Prospective Outcomes of Informal and Formal Home Care: Mortality and Institutionalization. 2.2 Measures

12/19/1990

The questionnaire employed for the Supplement on Aging was developed by a work group at NCHS in extensive consultation with other federal agencies and individuals with expertise in the suggested topic areas. These persons reviewed the literature and questionnaires previously employed among the elderly and participated in conferences on issues of aging. A draft questionnaire was developed in October of 1982 and pre-tested in Bradenton, Florida in June of 1983 and again in Wilmington, Delaware in September of 1983. Based upon these pre-tests, the final questionnaire was determined. The revised questionnaire, included sections on: disability and caregiving; living arrangements; social contacts; conditions and impairments; health opinions; health conditions, and demographic background.

Outcomes: In this study we have measured two outcomes, mortality and institutionalization in a nursing home. As noted above, the field staff ascertained the vital status of the people who had been contacted at baseline: 604 sample, people had died since the earlier interview. We created a working file with mortality information as well as caregiving arrangements, social and demographic characteristics, and health status. We have complete information on these variables for 537 individuals who died and 4,034 individuals alive at follow up. This data set contains 96.6 percent of persons whose vital status at follow-up was known.

The interviewers ascertained whether or not the individual had experienced a nursing home stay during the follow-up period. They also asked about nursing home stays as part of the decedent follow-up for those individuals who had died during the intervening period. The investigators found that 138 individuals were in a nursing home at the time of the follow-up. They were able to interview 126 of these persons. Another 59 individuals reported a nursing home stay since 1984. Finally, the decedent follow-up study ascertained that an additional 113 individuals had experienced a nursing home stay in the last year of life. This results in 298 individuals who were in a nursing home some time during the follow-up period. Our final data set includes 273 individuals with complete information on outcome, caregiving arrangements, sociodemographics, and health status.

In all, 11.7 percent of the initial sample died during the follow up period. Also, 6.5 percent of the initial sample were institutionalized at some time during the follow up period. About 40 percent of those who entered a nursing home in the follow-up period also died during that period.

Caregiving: We based the measure of caregiving arrangements on responses reported at baseline. In the LSOA interview caregiving is ascertained in the context of reports of decrements in activities of daily living and instrumental activities of daily living. In the baseline interview seven activities of daily living are ascertained: bathing or showering, dressing, eating, getting in and out of the bed or chair, walking, getting outside, and using or getting to the toilet. Six instrumental activities of daily living are included: preparing one's own meal, shopping for personal items, managing money, using the telephone, doing heavy housework, and doing light housework. Respondents were asked whether they had difficulty with a particular activity or instrumental activity of daily living, for example: "Do you have difficulty bathing or showering?" If the individual said "yes" they were asked what level of difficulty they experienced: "some," "a lot," or "unable to do." Then respondents were asked whether they received help from another person; and if, again, they responded in the affirmative, they were asked whether or not the person giving help was a relative or non-relative, whether or not the person lived in the household, and whether or not the person was paid for this service. It was assumed that spouse, child, and parent helpers were not paid.

Using these data elements, we constructed a set of orthogonal comparisons among a variety of categories of responses. The comparisons correspond to our hypotheses as only persons with at least one ADL or an IADL deficit were asked the questions about receiving help. Our first comparison was between those with a disability and those without. only among those with a disability (ADL or IADL impairment) is it meaningful to differentiate persons receiving help from those not receiving help. Because the help versus no help distinction is not made within the no disability category, then the two comparisons, disability versus no disability, and help versus no help are uncorrelated. This is an analytic advantage in that if both are related to an outcome, for example, to increased mortality, then the estimated effects are statistically independent. We have simply capitalized on the hierarchical and nested structure of the caregiving questions to develop analyses that provide independent assessments of our hypotheses. Following our discussion of hypotheses, we have constructed two forms of our orthogonal contrasts. Both are identical in having disability versus no disability and help versus no help as the initial contrasts. Figure 2-1 presents a tree diagram illustrating the logic of these contrasts.

We created the next differentiation among persons who obtained help. One contrast compares those who have any kind of unpaid help with those who only have paid help. Then, within those with any kind of unpaid help, we contrast those who have unpaid help provided by immediate family members (spouse or child) to those who have unpaid help provided by others. An alternative set of contrasts compares persons who received only unpaid help to those who received some paid and some unpaid help. Within the former category, we then distinguish between those who received all unpaid help from close family members versus those who received all unpaid help, but from other than their close family.

Orthogonal coding is a class of dummy variable coding. We simply have taken a mutually exclusive and exhaustive set of categories and developed a set of dummy variables. Typically we think of dummy variables as being coded 1 or 0 to identify the appropriate comparison. In this case we can think of the appropriate comparisons as being coded 1 or -1, say for disability versus no disability. Similarly, help could be coded as 1 and no help as -1, but all the persons without a disability would then not have a code. In this instance they are coded 0. A further complication occurs because we would like the logistic regression coefficients to be expressed as the logarithm of the odds ratio. This would work only if we had a balanced design i.e., one having the same number of cases in each of the categories of caregiving. We overcome this problem by weighting the codes according to the numbers of persons observed in the categories. This is explained in Appendix A. In the end, the orthogonal contrasts represent individual tests of the hypotheses we stated earlier. The test of the significance of the logistic regression coefficient associated with each contrast, or its antilog, the odds ratio, is a test of the significance of the hypothesis.

Other Measures: The remaining measures employed in this study fall into two categories: social and demographic characteristics and health status. In this section we will briefly introduce these measures. These variables represent potential confounders that past research suggests could influence the strength of association between caregiving and the outcome variables.

