Karla S. Reed

Factor Structure and Predictive Validity of Somatic and Nonsomatic Symptoms From the Patient Health Questionnaire-9: A Longitudinal Study After Spinal Cord Injury

OBJECTIVE To investigate the factor structure and predictive validity of somatic and nonsomatic depressive symptoms over the first 2.5 years after spinal cord injury (SCI) using the Patient Health Questionnaire-9 (PHQ-9). DESIGN Somatic and nonsomatic symptoms were assessed at baseline during inpatient hospitalization (average of 50 days after onset) and during 2 follow-ups (average of 498 and 874 days after onset). SETTING Data were collected at a specialty hospital in the Southeastern United States and analyzed at a medical university. We performed time-lag regression between inpatient baseline and follow-up somatic and nonsomatic latent factors of the PHQ-9. PARTICIPANTS Adults with traumatic SCI (N=584) entered the study during inpatient rehabilitation. INTERVENTIONS Not applicable. MAIN OUTCOME MEASURE PHQ-9, a 9-item measure of depressive symptoms. RESULTS The inpatient baseline nonsomatic latent factor was significantly predictive of the nonsomatic (r=.40; P=.000) and somatic latent factors at the second follow-up (r=.29; P=.006), whereas the somatic factor at inpatient baseline did not significantly predict either factor. In contrast, when regressing latent factors between the 2 follow-ups, the nonsomatic factor predicted only the nonsomatic factor (r=.66; P=.002), and the somatic factor predicted only future somatic symptoms (r=.66; P=.000). In addition, the factor structure was not stable over time. Item analysis verified the instability of somatic items between inpatient baseline and follow-up and also indicated that self-harm at inpatient baseline was highly predictive of future self-harm. CONCLUSIONS Nonsomatic symptoms are better predictors of future depressive symptoms when first assessed during inpatient rehabilitation, whereas somatic symptoms become stable predictors only after inpatient rehabilitation. Self-harm (suicidal ideation) is the most stable symptom over time. Clinicians should routinely assess for suicidal ideation and use nonsomatic symptoms when performing assessments during inpatient rehabilitation.

Psychologic Factors and Risk of Mortality After Spinal Cord Injury

OBJECTIVE To identify the association of 2 distinct psychologic constructs, personality and purpose in life (PIL), with risk of early mortality among persons with spinal cord injury (SCI). DESIGN Prospective cohort study with health data collected in late 1997 and early 1998 and mortality status ascertained in December 2005. SETTING A large rehabilitation hospital in the southeastern United States. PARTICIPANTS Adults (N=1386) with traumatic SCI, at least 1 year postinjury. INTERVENTIONS Not applicable. MAIN OUTCOME MEASURES We first evaluated the significance of a single psychologic predictor (a total of 6 scales) while controlling for biographic and injury predictors using Cox proportional hazards modeling and subsequently built a comprehensive model based on an optimal group of psychologic variables. RESULTS There were a total of 224 (16.2%) observed deaths in the full sample. The total number of deaths was reduced to 164 in the final statistical model (of 1128 participants) because of missing data. All 6 psychologic factors were statistically significant in the model that was adjusted for biographic and injury factors, whereas only 3 psychologic factors were retained in the final comprehensive model, including 2 personality scales (Impulsive Sensation Seeking, Neuroticism-Anxiety) and the PIL scale. The final comprehensive model only modestly improved the overall prediction of survival compared with the model with only biographic and injury variables, because the pseudo-R(2) increased from 0.121 to 0.129, and the concordance increased from 0.730 to 0.747. CONCLUSIONS The results affirm the importance of psychologic factors in relation to survival after SCI.

The Relationship of Pressure Ulcers, Race, and Socioeconomic Conditions After Spinal Cord Injury

Abstract Objective: To identify risks factors associated with pressure ulcers (PrU) after spinal cord injury (SCI) by examining race and indicators of socioeconomic status (measured by income and education). We hypothesize African Americans will have a greater risk for PrUs than whites, but this relationship will be mediated by the 2 socioeconomic status indicators. Design: Cohort study. Setting: A large rehabilitation hospital in the southeastern US. Participants: 1,466 white and African American adults at least 1-year post-traumatic SCI. Outcome Measures: (a) PrUs in the past year, (b) current PrU, (c) surgery to repair a PrU since injury. Results: In preliminary analyses, race was significantly associated with having a current PrU and with having surgery to repair a PrU since injury. In multivariable analyses, the relationships of PrU with having a current PrU and with having surgery to repair a PrU were both mediated by income and education such that the relationships were no longer significant. Lower income was associated with increased odds of each PrU outcome. After controlling for other variables in the model, education was associated with increased odds of having a current PrU. Conclusion: These findings help clarify the relationships between race and socioeconomic status with PrUs after SCI. Specifically, a lack of resources, both financial and educational, is associated with worse PrU outcomes. These results can be used by both providers and policy makers when considering prevention and intervention strategies for PrUs among people with SCI.

