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Does Social Isolation Predict Hospitalization and Mortality Among HIV+ and Uninfected Older Veterans? [yes]
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"In conclusion, social isolation is associated with greater risk of hospitalization and death in HIV+ and uninfected older veterans. Despite similar effects in both groups, the population level effect of social isolation may be even greater in those who are HIV+ because of the higher prevalence of social isolation, particularly in the oldest individuals. Because the "graying" of the HIV+ population is projected to accelerate in the coming decades, a broader understanding of social isolation and the application of geriatric principles of inpatient care for this population is needed."
"Although social isolation has similar effects on hospitalization and death for HIV+ and uninfected individuals, those with HIV are at substantially higher risk of being socially isolated. Although the effects of social isolation on mortality have been well documented in older adults,[3-5] this is the first study to include a large number of older HIV+ individuals; it also presents novel findings on the effects of social isolation on acute care use (incident hospitalization) in this population and suggests a need to reframe current paradigms about hospitalization in HIV+ older adults. Existing studies of hospitalization in HIV+ individuals focus on acute presentations or specific complications of HIV infection,[34] but in the current era of potent antiretroviral therapies, HIV+ individuals are frequently admitted for (and die from) chronic conditions that characterize the aging population as a whole.[35] Rather than focusing on HIV-related comorbidities, our findings suggest a need to understand aging HIV+ individuals' risks for hospitalization and mortality in the broader context of their social lives and to increase preventative efforts for those with low social support. Although it was found that social isolation affected these outcomes for HIV+ and uninfected individuals in the cohort, the finding that the prevalence of social isolation is higher in HIV+ older adults, particularly at older ages, underscores the need to prioritize such efforts for this population.
Several factors may explain the finding that social isolation is more prevalent in HIV+ than uninfected older adults, with increasing difference with older age (Figure 1). First, older adults with HIV are significantly more economically and politically marginalized than uninfected counterparts at all ages, which may predispose them to social isolation.[36, 37] Second, it may be that greater stress levels associated with long-term HIV survival[38] and intensified geriatric syndromes in HIV+ participants such as cognitive impairment further inhibit their ability to establish and maintain social ties.[39] Third, low social support itself is a predictor for delay in HIV testing[40] and treatment[41] thus placing older, more-isolated individuals at risk of worsening health and compounding isolation.[42] Fourth, many older adults with HIV experience a heightened sense of loneliness, which may lead to anxiety, depression, and further withdrawal from social networks that can have protective effects on isolation.[43, 44] Moreover, the young age of half of the sample (53% <60) probably attenuates the overall difference in prevalence of isolation seen between HIV+ (59%) and uninfected (51%) participants in this study; this overall difference seems likely to increase as this population continues to age. Finally, given recent research showing important effects of loneliness on overall health,[45, 46] disability, and mortality,[47] these findings underscore the need to study overlapping effects of social isolation and loneliness for aging populations.
These findings also have several important health policy implications. First, the study focused on individuals in the VA system for whom access to care is not a concern; the health effects and associated costs of isolation may be even greater for individuals outside this system. Second, although the number of older, HIV+ individuals is rising, the number of providers in HIV medicine and geriatrics remains small.[48] Thus, efforts to address social isolation in older, HIV+ adults will also need to engage hospitalists, emergency medicine physicians, and others in acute care specialties, as well as leverage nonphysician resources such as case management and community-based organizations.[49] Third, there is growing evidence that interventions to address social isolation through activities such as support groups, social activities, home visits, and Internet engagement can reduce isolation in older adults."
Abstract
Objectives
To compare levels of social isolation in aging veterans with and without the human immunodeficiency virus (HIV) and determine associations with hospital admission and mortality.
Design
Longitudinal data analysis.
Setting
The Veterans Aging Cohort Study (VACS), at eight VA Medical Centers nationally.
Participants
Veterans aged 55 and older enrolled in VACS from 2002 to 2008 (N = 1,836).
Measurements
A Social Isolation Score (SIS) was created using baseline survey responses about relationship status; number of friends and family and frequency of visits; and involvement in volunteer work, religious or self-help groups, and other community activities. Scores were compared according to age and HIV status, and multivariable regression was used to assess effects of SIS on hospital admission and all-cause mortality.
