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Correspondence: Address correspondence to Judith J. McCann, Rush Institute for Healthy Aging, Rush University Medical Center, 1645 W. Jackson Blvd., Suite 675, Chicago, IL 60612. E-mail: judy_j_mccann{at}rush.edu
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Abstract |
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Key Words: Community-based services • Institutionalization • Longitudinal study • Survival analysis
Of four randomized controlled trials of adult day care or other forms of respite, two reported no association (Hedrick et al., 1993; Weissert, Wan, Livieratos, & Katz, 1980), one found a small delay in nursing home placement (Lawton, Brody, & Saperstein, 1989), and one found increased risk of placement among spousal caregivers only (Montgomery & Borgatta, 1989). Although randomized controlled trials are generally most informative, the interventions in these studies consisted only of offering adult day care and other forms of respite. As a result, participants randomized to treatment and control groups differed little in the amount of respite or adult day care they used, and services were used at very low rates. An actual treatment reanalysis of one randomized controlled trial reported that those with high respite use were less likely to enter a nursing home than nonusers (Kosloski & Montgomery, 1995).
Three observational studies examined the effect of adult day care on nursing home placement in individuals with dementia. One small study (n = 47; Wimo et al., 1990) reported a lower risk of institutionalization with adult day care use than without it, although that study did not include a nonuser group and used a definition of institutionalization other than long-term nursing home placement. Two larger longitudinal studies, one of approximately 400 people (Gaugler & Zarit, 2001) and one of 3,944 participants in the Medicare Alzheimer's Disease Demonstration Evaluation (Gaugler, Kane, et al., 2003), found that adult day care use significantly increased the risk of nursing home placement. Investigators postulated that families did not use enough adult day care for it to be effective, and they waited too long in the disease process to begin adult day services. Thus, adult day care functioned more as a transition to nursing home placement than as a form of respite (Gaugler & Zarit; Zarit, Stephens, Townsend, Greene, & Leitsch, 1999).
Several studies concluded that research on the efficacy of formal community-based services should focus on the use of a specific service by a defined subgroup of elderly persons. The research reported here closely followed individuals with Alzheimer's disease who were adult day care users and comparable nonusers for up to 4 years. By focusing on a defined service and a group at high risk for nursing home placement, and by designing the study to ensure high rates of adult day care attendance, we intended to provide a rigorous test of the efficacy of adult day care to prevent or delay institutionalization. Using the behavioral model of health services utilization (Andersen, 1995) as our conceptual framework, we measured changes in adult day care use and other predisposing, enabling, and need variables associated with nursing home placement every 3 months. We hypothesized that, after we adjusted for other known predictors of nursing home placement in people with Alzheimer's disease, the use of adult day care would increase time to nursing home placement in a dose-response fashion.
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Methods |
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Consent procedures were approved by the Institutional Review Board at Rush University Medical Center, and we obtained signed consent from each participant with Alzheimer's disease and a family member. The participating family member was the individual who had the most face-to-face contact with the participant and who provided the most care. This individual, identified as the caregiver, provided baseline and follow-up data about the participant and for the caregiver measures.
Measurement Procedures
The diagnosis of possible, probable, or highly probable Alzheimer's disease was made by a board-certified neurologist using criteria of the joint working group of the National Institute of Neurologic and Communicative Disorders and Stroke and Alzheimer's Disease and Related Disorders Association (McKhann et al., 1984). We obtained medical history as well as data on participant and caregiver demographic, social, and health variables from an interview with the caregiver at baseline. Interviews were repeated either in person or by telephone at 3-month intervals for up to 48 months. Tests of participant cognitive function were administered in person at baseline and every 6 months during the observation period.
Trained research technicians conducted interviews and cognitive function tests. We specified all data-collection procedures in a project manual, and we used weekly staff meetings to address specific questions about data collection. The research technicians collected data by using computer-assisted interview procedures, and we monitored interrater reliability every 6 months with retraining provided as needed to maintain agreement at 90% or better. Average interrater reliability on all measures was 98.6% (range = 97.65–99.78%).
