Health‐related quality of life in full spectrum of Alzheimer’s disease: a longitudinal analysis

Abstract Background Understanding the health‐related quality of life (HR‐QoL) in subjective cognitive decline (SCD), mild cognitive impairment (MCI) and demented patients is essential from the health economic perspective for evaluating new disease‐modifying treatments and preventive interventions. This study aims to assess HR‐QoL and the factors associated with longitudinal change in HR‐QoL in the full spectrum of Alzheimer’s disease. Method Longitudinal data from 918 SCD and 1,346 MCI patients from the MEMENTO cohort were included in the study. MCI was defined as performing one standard deviation (SD) worse than the age, sex and education‐level thresholds in one or more cognitive domains identified within six months of the study enrollment. SCD was defined as having isolated subjective cognitive complaints but without any objective cognitive deficit and aged 60 years or older. HR‐QoL was measured by EuroQol EQ‐5D‐3L patient‐reported version. Linear mixed‐effect models with disease stage as a time‐varying covariate were used to (1) assess the utility changes over time across the dementia spectrum and (2) compare the utility changes between amyloid positive and negative SCD and MCI patients. Result At baseline, mean utilities were 0.84 ± 0.16 and 0.81 ± 0.18 in SCD and MCI patients. Linear mixed effect models estimated that the utilities were ‐0.016 (SE 0.003), ‐0.07 (SE 0.009), ‐0.18 (SE 0.014) and ‐0.36 (SE 0.034) lower than SCD in patients with MCI, mild, moderate and severe dementia over the study period. Time is associated with a significant decrease in utility with ‐0.008 (SE 0.001) per year. Baseline age, BMI, female, diabetes, cardiovascular history, neuropsychiatric symptoms and inability to perform Instrumental activity of daily living (IADL) were negatively associated with utilities. Amyloid‐positive SCD patients showed a faster decline in utility than amyloid‐negative SCD patients (p < 0.05). The decrease was not statistically significant in amyloid‐positive MCI patients compared to amyloid‐negative MCI. Conclusion Health utilities decrease over time in all stages of dementia, and the decline is steeper in moderate and severe stages. Positive amyloid accelerates health utility decline in SCD but not MCI individuals. The ability to perform IADL is the major factor affecting HR‐QoL in all phases of dementia.