Health outcomes among American Indians with spinal cord injury

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Health Outcomes Among American Indians With Spinal Cord Injury J. Stuart Krause, PhD, Jennifer L. Coker, BA, Susan Charlifue, MA, Gale G. Whiteneck, PhD ABSTRACT. Krause JS, Coker JL, Charlifue S, Whiteneck GG. Health outcomes among American Indians with spinal cord injury. Arch Phys Med Rehabil 2000;81:924-31. Objective: To identify factors related to risk for poor health outcomes and secondary conditions in a sample of American Indians with spinal cord injury (SCI). Design: Interviews were conducted by telephone with most participants; those who did not have telephones returned materials by mail. Setting: A large rehabilitation hospital in the Western/ Mountain region of the United States. Participants: Ninety-seven American Indians with SCI completed a comprehensive health interview. All participants were adults with traumatic SCI and were at least 1 year postinjury. Main Outcome Measures: Selected items from the Behavioral Risk Factor Surveillance System were used to assess health behaviors and general health outcomes. Two secondary conditions were also investigated as outcome measures: pressure sores and post-SCI injuries. Results: Multiple linear regression was used to predict seven health-related outcomes. Depressive symptomatology and postSCI injuries were the primary predictors of the majority of health outcomes. Alcohol consumption was associated with a greater risk for post-SCI injuries, and being older at injury was associated with poorer health outcomes. Conclusions: Interventions to reduce depression, injuries, and alcohol misuse have potential for improving health among American Indians with SCI. Key Words: Spinal cord injuries; Indians, North American; Health outcomes; Rehabilitation. 娀 2000 by the American Congress of Rehabilitation Medicine and the American Academy of Physical Medicine and Rehabilitation

T

HERE HAS BEEN a growing concern about the impact of spinal cord injury (SCI) on overall long-term health. The past decade has seen an increase in the number of studies of secondary health conditions and general health outcomes.1-3 These conditions generally result from a combination of the physiologic sequelae of SCI and a number of factors pertinent to health, including the strategies used to maintain health. Because of the importance of health maintenance behaviors, health outcomes vary considerably among individuals with SCI. Historically, pressure sores have been the secondary From the Crawford Research Institute, Shepherd Center, Atlanta, GA (Krause, Coker), and Craig Hospital, Englewood, CO (Charlifue, Whiteneck). Submitted March 25, 1999. Accepted in revised form November 22, 1999. Supported by grants from the Model Spinal Cord Injury Systems (grant H133N00023 awarded to Shepherd Center and grant H133N50001 awarded to Craig Hospital). No commercial party having a direct financial interest in the results of the research supporting this article has or will confer a benefit upon the authors or upon any organization with which the authors are associated. Reprint requests to J. Stuart Krause, PhD, Clinical Research, Crawford Research Institute, Shepherd Center, 2020 Peachtree Rd NW, Atlanta, GA 30309. 0003-9993/00/8107-5536$3.00/0 doi:10.1053/apmr.2000.5618

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condition that has received the most attention, although other conditions, particularly depression, have received increasing attention as well.3-7 Identifying factors associated with differential health outcomes after SCI is central to the development of clinical and public health practices to improve health among people with SCI. RACIAL/ETHNIC MINORITIES AND SCI OUTCOMES There has been a lack of research addressing outcomes among minority populations with SCI, particularly related to health. It is important to investigate outcomes among different racial and ethnic minorities because race and ethnicity may be related to differential patterns of behaviors, community integration, and subjective outcomes after SCI. For example, research on employment has found substantially lower employment rates among African Americans.8-11 Other research has identified lower levels of subjective well-being in highly specific areas consistent with access to resources among African Americans with SCI.11-13 In a recent study using a measure specifically designed for people with chronic health conditions (the Older Adult Health and Mood Questionnaire), Latinos with SCI were found to be at greater risk for depression after SCI than either African Americans or Caucasians.14 They reported both higher mean depression scores (6.9 for Latinos vs 4.5 for African Americans and 4.3 for Caucasians), as well as a higher percentage of probable major depression (26% for Latinos vs 15% for Caucasians and 0% for African Americans). AMERICAN INDIANS AS A SPECIAL POPULATION Despite being a population that may have a substantially different pattern of behaviors and outcomes than other racial and ethnic groups, there has been minimal research on American Indians with SCI (only two reports using the current sample). The health-related behaviors of 76 American Indian males with SCI were compared with those of American Indian males from the general population using the Behavioral Risk Factor Surveillance System (BRFSS).15 The BRFSS is utilized by the Centers for Disease Control and Prevention (CDC) to monitor health-related behaviors and disease in the general population. The results of these comparisons showed that American Indians with SCI were less likely than American Indians without SCI to rate their overall health as very good or excellent, and that fewer American Indians with SCI were satisfied with their health care. American Indians with SCI reported less tobacco and alcohol use in the past month; however, the average number of drinks (for those that did drink) of American Indians with SCI was significantly more than for American Indians in the general population study (from BRFSS). Finally, the study found that although American Indians with SCI were more likely to have had their blood pressure screened, a flu shot, and pneumonia vaccinations, they were less likely to have received cholesterol screens and a human immunodeficiency virus test. In a second report, subjective well-being scores of American Indians were compared with those of test norms.16 The Ameri-

