Type 2 diabetes: Does self-monitoring urine and blood glucose levels have benefits for people who do not inject insulin?

Regular self-monitoring of glucose levels has not been proven to have benefits for people with type 2 diabetes who do not inject insulin. It is not known whether self-monitoring can help prevent diabetes-related complications in this group of people.

Diabetes mellitus is a metabolic disorder which causes people to have higher levels of glucose (sugar) in their blood. If people constantly have clearly higher blood sugar levels, they are more likely to develop diabetes-related complications such as a heart attack or kidney disease. The risk of complications can be reduced through treatment and good self-management. You can read more about the different types of diabetes, the treatment options and living with this metabolic disorder in our feature (URL: http://www.informedhealthonline.org/diabetes.518.56.en.html) .

Type 2 diabetes typically first arises later on in life, but sometimes younger people get it too. It develops if a person either does not produce enough insulin themselves, or the tissues and cells in their body cannot use the insulin effectively. Insulin enables the sugar in our blood to be transported into our tissues and cells. If this stops working properly, blood sugar levels rise. Having too much sugar in your blood over several years can damage small blood vessels in your body (for example, in the eyes and kidneys) as well as nerves (particularly in the feet). The risk of heart attack or stroke increases, too.

This risk can be reduced with the help of particular medications. The medication sometimes has adverse effects, though. For example, it might make your blood sugar levels drop too low – a condition known as hypoglycemia, or a “hypo”. The risk of this happening is greatest in people who inject insulin. You can find out more about treatments for type 2 diabetes in our fact sheet (URL: http://www.informedhealthonline.org/index.413.en.html) .

Monitoring your own sugar levels

There are two commonly used methods to self-monitor sugar levels. People can measure their own sugar levels in their blood or in their urine. Blood sugar levels can be measured using an electronic device. Here a drop of blood is taken from the finger using a fine needle, for example, and placed onto a test strip that is then inserted into the blood glucose meter. The blood sugar level then appears on the digital display soon after. People who have diabetes can learn how to use the device, interpret the readings and react accordingly.

Sugar in urine is generally a sign of very high blood sugar levels. This is because our bodies usually only get rid of extra sugar in the blood via the kidneys if blood sugar levels are very high. Urine sugar levels can easily be measured using test strips. The test strips, which are dipped into the urine, indicate whether there is a high level of sugar in the urine. They do not give an exact value though. Blood sugar levels that are too low (hypoglycemia) cannot be detected using this method.

Blood sugar levels can go up and down throughout the day, depending on things like what you eat, how much you exercise and which medications you take. To check whether your blood sugar level is too high on average for a longer period of time, the HbA1c value of the blood is measured. The HbA1c value tells you how high, on average, your blood sugar level was over the last 3 months, and is typically measured by a doctor, not through self-monitoring. Knowing this value is also a good idea for people who have diabetes mellitus and do not inject insulin.

Benefit of self-monitoring blood sugar levels

For people who have type 1 or type 2 diabetes and inject insulin, self-monitoring of blood sugar levels is a routine and important part of treatment. It is the basis for adjusting the amount of insulin to be taken and directing the course therapy takes. But whether people who have type 2 diabetes and do not use insulin benefit from self-monitoring is contested. The following questions arise:

• Can someone directly influence his or her blood sugar level after doing self-monitoring by diet or pills, for example? If yes, by how much?
• Can therapy goals be achieved or can complications be prevented by self-monitoring?
• Can self-monitoring help to avoid hypoglycemia?
• Does self-monitoring help to motivate the person who has diabetes to commit to the therapy, leading to its success? Or do they find it to be a nuisance?

The German Institute for Quality and Efficiency in Health Care (IQWiG) – who produce this website – tried to answer these questions together with researchers from the Jena University Hospital. They looked for trials where people who measure their own blood sugar levels several times a week were compared with others who do not – and, for example, just have their HbA1c value read every few months. They also looked for trials that compared monitoring of blood and urine sugar levels.

The researchers analyzed 6 trials involving almost 2,700 participants in total. The trials lasted 6 to 12 months, which is too short to study possible long-term effects, such as heart attacks or strokes. The participants were about 60 years old on average and there were about as many women as men included. People in different trials measured their blood sugar level at various rates: for the most part, at mealtimes a few days a week. All trials looked into self-monitoring that was done as part of an education and treatment program. That means all participants were given instruction in measuring blood sugar at the start of the trial. Therapy involved various tablets and diets for lowering blood sugar levels. The researchers found no useful trials on the monitoring of urine sugar.

No real difference in regulation of blood sugar levels

All trials tested how regular self-monitoring affected the regulation of blood sugar levels. This was checked using the HbA1c value. The analysis showed that self-monitoring had little effect. The values for the self-monitoring group were indeed somewhat lower on average than in in the non-self-monitoring group – but the difference was so small that there are most likely no health benefits to be gained.

What is more, the HbA1c value alone is not enough to assess the benefit of self-monitoring. Because the more the blood sugar level, and with it the HbA1c value, is lowered, the likelier it might be that hypoglycemia occurs. Hypoglycemia can be unpleasant and lead to serious complications in some cases. So changes in the HbA1c value are also to be seen in connection with possible episodes of hypoglycemia. These trials were not suited to this purpose, though. They made it impossible to say whether instances of hypoglycemia are more or less frequent in regular self-monitoring.

Self-monitoring of sugar levels apparently has no effect on losing or gaining weight. Whether they did self-monitoring or not – over time people in both groups lost similar amounts of weight on average. Some trials recorded how satisfied participants were with their therapy and interviewed them about their quality of life. The results were contradictory and the data was not very conclusive. In one trial, individuals who monitored blood sugar levels themselves had more depressive symptoms, but in another trial they had fewer. That is why it cannot be said whether self-monitoring has positive or negative consequences for quality of life.

No data on long-term effects of self-monitoring of glucose levels

There were no trials able to answer the question of whether self-monitoring can help to prevent complications. So it remains unclear whether regular self-monitoring leads to fewer heart attacks or strokes, or less loss of sight or kidney disease, for instance. There is hardly any data on adverse effects of self-monitoring, either. The lack of data made it very difficult to say with certainty what effect self-monitoring has on quality of life and satisfaction with therapy. More research is needed to better assess this. There is also a general lack of good trials on self-monitoring of urine sugar, so that it is not possible to say how effective this is at all, or how it compares to self-monitoring of blood sugar levels.

Author: German Institute for Quality and Efficiency in Health Care (IQWiG)

Note

This health information is a summary of a scientific report published by IQWiG. It is not an assessment of the right to have health care services reimbursed by statutory health insurance funds in Germany. By law, decisions about the reimbursement of diagnostic and therapeutic procedures can only be made by the German Federal Joint Committee (G-BA). The Federal Joint Committee takes IQWiG reports into consideration in its decision-making process. You can find information about the decisions of the German Federal Joint Committee on its English-language website, www.english.g-ba.de (URL: http://www.english.g-ba.de) .