The prevalence of tuberculosis in diabetic patients is 2-4 times higher than in non-diabetic patients, and the incidence of tuberculosis in the poorly controlled diabetes group is 3 times higher than in the well-controlled diabetes group. In turn, active tuberculosis can aggravate diabetes, making blood sugar elevated and not easily controlled, and even inducing ketoacidosis. In other words, diabetes is silently contributing to the continuation of the tuberculosis family, while tuberculosis is also secretly helping diabetes to do bad things!
Which is the sister and which is the sister of these two good sisters?
In other words, is there an order of occurrence of these two diseases?
It is generally believed that diabetes precedes tuberculosis in about 70% of cases, and tuberculosis precedes diabetes in only 5-10% of cases. However, in fact, more are found clinically at the same time, accounting for about 50%.
In other words, the theoretical chance of diabetes being a sister is 70%, but in practice, in 50% of cases, it is found at the same time as a twin.
Since diabetics are more likely to develop tuberculosis than normal people, is there a need for a preventive drug intervention?
The need for prophylactic antituberculosis treatment in diabetic patients is still not clear due to the lack of randomized controlled studies. The World Health Organization (WHO) does not recommend the use of prophylactic antituberculosis treatment. What are the regulations in China? Our regulations stipulate that prophylactic chemotherapy may be administered to high-risk subjects for tuberculosis who are already infected with Mycobacterium tuberculosis, such as patients with diabetes, silicosis, and long-term use of adrenocorticosteroids and other immunosuppressive drugs.
The core treatment of tuberculosis combined with diabetes is twofold.
First, anti-tuberculosis treatment
Second, glycemic control.
Let’s start with anti-tuberculosis treatment. There is little controversy about the regimen of antituberculosis treatment. However, the course and dosage of anti-tuberculosis treatment are still controversial.
China stipulates that the course of chemotherapy should be 9-12 months, and can be extended if necessary. It is also clear from this that there is no consensus on the course of anti-tuberculosis treatment for tuberculosis combined with diabetes, and the length of treatment should be determined on an individual basis. In other words, if you are not sure, take more time.
In the case of coexisting diabetes, the actual blood concentration of antituberculosis drugs is lower than the expected concentration. Therefore, it has been proposed to adjust the patient’s anti-TB drug dosage based on the blood concentration test. This suggestion is constructive, but more challenging and, especially in our country, simply does not work.
Is there a target for blood glucose control?
According to the Chinese guidelines for the prevention and treatment of type 2 diabetes (2013 edition), it is recommended that
Fasting blood glucose targets for adults are 4.4-7.0 mmol/L, non-fasting blood glucose targets are 10.0 mmol/L, and glycated hemoglobin <7.0%.
In fact, both TB disease itself and anti-TB drugs hinder the control of blood glucose. Therefore, it is actually difficult to reach the target set by our country. In practice, we also have to take care of the patient’s age, nutritional status, complications as well as taking into account some safety factors, etc. Our target is relaxed a bit anyway.
The choice of glucose-lowering drugs is still preferred to insulin. The commonly used ones, whether sulfonylureas or biguanides, are affected by anti-tuberculosis drugs, which affects the effect of lowering sugar. Insulin, on the other hand, is not metabolized and will not be affected by the pharmacokinetics of anti-tuberculosis drugs, including rifampin. Therefore, insulin with guaranteed glucose-lowering effect is the best choice. Patients should not hesitate, let alone listen to any rumors that using insulin will become addictive and refuse to use it!
Diabetes is a good sister of tuberculosis, which not only affects the onset of tuberculosis, but also the treatment and regression of tuberculosis.
When diabetes is combined with TB, not only is the course of anti-TB treatment prolonged, but the failure rate of treatment is higher and the relapse rate is also higher. It has been shown that diabetes is an independent factor in TB treatment failure and relapse. However, it is reassuring to note that, to date, there is no evidence that diabetes increases mortality in patients with tuberculosis. Although, some studies have shown that the mortality rate for diabetes combined with TB is two times higher than for TB patients without diabetes.
The two are so closely related that it is not an overstatement to describe them as a wolf. Therefore, there is a consensus in the medical community to proactively detect them and deal with them proactively. The current effective way is two-way screening.
What is two-way screening? Simply put, it means screening for tuberculosis in patients with diabetes and screening for diabetes in patients with tuberculosis. All patients are routinely checked for blood glucose on admission, and it makes sense to find many asymptomatic diabetics.
As for how to screen for TB among diabetic patients, some studies have shown that symptom screening combined with chest imaging is a relatively economical and easy-to-use method. The tuberculosis branch of the Chinese Medical Association recommends that diabetic patients need 1-2 chest X-rays per year to help detect tuberculosis and other respiratory diseases.
In conclusion, the interaction between diabetes and tuberculosis and their mutual influence is a difficult problem for tuberculosis control and needs further research.