The Association between Alzheimer's Disease Severity as measured by RMBPC and Caregiver-reported Outcomes

Abstract

The objective was to describe the self-reported attributes and outcomes for caregivers of patients with Alzheimer's disease (AD) and quantify the association of patient severity with caregiving hours per week reported by caregiver. From a 2009 survey of 1079 AD caregivers, responses from unpaid primary caregivers of community-dwelling AD patients were selected. Patient severity was calculated from responses to the Revised Memory and Behavioral Problem Checklist (RMBPC) as a continuous (0-4) variable. Caregiver attributes and outcomes were described for three cohorts based on RMBPC; Mild (RMBPC < 1.25), Moderate (1.25 ≤ RMBPC < 2.25), and Severe (RMBPC ≥ 2.25) and compared using chi-square tests for categorical variables and ANOVA for continuous variables. A generalized linear regression model with a negative binomial distribution was constructed for ‘caregiving hours per week' with RMBPC, age, gender, marital status, relation to patient, living situation, employment and income as covariates. Of the 849 caregivers meeting study criteria, 18.8% were caring for persons categorized as Mild (n=160), 52.4% as Moderate (n=445) and 26.4% as Severe (n=244). Significant differences (p<0.05) were observed among the severity groups in attributes such as age, relation to AD patient, diagnosed depression and diagnosed anxiety and in caregiver outcomes such as Zarit Caregiver Burden Scale, Desire to Institutionalize Scale, SF-12 Mental and Physical Composite Summary Scores, work days per month missed due to caregiving and caregiving hours per week (Mild=43.6 hours, Moderate= 47.9 hours, Severe= 55.1 hours). A positive relationship between RMBPC and caregiving hours was seen in the multivariate analysis, with a 1 point change in RMBPC associated with a 10% change in hours (p=0.005). Two factors associated with less time caregiving were household income greater than $50,000 (p=0.013) and living apart from the AD patient (p<0.001). In this survey of unpaid caregivers of AD patients living in the community, differences in caregiver characteristics and outcomes were quantified among those caring for Mild, Moderate and Severe AD patients. The findings of this study suggest that higher patient severity is associated with increased burden on caregivers in terms of caregiving time, lost work time and quality of life.Tabled 1Caregiver Attributes and Outcomes by Patient SeverityTotal (N=849)Severity by RMBPC ScoreP ValueMild (N=160)Moderate (N=445)Severe (N=244)Caregiver AttributesAge (Mean ± SD)51.09 ± 13.4353.07 ± 14.6951.86 ± 13.2048.39 ± 12.63<.001Gender (Female)69.61%65.00%70.79%70.49%0.370Relationship to Alzheimer's Disease Patient0.007Spouse/significant other15.55%20.63%16.85%9.84%Daughter/Son/In-Law61.96%61.25%62.70%61.07%Grandchild15.43%12.50%13.03%21.72%Other7.07%5.63%7.42%7.38%Caregiver Employment0.838Full-Time, Part-Time, or Self Employed55.12%56.25%54.16%56.15%Not Employed44.88%43.75%45.84%43.85%Diagnosed with Anxiety28.15%10.00%29.44%37.70%<.001Diagnosed with Depression31.21%11.25%30.34%45.90%<.001Caregiver OutcomesZarit Caregiver Burden Scale (Mean ± SD)37.45 ± 16.9025.53 ± 14.2637.67 ± 15.5244.86 ± 16.56<.001Desire To Institutionalize Scale (Mean ± SD)2.50 ± 2.031.28 ± 1.522.56 ± 2.013.18 ± 2.02<.001SF-12v2: Mental Component Summary (Mean ± SD)42.43 ± 11.8748.41 ± 10.6742.58 ± 11.5338.25 ± 11.55<.001SF-12v2: Physical Component Summary (Mean ± SD)47.81 ± 11.2549.76 ± 9.6647.95 ± 11.2246.29 ± 12.070.009Work Days Missed Due to Caregiving (Mean ± SD)5.95 ± 15.131.39 ± 3.095.48 ± 12.499.75 ± 21.76<.001Hours per Week Providing Care (Mean ± SD)49.12 ± 37.3643.64 ± 34.5547.86 ± 37.6355.06 ± 38.000.013 Open table in a new tab