing 189/215 (88%) of patients who experienced microbiological failure. It is important to screen all newly diagnosed tuberculosis patients for diabetes mellitus as they require close monitoring for the control of both diseases, and health policies should be considered to assess the impact of DM. The study findings demonstrate the feasibility and the value of screening TB patients for DM in a predominantly health facility. The findings from this study will also be useful for national scale-up using simple diagnostic technology in place at the start of screening activities and that it needs to be a high priority area for implementation as a routine in all primary caregivers.