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can Indian sample reported elevated levels of depression and diminished subjective well-being in five of eight areas compared with previous studies on non–American Indians with SCI. Hierarchical multiple regression suggested significant associations between physical and emotional health. Activities, social support, and the frequency of alcohol use were among the primary predictors of the study outcomes. Taken together, these two studies suggest that American Indians with SCI perceive their health status to be diminished compared with American Indians without SCI, suggesting the need for investigation of health outcomes among this population. These studies also suggest that general activities, risk behaviors (particularly alcohol misuse), depressive symptomatology, and social support are important factors to investigate in relation to health outcomes. A review of the non-SCI literature with American Indians provides further insights into factors possibly associated with health outcomes among this population. HEALTH FACTORS AMONG AMERICAN INDIANS IN THE GENERAL POPULATION Research conducted with American Indians within the general population from different geographic regions across the United States found that they are at a greater risk for many chronic health conditions, including hypertension, obesity, diabetes, and cardiovascular disease.17 The average life expectancy of American Indians has been found to be 3 years less than that of the general population, and their mortality rate is two times higher.18 The United States Department of Health and Human Services reported in 1993 that American Indians are most likely to die of heart disease, cancer, injuries, stroke, and liver disease (similar causes of death as for the general population), but have a greater chance than the general population of dying from unintentional accidents, cirrhosis of the liver, homicide, suicide, pneumonia, or complications of diabetes.19 American Indians also have been found to participate in riskier behaviors than the general population. Although American Indians were found to have consumed alcohol less often than the general population, more American Indians reported ‘‘heavy drinking’’ (defined as consuming more than five drinks per occasion).17,20-23 Overall, American Indians also have been found to have a higher prevalence of current cigarette smoking than the general population, but reported smoking fewer cigarettes per day.20 American Indian women were four times more likely than women in the general population to smoke, whereas American Indian men were two times more likely to smoke.22 American Indians also appear to receive health services less frequently than other populations. For example, almost 50% say that it has been more than 2 years since their last visit to a physician.24 PURPOSE AND RATIONALE The purpose of this study was to identify factors associated with self-reported health outcomes among a sample of American Indians with SCI. These factors included biographic- and SCI-related factors (eg, age, injury, severity), social support, general activities, psychosocial adaptation (ie, depressive symptomatology), and health behaviors. Rather than basing variable selection on a particular theory, a broader range of variables was selected in accordance with previous empiric investigations, including those of the general population. For instance, general activity and social support variables were selected because of their relationship with subjective outcomes among American Indians with SCI, includ-

ing both depressive symptomatology and well-being.16 Selection of depressive symptomatology as a predictor was based on the substantial associations with health in the previous study. Alcohol usage was selected because of the findings that American Indians with SCI report more episodes of heavy drinking, the extent to which alcohol misuse was associated with poorer subjective outcomes, and studies within the general population reporting a high frequency of heavy drinking episodes.15,16 Cigarette use was included because it is a fundamental risk factor for multiple diseases in the general population and because studies of American Indians in the general population show differential usage patterns compared with other racial and ethnic groups.20,22 Because of the self-report methodology, we were restricted to self-reported general health outcomes. We selected those most widely used by the CDC using the BRFSS as the most appropriate and valid outcomes for this study (eg, self-ratings of health and number of poor health days). However, because of the importance of secondary conditions to people with SCI, we added pressure sores and subsequent injuries as both outcomes and predictors. Whereas pressure sores have been widely studied, subsequent injuries have only recently come under investigation25-30 (also Krause JS, Dunn KE, unpublished data). The finding that unintentional injuries are a prominent cause of death among American Indians in the general population reinforced our decision to use it in this study.19 The following four hypotheses follow the existing literature on American Indians, both with and without SCI: (1) biographic and injury factors will not be highly predictive of health outcomes; (2) among behaviors, alcohol misuse will be most highly predictive of adverse health outcomes; (3) depressive symptomatology will be the single most important predictor of health outcomes; and (4) activities, social support, and secondary conditions (injuries and pressure sores) will be moderately predictive of health outcomes. METHODS Participants All participants were selected from files of a large rehabilitation hospital located in the Western/Mountain area of the United States. There were five selection criteria for the study: (1) traumatic SCI, (2) some residual impairment from SCI (ie, not a complete recovery), (3) the SCI occurred no less than 1 year earlier, (4) at least 18 years of age at the time of the study, and (5) American Indian heritage. A total of 107 individuals were identified who met the criteria, 4 of whom could not be found and 3 of whom refused to participate. Of the 100 remaining individuals, 97 returned usable materials. Most of the participants were members of Navajo and Zuni ancestry, 12 were Sioux, and 4 were of mixed ancestry. All were from the western United States, most living on reservations in Colorado. Seventytwo participants completed the interview over the telephone, whereas 25 participants did not have telephones and completed and returned the interview by mail. Instruments An interview schedule was developed for this study that surveyed a wide range of content areas, and included a subset of items from the BRFSS, the Reciprocal Social Support scale (RSS), the Older Adult Health and Mood Questionnaire (OAHMQ), and the Craig Handicap Assessment and Reporting Technique (CHART). Basic descriptive information regarding biographic- and SCI-related variables, employment status, years of education, and marital status was also obtained. Arch Phys Med Rehabil Vol 81, July 2000