Measures
Time to Nursing Home Placement
Research technicians obtained the date of placement from the caregiver and verified it with the facility. We defined the time to nursing home placement as the interval from date of study enrollment to date of nursing home admission for permanent custodial care. We did not consider short-term stays for rehabilitative purposes to be nursing home placements.
Use of Adult Day Care Services
At each interview, we recorded any use of adult day services over the previous 3 months (0–1) and the average weekly number of days of attendance over the previous month (0–7). Because of the possibility of crossover between the adult day care user and nonuser groups, we obtained this information for both groups.
Use of Other Community-Based Services
We recorded the use of visiting nurse, personal care, and homemaker services at each follow-up. We summarized each service as any use over the past 3 months (0–1) and as a categorical variable (1–5) representing frequency of use over the past 3 months, from less than once a month to 5 or more times a week. We also created summary variables of the total number of services used (0–3) and the total frequency of service use (Sum of Service x Frequency; range = 0–15) over the past 3 months.
Financial Measures
At baseline, caregivers reported the participants' total annual family income using 10 income categories and the show-card method employed in the Established Populations for Epidemiologic Studies of the Elderly projects (Cornoni-Huntley, Brock, Ostfeld, Taylor, & Wallace, 1986). We also recorded ownership of long-term-care insurance as a dichotomous variable.
Participant Measures
At baseline, we obtained data on participant age, gender, marital status, race, education, and living arrangement. We analyzed age as a continuous variable, and we analyzed marital status as married or not married. We summarized race as Black or White (and others) because less than 2% of the participants were some other race. We assessed education in terms of years of completed schooling and analyzed it as a continuous variable. We characterized living arrangement as living alone or living with others, and we determined it at baseline and each follow-up.
At each 3-month follow-up with the caregiver, we collected data on participant physical function by using three standard physical function or disability scales (Katz & Akpom, 1976; Nagi, 1976; Rosow & Breslau, 1966). For each measure, we summed items to produce a score ranging from 0 (no disability) to the maximum score indicating disability on all items (6 for the Katz, 5 for the Nagi, and 3 for the Rosow–Breslau). Baseline internal consistency reliability coefficients for the three disability scales ranged from.74 to.89. We also collected data on number of hospitalizations and the occurrence of positive (0–5) and negative (0–5) behaviors (Gilley et al., 2004) and urinary or bowel incontinence. At baseline and every 6 months, we assessed cognitive impairment by using the Mini-Mental State Examination (MMSE; Folstein, Folstein, & McHugh, 1975), a 20-item measure of orientation, memory, attention, language, and visual-spatial abilities. The baseline internal consistency reliability coefficient for this measure was.92.
Caregiver Measures
At baseline, we collected data on caregiver age, gender, marital status, race, education, relationship to the participant with Alzheimer's disease, and the number of years the caregiver had been providing care (duration of caregiving). We analyzed years of age, education, and caregiving as continuous variables. The coding of marital status and race was identical to the participant data. We coded the relationship to the participant as spouse, child, or other.
Research technicians interviewed caregivers every 3 months by using standard measures. We computed time spent in caregiving each week by multiplying the average weekly days of care by the average daily hours of care (range = 0–168). We coded employment status as currently employed or not employed, and if caregivers were employed, we recorded the average weekly hours of work. We also administered a modified 7-item measure (Pearlin, Mullan, Semple, & Skaff, 1990) of the extent to which caregiving interfered with the caregivers' work, with higher scores indicating more interference. We assessed caregiver negative and positive affect with self-report measures that used the past week as the reference period. We measured depressive symptoms with the 10-item short form of the Center for Epidemiologic Studies Depression scale (Kohout, Berkman, Evans, & Cornoni-Huntley, 1993), with higher scores indicating greater depressive symptoms. We measured positive affect with the 10-item positive mood scale of the Positive and Negative Affect Scale (Watson, Clark, & Tellegen, 1988), with higher scores indicating more positive affect. We measured caregiving specific negative and positive appraisals with a 10-item Subjective Caregiving Burden scale and a 5-item Caregiving Satisfaction scale (Lawton, Moss, Kleban, Glicksman, & Rovine, 1991). The burden and satisfaction scales used a 4-point Likert response format, with higher scores indicating greater subjective stress and greater personal satisfaction associated with providing care.
