Hypoglycemic Episodes and Risk of Dementia in Older Patients With Type 2 Diabetes Mellitus

Abstract

Context Although acute hypoglycemia may be associated with cognitive impairment in children with type 1 diabetes, no studies to date have evaluated whether hypoglycemia is a risk factor for dementia in older patients with type 2 diabetes. Objective To determine if hypoglycemic episodes severe enough to require hospitalization are associated with an increased risk of dementia in a population of older patients with type 2 diabetes followed up for 27 years. Design, Setting, and Patients A longitudinal cohort study from 1980-2007 of 16,667 patients with a mean age of 65 years and type 2 diabetes who are members of an integrated health care delivery system in northern California. Main Outcome Measure Hypoglycemic events from 1980-2002 were collected and reviewed using hospital discharge and emergency department diagnoses. Cohort members with no prior diagnoses of dementia, mild cognitive impairment, or general memory complaints as of January 1, 2003, were followed up for a dementia diagnosis through January 15, 2007. Dementia risk was examined using Cox proportional hazard regression models, adjusted for age, sex, race/ethnicity, education, body mass index, duration of diabetes, 7-year mean glycated hemoglobin, diabetes treatment, duration of insulin use, hyperlipidemia, hypertension, cardiovascular disease, stroke, transient cerebral ischemia, and end-stage renal disease. Results At least 1 episode of hypoglycemia was diagnosed in 1465 patients (8.8%) and dementia was diagnosed in 1822 patients (11%) during follow-up; 250 patients had both dementia and at least 1 episode of hypoglycemia (16.95%). Compared with patients with no hypoglycemia, patients with single or multiple episodes had a graded increase in risk with fully adjusted hazard ratios (HRs): for 1 episode (HR, 1.26; 95% confidence interval [CI], 1.10-1.49); 2 episodes (HR, 1.80; 95% CI, 1.37-2.36); and 3 or more episodes (HR, 1.94; 95% CI, 1.42-2.64). The attributable risk of dementia between individuals with and without a history of hypoglycemia was 2.39% per year (95% CI, 1.72%-3.01%). Results were not attenuated when medical utilization rates, length of health plan membership, or time since initial diabetes diagnosis were added to the model. When examining emergency department admissions for hypoglycemia for association with risk of dementia (535 episodes), results were similar (compared with patients with 0 episodes) with fully adjusted HRs: for 1 episode (HR, 1.42; 95% CI, 1.12-1.78) and for 2 or more episodes (HR, 2.36; 95% CI, 1.57-3.55). Conclusions Among older patients with type 2 diabetes, a history of severe hypoglycemic episodes was associated with a greater risk of dementia. Whether minor hypoglycemic episodes increase risk of dementia is unknown.

Severe hypoglycaemia and cognitive impairment in older patients with diabetes: the Fremantle Diabetes Study

“…In a recent study using a large health database of insured US patients, a history of severe hypoglycaemia assessed from hospital discharge and emergency department data was associated with a greater risk of dementia in those with type 2 diabetes [29]. The diagnosis of dementia was based on inpatient and outpatient diagnosis codes rather than formal cognitive assessment, and no serial assessments of cognitive function were performed.…”

Comorbidity and dementia: a mixed-method study on improving health care for people with dementia (CoDem)

“…For example, there is evidence that cognitive decline may be accelerated in older people with type 2 diabetes. 18,19 Moreover, the presence of dementia may adversely affect the clinical care of other conditions and undermine a patient's ability to self-manage chronic conditions and engage in health maintenance activities. 20,21 The presence of dementia can be a key factor in how different specialist and emergency services are used and in decision-making about transfer to long-term care (nursing homes).…”

Intensified glucose lowering in type 2 diabetes: time for a reappraisal

“…This side of the equation is rarely taken into consideration when intensified control is advocated. Furthermore, and in stark contrast to lipid-lowering or antihypertensive therapies, intensive glucose-lowering may require several injections each day [45], requires regular fingerprick blood testing and is associated with side effects that include hypoglycaemia and loss of consciousness, and perhaps an increased future risk of dementia [46]. Our data (Fig.…”