Social and Demographic Measures: This category of confounders includes measures of age, sex, race/ethnicity, education, income, living arrangements, social contactsf volunteering, and perceived control over health. Table 2-1 reports the distribution of these variables in the two analytic data sets. Age, sex, and race/ethnicity are self-reported. race/ethnicity reflects the group that the respondent felt best reflected his or her origin or ancestry. Hispanic refers to any person, black or white, whose family originated in a Spanish-speaking country. The categories, White and Black, reflect nonSpanish speakers. The other category contains largely native Americans and Asians. Education reflects the highest grade in school ever attended. We recoded this to eighth grade or less, some high school or high school graduate, and some college or college graduate. Income originally reported in broad categories is coded as follows: below poverty; poverty to $9,999; $10,00019,999; $20,000-29,999; and $30,000 or more. The poverty level is based on family size, number of children under eighteen years of age, and family income, using the 1983 poverty levels by the Census Bureau published in August 1984 (NCHS, 1984). An indicator is also included for persons refusing to report their income.

TABLE 2-1. Distribution of Confounding Variables in the Mortality and Institutionalization Data Sets
Variable Data Set
Mortality Institutionalization
No. of cases 4571 4184
Proxy
   Yes
   No
 
8.3%
97.1
 
8.2%
91.8
Age (yrs.) 78.0 77.9
Sex
   Female
   Male
 
63.5
36.5
 
63.6
36.4
Race
   White
   Black
   Hispanic
   Other
 
85.8
10.2
2.8
1.2
 
86.4
9.8
2.71.1
Education
   Grade School
   High School
   College
 
41.8
40.8
17.4
 
41.1
41.0
17.9
Income
   Missing
   <Poverty
   >Poverty, <$10,000
   $10,000-19,000
   $20,000-34,000
   <$35,000
 
16.4
15.5
23.1
26.8
12.6
5.6
 
15.9
15.3
22.9
27.3
12.9
5.7
Living Arrangements
   Lives w/Spouse
   Lives Alone
   Lives w/Other Persons
 
44.6
37.5
17.9
 
45.4
36.7
17.9
Social Contacts (#/2 wks) 4.0 4.1
Volunteers in Community
   Yes
   No
 
14.3
85.7
 
14.9
85.1
Control Over Health
   A lot
   Some
   Little
   None
   Unknown (proxy)
 
30.3
41.1
8.0
6.5
14.1
 
30.4
41.9
7.8
6.1
13.8
Health Status
   Excellent
   Very Good
   Good
   Fair
   Poor
 
15.9
20.7
30.8
21.3
11.3
 
15.9
21.1
30.9
21.0
11.1
Activities of Daily Living (#) 0.4 0.4
Instrumental Activities of Daily Living (#) 0.6 0.6
Confusion
   Yes
   No
 
3.9
96.1
 
3.9
96.1
Alzheimer's
   Yes
   No
 
0.5
99.5
 
0.6
99.4
Urinary Incontinence
   Yes
   No
 
9.6
90.4
 
9.5
90.5
Bowel Incontinence
   Yes
   No
 
6.7
93.3
 
6.6
93.4
Cancer
   Yes
   No
 
12.0
88.0
 
12.2
87.8
Heart Disease
   Yes
   No
 
17.0
83.0
 
16.3
83.7
Cerebrovascular Accident (Stroke)
   Yes
   No
 
7.3
92.7
 
7.2
92.8
Osteoporosis
   Yes
   No
 
3.4
96.6
 
3.4
96.6
Hip Fracture
   Yes
   No
 
4.9
95.1
 
4.9
95.1
Fell 2 or More Times
   Yes
   No
 
10.8
89.2
 
10.8
89.2
Fell Because of Dizziness
   Yes
   No
 
4.3
95.7
 
4.2
95.8
Nursing Home Stay Prior to 1st Interview
   Yes
   No
 
2.6
97.4
 
2.4
97.6
Hospital Inpatient Stays (# Stays/yr) 0.3 0.3

Living arrangements differentiate persons living alone from those living with their spouse and those living with someone other than a spouse. To measure social contacts we combined in an additive scale seven questions that were included in the baseline questionnaire: interaction with relatives (in person or by telephone), interaction with friends (in person or by telephone), attendance at church, attendance at public or social functions, and volunteering for organized groups. We separately include the measure of volunteering for organized groups, because in previous research (Wells and Dunlop), we found this component of an index of social contact to be the most discriminating predictor of survival. Self-reported belief in control over future health is categorized according to responses: "a great deal," "some," "a little," or "none at all". Because proxies could not appropriately answer this question, we include an indicator of proxy response.

Health Measures: A second set of confounding variables includes health variables: self-reported health status, activities of daily living, instrumental activities of daily living, impairments and chronic conditions, and prior utilization in hospital or nursing home. The categories of self-reported health status are "excellent", "very good", "good", "fair or poor". Methods of ascertaining ADLs and IADLs are described above in introducing our measures of caregiving. Here, however, we include an additive scale of the number of each type of dependency the respondent reported. Impairments and chronic conditions include the presence of or a history of mental confusion, Alzheimer's, urinary and bowel incontinence, cancer, heart disease, cerebrovascular accident, osteoporosis, hip fracture, having fallen twice or more, or having fallen because of dizziness. Prior utilization measures include an indicator of a nursing home stay prior to the baseline interview, and the number of hospital inpatient stays in the year prior to the baseline interview.

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