A structural analysis of health outcomes after spinal cord injury.

Abstract Objective: To develop and validate a latent model of health outcomes among persons with spinal cord injury. Methods: Survey data were collected at a large specialty hospital in the southeastern USA from 1,388 adult participants with traumatic spinal cord injury of at least 1 years duration. Multiple indicators of health outcomes were used, including general health ratings, days adversely affected by poor health and poor mental health, treatments and hospitalizations, depressive symptoms, symptoms of illness or infection (eg, sweats, chills, fever), and multiple individual conditions (eg, pressure ulcers, subsequent injuries, fractures, contractures). Results: We performed exploratory factor analysis on half of the sample and confirmatory factor analysis on the other. A 6-factor solution was the best overall solution, because there was an excellent fit with the exploratory factor analysis (root mean square error of approximation = 0.042) and acceptable fit with the confirmatory factor analysis (root mean square error of approximation = 0.065). Four of the factors were types of secondary conditions, including symptoms of illness or infection, orthopedic conditions, pressure ulcers, and subsequent injuries. The 2 remaining factors reflected global health and treatment. Gender, race-ethnicity, age, injury severity, and years of education were all significantly related to at least 1 factor dimension, indicating variations in health outcomes related to these characteristics. Conclusion: Identification of the 6 factors represents an improvement over the utilization of multiple individual indicators, because composite scores generated from multiple individual indicators provide more informative and stable outcome scores than utilization of single indicators. J Spinal Cord Med. February 2010; 33(1): 22–32

Barriers and facilitators to employment after spinal cord injury: underlying dimensions and their relationship to labor force participation

Study design:Cross-sectional survey.Objective:To identify barriers and facilitators to employment after spinal cord injury (SCI) and their relationship with labor force participation.Methods:Participants were initially identified through specialty hospitals in the Midwest and Southeastern United States of America. 781 adults with traumatic SCI, at least 1 year post-injury, and between the ages of 18–64, participated. A 30-item instrument on barriers and facilitators to employment was administered. Analyses included exploratory factor analysis (EFA), confirmatory factor analysis (CFA) and comparisons of scores as a function of employment status.Results:EFA indicated six primary themes (root mean square error of approximation (RMSEA)=0.040), including: (a) resources, (b) health status, (c) disability considerations, (d) lack of importance, (e) disincentives and (f) motivation. CFA indicated an acceptable fit (RMSEA=0.078). Univariate analyses indicated each item and factor was significantly different as a function of labor force participation. After controlling for biographical and injury factors, multinomial logistic regression indicated three factors significantly differentiated those never employed, those currently unemployed but had worked since injury and those currently employed. Those employed reported higher scores for resources and motivation and lower scores for lack of importance.Conclusions:Barriers and facilitators were consistently related to labor force participation, with facilitators more highly related to labor force participation than barriers. Although loss of financial and medical benefits (disincentives) as well as health status have been reported as barriers to employment, they were not as highly correlated with labor force participation as were other factors.

Obtaining Employment After Spinal Cord Injury: Relationship With Pre- and Postinjury Education

The authors identify the association of educational milestones obtained before and after spinal cord injury (SCI) with postinjury employment (PIE). Survey data were collected from 1,362 adults younger than 65, with traumatic SCI of at least 1 year duration who were not currently attending school. The sole outcome was obtaining PIE—whether the individual had worked at any time since SCI onset. Approximately 54% of eligible participants worked post-SCI. Logistic regression was used to identify the odds of employment as a function of the educational milestones while controlling for other characteristics.With the exception of a high school certificate, completing educational milestones after injury was associated with substantially higher odds of employment than when they were completed prior to injury. The results underscore the need for postinjury education, even among individuals who have extensive training and education at the time of injury.

A latent variable structural path model of health behaviors after spinal cord injury.

