Study Design and Participants
This is a cross-sectional study using data from the Health Information National Trends Survey (HINTS, 2018) Version 5, Cycle 2, a nationally representative survey of U.S. adults aged ≥ 18 years (civilian and non-institutionalized) [33]. The survey is first conducted by the National Cancer Institute (NCI) in 2003, aiming to gauge how Americans seek, share, and use cancer-related health information in their daily interactions [34]. The HINTS 5 (Cycle 2) survey used in this study was administered from January 26 to May 2, 2018. We utilized data from the 2018 HINTS survey because, by far, caregiver burden related variables were only included in this particular HINTS survey. Of all the 14,585 surveys mailed, 3,527 participants returned their questionnaires (response rate: 24.2%) [34]. As this study mainly focuses on the caregiver population, we used “Are you currently caring for or making health care decisions for someone with a medical, behavioral, disability, or other condition?” as the screening question to identify caregivers. A total of 458 (13.0%) participants who self-identified as caregivers (i.e., replied “yes” to the question) were included in the final data analysis.
Measures
To adequately gauge the impact of patients’ disease types on caregiving consequences, both direct and indirect consequences were evaluated in this study. Based on insights gained from the literature [35–38], direct consequence of caregiving is measured by caregiving time, in terms of caregiving duration and caregiving hours spent per week, while indirect consequences of caregiving are measured by caregiver burden in terms of caregivers’ self-rated health, BMI, and psychological distress. Details of all measures used in this study are reported by the National Cancer Institute and available online [34].
Caregiving time
We adopted two measures to gauge caregivers’ time spent on providing care to patients: caregiving duration and caregiving hours spent per week [34].
Caregiving duration. Participants were directed to “Think about the individual for whom you are currently providing the most care. About how long have you been providing care for this person?” and asked to choose one response from the 5 available choices (i.e., “Less than 30 days”=1, “1 to 6 months” = 2, “7 months to 2 years” = 3, “3 to 5 years” = 4, “More than 5 years”=5).
Caregiving hours spent per week. Participants were asked to “Think about the individual for whom you are currently providing the most care. About how many hours per week do you spend in an average week providing care?” and indicate hours they spent per week on offering care to the patients.
Caregiver burden
In line with the literature [35–38], caregiver burden was gauged using three variables: Self-rated health, BMI, and psychological distress.
Self-rated health. To assess respondents’ self-rated health status, participants’ were asked to respond to the question “In general, would you say your health is. .. ” on a five-point scale (“excellent” = 1, “very good” = 2, “good” = 3, “fair” = 4, “poor” = 5).
BMI. Participants’ BMI levels were calculated using information on participants’ self-rated weight and height (formula: weight (kg) / [height (m)]2). Based on Centers for Disease Control and Prevention’s guidelines, BMI was subsequently coded into three categories: underweight or normal (< 25), overweight (25–29.9), and obese (≥ 30) [39].
Psychological distress. Participants’ psychological distress was measured with the four-item Patient Health Questionnaire (PHQ-4) [34, 40]. Participants completed four items in response to “Over the past 2 weeks, how often have you been bothered by any of the following problems?”: (a) Little Interest, (b) hopeless, (c) nervous, (d) worrying on scales from 0 (Not at all) to 3 (nearly every day). Based on available guidelines, the four items were subsequently summed [34, 40]. The summed scores ranged from 0 to 12, with a higher score indicating a higher level of psychological distress [40].
Caregiver Characteristics
Demographic factors included were gender ( “male” = 0 vs. “female” = 1), race/ethnicity (“non-Hispanic White” = 1, “other” = 0), and marital status (“married” or “living as married” = 1 vs. “divorced,” “widowed,” “separated,” or “single, never been married” = 0). Other covariates examined were household income (“US$50,000 or more” = 1, or “less than US$50,000/year” = 0), education (coded into four categories: less than high school, high school graduate, some college, and college graduate or more), and employment status (“employed” = 1 vs. “unemployed,” “homemaker,” “student,” “retired,” “disabled,” or “other” = 0). A 9-point rural urban continuum code was used to classify participants as residing either in metropolitan (codes 1–3) or nonmetropolitan (codes 4–9) areas [41]. Smoking status (categorized as current smoker, former smoker, or never smoker). Drinking status (“having at least one drink of any alcoholic beverage more than 1 day per week”= 1, “none” = 0). We reclassified the response options into a single dichotomous outcome variable for physical activity, that is, whether the subject (1) met physical activity recommendations (≥ 150 minutes per week) or did not meet the physical activity recommendations (< 150 minutes per week). Having health insurance (“yes” = 1, “not” = 0).
Data Analyses
First, the characteristics of the participants were described using descriptive statistics (means accompanied with SDs or frequencies, as appropriate). Second, to explore the relationship between health outcome and independent variables, we used multivariate logistic regression method for analyzing the self-rated health variable and ordered logistic regressions for the BMI and psychological distress variables. In order to test the potential interaction, we generated several interaction terms by multiplying the categorical variables. Third, we calculated the mean scores of health indicators and caregiving burden of caregivers. In order to adjust for HINTS’ multistage probability sampling design, a set of 50 jackknife replicate weights was applied to all analyses, estimating the model parameters for the U.S. population as a whole. Finally, to explore the association between caregiver burden, caregiver health outcomes, and independent variables, we used ordered logistic regression for analyzing self-rated health, BMI, psychological distress and applied linear regression analyses to examine caregiving duration and caregiving hours spent per week to answer the research question.
Odds ratios (ORs) or regression coefficients with CI were employed to depict the relationships between caregiver burden, caregiver health outcomes, and independent variables while controlling for covariates. Listwise deletion of each subjects were used for participants who provided invalid or missing responses for the dependent variables; sample sizes for each regression analysis are noted in Table 3 ranging from 3,256 to 3,264. All covariates with missing data were multiple imputed. All analyses were performed using Stata 14 [42] .