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Behavioral Risk Factor Surveillance System. The BRFSS was developed by the CDC as a means of gathering information on health and risk behaviors of adults in each of the 50 states.31 The BRFSS survey is composed of three parts: (1) a standardized core section that consists of 78 questions divided into 10 sections covering topics such as health care access, exercise, tobacco use, and women’s health; (2) optional modules with questions about diabetes, sexual behavior, injury control, and alcohol use; and (3) a group of questions added by the individual state that focuses on a topic of special interest to that state.31 Only selected portions of the BRFSS were used in the current study and fell into two general categories: health status and risk behaviors. Health status variables included (1) ratings of general health (poor to excellent), (2) change in health status during the past year, (3) number of days of poor physical health in the last month, (4) number of days of poor mental health in the last month, and (5) number of days that usual activities had to be stopped because of poor health. Risk behaviors included tobacco use and alcohol use. Tobacco use was dichotomized based on current usage (smoker, nonsmoker), whereas alcohol use was measured by the average number of days per month that the individual consumed alcohol. The 1996 version of the BRFSS was used for the study. In reliability studies, the demographic and risk factor sections of the BRFSS have been found to be highly consistent within households.32 Reciprocal Social Support scale. The RSS was developed to measure the amount of support given to and received from family members, friends, and the community.33 However, for this study, participants were only asked to indicate the amount of support received (as opposed to both given and received). A 7-point scale ranging from never (1) to always (7) was used to have individuals rate the frequency with which they received support in the areas of social interaction, material assistance, emotional support, and nonpaid personal assistance. Separate frequencies were obtained for support received from family, friends, and the community. Participants were also asked the frequency with which upsetting things happened between them and their family, their friends, or their community. Two scales were used in this study: total support received and total upsets. Alpha coefficients for the current sample ranged from .70 to .76 for the four types of support, with an average of .73. The alpha coefficient for the upsets scale was only .55; however, low internal consistency is expected given that the scale sums interactions with three groups of people (ie, family, friends, community). Older Adult Health and Mood Questionnaire. The OAHMQ is a measure of depressive symptoms that consists of 22 true-false items.34 It was designed to include few physiologic (‘‘vegetative’’) symptoms of depression, as these types of symptoms may parallel the actual sensory and motor complications associated with SCI.35,36 The instrument is scored by giving 1 point per ‘‘true’’ answer (total possible is 22 points). There are three diagnostic categories with the OAHMQ: (1) nondepressed (0 to 5 points); (2) clinically significant symptomatology (6 to 10 points); and (3) probable major depression (11 to 22 points). The OAHMQ was validated against clinical assessments by psychiatrists and psychologists and was found to have highly acceptable internal (.87) and retest reliability (.84). Validity ranged from .80 for sensitivity to .87 for specificity. Craig Handicap Assessment and Reporting Technique. The CHART is a measure of community integration that includes five domains: (1) physical independence, (2) mobility, (3) occupation, (4) social integration, and (5) economic selfsufficiency.37 Items from the CHART included in this study Arch Phys Med Rehabil Vol 81, July 2000

