A key pillar of diabetes therapy is self-monitoring. This not only includes the independent checking of blood glucose levels, which can be done either through spot blood glucose measurements (SMBG) or, very effectively and in real time, using continuous glucose monitoring (CGM)*.
For people with insulin-treated diabetes—especially for users of insulin pumps, whether manually controlled under CSII (Continuous Subcutaneous Insulin Infusion) or partially automated as an AID system (Automatic Insulin Delivery)—self-monitoring of both glucose and ketones is essential. In these therapy forms, only short-acting insulin is used, which increases the risk of developing diabetic ketoacidosis, for example if the infusion set accidentally slips out of the subcutaneous tissue without being noticed [1,2]. Independent monitoring of ketones is also important for people with type 2 diabetes who use SGLT-2 inhibitors (Sodium-dependent glucose co-transporter 2) in their therapy, since atypical euglycemic ketoacidosis can occur [3,4]. For this reason, dual sensors for simultaneous continuous monitoring of glucose and ketones (CKM) are currently being developed.
Self-monitoring also includes measuring blood pressure. This is particularly relevant for individuals with hypertension, but it can also be useful periodically for all people with diabetes. Another important self-monitoring measure is weight control, which is essential for overweight patients. Equally important is checking injection sites for people treated with insulin. For those with existing diabetic complications—especially diabetic neuropathy—regular foot checks are crucial, including examining the soles of the feet with a mirror.
Continuous glucose monitoring is generally abbreviated as CGM. In many cases, patients’ use of CGM is referred to as real-time CGM (rtCGM). In the texts on self-monitoring presented here, CGM always refers specifically to rtCGM, even when the general abbreviation CGM is used.
Digital Health Management Is Gaining Importance
Modern information technology—especially smartphones and smartwatches equipped with various health apps—facilitates self-monitoring. An important advantage is that data can be transmitted, for example to the diabetes care team. The range of available apps is wide and includes, for instance, step counters, heart rate monitors, ECG measurements, and more. Devices claiming to measure glucose levels “non-invasively” via wristwatches are repeatedly offered. However, none of these have yet demonstrated reliable measurement accuracy, and some have even been classified as fraudulent [5].
To support the use and evaluation of such apps, the German Medical Association (Bundesärztekammer), together with the National Association of Statutory Health Insurance Physicians (KBV) and the Agency for Quality in Medicine (ÄZQ), has developed a practical guide for physicians [6]. This brochure is intended to assist doctors in handling health apps in clinical and practice settings by providing concrete tips for their use [7].
In a narrower sense, digital health applications (DiGA) also support and require self-monitoring, even though they represent a form of therapy. These apps are often unusable without active self-monitoring. Currently, in the category “Hormones and Metabolism,” seven DiGA are listed, four of which focus on the treatment of type 2 diabetes.