Living with diabetes means dealing with daily decisions about food, exercise, medication, and, of course, blood sugar levels. Thanks to the continuous glucose monitoring (CGM) and the use of mobile appsThis control no longer depends solely on occasional finger pricks and paper notebooks, but on digital systems that measure, record and analyze your glucose almost in real time.
In recent years, so many apps and devices have appeared that it can be difficult to know which ones to use. What does each type of CGM do, what do diabetes apps offer And what real advantages do they have over a traditional glucometer? Furthermore, not all apps are the same: some are certified as medical devices, others function more as health diaries, and still others integrate with insulin pumps or allow remote monitoring by medical professionals.
What is a continuous glucose monitoring (CGM) system?
A CGM is a system that allows measure glucose levels automatically and frequentlyTypically every 1 to 5 minutes, without the need for frequent finger pricks. Instead of analyzing blood directly, the sensor measures glucose in the interstitial fluid, that is, the fluid surrounding the cells under the skin.
This data is sent to a receiver or to a diabetes mobile appwhere readings are displayed as numerical values, trend arrows, and daily or weekly graphs. This allows people with diabetes to see if their glucose levels are rising, falling, or stable, and to fine-tune their diet, insulin, or physical activity.
Continuous monitoring has been a true revolution because it allows going from individual photos to a complete glucose filmfacilitating informed decision-making throughout the day and night, when it was traditionally more difficult to detect hypoglycemia.
Basic components of a CGM system and types of devices
A CGM system is usually made up of several elements that work in a coordinated way so that all the information ends up in the mobile diabetes app:
- SensorIt is inserted under the skin, usually in the abdomen or arm, and measures glucose in the interstitial fluid. Its lifespan depends on the model: some sensors are changed every 7, 10, or 14 days, while others (like Eversense) are for longer use and are implanted for several months.
- TransmitterThis is the component that sends the sensor's measurements to a receiver, insulin pump, or directly to a smartphone. In some systems, it's integrated into the sensor itself, while in others, it's a reusable module that attaches to the implanted or subcutaneous sensor.
- Receiver or mobile applicationThis is where the data is displayed. It could be a dedicated reader, a compatible insulin pump, or a phone app that shows readings, trends, alerts, and historical graphs.
Today, many devices are integrated with the mobile phone so that the Glucose management is primarily done through the app, with the possibility of sharing the information with family members, caregivers or health professionals.
Clinical and practical benefits of CGM in diabetes management
CGM systems and associated apps have been shown to significantly improve the medium and long-term glycemic controlOne of the most relevant effects is the reduction of glycosylated hemoglobin (A1C), since having continuous data allows for much more precise adjustment of insulin doses, meal times and exercise.
Another key aspect is the Prevention and early detection of hypoglycemiaMany glucose monitors include alarms that alert you when your blood glucose is low or when it is expected to drop below a certain threshold in the next few minutes. This helps prevent severe drops, especially in people with unaware hypoglycemia or hypoglycemia during sleep.
CGMs also allow the calculation of Glucose Management Indicator (GMI)This provides an estimate of A1C based on the average recorded glucose level. This way, it's not necessary to wait for the next blood test to know if blood sugar control is improving or worsening.
One parameter that is increasingly used is the time in range (e.g., 70-180 mg/dL). Increasing the percentage of time that glucose is maintained within this range is associated with a lower risk of long-term complications, and CGM reports greatly facilitate working towards this goal in clinical practice and on a daily basis.
Beyond the numbers, the combination of CGM and mobile apps can reduce the daily burden of diabetes by automating records, generating visual reports, and facilitating remote monitoring, which translates into Less uncertainty and a greater sense of control.
Limitations and challenges of CGMs compared to the traditional glucometer
Although CGMs have changed the game, they are not perfect. One important difference compared to glucometer measurement is that the sensor measures interstitial glucose and not directly in the bloodThis introduces a delay of about 5 to 15 minutes between the actual changes in blood and what the system displays.
In practice, this means that in situations of very rapid glucose changes, such as after a high-carbohydrate meal or during intense exercise, there may be some discrepancy between how the person feels and what the CGM reflects. In these cases, if there are symptoms that don't match the reading, it is recommended confirm with a capillary blood test using a glucometer before making critical decisions.
Furthermore, the continuous flow of data can generate in some people added stress, anxiety, or analysis paralysisConstantly viewing graphs, arrows, and numbers can be overwhelming, particularly if you lack the proper diabetes education to interpret the information.
There are also practical problems: sensor adhesion failures during physical activities or when sweating, connectivity or software issues, compatibility requirements with certain smartphone models, or the need for additional equipment to synchronize data.
For healthcare professionals, the advanced use of CGM reports requires specific training in glucose pattern interpretation and time spent in consultation reviewing the data with the person. Integrating this systematic analysis into clinical practice can be a challenge in healthcare systems with limited resources.
