The link between diabetes mellitus and tuberculosis (TB) has long been recognized. Recently, evidence has been generated to demonstrate that diabetes increases risk of developing TB (1). In addition, this relationship appears especially strong among Hispanic people in Latin America and in the United States and among young people under 40 years of age (1, 2). Additional evidence suggests that the severity of diabetes and poor glycemic control further increase risk of TB. The probable pathway of disease is that diabetes depresses immune function, which in turn increases susceptibility to TB infection.
The impact of TB on diabetes is also an important health concern. Infections of all types, including TB, can worsen glycemic control in people with diabetes. In addition, some evidence suggests that TB can cause glucose intolerance (1). There are also some studies that indicate that TB drug treatment may hinder glycemic control, and that diabetes drugs might also affect the performance of TB drug treatment.
Both diabetes and tuberculosis are chronic diseases and major public health problems worldwide. TB predominantly affects developing countries, where it is one of the major causes of death. Diabetes, although historically a problem of developed countries, it is now on the rise worldwide, with projections indicating that it will rise considerably in developing countries in the coming years. Given the link between the two diseases, this rise in DM will have an impact on the future burden of TB. For example, a recent illustrative study using data from India estimated that approximately 15% of TB incidence in India was attributable to diabetes (3). With diabetes projected to increase, this impact is slated to increase in the coming years.
The problems of TB and diabetes are significant in the three proposed project areas.
Along the US-Mexico border, the incidence of TB is 7.9 per 100,000 population in US border states and 26.3 per 100,000 population in Mexican border states, both of which are higher than the national averages in the US and Mexico, respectively (4). Diabetes is a major problem along the US-Mexico border. In 2003, diabetes was the third leading cause of death on the Mexican side of the border, and the sixth on the US side (4). Recent prevalence estimates indicate that approximately 16% of the people living along the border have diabetes, and another 14% of adults on the US side have pre-diabetes (4). Recent evidence found that TB-diabetes comorbidity exceeded that of comorbidity with HIV/AIDS (5).
In Brazil, diabetes is the sixth overall cause of death, and risk factors are on the rise. Tuberculosis continues to be a public health priority in Brazil, which is home to 35% of all TB cases in the Americas region. The states of Rio de Janeiro and Amazonas had the highest incidence rates in 2004; 94.5 and 70.6 per 100,000 population, respectively (6). Recent evidence from Sao Paolo, Brazil found that diabetes-TB comorbidity is common, with diabetes present in 16% of TB deaths in the year 2002 (1).
A recent mini-review article poses the question "Should TB patients be screened for DM?" and suggests that further investigation is needed to determine the most adequate way to conduct screening (7). In addition, the article reiterates the message that developing countries need to improve chronic disease management. The authors pose a few suggestions to improve disease management in resource-poor settings, including applying successful TB treatment methods to the treatment of diabetes. This may include the use of treatment cards and patient registers for monitoring and evaluation purposes (7).
Result of a preliminary analysis conducted by PAHO indicates that more than 30,000 cases of tuberculosis are related to diabetes in the Americas every year, with the highest numbers corresponding to Brazil and Mexico with more than 9,000 and 3,000 cases per year respectively.
There is a risk that the current diabetes epidemic will contribute to the resurgence of TB as an endemic disease in the Americas. Therefore, the overall goal of the proposed project is to improve the timely identification of diabetes and TB in people of the Americas.
The objectives of the proposed project are:
- To apply the DM-TB guidelines to develop an instrument to facilitate TB screening among people with diabetes in primary care.
- To include TB risk assessment as established in the new guidelines in the standard of care for people with diabetes, especially at diagnosis,
- Incorporate TB screening to existing diabetes guidelines.
- To increase awareness among health professionals of the double burden of TB and diabetes.
- To improve monitoring of cases screened, diagnosed, and treated via the development of a form and database to facilitate data collection and analysis.
- Data Collection Forms