We assessed self-reported health with three items from the Health-Related Quality of Life measure (Hennessy, Moriarty, Zack, Scherr, & Brackbill, 1994). Caregivers rated their overall health as poor, fair, good, or excellent, and they estimated the number of days in the previous month that their physical health was not good (0–30) and their mental health was not good (0–30). We combined responses to these last two questions to calculate a summary index of overall unhealthy days (Centers for Disease Control and Prevention, 2000), with a logical maximum of 30 unhealthy days. We measured physical function and disability with the same Nagi (1976) and Rosow-Breslau (1966) disability scales used with the participant.
We measured social support with the Perceived Social Support Scale (Zimet, Powell, Farley, Werkman, & Berkoff, 1990), a 12-item measure of perceived availability and satisfaction with support received from family, friends, and a "special person." Higher scores on this measure indicate greater perceived support. We assessed spirituality with 6 items that measure religious coping, support, beliefs, and practices (Fetzer Institute, 1999). Although the measure taps various aspects of spirituality, we treated the scale as unidimensional, and it had a Cronbach's coefficient of 
= 0.92 in our sample. Higher scores on this measure indicate greater spirituality. The baseline internal consistency reliability coefficients for the caregiver measures used in this study ranged from.74 to.92, with one exception of.57 for the scale measuring caregiving–work interference.
Statistical Analysis
We compared time to nursing home placement between participants who used adult day care and those who did not. We used Kaplan–Meier survival curves to graphically display the association between adult day use and nursing home placement, and we used Cox proportional hazards modeling to examine the simultaneous effects of adult day care use and other fixed and time-varying predictors on institutionalization risk. Our model development was based on the behavioral model of health services utilization (Andersen, 1995) and proceeded in four steps. We first examined the relation of institutionalization risk to participant age, gender, race, and time-varying MMSE score, and in separate models adjusting for the main effects of these variables, we examined all interactions among these variables. Second, we examined the effect of adult day care use, adjusting for age, gender, race, and time-varying MMSE score, and in separate models controlling for the main effects of these variables, we examined the interaction of adult day care use with each of these variables. We quantified adult day care use in two ways: (a) as a dichotomous variable reflecting adult day care user and nonuser groups as constituted at baseline (0–1), and (b) as a continuous and time-varying variable reflecting the weekly average days of adult day care received over the previous month (0–7). The results reported in this article are based on the latter approach, which allowed us to adjust for the initiation of adult day care by participants who were nonusers at baseline and to examine the dose effect of adult day care.
Third, in separate stepwise selection models that adjusted for participant age, gender, race, time-varying MMSE score, and time-varying adult day care use, we examined groups of predisposing, enabling, and need variables from the behavioral model known to be associated with nursing home placement, and we tested for interaction of adult day care use with the significant predictors in each group. Fourth, we used one stepwise selection model adjusted for participant age, gender, race, time-varying MMSE score, and time-varying adult day care use to select the significant predictors from among all the significant predictors in the separate stepwise selection models. This provided a parsimonious final model of predictors of nursing home placement in this cohort of people with Alzheimer's disease.
Sensitivity Analysis for Differences Between Adult Day Care User and Nonuser Groups
A major concern in any observational study is the possibility of selection bias (D'Agostino, 1998; Rubin, 1979). That is, despite our matching efforts, differences in the comparison groups might still affect the study findings. We addressed this in two ways. First, following standard procedures (D'Agostino; Rubin), we used multivariable logistic regression to model whether the participant was in the adult day care user versus nonuser group at baseline. This model incorporated all measured variables at baseline. We then included the predicted probability of group status (i.e., the propensity score) as a predictor of risk of nursing home placement in a Cox proportional hazards model. This facilitated a simple and direct comparison of the two groups in this observational study. Second, we reran our final model, including 11 additional variables for which there were significant group differences at baseline.