Access to CGM technology and inequalities between countries
Although CGMs are now widespread in many settings, access to this technology is not equal for everyone. Even in high-income countries, insurance coverage or public health systems It can limit who can qualify for a CGM and how often sensors and transmitters are covered.
In low- and middle-income countries, the obstacles multiply: high costs relative to income level, difficulties in distribution and maintenance, and less prepared healthcare infrastructure for digital data integration and remote monitoring.
There is also a gap in the training of professionals to make the most of the information offered by CGMs. Without continuing education programs and specific resources, it is difficult for this technology to be used effectively and equitably.
For this reason, organizations like the International Diabetes Federation (IDF) They have promoted initiatives together with other partners (such as FIND) to develop online educational material aimed at both people with diabetes and healthcare professionals, with the goal of facilitating the incorporation of continuous glucose monitoring into healthcare systems, especially in less resourced settings.
The role of mobile applications in glucose management
Diabetes apps have gone from being simple digital notebooks to becoming authentic platforms for comprehensive disease managementThey allow you to record blood glucose, weight, insulin dose, oral medication, physical exercise and other parameters, and many connect directly with glucometers or sensors to automatically transfer the data.
One clear advantage is that having all the information well archived and organized over time facilitates the creation of charts, tables and reports This makes interpretation much easier for both the person with diabetes and the medical team. In this way, patterns, problematic times, spikes after certain meals, or nights with repeated hypoglycemia can be identified.
Another group of applications focuses on the food and carbohydrate logThey allow users to manually enter food items, scan barcodes, or even use photos to estimate portions. This enables more accurate calculation of prandial insulin doses and helps reduce both postprandial hyperglycemia and unexpected drops in blood sugar.
In the case of some apps considered medical devices, the application cross-references glucose data, carbohydrate intake, biometric parameters, and user history to suggest insulin dosageThese clinical decision support functions require compliance with demanding standards of safety, accuracy, and validation.
In addition, many modern apps incorporate features of remote monitoring and data sharingThis allows family members, caregivers, or healthcare professionals to follow the progress in real time or review periodic reports, which is especially useful for children, the elderly, or patients with difficulties in self-management.
Certified and recommended diabetes apps in Spain
In Spain, the TIC Salut Social Foundation has a Mobile application certification service which evaluates quality in aspects such as usability, accessibility, technology, security, functionality, and content. Apps that pass this filter receive a quality seal and are added to a public directory.
Among the diabetes apps that have obtained this certification are several focused on CGM management and glucose control:
- FreeStyle Libre 3This app is designed for use with the FreeStyle Libre 3 sensor, an advanced continuous glucose monitoring system. It displays measurements on your mobile device and allows for very detailed tracking of your glucose profile. It was certified in March 2023.
- HumanITcareA platform primarily designed for professionals, enabling remote monitoring of patients' physical and psychological condition, including parameters such as glucose, blood pressure, oxygen saturation, heart rate, temperature, and weight. Updated January 2023.
- Eversense CGMAn app associated with a long-term glucose monitoring system, with a subcutaneous implantable sensor and smart transmitter. The app continuously receives and displays glucose data. Certified in December 2022.
- MiniMed MobileDesigned to work with MiniMed 700 series insulin pumps and the associated glucose monitor, facilitating the viewing and interaction with glucose and insulin data from a smartphone. Certified in December 2022.
- GuardianApp for the Guardian 4 continuous glucose monitoring system, which includes a sensor and transmitter and allows blood glucose monitoring without the need for routine finger pricks. Certified in December 2022.
- SocialDiabetesA diabetes self-management app that helps calculate insulin doses, record blood glucose levels and other clinical data, and improve blood sugar control. It received certification in March 2022.
- FreeStyle LibreLinkApproved for use with the FreeStyle Libre and FreeStyle Libre 2 sensors. Allows you to check your glucose levels by scanning the sensor with your phone and view trends and graphs. Certified in July 2021.
- mySugrThis app integrates with Accu-Chek blood pressure monitors and allows for automatic recording of readings, as well as logging meals (including carbohydrates) and medication. It has been certified since December 2020.
- One Touch RevealIt syncs with systems such as the OneTouch Verio Reflect, Verio Flex, and other OneTouch range meters, offering analysis and visualization of glucose data. Certified in April 2022.
- Contour DiabetesDesigned to work with Contour glucometers, generating an organized blood glucose analysis with simple graphs and reports. Certified in March 2020.
All these applications have in common that they are Returns These tools meet minimum quality standards for security and functionality, providing added confidence compared to other, unevaluated options. Specific details for each tool, along with download links and recommended healthcare centers, can be found in the Fundación TIC Salut Social directory.
