Does Lower Diabetes-Related Numeracy Lead to Increased Risk for Hypoglycemic Events?

IN RESPONSE:

We agree that interventions to reduce the frequency and severity of hypoglycemic episodes in patients are an integral component of diabetes care and patient safety. Patient literacy and numeracy may play an important role in adverse events related to blood sugar management. For a subgroup of patients in our study (n = 163 [41% of the primary sample]), we were able to download data from their blood glucose meters and obtain information about the frequency of hypoglycemic events (defined as blood glucose level <3.33 mmol/L [<60 mg/dL]) and the proportion of blood glucose measures less than 3.89 mmol/L (<70 mg/dL). Most of these patients (58%) did not have a measured hypoglycemia event; however, 42% recorded at least 1 event, and 10% of these patients had more than 5 events recorded. Although patients with type 1 diabetes (n = 42) were more likely to have hypoglycemic events than patients with type 2 diabetes (n = 121) (86% vs. 27%; P < 0.001), neither health literacy nor diabetes-related numeracy was associated with the number of hypoglycemic events as measured by self-monitoring of blood glucose levels in patients with either type of diabetes. Health literacy or diabetes-related numeracy was also not found to be statistically significantly associated with a proportion of blood glucose meter readings that were low (<3.89 mmol/L [<70 mg/dL]). Results were also similar if patients using only insulin (n = 121) were included in the analysis. This subgroup evaluation was limited by its small, selected sample of patients, and it was not adequately powered to evaluate this important question. Patients with lower numeracy may have had higher rates of hypoglycemic episodes but did not record these episodes with their glucose meter or did not bring their meter to clinic for download. Additional, larger studies are needed to define the role of literacy and numeracy in the prevention of serious adverse events and overall safety of patients with diabetes and other chronic diseases.