Flash Glucose Monitoring for Patients with Type1 Diabetes Mellitus During Ramadan Fasting

Why Flash Glucose Monitoring (FGM) Matters in Ramadan

Ramadan obliges Muslims to abstain from food and drink from sunrise (Suhoor) until sunset (Iftar). For people with type1 diabetes mellitus (T1DM) this period creates a unique metabolic challenge: insulin dosing must be balanced against long periods without caloric intake, and the risk of hypoglycaemia rises sharply during daylight hours. Traditional fingerprick testing, although accurate, can be cumbersome when multiple checks are needed throughout the fast. Flash glucose monitoring (FGM) offers continuous, painless glucose data that can be reviewed at any time, making it especially valuable for patients who choose to fast.

How Flash Glucose Monitoring Works

FGM systems consist of a small, disposable sensor (usually 14days long) placed on the back of the upper arm. The sensor measures interstitial glucose every minute and stores the data internally. By gently sweeping a dedicated reader or a compatible smartphone over the sensor, the user obtains an instant glucose reading, a trend arrow, and a graphical view of the last 8hours. Unlike realtime continuous glucose monitors (CGMs), FGM does not provide automatic alerts; however, most modern readers allow the user to set threshold warnings.

Key Benefits for Ramadan Fasting

• Frequent, painless readings patients can check glucose before Suhoor, before prayers, and at any time during the day without fingerstick discomfort.
• Trend information arrows (, , ) and a 8hour history help anticipate rapid falls or rises before they become dangerous.
• Reduced hypoglycaemia risk early detection of downward trends enables prompt carbohydrate intake or insulin adjustment.
• Data for healthcare professionals downloadable reports simplify preRamadan assessment and postfast review.
• Improved adherence the unobtrusive nature of the sensor encourages more consistent monitoring.

PreRamadan Preparation

Before the first day of fasting, patients should work with their diabetes team to:

1. Assess suitability for fasting. Consider age, duration of diabetes, recent episodes of severe hypoglycaemia or ketoacidosis, and comorbidities.
2. Install a fresh sensor. Starting the fast with a new sensor ensures accurate readings for the entire month.
3. Review insulin regimen. Many physicians switch to a basalbolus or basalonly regimen with reduced basal dose (1020%) during daylight fasting, and increased rapidacting insulin at Iftar.
4. Set target glucose ranges. Typical safe ranges during fasting are 70130mg/dL (3.97.2mmol/L) before Suhoor and 90150mg/dL (5.08.3mmol/L) after Iftar.
5. Plan glucose checks. Minimum recommended checks: before Suhoor, before Dhuhr prayer, midafternoon (around 4pm), before Iftar, and 2hours after Iftar.

Practical Guidance During the Fast

1. Before Suhoor (predawn meal)

Check glucose 30minutes before eating. If the reading is <70mg/dL (3.9mmol/L) or the trend arrow points down rapidly, break the fast and treat hypoglycaemia with 1520g of fastacting carbohydrate.

2. During Daylight Hours

Even if you feel well, perform a quick scan at least twice: before Dhuhr and midafternoon. When the sensor shows a decreasing trend (<2mg/dL/min) and the absolute value is 100mg/dL (5.6mmol/L), consider taking a small carbohydrate snack (e.g., 510g glucose) even though you are fasting; this is permissible in most Islamic jurisprudence for health preservation.

3. Before Iftar (sunset)

Check glucose 15minutes before breaking the fast. If the level is >250mg/dL (13.9mmol/L) with upward trend, postpone Iftar, administer corrective rapidacting insulin, and recheck after 15minutes.

4. After Iftar

Two hours after the meal, verify that glucose is within 90150mg/dL. If it exceeds 180mg/dL (10mmol/L) with a rising arrow, give an additional correction dose according to your insulintocarbohydrate ratio.

Managing Exercise and Physical Activity

Many Muslims engage in light to moderate activity (e.g., walking, prayerrelated movements) during Ramadan. Exercise can further lower glucose, especially after an insulin dose. Use the FGM sensor to scan before, during, and after activity. If the trend shows a rapid decline, pause activity, consume a carbohydrate snack, and reevaluate.

Special Situations

Illness or Vomiting

Illness can cause unpredictable glucose swings. Monitor every 30minutes and treat according to standard sickday rules. If vomiting is present, break the fast and seek medical advice.

Pregnancy

Pregnant women with T1DM are generally advised not to fast. If fasting is insisted upon, close supervision with FGM, daily review by obstetric and diabetes teams, and readiness to break the fast at any sign of hypo or hyperglycaemia are mandatory.

PostRamadan Review

After the month, download the sensors glucose report and discuss the following with your clinician:

• Timeinrange (TIR) during fasting versus nonfasting days.
• Number of hypoglycaemic episodes (<70mg/dL) and severe events.
• Average daily basal insulin dose and any adjustments needed for future fasts.
• Patient comfort and satisfaction with FGM.

These data help finetune future fasting plans or decide whether fasting should be avoided.

Safety and Religious Considerations

Islamic scholars generally permit breaking the fast for any health condition that may endanger life, including severe hypoglycaemia (blood glucose<50mg/dL) or ketoacidosis. Using FGM to detect early glucose changes aligns with the principle of preserving health while honoring spiritual commitments.

Conclusion

Flash glucose monitoring equips people with type1 diabetes with a practical, minimally invasive tool to navigate the metabolic stress of Ramadan fasting. By delivering realtime glucose trends, reducing the need for fingersticks, and providing data that can be shared with clinicians, FGM improves safety, confidence, and overall glycaemic control during this sacred month. Successful fasting hinges on thorough prefast preparation, diligent monitoring, and timely therapeutic adjustmentsall of which are facilitated by the continuous insight that flash glucose monitoring provides.

References: International Diabetes Federation (IDF) guidelines on diabetes and Ramadan; American Diabetes Association Standards of Care 2024; AlRashid etal., Flash Glucose Monitoring During Ramadan in T1DM, Diabetes Res Clin Pract, 2023.