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Results |
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At baseline, adult day care users (n = 218) had been enrolled in adult day care for an average of 2.0 years (SD = 1.9) and were attending adult day care an average of 3.9 days per week (SD = 1.2). Over the entire 48-month observation period, the average weekly attendance was 3.6 days (SD = 1.4). Among participants not using adult day care at baseline (n = 298), 13% reported prior use and 16% used adult day care during the study period.
Although we frequency matched adult day care nonusers to users by age and MMSE groups, we found small but statistically significant differences for the continuous measures of these two variables (Table 1). However, there was sufficient distribution of age and MMSE scores in each group to permit adjustment in analyses. There were no significant differences in the matching variables of participant gender or race. The distributions of the other analytic variables are shown in Table 1. Compared with nonusers, adult day care users had significantly lower education and household income, and they were less likely to be married or living alone. Adult day care users had higher functional limitation and disability scores, but they used significantly fewer community-based services at baseline.
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Table 2 displays descriptive data on the 16 adult day care programs. All programs were nonprofit, and private pay and the Illinois Department on Aging were the largest payment sources. All programs provided assistance with personal care, oral medication administration, and blood pressure and weight monitoring, and about half of the programs provided more extensive health and rehabilitation services. Programs did not vary in terms of the types of activities offered to clients, but they did vary on services offered to families. About half provided support groups, counseling, and case management; none offered overnight or weekend respite. Admission and discharge criteria were similar across programs. The most common reasons for not admitting or for discharge were uncontrollable disruptive behavior and the need for one-to-one supervision. Programs differed most on whether they could handle participants who were incontinent or were highly dependent in activities of daily living.
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We considered Model B in Table 3 our base model and tested the effect of additional participant and caregiver variables on risk of nursing home placement by adding them to this base model. We grouped these variables into categories reflecting predisposing, enabling, and need variables specified in the behavioral model of health services utilization (Andersen, 1995). Predisposing variables influence the tendency to use services; enabling variables influence access to services; and need variables refer to the health care requirements of the individual with Alzheimer's disease and the primary caregiver.
Predisposing Variables
We examined the influence of relation of the caregiver to the participant and the marital status of both, using grouping variables of spouse (reference category), married child, unmarried child, and other. None of the latter three groups had a significantly different risk of nursing home placement than the spouse category, and none affected the risk associated with adult day care attendance. We characterized living arrangement in two ways: (a) living alone versus living with others, and (b) living alone for all follow-up observations, living with others previously and then changing to living alone, or living with others. None of these characterizations of living arrangement was a significant predictor of institutionalization risk, and they did not affect the risk associated with adult day care. We also did not find a difference in risk for the 10% of participants whose caregiver changed during the course of follow-up.
Enabling Variables
About 10% of participants had long-term-care insurance. Neither this nor a 10-category measure of income group analyzed as a continuous variable significantly predicted risk of nursing home placement. We then grouped income as $25,000 or more versus less than $25,000, which was the cutoff for those whose adult day care was paid by Medicaid or Veterans Affairs (VA) benefits. We used a second indicator variable for those whose income was unknown. Neither low income nor missing income was significant. To control for the potential effect of community-based services on nursing home placement, we examined the use of visiting nurse, personal care, and homemaker services at each follow-up by using the individual and summary variables described in the Methods section. These service-use variables neither significantly predicted the risk of nursing home placement nor altered the risk associated with adult day care attendance.
Need Variables
We tested for Alzheimer's disease participant condition by using several time-varying measures. In stepwise analyses, with the Katz, Nagi, and Rosow–Breslau functional status and disability scales as candidate variables, only the Rosow–Breslau scale entered the model. The risk associated with adult day care attendance did not change with the Rosow–Breslau scale in the model. Hospitalization in the previous 3 months and depressed mood significantly increased the risk of nursing home placement, and higher levels of positive behavior significantly decreased the risk of placement. However, none of these variables altered the risk associated with adult day care.