were number of hours per day spent out of bed, number of days per week out of the home, number of nights in past year spent away from home, and current employment status. Also included were simple questions regarding the individual’s history of pressure sores and injuries. Pressure sores were defined as open sores in pressure areas (such as tailbone, heel, and elbows) caused by pressure, friction, moisture, burns, or falls. Participants were asked to give the number of pressure sores that they have had in the past year and the number that they have had since their SCI. Injuries were defined as broken bones, burns, or lacerations resulting from some type of mishap, such as a fall, collision, motor vehicle wreck, or act of violence, that were serious enough to require medical care in a clinic, emergency department, or hospital. Participants were asked to give the number of injuries that occurred in the past year, since their SCI, and the number of hospitalizations caused by injuries since their SCI. Data Collection Procedures Participants were mailed a copy of the questionnaire with a cover letter explaining that they would be telephoned to complete the enclosed questionnaire. They were also told of a $50 stipend as incentive to participate. Two to 3 weeks after the mailing all potential participants were contacted. Those participants without telephones were asked to complete the questionnaire and mail it back to us (a self-addressed stamped return envelope was included for this purpose). All those who agreed to participate were first sent copies of the interview schedule (with interviewer prompts removed) to allow them to review the content before the calls. An interviewer then took participant responses by phone. Individuals who did not have telephones were asked to return the materials by mail. Analyses Descriptive statistics were reported to summarize the characteristics of the sample. Correlation matrices were generated for sets of predictor and outcome variables to describe further the interrelationships of study variables. Linear multiple regression was used to identify the optimal predictors of each of seven study outcomes. These outcomes included five health variables from the BRFSS: (1) self-rated health, (2) health status compared with 1 year ago, (3) number of poor health days in the past month, (4) number of poor mental health days in the past month, and (5) number of days in the past month in which poor health disrupted normal activities. In addition, two secondary conditions were included as outcomes (injuries and pressure sores in past year). Two sets of predictors were used. The first set was composed of four biographic and injury-related variables, including gender, injury level (cervical, noncervical), age at injury onset, and years since injury. These variables were selected primarily as controls for the more relevant second set of predictors, the selection of which was based on a review of the SCI and non-SCI literature. The second set of predictors were psychosocial and behavioral variables that included average hours out of bed per day, average days per week leaving home, nights per year stayed away from home, employment status, current smoking status, alcohol consumption (number of days per month), total upsets scale, total support scale, depressive symptomatology score, number of injuries in past year, and number of pressure sores in past year. These variables were selected based on a review of the relevant SCI and non-SCI literature. For instance, the first four predictors reflect aspects of community integration that have previously been found predictive of self-reported health after

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SCI.38,39 Tobacco and alcohol use are primary factors related to health in the general population, and American Indians in the general population have been found to have a different pattern of usage than non–American Indians.15,17,20-23,40,41 Last, social support has been found to be an important predictor of SCI outcomes among non–American Indians with SCI.42-44 A two-stage regression procedure was utilized, with the biographic and injury-related variables reviewed first using stepwise hierarchical inclusion, before entry of the psychosocial and behavioral variables (using the same stepwise procedures). By reviewing the biographic and injury variables first, they serve essentially as statistical controls for predictors in stage 2, if any were indeed significantly associated with that particular outcome. Stepwise procedures were used to identify the optimal predictors of each outcome by selecting variables most strongly associated with each outcome, thereby identifying the most parsimonious factors associated with each outcome (ie, those that account for the greatest variance in the outcome). Squared multiple correlations were calculated for each outcome. The two secondary condition variables (injuries and pressure sores) were included in the prediction of the general health outcomes, as well as in the prediction of each other (ie, injuries were used as a predictor of pressure sores and pressure scores were used as a predictor of injuries). The rationale behind using these two variables as predictors of general BRFSS outcomes was that these variables could be factors impacting overall health. RESULTS Participant Characteristics Men comprised 78% of the sample, and 49% reported cervical injuries. Twenty-nine percent reported no sensation or movement below the level of the lesion, 39% reported some sensation with no movement, 32% reported some movement below the level of the lesion, and 13% reported functional movement. The average age was 28.1 years at the onset of SCI (SD ⫽ 9.5) and 40.4 years at the time of the study (SD ⫽ 10.2). An average of 12.4 years had passed since the onset of SCI (SD ⫽ 6.5). Motor vehicle accidents were the cause of the majority of SCIs (83.5%). Alcoholic beverages were consumed

within 6 hours of the SCI by 49% of the participants. Participants averaged 11.9 years of education (SD ⫽ 2.8), and 21% were employed at the time of the study. In terms of combined family income, 69.1% reported less than $10,000 annual income, 19.1% between $10,000 and $25,000, 7.4% between $25,001 and $40,000, and the remaining 4.3% had family incomes between $40,001 and $55,000. Descriptive Findings The average rating of overall health was 3.0 (3 ⫽ average), whereas the average change in health during the past year was 3.5 (participants reported somewhat better health than the previous year). The average number of days in poor health during the past month was 4.5, and the average number of poor mental health days was 4.8. Participants reported an average of 4.3 days in the past month in which normal activities were disrupted by poor health. Half the participants reported at least one pressure sore in the past year, and 28.7% reported two or more pressure sores. Twenty-five percent of the participants reported at least one injury in the past year, whereas 8.7% reported more than one injury. Of those with at least one injury in the past year, 59% reported spending at least one night in the hospital as the result of an injury. Correlations Intercorrelations between predictor variables. There was a moderate degree of colinearity between the study predictors (table 1). The biographic- and injury-related variables were relatively uncorrelated, as the only significant correlation was between time since SCI and age at injury onset (r ⫽ ⫺.23). With regards to correlations between the biographic- and injury-related predictors and the psychosocial and behavioral predictors, days out (days leaving home per week) negatively correlated with age at injury onset (r ⫽ ⫺.35) and injury level (r ⫽ ⫺.26), smoking negatively correlated with time since injury (r ⫽ ⫺.24) and injury level (r ⫽ ⫺.34), and social support negatively correlated with time since injury (r ⫽ ⫺.28). There were also several significant intercorrelations among the explanatory variables. Activity variables were generally