Abstract Background/Objective: To develop a latent behavioral model by identifying and confirming the factor structure of health behaviors of people with spinal cord injury (SCI) and their relationships with biographic, injury, and educational characteristics. Research Design: Survey data were collected from 1,388 adults with traumatic SCI of at least 1 year duration. Main Outcome Measures: Selection of health behaviors was based on a bidimensional behavioral risk model. Behaviors were measured by core item sets from the Behavioral Risk Factor Surveillance System and supplemented by an alcohol screening measure, select fitness proxies, and the SCI Health Survey. Results: Latent variable structural equation modeling was used to identify underlying factors and their relationship with participant characteristics. Seven specific factors were identified by exploratory factor analysis and were cross-validated using confirmatory factor analysis. They included: (a) healthy nutrition, (b) unhealthy nutrition, (c) fitness, (d) smoking, (e) alcohol use, (f) psychotropic prescription medications, and (g) SCI healthy activities. Two higher-order dimensions were also identified, including a risk dimension (b, d, e) and a protective dimension (a, c, g). Participant characteristics were associated with the domains. For instance, participants with the most severe injuries scored lower on smoking and alcohol but higher on psychotropic medications; age was positively correlated with healthy nutrition and negatively correlated with alcohol and tobacco use but also negatively correlated with fitness. Conclusion: Behaviors can be meaningfully combined into underlying dimensions to more efficiently use them as predictors of secondary conditions.

Comparison of the Patient Health Questionnaire and the Older Adult Health and Mood Questionnaire for self-reported depressive symptoms after spinal cord injury.

OBJECTIVE To directly compare estimates of potential depressive disorders and clinically significant depressive symptoms using the Patient Health Questionnaire-9 (PHQ-9) and Older Adult Health and Mood Questionnaire (OAHMQ) among participants with spinal cord injury (SCI). RESEARCH DESIGN 727 participants from a hospital in the Southeastern United States were administered the PHQ-9 and OAHMQ during a follow-up survey. We compared the rates of depressive disorders using cutoff scores and diagnostic criteria for each instrument. No independent psychiatric diagnostic interviews were conducted. RESULTS The PHQ-9 and OAHMQ were significantly correlated (r = .78), and both were correlated with satisfaction with life (r = -.48, -.54). Using recommended diagnostic scoring procedures, 10.7% of participants met the diagnostic criteria for major depressive disorder with the PHQ-9; 9.3% met the criteria for major depression based on PHQ-9 > or = 10; and 19.7% based on PHQ-9 > or = 15. Using the OAHMQ, 19.7% reported probable major depression and 44.5% clinically significant symptomatology. CONCLUSIONS The measures were highly correlated overall. However, the estimated prevalence of depressive disorders varied substantially between the 2 instruments. These estimates were comparable to those previously reported for each instrument (i.e., higher rates with the OAHMQ). Therefore, differing estimates of depressive disorders reported in the literature using these instruments were largely attributable to the instruments themselves.

Life satisfaction and self-reported problems after spinal cord injury: measurement of underlying dimensions.

OBJECTIVE Evaluate the utility of the current 7-scale structure of the Life Situation Questionnaire-Revised (LSQ-R) using confirmatory factor analysis (CFA) and explore the factor structure of each set of items. DESIGN Adults (N = 1,543) with traumatic spinal cord injury (SCI) were administered the 20 satisfaction and 30 problems items from the LSQ-R. RESULTS CFA suggests that the existing 7-scale structure across the 50 items was within the acceptable range (root-mean-square error of approximation [RMSEA] = 0.078), although it fell just outside of this range for women. Factor analysis revealed 3 satisfaction factors and 6 problems factors. The overall fit of the problems items (RMSEA = 0.070) was superior to that of the satisfaction items (RMSEA = 0.80). RMSEA fell just outside of the acceptable range for Whites and men on the satisfaction scales. All scales had acceptable internal consistency. CONCLUSION Results suggest the original scoring of the LSQ-R remains viable, although individual results should be reviewed for special population. Factor analysis of subsets of items allows satisfaction and problems items to be used independently, depending on the study purpose.

Prediction of somatic and non-somatic depressive symptoms between inpatient rehabilitation and follow-up.

Study design:Longitudinal.Objective:We identified changes in the association of somatic and non-somatic symptoms (as measured by the Patient Health Questionnaire-9, PHQ-9) between inpatient rehabilitation after spinal cord injury (SCI) and 1 year after discharge.Setting:A specialty hospital in the Southeastern USA.Methods:A total of 584 adults with traumatic SCI were administered the PHQ-9 during inpatient rehabilitation. Of them, 227 completed the PHQ-9 by survey at 1-year follow-up. We performed time-lagged regression between times of measurement for somatic and non-somatic factors of the PHQ-9.Results:The non-somatic factor at baseline was significantly predictive of the non-somatic (r=0.67, P=0.002) and somatic factors at follow-up (r=0.53, P=0.019). The somatic factor did not significantly predict either the somatic (r=0.10, n.s.) or non-somatic factors at follow-up (r=−0.01, NS). Factor analysis also indicated changing factor structure between inpatient rehabilitation and follow-up.Conclusions:Our results question the interpretation of somatic items during inpatient rehabilitation, as they are not predictive of either somatic or non-somatic symptoms at follow-up.