Effect of Chronic Dementia Caregiving and Major Transitions in the Caregiving Situation on Kidney Function: A Longitudinal Study

Objective: To estimate the glomerular filtration rate (GFR) in relation to the chronic stress of dementia caregiving and major transitions in the caregiving situation. Methods: We longitudinally assessed 119 people serving as caregivers for their spouses with Alzheimer's disease and 58 noncaregiving controls for a period of up to 3 years (mean of 2.8 assessments per participant). At baseline, the mean (standard deviation [SD]) age of all participants was 74.5 (7.5) years. Random regression models with fixed and time-variant effects for psychosocial factors, risk factors of chronic kidney disease, and caregiving transitions were used to evaluate changes over time in estimated GFR. Results: The change in GFR did not differ between caregivers and controls during follow-up (p = .77). Further analyses revealed that GFR declined disproportionately after placement of the spouse in a nursing home at 3 months after placement (-4.9 [2.2] mL/min per 1.73 m(2); p = .03). Post hoc analyses showed that this effect was stronger in caregivers with hypertension compared with those without hypertension (-5.7 [3.1] versus -2.4 [3.4] mL/min per 1.73 m(2)), as well as in caregivers with diastolic blood pressure (BP) levels at I SD above the mean than in those with diastolic BP levels at 1 SD below the mean (-8.3 [2.9] versus -1.4 [2.7] mL/min per 1.73 m(2)). Conclusions: Kidney function did not differ between caregivers and controls over time. However, GFR had impaired at 3 months after a major caregiving transition. Because the effect of placement of the spouse with Alzheimer's disease on the decline in GFR was moderated by BR it might be confined to caregivers who experience increased sympathetic activation after placement.