Table 1: Intercorrelation Matrix for Predictor Variables

Gender Age at onset Time since SCI Injury level Hours out of bed Days out Nights out Employed Smoke now Alcohol use Injuries Pressure sores Social support Upsets OAHMQ

Gender

Age at Onset

Time Since SCI

Injury Level

Hours Out of Bed

— .03 .06 .09 .12 .02 .00 .04 ⫺.01 ⫺.13 ⫺.12 .06 ⫺.02 .15 ⫺.17

— ⫺.23* .14 ⫺.13 ⫺.35† ⫺.16 ⫺.08 .02 ⫺.03 .05 .20 ⫺.12 ⫺.11 .01

— ⫺.02 .02 ⫺.01 ⫺.09 ⫺.08 ⫺.24* ⫺.03 ⫺.01 ⫺.12 ⫺.28‡ .05 .02

— .01 ⫺.26‡ .12 ⫺.05 ⫺.34† ⫺.12 ⫺.09 ⫺.01 ⫺.07 ⫺.10 .14

— .30‡ — ⫺.09 .16 .28‡ .26‡ .13 ⫺.16 ⫺.15 .10 ⫺.22* ⫺.05 ⫺.07 ⫺.04 .09 .11 .07 .09 ⫺.16 .23*

Days Out

Nights Smoke Alcohol Pressure Social Out Employed Now Use Injuries Sores Support Upsets OAHMQ

— .04 .01 .05 .19 ⫺.06 ⫺.01 .05 ⫺.03

— ⫺.11 ⫺.11 ⫺.12 .04 .00 .09 ⫺.01

— .18 .16 .14 .12 .07 ⫺.02

— .47† .01 .21* .00 .24*

— ⫺.04 .04 .15 .22*

— .05 .09 ⫺.04

.09 ⫺.24*

— .21*

—

Abbreviations: SCI, spinal cord injury; OAHMQ, Older Adult Health and Mood Questionnaire. * p ⬍ .05. † p ⬍ .001. ‡ p ⬍ .01.

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intercorrelated (eg, employment positively correlated with hours out of bed, .28, and days out, .26). Depressive symptomatology (OAHMQ) moderately correlated with several other predictors (ranging from .21 to .24). Correlations with outcome variables and between outcome variables. Table 2 summarizes the intercorrelations among the outcome variables. The highest correlation was between days stopped normal activities and days in poor mental health (r ⫽ .66). No other correlation exceeded .45, although several other outcome variables were moderately correlated (generally between .23 and .45). Of the two secondary conditions variables, the number of injuries significantly correlated with several other outcomes, whereas the number of pressure sores did not correlate with any other outcome. With regards to correlations between predictors and outcomes (table 3), depressive symptomatology scores (OAHMQ) correlated with all but one outcome (pressure sores), with the correlations ranging between .21 to .57. The next highest correlation was between alcohol use and injuries (.47). Outside of these, social support was the most highly correlated with study outcomes. Prediction Table 4 summarizes the results of the regression analysis across the seven outcome variables (see table 5 for a complete summary of each model). The multiple correlations between the predictors and the seven outcome variables ranged from a low of .22 for pressure sores to a high of .73 for the number of poor mental health days in the past month; whereas, the squared multiple correlations (SMC) ranged between .05 and .53, with an average SMC of .25. The number of predictors that entered the equation ranged between one and four variables. General health. Three variables entered into the prediction of general health and accounted for 25% of the variance in general health ratings (none of the biographic or injury variables was significant). The first variable to enter the equation was depressive symptomatology score (OAHMQ), followed by the number of injuries in the last year and total support. General health ratings were highest (more favorable) among individuals who had lower depressive symptomatology scores, fewer injuries in the past year, and higher overall support. Current health compared with 1 year ago. Two variables entered into the prediction and accounted for 11% of the variance. The variable of primary importance was age at onset of injury, which accounted for 6% of the variance. The other variable that significantly added to the prediction was number of injuries in the last year. In sum, better ratings of current health compared with 1 year ago were associated with younger age at onset of SCI and fewer injuries in the last year. Days in poor physical health. Three variables predicted the number of days during the last year the participant was in

