Dyslipidemia and Ischemic Cardiopathy Associated with Duration of Diabetes Mellitus in the Oldest Old: The Octabaix Study

Field: Medicine (Health Sciences)

To the Editor: Diabetes mellitus (DM) is one of the most serious challenges for healthcare systems worldwide, and a large percentage of very old patients develop other geriatric syndromes due to DM.1, 2 Glycemic control, insulin use, and duration of DM type 2 have been associated with cardiovascular risk in adults, although not in the oldest group (≥85).2 Therefore, the aim of this study was to examine the effect on morbidities of DM duration in a community-dwelling group of oldest old. The study data were collected within the framework of the OCTABAIX study, a prospective population-based study of 328 community-dwelling elderly adults, all born in 1924. The sampling procedures and data collection methods have been described elsewhere.3 The assessment included sensory status, cardiovascular risk factors, customary geriatric tests, and analytical blood samples. Inclusion criteria were having DM type 2 on the basis of self-report, diagnosis by a physician, use of antidiabetic agents, or a plasma glucose concentration of 126 mg/dL or greater at baseline. The sample was divided into two groups according to duration of DM, with a cut off of 10 years. The total sample for this study was 85 elderly adults; 53 were women (62.4%). The median duration since diagnosis was 5.8 years (interquartile range (IQR) 3.5–10.6 years) in the total sample, 16.8 years (IQR 13.8–19.8 years) in the longer-duration group, and 4.64 years (IQR 2.14–6.46 years) in the shorter-duration group. Median glycosylated hemoglobin (HbA1c) level was 6.4%. Table 1 shows the characteristics of the groups according to duration of DM. Logistic regression identified dyslipidemia (odds ratio (OR) = 2.94, 95% confidence interval (CI) = 1.02–8.33, P = .046) and ischemic cardiopathy (OR 5.06, 95% CI = 1.22–21.01, P = .03) as independently associated morbidities with an onset of longer than 10 years. The mean duration of DM in this study was low (6 years). A mean duration of 8 years was found in 66-year-old participants in the Action in Diabetes and Vascular Disease: Preterax and Diamicron Modified Release Controlled Evaluation Trial4 and of 13 years in 74-year-old participants in the National Health and Nutrition Examination Survey study.5 One explanation for this may be that individuals with DM are more likely to die at a younger age, and therefore, by the age of 85, diagnoses of DM are relatively recent (survival bias).6 Another possible explanation is that new cases of DM in this population group are increasing, with the result that disease duration is shorter. An interesting finding in this study was the good rate of glycemic control (6.4%), which is lower than the rates recorded in other community studies in younger elderly (<80).7 This highlights that, in older adults recently diagnosed with DM, glycemic control (HbA1c <7%) could be a factor in diminishing microvascular disease and other complications of DM.6 However, the goal that expert committees recommend of achieving higher HbA1c targets8 should not be forgotten. Moreover, the paradox is that aging is associated with lower body weight, less food intake, and a high prevalence of malnutrition, which may also impair survival or improve glycemic control by reducing insulin resistance, albeit at the expense of a catabolic state.7 Another important finding was the significantly higher proportion of dyslipidemia diagnoses in the group with longer-duration DM. The risk of dyslipidemia was three times as high in this group. Additionally, neither group in this study achieved the low-density lipoprotein cholesterol level of 100 mg/dL recommended in individuals aged 40 and older with DM,8 and despite the fact that “the lower the better” approach does not involve the secondary effects associated with the treatment of other cardiovascular risk factors such as hypertension and DM.9 The results of the current study showed that prescription of statins was lower (44%) than reported (66%) in other studies.10 Many participants in the current study had comorbid conditions. This study supports the notion that ischemic cardiopathy is independently associated with duration of DM in elderly adults, because this association was five times as great in the group with longer-duration DM. This macrovascular complication is important because it extends the association between poor prognosis with DM and duration of illness established in younger adults to older adults and indicates that ischemic cardiopathy in elderly adults should be controlled as quickly as possible. In conclusion, this study reported a short duration of DM in oldest old individuals, indicating that screening for DM type 2 should be performed in this group just as it is in other adult groups, and in individuals with DM of 10 years' duration or longer, targeted monitoring should be performed to optimize dyslipidemia and decrease ischemic cardiopathy. Conflict of Interest: The editor in chief has reviewed the conflict of interest checklist provided by the authors and has determined that the authors have no financial or any other kind of personal conflicts with this paper. Author Contributions: G.P. and A.F.: Wrote the manuscript and researched data. F.F.: Contributed to the discussion and reviewed the manuscript. J.A.: Performed statistical analysis and reviewed the manuscript. M.-A.M. and R.P.: Reviewed the manuscript. The Octabaix Study Group researched data and reviewed the manuscript. Sponsor's Role: None.