Impact of diabetes on caregiver stress in patients with Alzheimer's disease: data from the ICTUS study

Background: To estimate the impact of comorbid diabetes on caregiver stress in Alzheimer's disease (AD) patients from the Impact of Cholinergic Treatment Use (ICTUS) study. Methods: Using the Data from the ICTUS study, diabetes mellitus (DM) was recorded at baseline and caregiver burden was assessed twice per year using the Zarit Burden Interview (ZBI) scale. The three-factorial model of ZBI (the effect on the social and personal life of caregivers, the psychological burden and the feelings of guilt) was adopted. Linear mixed models were used to examine the relation between DM and the scores of ZBI. Results: The present analyses were conducted on 1,264 AD subjects. A total of 156 patients (12.3%) had DM with taking antidiabetic medication and/or self-report of a history. At baseline, the caregivers of patients with or without DM had similar ZBI global scores and similar scores of three different factors of ZBI. Unadjusted and adjusted models both indicated that ZBI global score increased over a 24-month follow-up without significant effect of DM. Similarly, unadjusted model showed that DM was not determining any significant difference in the score of any factor. However, adjusted model indicated that in diabetic patients, the scores of the social and personal life of caregivers and the psychological burden increased more slowly than those in non-diabetic patients (p = 0.04 and 0.01, respectively). Conclusions: DM may affect the caregivers' daily social and personal life and psychological burden in AD patients. It is necessary for further research.