poor physical health (accounting for 18%). Age at onset of SCI entered first, accounting for 5% of the variance, followed by the number of injuries in the last year (6%) and the total amount of social support (5%). Older age at onset and a higher number of injuries were associated with more days in poor physical health, whereas fewer days in poor physical health was associated with more social support. Days in poor mental health. Four variables entered into the prediction of the number of poor mental health days in the last year (accounting for 53%). Time since injury accounted for 6%. Scores on the depression scale (OAHMQ) entered second, accounting for an additional 37%, followed by the number of days in the last month the participant drank alcohol (3%) and the number of injuries in the last year (7%). Poor mental health was associated with greater time since injury, higher scores on the OAHMQ (indicating high levels of depressive symptomatology), less alcohol use, and more injuries in the last year. It is noteworthy that alcohol use entered with a negative weight, despite being uncorrelated with the outcome (ie, it functioned as a suppressor variable). Number of days stopped activities, and pressure sores and injuries in the last year. Only one variable entered into each of the final three outcomes. Scores on the depression measure (OAHMQ) accounted for 39% of the variance for number of days that poor health kept participants from usual activities (higher scores were associated with more days). Age at onset of injury was predictive of pressure sores, with those older at injury at greater risk for pressure sores, but the prediction accounted for only 5% of the variance. Injuries in the last year were predicted by the number of days in the last month the participant drank alcohol (more alcohol use was associated with more injuries), accounting for 24% of the variance. DISCUSSION The purpose of this study was to identify predictors of self-reported health outcomes among American Indians with SCI. Researchers have rarely focused their attention on populations that are underrepresented in SCI research, such as women and racial and ethnic minorities. The current study is one of the first efforts to address post-SCI outcomes among American Indians with SCI. We focused this exploratory study on the variables suggested by the SCI and non-SCI literature as important factors to consider in relation to health outcomes among American Indians. General Findings Several observations are readily apparent from this study. First, the primary predictors of general health outcomes were two types of secondary conditions—depressive symptomatol-

Table 2: Intercorrelations Between Outcome Variables

General health Current health Poor physical health days Poor mental health days Days stopped activities Injuries Pressure sores

General Health

Current Health

Poor Physical Health Days

Poor Mental Health Days

Days Stopped Activities

Injuries

Pressure Sores

— .34* ⫺.18 ⫺.39* ⫺.45* ⫺.33* .04

— ⫺.24† ⫺.11 ⫺.08 .27‡ ⫺.02

— .43* .40* .27‡ ⫺.02

— .66* .23† ⫺.10

— .13 ⫺.08

— ⫺.04

—

* p ⬍ .001. † p ⬍ .05. ‡ p ⬍ .01.

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SPINAL CORD INJURY AND HEALTH, Krause Table 3: Correlation Matrix for Predictor Variables and Outcome Variables

Gender Age at onset Time since SCI Injury level Hours out of bed Days out Nights out Employed Smoke now Alcohol use Social support Upsets OAHMQ

General Health

Current Health

Poor Physical Health Days

Poor Mental Health Days

Days Stopped Activities

Injuries

Pressure Sores

.09 ⫺.09 ⫺.09 ⫺.03 .18 .10 .04 .02 ⫺.15 ⫺.16 .28† ⫺.13 ⫺.44‡

⫺.02 ⫺.23* ⫺.09 ⫺.07 .08 .19 .09 ⫺.04 ⫺.12 ⫺.07 .13 ⫺.05 ⫺.21*

.13 .22* ⫺.03 .06 .07 .10 .13 .02 .26† .09 ⫺.16 .00 .22*

⫺.01 ⫺.11 .18 .13 .02 .00 .08 .07 ⫺.05 .00 ⫺.29† .09 .55‡

⫺.09 ⫺.04 .15 .14 ⫺.04 ⫺.04 .04 ⫺.09 .11 .07 ⫺.22* ⫺.03 .57‡

⫺.12 .05 ⫺.01 .09 ⫺.22* ⫺.05 .19 .12 ⫺.16 .47‡ .04 .15 .22*

.06 .20* ⫺.12 .01 ⫺.07 ⫺.04 ⫺.07 ⫺.04 ⫺.14 .01 .05 .09 ⫺.04

Abbreviations: SCI, spinal cord injury; OAHMQ, Older Adult Health and Mood Questionnaire. * p ⬍ .05. p ⬍ .01. ‡ p ⬍ .001. †

ogy and post-SCI injuries. With regard to depression, poor health may have led to depressive symptomatology or, conversely, depressive symptomatology could have actually contributed to diminished health. It is also likely that people who are distressed (ie, experiencing negative effect or depressive symptomatology) give more negative appraisals of their health and overall functioning to a greater extent than those who are not distressed. Therefore, the appraisals of health reflect subjective evaluations of health that may or may not covary with actual health. Regardless of causality, it is important for rehabilitation professionals to understand the interrelationships between depressive symptomatology and health, and to assess both physical and mental health among individuals presenting with either problem years after injury. The relationship of post-SCI injuries to multiple health outcomes was striking, as it was related to several outcomes including overall health, poor health days, change in health during the past year, and poor mental health days. In contrast, pressure sores were not predictive of any health outcomes in this study, even though they were more prevalent than secondary injuries during the past year among the current study participants. Prevention of pressure sores has received a great deal of attention among rehabilitation professionals, whereas post-SCI injuries have been virtually ignored as a secondary condition. It is noteworthy that 59% of individuals who reported at least one secondary injury reported being hospitalized in the past year as the result of one or more injuries. In sum, Table 4: Summary Regression Table Outcome Variable