Other notable CGM and glucose diary apps
In addition to applications certified by organizations such as the TIC Salut Social Foundation, there are other widely used tools in the field of digital diabetes managementOne of them is Diabetes Diary Plus, an advanced diary geared towards people with type 1 diabetes, type 2 diabetes and also women with gestational diabetes.
This application allows for easy registration. glucose levels, insulin doses, and meal details in a matter of seconds. It offers interactive charts that show patterns over weeks or months, making it easy to detect trends that might otherwise go unnoticed.
Among its strengths are its integration with Apple Health and other health appsas well as the ability to view data on the Apple Watch when paired with systems like Dexcom. It also supports custom fields for recording basal rates, ketones, contextual notes, and other relevant parameters.
iCloud synchronization allows you to switch devices without losing your history, and an important privacy detail is that It does not require you to create an accountThis is something that many users concerned about the management of their personal data appreciate.
In the specific case of pregnancy, it offers sections focused on blood sugar management during this stage, where glycemic control is especially crucial for the health of the mother and baby.
Dexcom G6, FreeStyle Libre and other reference systems
Within the CGM universe, there are some names that have become almost obligatory references. One of them is Dexcom G6, a continuous real-time monitoring system that sends readings directly to a compatible smartphone or smartwatch.
The Dexcom G6 companion app provides continuous readings without needing to scan the sensorwith configurable alerts to notify of high or low glucose levels and options to share data with family members or caregivers. This combination of constant visibility and support from one's environment significantly reduces the stress associated with managing diabetes for many people.
On the other hand, the FreeStyle Libre family has popularized the so-called flash monitoringWith FreeStyle LibreLink, the user scans the sensor placed on the arm with their mobile phone and instantly obtains the glucose value, the trend arrow, and a graph of the last few hours.
Although the flash glucose monitoring system is not strictly continuous glucose monitoring (CGM) because it requires scanning the sensor, it offers a wealth of information through a simple and minimally invasive procedure. The FreeStyle Libre 2 version added alarms for hypoglycemia and hyperglycemia, and the FreeStyle Libre 3 has taken a further step towards... continuous real-time monitoringsending data directly to the mobile phone without the need for manual scanning.
Many of these systems are also integrated with insulin pumps to create closed or semi-automated loopsIn this context, if the CGM detects a rise in glucose, the pump can increase insulin delivery; if it detects a drop, it can reduce or temporarily suspend it. This does not eliminate the need for monitoring, but it does significantly reduce the burden of constant decision-making.
Nutritional support and use of CGM data in consultation
The data generated by a CGM is a gold mine for the nutritionists-dietitians and diabetes educatorsprovided they are properly interpreted and integrated into a personalized plan. Analyzing how glucose responds to different breakfasts, types of dinners, times of day, or exercise sessions It allows for much more precise recommendations.
A registered dietitian nutritionist can help Identify foods or combinations that trigger glucose.Adjust the amount and type of carbohydrates, and decide which meals should be accompanied by more fiber, healthy fat, or protein to smooth out spikes. You can also suggest timing strategies (for example, eating dinner earlier or distributing carbohydrate portions more evenly throughout the day).
In some cases, such as in centers that work with FreeStyle Libre 3, the healthcare professional may have remote access to patient data If this adds a consultation or medical team identifier to the app, reports can be reviewed directly during visits, whether in person or online, to identify problematic patterns and agree on realistic changes to diet or lifestyle.
This collaborative approach helps the person not only to "receive data", but to understand what causes it and how they can modify it, which increases the feeling of security and autonomy in daily life.
Diabetes, clinical context and need for metabolic control
diabetes is one chronic disease of high prevalence This condition occurs when the pancreas does not produce enough insulin or the body does not use it properly. When insulin fails, glucose accumulates in the blood (hyperglycemia), and if this situation persists, it can lead to complications such as heart attack, stroke, kidney failure, retinopathy with risk of blindness, or amputations.
In Spain, the Spanish Diabetes Society estimates that One in seven adults has diabetesand that around 30% are still undiagnosed. The vast majority of cases (around 90%) are type 2 diabetes, linked to excess weight, sedentary lifestyle, hypertension, and abnormal blood lipid levels.
Although many people with type 2 diabetes don't need insulin initially, without proper treatment and close monitoring, it may become necessary over time. Maintaining metabolic control is crucial in all types of diabetes, and this is where the use of CGM and mobile applications It greatly facilitates the collaborative work between the patient and the healthcare team.
Continuous monitoring systems do not replace traditional diabetes education, but they do provide much more sophisticated tools to understand how each body reacts and to adapt treatment dynamically, rather than relying solely on sporadic measurements or quarterly A1C.
By combining CGM technology, reliable apps, professional support, and sustainable lifestyle changes, it's possible to transform what was once a difficult and very manual process into a more flexible, informed and personalized glucose managementreducing complications and improving the quality of life for people living with diabetes.
