Blood Glucose Monitoring Devices for CF-Related Diabetes: Part 1

Cystic fibrosis (CF)-related diabetes is a common complication of CF. The treatment of CF-related diabetes (CFRD) is important as diabetes is associated with worsening lung function, increased risk of infections, and worsening nutritional status in people with CF.¹ Blood glucose monitoring is an important tool to help manage blood glucose levels.

However, with the increased options of blood glucose monitoring devices available on the market these days, it may be overwhelming to know where to start. Ultimately, your endocrinologist and/or diabetes nurse is best suited to provide a recommendation that fits your unique needs. The following article will outline the prevalence of CFRD and the role of glucose monitoring. Stay tuned for part 2 of the article on the types of monitoring devices!

Prevalence of CF-Related Diabetes

In general, the risk of CFRD increases with age. A study conducted in the 1990s revealed the following prevalence of CFRD of those diagnosed with CF, categorized by age groups:¹

• Children age 10 and younger: 2% had CFRD
• 11 to 17 years of age: 19%
• Adults 18 to 29 years of age: 40%
• Those above the age of 30: 45-50%

Of course, this study was conducted decades ago, so the prevalence may be lower now given that we have better treatment options. Some recent studies have confirmed this.¹

Role of insulin therapy

In general, insulin is prescribed for most cases of CFRD. While the goals of therapy differ and depends on each individual case, in general, the goals of therapy of insulin treatment is:

• Lower hemoglobin A1C levels: A1C is a measure of your average blood glucose readings over the previous 3 months. It provides a good snapshot for doctors and patients alike. For most people, the goal is to reduce A1C below 7%.¹ Your doctor will give you your specific target if it differs.
• Reduce the risk of hypoglycemia: hypoglycemia is a condition that occurs when blood sugar gets too low. This can occur if the insulin dose is too high or during periods of sickness or high activity levels.

Role of blood glucose monitoring

Managing insulin therapy – in addition to all the treatments needed for CF – is no easy task. For people with a sole diagnosis of diabetes, managing diabetes is hard enough. Add that in with the extensive therapies required for CF, and it can be incredibly burdensome. For this reason, the selection of an appropriate blood glucose monitor will often depend on the additional burden invoked and the age of the patient with CF.

Frequency of blood glucose monitoring

The general recommendation is that people with CFRD perform self-monitoring of their blood glucose (SMBG) at minimum 3 times a day.¹ However, this again differs on the patient and some patients may be recommended less or more monitoring. The guidelines recommend the following time periods, at minimum, to monitor:¹

• Pre-eating, or fasting blood glucose: this is particularly important if an acute illness is present, to rule out hypoglycemia. This is because an illness, such as a lung exacerbation, can cause blood sugars to fall to dangerously low levels. Your doctor will provide you with a specific recommended range to aim for when taking your fasting blood glucose levels.
• Post-meal readings: this reading should be done 1-2 hours after a meal. Insulin is steadily adjusted until the target reading is reached.

Overall, the frequency of testing varies on the individual and on the day. For example, people who are at a higher risk of hypoglycemia, such as children, may need to monitor more frequently.

Read Part 2 here!