General health Current health Poor physical health days Poor mental health days Days stopped activities Injuries Pressure sores

No. of R Predictors Multiple R Square Entered

F Value

3 2

.50 .34

.25 .11

F(3, 79) ⫽ 8.59, p ⬍ .001 F(2, 80) ⫽ 5.14, p ⬍ .01

3

.43

.18

F(3, 79) ⫽ 5.85, p ⬍ .001

4

.73

.53

F(4, 78) ⫽ 21.86, p ⬍ .001

1 1 1

.62 .49 .22

.39 .24 .05

F(1, 80) ⫽ 50.38, p ⬍ .001 F(1, 81) ⫽ 25.53, p ⬍ .001 F(1, 81) ⫽ 4.20, p ⬍ .05

the impact of injuries on ratings of health was substantial and not easily explained away by the cross-sectional design. It is also noteworthy that alcohol use highly correlated with injuries. This is in contrast to cigarette smoking, which did not enter into the prediction of any health outcome (it did correlate with several outcomes). It was rather surprising that none of the general activity variables entered into the prediction of the health outcomes. This is not to say that overall activity and health were unrelated (they were correlated), but rather that other factors were found to be more important. Among other key findings, being older at injury onset was associated with several poorer health outcomes. An older age at injury was predictive of several types of health, including declines in health during the past year and the number of pressure sores. In contrast, years lived since the onset of SCI was predictive of only one outcome (poor mental health days), reaffirming the adverse outcomes generally observed among individuals who were older at injury. Limitations There are several limitations in this study. First, all data were obtained via self-report. Therefore, there is a subjective component to measurement of both study outcomes and predictor variables. The results would have been bolstered by a combination of objective and subjective measures. Second, all data are cross-sectional. Therefore, it is not possible to determine direction of causation. For example, poor health may have led to depressive symptomatology or, conversely, depressive symptomatology could have actually contributed to diminished health. Third, this study was not based on any particular theoretical orientation; rather, selection of variables was based on a broad range of variables identified empirically through diverse studies. This had the benefit of leading to investigation of a wide range of variables, which was beneficial in this type of exploratory study in which so little direct research has been conducted. However, theory-based research would have the advantage of more narrowly focusing on particular predictors and outcomes, would allow for theory-driven hypotheses, and would build on a focused component of the literature. Last, this study used a select participant sample of American Indians. As a result, the study has unknown generalizability to other SCI populations (including those populations most representative in SCI research). Also, the study sample was itself a select group Arch Phys Med Rehabil Vol 81, July 2000

930

SPINAL CORD INJURY AND HEALTH, Krause Table 5: Complete Summary of Regression Analyses

Outcome Variable Entered

General health OAHMQ (depression scores) Injuries in last year Social support Current health Age at onset of injury Injuries in last year Poor physical health days Age at onset of injury Injuries in last year Social support Poor mental health days Time since injury OAHMQ (depression scores) Days in last month drank alcohol Injuries in last year Days stopped activities OAHMQ (depression scores) Pressure sores in last year Age at onset of injury Injuries in last year No. days last month drank alcohol

Multiple R

R2

Change in R 2

Beta

t Value

.39 .45 .50

.15 .20 .25

— .05 .05

⫺.29 ⫺.25 .21

⫺2.86* ⫺2.53* 2.10†

.25 .34

.06 .11

— .05

⫺.24 ⫺.22

⫺2.28† ⫺2.12†

.23 .37 .43

.05 .13 .18

— .06 .05

.19 .29 ⫺.22

1.86 2.86* ⫺2.15*

.25

.06

—

.21

2.73*

.66

.43

.37

.64

7.78‡

.68 .73

.46 .53

.03 .07

⫺.32 .30

⫺3.51‡ 3.40‡

.62

.39

—

.62

7.10‡

.22

.05

—

.22

2.05†

.49

.24

—

.49

5.05‡

Abbreviation: OAHMQ, Older Adult Health and Mood Questionnaire. * p ⬍ .01. † p ⬍ .05. ‡ p ⬍ .001.