Results
Mean SIS was higher for HIV-positive (HIV+) individuals, with increasing difference according to age (P = .01 for trend). Social isolation was also more prevalent for HIV+ (59%) than uninfected participants (51%, P < .001). In multivariable regression analysis of HIV+ and uninfected groups combined, adjusted for demographic and clinical features, isolation was independently associated with greater risk of incident hospitalization (hazard rate (HR) = 1.25, 95% confidence interval (CI) = 1.09–1.42) and risk of all-cause mortality (HR=1.28, 95% CI = 1.06–1.54). Risk estimates calculated for HIV+ and uninfected groups separately were not significantly different.
Similar to incident hospitalization, incidence of mortality was higher for HIV+ participants (56/1,000 person-years) than for uninfected participants (33/1,000 person-years; P < .001), and time to death was shorter for HIV+ than uninfected participants (3.9 vs 4.8 years, P < .001).
Social Isolation Scores for the entire sample ranged from 0 to 8 (mean 3.9 ± 1.2). Social Isolation Scores were also calculated for HIV+ and uninfected participants separately (Table 2). As shown in Table 2, mean scores for five of eight SIS components were higher for HIV+ participants, but only two of these (number of friends and family, relationship status) were significantly different. The overall mean SIS for HIV+ participants (4.0) was significantly higher than for uninfected participants (3.8; P < .001), and the odds of being isolated were significantly higher for HIV+ participants in all age brackets (except 60–64) with a trend toward greater odds of isolation with older age (Figure 1). The overall prevalence of isolation (SIS ≥ 4) was also greater for HIV+ participants (59%) than uninfected participants (51%; P < .001).
Conclusion
Social isolation is associated with greater risk of hospitalization and death in HIV+ and uninfected older veterans. Despite similar effects in both groups, the population-level effect of social isolation may be greater in those who are HIV+ because of the higher prevalence of social isolation, particularly in the oldest individuals.
Social isolation is common in older adults and has important effects on health care and health outcomes.[1, 2] Numerous studies have demonstrated greater overall risk of mortality[3-5] and geriatric morbidity such as falls[6] and cognitive and functional decline,[7, 8] especially in individuals with chronic conditions such as coronary artery disease,[9, 10] cancer,[11] and diabetes mellitus.[12] There is less information about isolation of older adults with human immunodeficiency virus (HIV) despite recent advances in antiretroviral therapy that have transformed HIV to a chronic condition with longer life expectancy and "graying" of the infected population.[13, 14] The incidence of new HIV infections in older adults has also increased dramatically in the last decade.[15] These trends suggest not only a need for more information about effects of isolation on mortality for the growing number of older adults living with chronic HIV infection, but also a need to understand possible effects on acute care usage, given longer life expectancies in this population.
Adults living with HIV may be at higher risk than the aging population with other chronic conditions for social isolation as they age. Many have lost friends or partners who were also infected but did not survive the early years of the epidemic.[16, 17] The stigma attached to HIV may also inhibit social networks and support. This stigma is especially strong for populations who are disproportionately infected, such as African Americans and Hispanics,[18, 19] as well as men who have sex with men.[20] Furthermore, HIV infection itself intensifies many normal aging processes and increases the incidence and severity of frailty.[21-23] Thus, HIV-positive (HIV+) individuals may be at greater risk of isolation and frailty, leading to greater overall risk of hospitalization and death than an uninfected cohort. Comparisons of the prevalence and effects of social isolation between HIV+ and uninfected older adults are lacking. Specifically, current studies have yet to examine how components of social isolation, such as limited engagement with friends, family, or community, may differentially affect acute care usage and mortality of HIV+ and uninfected older adults.
The Veterans Aging Cohort Study (VACS) dataset provides a unique opportunity to study the prevalence and effects of social isolation on inpatient admission and outcomes of care in an aging population in a multisite, longitudinal cohort of veterans and to compare these effects on HIV+ individuals with those on uninfected individuals. The objectives were to compare levels of social isolation in aging veterans with and without HIV and to determine associations with incident hospital admission and all-cause mortality.