We examined the effect of duration of caregiving on risk of nursing home placement. We also examined two other measures of time at risk: time since onset of any cognitive symptoms and time since onset of memory problems. None of these variables was significant. Time spent providing care each week, employment and hours worked each week, the extent to which caregiving interfered with work, and measures of caregiver depression, burden, positive affect, satisfaction, social support, and spirituality were all considered as candidates in a stepwise analysis. Only caregiver burden entered the model. Greater burden was associated with a significant increase in risk of nursing home placement, but the risk associated with adult day care remained the same. We also examined caregiver age and several measures of caregiver physical health as candidates in a stepwise model. Only caregiver age was significant, and it did not alter the risk associated with adult day care.
In individual models adjusting for age, gender, race, time-varying MMSE score, and adult day care use, we examined the interaction of day care use with each of the significant predictors from the previous models (participant Rosow–Breslau disability score, depressed mood, positive behavior, and hospitalizations, as well as caregiver age and burden). Interactions of adult day care use with participant hospitalizations and caregiver age were significant; however, neither of these interactions was retained in our final stepwise model. In our final stepwise model, we forced in age, gender, race, time-varying MMSE score, and adult day care use, and we considered as candidates for selection all of the significant main and interaction effects from previous models. Only participant disability and hospitalizations and caregiver age and burden entered the model as independent predictors of nursing home placement. The interaction of gender and adult day care use remained significant in this final model (Table 4). Figure 1 graphically displays the results from this final model.
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Some investigators have suggested that the reason adult day care does not delay nursing home placement is because caregivers wait too long to begin using it. According to Gaugler and Zarit (2001) and Zarit and colleagues (1999), the caregivers are so burdened and the patient so severely impaired that the relief that adult day care provides may actually expedite nursing home placement. Zarit and colleagues found that caregivers who used adult day care for 3 months or less had higher baseline levels of role captivity and were caring for relatives with more severe functional and behavioral problems. More than one third of these brief users immediately placed their relative in a nursing home. This scenario is not a likely explanation for our findings because our inclusion criteria required a minimum of 3 months of adult day care use at baseline. We also examined a large number of measures of disease severity and caregiver burden, and they did not change the risk associated with day care attendance.
An alternative explanation is that some caregivers may not view adult day care as a reasonable alternative and may institutionalize their family members at a higher rate earlier in their caregiving careers, thus taking them out of the risk pool and leaving adult day care nonusers who are particularly resistant to nursing home placement. However, we do not believe this explanation accounts for our study findings: first, because three measures of time at risk (duration of caregiving, time since onset of any cognitive problems, and time since onset of memory problems) were not significantly associated with nursing home placement and did not alter the effect of adult day care; and second, because more days of day care attendance increased the risk of nursing home placement, suggesting that the increased risk is not due solely to differences between users and nonusers.
Considering our results in light of the behavioral model of health service utilization, we found that few of the predisposing or enabling variables were associated with nursing home placement, and that need variables (participant disease characteristics and caregiver burden) were the most important predictors with adult day care. We found that the risk of nursing home placement increased with caregiver age and that nearly all the increased risk associated with adult day care use was limited to male participants. We are not sure why the risk associated with day care was greater for men than for women; it might be that more men have access to VA nursing home care. We found no effect of income or long-term-care insurance on nursing home risk, but we did not ask specifically about eligibility for VA benefits. Other studies that examined the use of respite or day care reported contradictory findings regarding the effect of financial resources on nursing home placement (Gaugler, Kane, et al., 2003; Kosloski & Montgomery, 1995).
