The co-occurrence of TB and DM has been recognized for centuries.9 In LAC, TB and DM disproportionately affect Asians and Hispanics. Furthermore, a majority (91%) of TB cases with DM were born outside the U.S. Spatial analyses identified hot spots of TB and DM among Asian TB cases residing in the southwestern and southern regions of LAC. These regions correspond to areas in LAC with large Asian populations,14 with the southern region being an area where low English language proficiency is reported.14 TB and DM burden was identified among Hispanic TB cases residing in southcentral and northwestern LAC, regions with large concentrations of Hispanics with low English language proficiency.14
The elevated TB and DM burden delineated in the maps presented here are in line with reports and prior research indicating that TB and DM disproportionately and unequally affect racial/ethnic minorities and non-U.S. born persons.2, 5, 10, 17, 18 The co-occurrence of TB and DM should be closely examined by race/ethnicity given the increasing prevalence of DM,13 the growing non-U.S. born population in LAC,19 and the contribution of DM to poor TB treatment outcomes.10, 17, 20 Future research should focus on identifying areas where non-U.S. born individuals reside and examine the factors associated with disease co-occurrence. Also, spatial analyses by country of birth, primary language, and English language proficiency can inform when and where bilingual educational and culturally sensitive services are needed to reach target populations.
GIS methods serve as important epidemiological tools to identify geographic areas experiencing disproportionate burden of TB and DM and can help inform future activities and interventions. Interventions tailored to specific groups can aid in addressing TB morbidity and mortality and help continue our work towards reaching TB elimination. However, turning future activities and interventions into cost-effective and high-impact public health programs requires improvements in continuity of care delivery, through integration and coordination of care, across providers. For example, co-management of both TB and DM can be crucial to the optimal treatment and control of both diseases. Co-management would require collaboration from health professionals and patients to clearly assess all factors related to the monitoring and treatment of each disease.21 A disease co-management strategy would benefit from a patient education component that facilitates self-care by promoting adherence and completion of TB treatment and emphasizing the importance of disease monitoring and management. In fact, WHO’s “Collaborative Framework for Care and Control of Tuberculosis and Diabetes” provides guidelines for integrated management of both diseases.6, 22 Facilitating patient awareness and education for prevention, diagnosis, and treatment of TB and DM can help address health disparities among vulnerable populations.
While the strength of this paper is the application of GIS methodology to identify geographical areas and populations in LAC burdened by TB and DM, there are some limitations to these findings. Assessment of DM status was partly based on patient self-report. However, it should be noted that national estimates of DM incidence and prevalence are also based on self-report data.25 Furthermore, self-reported DM status is reliable and has high sensitivity and specificity.26, 27, 28 The data presented here are cross-sectional and do not indicate temporal order of onset of DM or TB. The TB and DM surveillance data do not provide information on severity or duration of DM among TB cases. Also, we did not examine the data by nativity to assess disease burden in areas where people from common nationalities reside. Despite these limitations, to our knowledge, this is one of the first set of analyses to examine spatial patterns of TB and DM burden.