Diabetes mellitus as a risk factor for functional and cognitive decline in very old people: the Octabaix study

Abstract

Objectives: To examine the incidence of functional or cognitive impairment and its associated factors in a sample of individuals aged 85 years or older with and without diabetes mellitus, who were free of significant impairment at baseline.

Design: Longitudinal study.

Setting: Community-based survey study of 7 primary health care centers.

Participants: A total of 167 individuals born in 1924 who completed 2 years of follow-up.

Measurements: Sociodemographic variables, the Barthel Index (BI), the Spanish version of Mini-Mental State Examination (MEC), the Mini Nutritional Assessment (MNA), the Charlson Comorbidity Index, and a list of chronic drug prescriptions. A comparative analysis was performed between diabetic and nondiabetic patients regarding the rate of functional and cognitive impairment. In addition, in older people with diabetes experiencing incident disability, an analysis of the potential factors involved was carried out.

Results: The prevalence of diabetes (DM) at baseline in this population was 25.1%. After 2 years of follow-up, 66.8% of patients with DM had developed a new impairment measured as 38.1% for the defined target of loss of BI of 10 or more and 33.3% for the cognitive target (MEC scores lower than 24 or loss >4 points in MEC). In a multivariate analysis, diabetic patients had an increased risk of any new disability (OR 2.05, 95% CI 1.01-4.36; P = .04). Logistic regression showed an association between any new disability and baseline scores of MNA (OR 1.35, 95% CI 1.01-1.82; P = .04) and MEC (OR 1.38, 95% CI 1.02-1.85; P = .003).

Conclusion: This study has identified that in the oldest old, community-dwelling individuals without evidence of severe functional impairment at baseline, diabetes increases the risk of incident disability in only 2 years.

Keywords: Diabetes mellitus; cognitive status; disability; functional status; geriatric assessment; oldest old.