Results of this study suggest that more frequent use of adult day care is not a proxy for greater disease severity or caregiver burden, and that there remain unmeasured differences between users and nonusers. That is, there appear to be important risk factors for nursing home placement that cannot be characterized by commonly used measures and that are captured by adult day care use. Perhaps the risk has to do with the willingness of a particular type of caregiver to relinquish care when it becomes too difficult. Willingness to use a service such as adult day care may be indicative of a greater proclivity to choose institutional care, signifying a self-selection bias. The idea that there may be fundamental differences between caregivers who actively seek out services and those who do not has been proposed as an explanation for lack of treatment effects in studies of respite and adult day care (Kosloski & Montgomery, 1995; Lawton et al., 1989). Indeed, research has shown significant associations between family caregiver attitudes, beliefs, and perceptions and the use of various clinical and community services (Kosloski, Montgomery, & Karner, 1999; Kosloski, Schaefer, Allwardt, Montgomery, & Karner, 2002; Pedlar & Biegel, 1999), and these factors tend to vary by race or ethnicity of the caregiver (Kosloski et al., 2002; Miller & Mukherjee, 1999). We attempted to account for this by adjusting for race and for the use of other community-based services in our analysis. However, none of the service-use variables significantly predicted the risk of nursing home placement, and neither race nor service use altered the risk associated with adult day care attendance. This suggests that service use in general does not increase nursing home placement but that something associated with adult day care does—either characteristics of people who use adult day care or something about the experience itself. As suggested by others (Gaugler & Zarit, 2001), caregivers who use adult day care or other respite services may become more aware of their level of stress and more willing to consider nursing home placement as an acceptable option, especially if the service experience is positive or if the caregiver receives encouragement to institutionalize from professionals or other caregivers. Future researchers need to develop and incorporate measures of these potential factors in order to explore these complex issues.
The strengths of this study include specificity, both in the service used and in the condition of the person receiving the service. We limited the study to people with Alzheimer's disease using an adequate amount of adult day care at baseline to be considered truly exposed. We also measured day care use in all participants at each follow-up to capture changes in both the user and nonuser groups. We adjusted for many known predictors of nursing home placement in persons with Alzheimer's disease, including the use of other community-based services. Finally, we created a dynamic model by using time-varying measures, which evaluated changes in important predictors every 3 months, and we had high baseline and follow-up participation rates.
An important limitation of this study is that it was observational rather than a randomized controlled trial. This introduced the possibility of sample selection bias because we obtained our adult day care users and nonusers from different sources. The most comparable group of nonusers came from an Alzheimer's diagnostic center that provided a common factor of caregivers seeking clinical services. Despite careful matching on some variables and statistical control for a large number of factors in our analysis, we probably did not account for all the differences between individuals who do and do not use adult day care. However, results from our sensitivity analyses revealed that our findings were robust when all baseline group differences were considered. Even randomized controlled trials seem unable to obtain a clear comparison, because adult day care has only been offered, not forced, and individuals differ in ways we have yet to measure in their interest in using this service. Thus it is likely that the effect of adult day care use was not caused by the different sample sources but rather by true differences between users and nonusers in the underlying population. A different source of lack of representativeness is that we used a convenience sample of adult day care users, and our nonuser sample was drawn from a single source, so users and nonusers may not be representative of all individuals with Alzheimer's disease. In addition, the 16 participating adult day care sites are not necessarily representative of sites in the region.
In summary, we found that risk of nursing home placement increased with increasing use of adult day care. A detailed analysis suggests differences between caregivers who use adult day care and those who do not that are not accounted for with the standard measures of demographic characteristics, disease severity, and caregiver burden. An investigation of factors involved in willingness to obtain help with care may be fruitful.
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Footnotes |
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1 Rush Institute for Healthy Aging, Rush University Medical Center, Chicago, IL.
2 Department of Health Management and Policy, the Center for Research in the Implementation of Innovative Strategies in Practice and the University of Iowa, Iowa City.
3 Department of Neurological Sciences and Rush Alzheimer's Disease Center, Rush University Medical Center, Chicago, IL.
4 College of Nursing, Rush University Medical Center, Chicago, IL.
Decision Editor: Linda S. Noelker, PhD
Received for publication November 4, 2004. Accepted for publication June 6, 2005.
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