Hypoglycemia is more common among type 2 diabetes patients with limited health literacy: the Diabetes Study of Northern California (DISTANCE).

BACKGROUND

Little is known about the frequency of significant hypoglycemic events in actual practice. Limited health literacy (HL) is common among patients with type 2 diabetes, may impede diabetes self-management, and thus HL could increase the risk of hypoglycemia.

OBJECTIVE

To determine the proportion of ambulatory, pharmacologically-treated patients with type 2 diabetes reporting > or =1 significant hypoglycemic events in the prior 12 months, and evaluate whether HL is associated with hypoglycemia.

RESEARCH DESIGN

Cross-sectional analysis in an observational cohort, the Diabetes Study of Northern California (DISTANCE).

SUBJECTS

The subjects comprised 14,357 adults with pharmacologically-treated, type 2 diabetes who are seen at Kaiser Permanente Northern California (KPNC), a non-profit, integrated health care delivery system.

MEASURES

Patient-reported frequency of significant hypoglycemia (losing consciousness or requiring outside assistance); patient-reported health literacy.

RESULTS

At least one significant hypoglycemic episode in the prior 12 months was reported by 11% of patients, with the highest risk for those on insulin (59%). Patients commonly reported limited health literacy: 53% reported problems learning about health, 40% needed help reading health materials, and 32% were not confident filling out medical forms by themselves. After adjustment, problems learning (OR 1.4, CI 1.1-1.7), needing help reading (OR 1.3, CI 1.1-1.6), and lack of confidence with forms (OR 1.3, CI 1.1-1.6) were independently associated with significant hypoglycemia.

CONCLUSIONS

Significant hypoglycemia was a frequent complication in this cohort of type 2 diabetes patients using anti-hyperglycemic therapies; those reporting limited HL were especially vulnerable. Efforts to reduce hypoglycemia and promote patient safety may require self-management support that is appropriate for those with limited HL, and consider more vigilant surveillance, conservative glycemic targets or avoidance of the most hypoglycemia-inducing medications.