of American Indians (mostly from the Navajo nation and, to a lesser degree, the Sioux nation); therefore, generalizability to other American Indian populations is unknown. Implications The relationship between depressive symptomatology and health suggests a need to evaluate individuals routinely for depression after SCI, particularly in cases in which individuals are seen with health-related problems. When depression is significant, intervention is necessary. A second implication is that post-SCI injuries appear to be a significant problem after SCI. Because alcohol misuse appears to underlie many injuries and poor health outcomes, alcohol usage patterns should also be the focus of both assessment and intervention efforts. It is not possible to determine the extent to which these implications apply primarily to American Indians with SCI. However, it is clear from previous findings that American Indian men with SCI have much lower self-reported health compared with American Indians in the general population.15 They also show a different pattern of risk behaviors, with more frequent episodes of heavy drinking, and they pay less attention to health screens for chronic diseases, as opposed to those that may be more directly relevant to SCI (eg, pneumonia vaccinations). Although it is not possible to separate fully the role of disability (ie, SCI) from that of race and ethnicity in the current study, other evidence clearly suggests that the health and health behaviors of American Indians with SCI are different from Arch Phys Med Rehabil Vol 81, July 2000

those of American Indians and non-American Indians in the general population. It is reasonable, therefore, to hypothesize that the current findings reflect the combined effects of disability and race and ethnicity. At a minimum, the current findings suggest a need for further study with other racial and ethnic groups to determine whether the similar factors are predictive of health outcomes in these other populations. Acknowledgments: The authors thank the following people, without whose contributions completion of this article would not have been possible: Linda Singer from Craig Hospital, who conducted all the interviews, and Athena Gemella, Else Henry, Sam Jones, Sarah Lottes, Kyle Massey, and Glen Sutton from the Shepherd Center who contributed to the completion of this study. References 1. Krause JS. Skin sores after spinal cord injury: relationship to life adjustment. Spinal Cord 1998;36:51-6. 2. National Spinal Cord Injury Statistical Center. Annual report for the model spinal cord injury care systems. Birmingham (AL): University of Alabama; 1997. 3. Krause JS. Secondary conditions and spinal cord injury: a model for prediction and prevention. Top Spinal Cord Inj Rehabil 1998;2:58-70. 4. Boekamp JR, Overholser JC, Schubert DS. Depression following a spinal cord injury. Int J Psychiatry Med 1996;26:329-49. 5. Elliot TR, Frank RG. Depression following spinal cord injury. Arch Phys Med Rehabil 1996;77:816-23. 6. Jacob KS, Zachariah K, Bhattacharji S. Depression in individuals with spinal cord injury: methodological issues. Paraplegia 1995;33: 377-80. 7. Kishi Y, Robinson RG, Forrester AW. Comparison between acute and delayed onset major depression after spinal cord injury. J Nerv Ment Dis 1995;183:286-92. 8. James M, DeVivo MJ, Richards JS. Postinjury employment outcomes among African American and white persons with spinal cord injury. Rehabil Psychol 1993;38:151-64. 9. DeVivo MJ, Rutt RD, Stover SL, Fine PR. Employment after spinal cord injury. Arch Phys Med Rehabil 1987;68:494-8. 10. DeVivo MJ, Fine PR. Employment status of spinal cord injured patients 3 years after injury. Arch Phys Med Rehabil 1982;63: 200-3. 11. Krause JS, Anson CA, Maides J. Locus of control and life adjustments relationship among people with spinal cord injury. Rehabil Couns Bull 1998;41:162-72. 12. Krause JS. Activity patterns after SCI: relationship to gender and race. Top Spinal Cord Inj Rehabil 1998;4:31-41. 13. Krause JS. Dimensions of subjective well-being: an empirical analysis by gender and race/ethnicity. Arch Phys Med Rehabil 1998;79:900-9. 14. Kemp BJ, Krause JS, Adkins RA. Depressive symptomatology among African-American, Latino, and Caucasian participants with SCI. Rehabil Psychol 1999;44:235-47. 15. Krause JS, Coker JL, Charlifue SW, Whiteneck GG. Health behaviors among American Indians with spinal cord injury: comparison with data from the 1996 Behavioral Risk Factor Surveillance System. Arch Phys Med Rehabil 1999;80:1435-40. 16. Krause JS, Coker JL, Charlifue S, Whiteneck GG. Depression and subjective well-being among 97 American Indians with spinal cord injury. Rehabil Psychol 1999;44:357-72. 17. Pearson D, Cheadle A, Wagner E, Tonsberg R, Psaty BM. Differences in sociodemographic, health status, and lifestyle characteristics among American Indians by telephone coverage. Prev Med 1994;23:461-4. 18. Indian Health Service. Indian health service chart series book. Rockville (MD): US Department of Health and Human Services, IHS; 1988. 19. United States Department of Health and Human Services, Public Health Service. Healthy people 2000. Washington (DC). Government Printing Office; 1990. DHHS Publication No. (PHS) 9150212.

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