Results
Complete data were available for 1,836 veterans aged 55 and older. Ages ranged from 55 to 91 (mean 61); 54% were uninfected, and 46% were HIV+; 99% were male; 68% were Hispanic or non-white; and 76% reported an annual income of less than $25,000 (Table 1). Most participants (72%) had one or more comorbid condition, and most screened negative for depression (76%) and alcohol abuse (75%).
Social Isolation Scores for the entire sample ranged from 0 to 8 (mean 3.9 ± 1.2). Social Isolation Scores were also calculated for HIV+ and uninfected participants separately (Table 2). As shown in Table 2, mean scores for five of eight SIS components were higher for HIV+ participants, but only two of these (number of friends and family, relationship status) were significantly different. The overall mean SIS for HIV+ participants (4.0) was significantly higher than for uninfected participants (3.8; P < .001), and the odds of being isolated were significantly higher for HIV+ participants in all age brackets (except 60–64) with a trend toward greater odds of isolation with older age (Figure 1). The overall prevalence of isolation (SIS ≥ 4) was also greater for HIV+ participants (59%) than uninfected participants (51%; P < .001).
With respect to incident hospitalization, 805 veterans (43%) had at least one admission to a VAMC between 2002 and 2008 (Table 1). Overall, incidence of hospitalization was higher in HIV+ (113/1,000 person-years) than uninfected participants (70/1,000 person-years; P < .001), and mean time to admission was shorter in HIV+ than uninfected participants (1.8 vs 2.2 years; P = .001). After adjusting for age, race and ethnicity, income, number of comorbidities, depression, substance abuse, and HIV status, isolation was independently associated with greater risk of incident hospitalization (HR = 1.25, 95% CI = 1.09–1.42) in combined analyses of HIV+ and uninfected participants (Table 3).
Similar to incident hospitalization, incidence of mortality was higher for HIV+ participants (56/1,000 person-years) than for uninfected participants (33/1,000 person-years; P < .001), and time to death was shorter for HIV+ than uninfected participants (3.9 vs 4.8 years, P < .001). After adjusting for age, race and ethnicity, income, number of comorbidities, depression, substance abuse, and HIV status, isolation was independently associated with greater risk of all-cause mortality during the study period (HR = 1.28, 95% CI = 1.06–1.54) in combined analyses of HIV+ and uninfected participants (Table 3, Figure 2).
Discussion
Although social isolation has similar effects on hospitalization and death for HIV+ and uninfected individuals, those with HIV are at substantially higher risk of being socially isolated. Although the effects of social isolation on mortality have been well documented in older adults,[3-5] this is the first study to include a large number of older HIV+ individuals; it also presents novel findings on the effects of social isolation on acute care use (incident hospitalization) in this population and suggests a need to reframe current paradigms about hospitalization in HIV+ older adults. Existing studies of hospitalization in HIV+ individuals focus on acute presentations or specific complications of HIV infection,[34] but in the current era of potent antiretroviral therapies, HIV+ individuals are frequently admitted for (and die from) chronic conditions that characterize the aging population as a whole.[35] Rather than focusing on HIV-related comorbidities, our findings suggest a need to understand aging HIV+ individuals' risks for hospitalization and mortality in the broader context of their social lives and to increase preventative efforts for those with low social support. Although it was found that social isolation affected these outcomes for HIV+ and uninfected individuals in the cohort, the finding that the prevalence of social isolation is higher in HIV+ older adults, particularly at older ages, underscores the need to prioritize such efforts for this population.
