With diabetes largely associated with over-consumption of sugar by many Zimbabweans, it is hardly surprising that its link to tuberculosis (TB) is hardly a public health matter. TB kills more than 3,500 people each day worldwide, leading to approximately 1.4 million deaths every year. One-third of the world's population is currently infected with the causative agent of TB, and 8.8 million new cases of active TB are estimated to occur around the world each year.
Among African nations, Zimbabwe is one of those most heavily affected by TB. The deadly combination of TB and HIV epidemics is igniting a silent and uncontrollable epidemic of drug resistant TB that will negate previous national health gains. The 2011 Global Tuberculosis Control Report from the World Health Organization (WHO) ranks Zimbabwe 17th among 22 countries worldwide with the highest TB burden. Zimbabwe had an estimated total number of 47,557 notified TB cases in 2010, with an estimated incidence rate of 633 cases per 100,000 population.
TB is fuelled by several social and economic factors, such as poverty and/or malnutrition, as well as other infectious diseases, such as HIV. In recent years, strong evidence has been gathered to confirm a link between TB and yet another disease: diabetes mellitus. According to public health activist, Godsway Shumba, there is very little knowledge of the link between TB and diabetes among Zimbabweans.
“Ordinary people really don't know about this linkage between the diseases - awareness raising is needed. Even the media do not talk about it. There are very few stories on diabetes in the local media. Most of the stories are all AIDS-related stories,” he said.
Shumba added that most people are only aware of the linkage between TB and HIV and increased public health awareness is required around TB and diabetes as well. “Community health workers should be trained so that they can talk about those issues at community level but they need capacity building through the Ministry of Health and Child Welfare,” he said.
Several recent publications have described the association between diabetes and TB, specifically the increased prevalence of active TB among patients with diabetes and the poorer treatment outcomes in these patients when compared to those without diabetes.
In 2011, the World Health Organization (WHO) and The International Union Against Tuberculosis and Lung Disease (The Union) released a report acknowledging the association between TB and diabetes and similarly calling for increased collaboration between TB and diabetes control efforts.
According to PLoS Medicine, a major impediment to expanding diabetes care in the developing world is the high cost. One study in Tanzania showed that the monthly cost of insulin treatment represents 25% of the minimum wage, while another showed that the yearly cost of diabetes treatment with insulin amounted to 75% of the per capita income in Mozambique and 61% in Mali.
“In addition to the expenses linked to insulin and oral hypoglycemic medications, the direct costs of diabetes care include outpatient visits, inpatient admissions, and the management of the micro and macrovascular complications of this disease,” states PLoS Medicene. Although expanding TB treatment to include diabetes care would be expensive, perhaps existing health systems used for TB could be adapted to diabetes management, which may help control costs.
Dr Anthony Harries, senior adviser, The Union, said: "We have always known about the linkages between diabetes and TB but till recently we had never really thought about them seriously. It was only in 2008 that studies suggested that diabetes increases the risk of TB by a factor of 3. If we do not seriously think about the link between TB diabetes my feeling is that it may begin to derail some of the good advances made in the field of TB control, especially in China and India which together constitute 40% of the world’s diabetes population of 400 million people which is likely to go up to half a billion by 2020.” He further added: "People will have to make life style modifications in order to lessen the impact of non-communicable diseases (NCDs) like diabetes. It is good to link up smoking with diabetes, hypertension which are all chronic diseases. The big issue with chronic diseases is that you cannot cure them, you can just treat them. We can cure TB but we cannot cure HIV/AIDS, we cannot cure diabetes. We can only control them."