Fasting Ramadan with type 2 diabetes? Medication choice shapes the risk of lows

During Ramadan, Muslims abstain from food and drink between dawn and sunset for 30 consecutive days, and many people with type 2 diabetes choose to fast alongside healthy adults. For anyone on glucose-lowering medication, going all day without food raises an obvious worry: episodes of dangerously low blood sugar, known as hypoglycaemic events. These episodes are a serious complication of diabetes management and are associated with increased cardiovascular disease risk. Previous studies have reported conflicting results on how often they actually occur during the fasting month, so this review set out to organise what the evidence says.

Researchers searched ten databases from inception to 31 October 2020 for studies of people with type 2 diabetes who fasted during Ramadan, with hypoglycaemic events as the primary outcome. They included both trials where people were assigned at random and studies that simply followed people through the fasting month. In total, 68 studies met the inclusion criteria, made up of 35 randomised trials and 33 observational studies. The authors describe this as the most comprehensive review on this question to date, covering the largest number of studies of its kind.

The clearest pattern concerned medication: non-sulfonylurea glucose-lowering drugs were superior to sulfonylureas at lowering the incidence of hypoglycaemic events during the fast. Beyond medication, a long list of moderators influenced who experienced lows, including sex, geographical location, body measurements, season, dietary behaviours, fasting duration, time since diagnosis and whether people received education before the fast. These moderators appeared in both the trial evidence and the studies that followed people. The review did not distil everything into a single pooled risk figure.

Reports on hypoglycaemia during Ramadan have long disagreed with each other, and this review is an attempt to organise that scattered evidence rather than add a new experiment. Its contribution is breadth: 68 studies is far more than previous efforts covered. It supports the clinical suspicion that sulfonylureas are the riskier medication class during prolonged daytime fasting, and it highlights that context, from season and country to pre-fast education, genuinely matters. Open questions remain about exact risk sizes, since the underlying studies varied widely in design and population.

For a reader with type 2 diabetes who observes Ramadan, this is a reason to think the risk of low blood sugar during the fast is not fixed: it depends heavily on which medication class you are on and on preparation before the month begins. Pre-fasting education stood out as one of the factors linked with the incidence of events, which suggests planning the fast with a clinician is not a formality. Nothing here declares fasting safe or unsafe in general; it says the details shape the risk, and many of those details can be discussed in advance.