Which Patient Factors Help Predict Cognitive Decline in Alzheimer’s Disease?

Patient age, sex, and activities of daily living (ADL) at baseline are some of the best predictors of cognitive decline among patients with Alzheimer’s Disease (AD), according to study findings in PLoS ONE.

With the increasing life expectancy of patients with AD, it becomes important to understand predictors of cognitive decline in patients. Researchers conducted an observational study to evaluate the impact of somatic and functional risk factors on cognitive deterioration. The researchers Liane Kaufmann from the Ernst von Bergmann Clinic in Potsdam, Germany, Josef Marksteiner from the General Hospital in Hall, Austria, and colleagues also assessed the relationship between caregiver burden and patient health status.

Data were collected from the Prospective Registry on Dementia (PRODEM) in Austria, a prospective cohort study that followed patients for 2 years. The PRODEM study assessed patients at 4 timepoints: baseline, 6 months, 1 year, and 2 years. 

While the study cohort initially included 500 Austrian patients who had probable or possible AD, a total of 169 patients remained at the end of the study. 

Identified Risk Factors

Somatic risk factors included atrial fibrillation, coronary heart disease, hypercholesterolemia, hypertension, diabetes, blood pressure. Some functional risk factors included ADLs, depression, pain, and neuropsychiatric symptoms. 

Cognitive functioning was evaluated by the Consortium to Establish a Registry for Alzheimer’s Disease (CERAD) neuropsychologic test battery and ADLs were assessed using the Disability Assessment for Dementia (DAD). Neuropsychiatric symptoms were assessed using the Neuropsychiatric Inventory (NPI) and caregiver load was evaluated based on the Zarit Buden Inventory (ZBI).

Significant Changes Seen

When tracking changes from baseline to the end of the study, researchers noted significant changes on the CERAD scale, indicating the progression to poorer cognition. The ADL and caregiver burden measurements also demonstrated a significant increase in functional dependency and caregiver load over time. However, the GDS, pain, and NPI scales did not show significance. 

The strongest and statistically significant correlations were demonstrated between caregiver load (ZBI) and patient’s ADL (DAD), neuropsychiatric symptoms (NPI), and cognitive functioning (CERAD). An increased caregiver load was correlated with poorer ADLs (correlation coefficient > -0.50 at all time points), more neuropsychiatric symptoms (correlation coefficient range, 0.42 to 0.45), and lower cognitive functioning (correlation coefficient range, -0.14 to -0.35). Additionally, an increased caregiver load was positively and significantly associated with patient depression (GDS) at 3 out of 4 time points. 

The correlation between cognitive function (CERAD) and ADLs (DAD) was significant, with the correlation growing stronger over time (correlation coefficient range, 0.23 to 0.46). 

Predictive Indicators Identified

The stepwise regression analysis revealed that patients’ cognition 2 years after baseline was predicted by patient age, sex, atrial fibrillation, and ADLs (DAD) at baseline. The overall model had a medium effect size according to Cohen (adjusted R², 0.137). 

The linear mixed model showed that cognitive function is best associated with disease duration, age, sex, ADLs, and GDS, with a medium effect size according to Cohen (marginal R², 0.157). Specifically, increasing disease duration, higher age, female sex, higher functional dependency, and increased depression were associated with cognitive decline. 

Study limitations include the potential inability to generalize to a broader population, a high patient drop-out rate, and the subjective nature of patient and caregiver reports. 

“These findings underscore the importance of a comprehensive treatment approach, considering both patient and caregiver variables, in the diagnosis and treatment of early-stage AD,” study authors concluded. “Such as, our findings disclosing strong correlations between caregiver load and various patient-related measures strongly suggest that the clinical management of early-stage AD should be targeted at the patient-caregiver dyad (instead of solely focusing on the patient).”

For a review of Alzheimer Dementia treatments, click here.

This article originally appeared on Clinical Advisor