Several factors may explain the finding that social isolation is more prevalent in HIV+ than uninfected older adults, with increasing difference with older age (Figure 1). First, older adults with HIV are significantly more economically and politically marginalized than uninfected counterparts at all ages, which may predispose them to social isolation.[36, 37] Second, it may be that greater stress levels associated with long-term HIV survival[38] and intensified geriatric syndromes in HIV+ participants such as cognitive impairment further inhibit their ability to establish and maintain social ties.[39] Third, low social support itself is a predictor for delay in HIV testing[40] and treatment[41] thus placing older, more-isolated individuals at risk of worsening health and compounding isolation.[42] Fourth, many older adults with HIV experience a heightened sense of loneliness, which may lead to anxiety, depression, and further withdrawal from social networks that can have protective effects on isolation.[43, 44] Moreover, the young age of half of the sample (53% <60) probably attenuates the overall difference in prevalence of isolation seen between HIV+ (59%) and uninfected (51%) participants in this study; this overall difference seems likely to increase as this population continues to age. Finally, given recent research showing important effects of loneliness on overall health,[45, 46] disability, and mortality,[47] these findings underscore the need to study overlapping effects of social isolation and loneliness for aging populations.
These findings also have several important health policy implications. First, the study focused on individuals in the VA system for whom access to care is not a concern; the health effects and associated costs of isolation may be even greater for individuals outside this system. Second, although the number of older, HIV+ individuals is rising, the number of providers in HIV medicine and geriatrics remains small.[48] Thus, efforts to address social isolation in older, HIV+ adults will also need to engage hospitalists, emergency medicine physicians, and others in acute care specialties, as well as leverage nonphysician resources such as case management and community-based organizations.[49]
Third, there is growing evidence that interventions to address social isolation through activities such as support groups, social activities, home visits, and Internet engagement can reduce isolation in older adults.[50] Although these interventions will have associated costs in terms of time, effort, and funding, they may be less expensive than high rates of acute care utilization and may result in better outcomes as well. Fourth, it is likely that socioeconomic status plays an important role in mediating social isolation as well as the outcomes of hospitalization and mortality reported. Although further study is needed to explore this relationship, as well as possible effects on overall quality of life, it is recommended that clinicians prioritize screening for social isolation of the most-vulnerable individuals first; the oldest and poorest, with the worst quality of life, may be most likely to be clinically affected by social isolation. Finally, as HIV+ individuals age, high levels of social isolation may place additional strain on an overburdened system of nursing homes and skilled nursing facilities.[51, 52] Previous studies have shown that living alone,[53, 54] fewer family contacts,[53, 55] and fewer non-kin social supports[52] are all correlated with nursing home placement, although a more-comprehensive assessment of isolation factors such as those contained in the SIS has not been studied. This is an important area for future aging research, with a specific focus needed on HIV+ individuals, given their risk of isolation as they age.
This study has several limitations. First, it is a longitudinal study using observational data, so inferences cannot be made about causality between social isolation and inpatient admission or mortality. Second, data were used from baseline surveys to create the SIS, and thus, components of this measure were considered to have "fixed effects" on overall social isolation. Third, severity of illness was not adjusted for in the final analysis because when scores from a validated HIV morbidity and mortality prediction tool (the VACS Risk Index)[56] were included in the models, it was found that differences in the outcomes of interest were no longer significant. Given that social isolation may well mediate poor disease control and overall severity of illness,[57] it was felt that inclusion of these risk index scores in the models would be overadjustment. The causal pathways between social isolation and outcomes remain unknown and represent an important area for future research. Fourth, although items for the SIS were carefully selected based on current literature on this topic and tested for construct validity, more formal psychometric testing for internal and external validity were not performed. The scale also differs from one of the most rigorously validated instruments to assess social isolation (the Lubben Social Network Scale, which focuses on closeness and redundancy of social contacts in family and friends) in that the SIS incorporates forms of social engagement beyond family and friends such as community volunteering, self-help groups, and religious activity that are not captured in the Lubben Social Network Scale.[58] Finally, the sample of veterans is predominantly male and non-white, so the results may not be generalizable to women and whites.
In conclusion, social isolation is associated with greater risk of hospitalization and death in HIV+ and uninfected older veterans. Despite similar effects in both groups, the population level effect of social isolation may be even greater in those who are HIV+ because of the higher prevalence of social isolation, particularly in the oldest individuals. Because the "graying" of the HIV+ population is projected to accelerate in the coming decades, a broader understanding of social isolation and the application of geriatric principles of inpatient care for this population is needed.
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