Mercedes Sánchez Martínez, Augusto Blanco, María Victoria Castell Alcalá, Alicia Gutiérrez Misis, Juan Ignacio González Montalvo, M. Victoria Zunzunegui Pastor, Ángel Otero Puime
Objective To estimate the prevalence and incidence of self-reported diabetes and to study its association with medium- and long-term mortality from all causes in persons =65 years.
Design A population-based cohort study begun in 1993.
Setting �Envejecer en Leganés� cohort (Madrid).
Participants A random sample of persons =65 years (n = 1277 in the 1993 baseline sample).
Methods Participants were classified as having diabetes if they so reported and had consulted a physician for this reason within the last year. Diabetes history was categorized in <10 and =10 years in 1993. Incidence density was calculated in 2-year periods in non-diabetic individuals (1965 persons/2 years). Vital status was recorded on 31 December 2011. The association between diabetes history =10 years and mortality at 6 and 18 years follow-up was studied by the Kaplan�Meier and Cox regression analyses after adjusting for age, sex, heart disease and comorbidity.
Results The prevalence of self-reported diabetes rose from 10.3% in 1993 to 16.1% in 1999 (p = 0.001) and was higher in women than men (p = 0.05). Total incidence density was 2.6 cases/100 persons/2 years (95% CI: 2.0�3.3). Medium- and long-term mortality was higher in persons with diabetes history =10 years than in non-diabetic individuals (HR: 2.0; 95% CI: 1.2�3.3 and HR: 1.7; 95% CI: 1.1�2.5, respectively). In diabetics with history <10 years the HR was 1.3 (95% CI: 0.9�1.9) and HR: 1.5 (95% CI: 1.2�1.9, respectively).
Conclusions Although diabetes is clearly associated with increased risk of mortality, it is significant only for patients with =10 years� history of diabetes.