Delayed diagnosis of tuberculosis in patients with diabetes mellitus co-morbidity and its associated factors in Zhejiang Province, China

Background Tuberculosis (TB) remains a significant global public health problem. China has the second highest TB burden in the world. With a growing TB population with diabetes mellitus (DM), the TB control system faces mounting challenges. To date, evidence remains inconclusive regarding the association between TB-DM co-morbidity and delayed diagnosis of TB patients. This study aims to assess the diagnostic delay of TB patients with known DM and identify the factors associated with this delay. Methods Data was collected from China’s Tuberculosis information management system in two counties of Zhejiang province, China. Patient delay, health system delay and total diagnostic delay are defined as follows: 1) the interval between the onset of TB symptoms and first visit to any health facility; 2) from the first visit to the health facility to the confirmed TB diagnosis in the designated hospital; 3) the sum of patient and health system’s respective delays. Comparison of these delays was made between TB patients with and without DM using Mann-Whitney U test and Chi-square test. Univariate and multivariate regression analysis was used to identify factors influencing delays among TB patients with DM. Results Of 969 TB patients, 67 (7%) TB patients had DM co-morbidity. Compared with TB patients without DM, TB patients with DM experienced significantly shorter health system delays ( p < 0.05), and there was a significantly lower proportion of patients whose health system delayed> 14 days (7.0% vs. 18%, p < 0.05). However, no significant difference was observed between both patient categories regarding patient delay and total diagnostic delay. The multivariate regression analysis suggested that TB patients with DM who were aged < 60 years (AOR = 3.424, 95%CI: 1.008–11.627, p < 0.05) and non-severe cases (AOR = 9.725, 95%CI: 2.582–36.626, p < 0.05) were more likely to have a total diagnostic delay of> 14 days. Conclusions Our study suggests that DM does not contribute to further diagnostic delay as expected. Instead, we observed significantly improved health system delay among TB patients with DM. The findings indicate the importance of early screening and diagnosis for TB among diabetic patients and of strengthening the integrated control and management of TB and diabetic programs.