Travel time and attrition from VHA care among women veterans: how far is too far?

BACKGROUND: Travel time, an access barrier, may contribute to attrition of women veterans from Veterans Health Administration (VHA) care. OBJECTIVE: We examined whether travel time influences attrition: (a) among women veterans overall, (b) among new versus established patients, and (c) among rural versus urban patients. RESEARCH DESIGN: This retrospective cohort study used logistic regression to estimate the association between drive time and attrition, overall and for new/established and rural/urban patients. SUBJECTS: In total, 266,301 women veteran VHA outpatients in the Fiscal year 2009. MEASURES: An "attriter" did not return for VHA care during the second through third years after her first 2009 visit (T0). Drive time (log minutes) was between the patient's residence and her regular source of VHA care. "New" patients had no VHA visits within 3 years before T0. Models included age, service-connected disability, health status, and utilization as covariates. RESULTS: Overall, longer drive times were associated with higher odds of attrition: drive time adjusted odds ratio=1.11 (99% confidence interval, 1.09-1.14). The relationship between drive time and attrition was stronger among new patients but was not modified by rurality. CONCLUSIONS: Attrition among women veterans is sensitive to longer drive time. Linking new patients to VHA services designed to reduce distance barriers (telemedicine, community-based clinics, mobile clinics) may reduce attrition among women new to VHA.

Establishing a data monitoring committee for clinical trials.

SUMMARY: A data monitoring committee (DMC) is a group of clinicians and biostatisticians appointed by study sponsors who provide independent assessment of the safety, scientific validity and integrity of clinical trials. In the United States, the Food and Drug Administration requires the formation of DMC in all trials that assess new interventions. DMC are also strongly recommended in other clinical studies that have substantial safety issues, that have double-blind treatment assignment or that are expected to have a major impact on clinical practice. They are important in clinical research in psychiatry because they provide an added layer of protection for the vulnerable populations that are often enrolled in such studies. This report describes the role, formation and operation of DMC.

Prevalence, risk, and correlates of posttraumatic stress disorder across ethnic and racial minority groups in the United States.

OBJECTIVES: We assess whether posttraumatic stress disorder (PTSD) varies in prevalence, diagnostic criteria endorsement, and type and frequency of potentially traumatic events (PTEs) among a nationally representative US sample of 5071 non-Latino whites, 3264 Latinos, 2178 Asians, 4249 African Americans, and 1476 Afro-Caribbeans. METHODS: PTSD and other psychiatric disorders were evaluated using the World Mental Health-Composite International Diagnostic Interview (WMH-CIDI) in a national household sample that oversampled ethnic/racial minorities (n=16,238) but was weighted to produce results representative of the general population. RESULTS: Asians have lower prevalence rates of probable lifetime PTSD, whereas African Americans have higher rates as compared with non-Latino whites, even after adjusting for type and number of exposures to traumatic events, and for sociodemographic, clinical, and social support factors. Afro-Caribbeans and Latinos seem to demonstrate similar risk to non-Latino whites, adjusting for these same covariates. Higher rates of probable PTSD exhibited by African Americans and lower rates for Asians, as compared with non-Latino whites, do not appear related to differential symptom endorsement, differences in risk or protective factors, or differences in types and frequencies of PTEs across groups. CONCLUSIONS: There appears to be marked differences in conditional risk of probable PTSD across ethnic/racial groups. Questions remain about what explains risk of probable PTSD. Several factors that might account for these differences are discussed, as well as the clinical implications of our findings. Uncertainty of the PTSD diagnostic assessment for Latinos and Asians requires further evaluation.

Consequences of radial artery harvest: results of a prospective, randomized, multicenter trial.

IMPORTANCE: To date, no study has defined the consequences of radial artery harvest based on a large number of patients in a prospective randomized trial. OBJECTIVE: To compare pain at the harvest site and functional changes associated with harvesting the radial artery vs saphenous vein for coronary artery bypass grafting. DESIGN, SETTING, AND PARTICIPANTS: This study compares the consequences of radial artery harvest with saphenous vein harvest in patients undergoing elective coronary artery bypass grafting procedures in Veterans Affairs hospitals. MAIN OUTCOMES AND MEASURES: Eleven hospitals screened 6148 patients, of whom 751 were included in this trial. We analyzed 2 variables: pain at the harvest site as measured on a scale of 0 to 100 (least to most painful) and hand performance testing. Patients included in this analysis had radial artery only (n = 80) or saphenous vein only (n = 337) harvest. Pain score, grip strength, and dexterity were measured before surgery and at 3 and 12 months after surgery. We adjusted for pain scores of the nonharvested extremity, age, whether the patient underwent endoscopic vein harvesting, and comorbid health conditions (smoking history, type 2 diabetes mellitus, hypertension, and heart failure). RESULTS: There was a significant difference in change of pain score at 3 months from the preoperative baseline between radial artery and saphenous vein groups after adjusting for covariates (P < .001) but not at 12 months (P = .07). No significant changes occurred in grip strength or dexterity from preoperative baseline to 3 and 12 months after surgery (P > .05). CONCLUSIONS AND RELEVANCE: The radial artery group reported significantly more pain than the saphenous vein group 3 months after surgery; however, similar levels of pain were observed in both groups at 12 months after surgery. Grip strength and manual dexterity were not changed by radial artery harvesting at 3 and 12 months.

Diagnostic validity across racial and ethnic groups in the assessment of adolescent DSM-IV disorders.

We examine differential validity of the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) diagnoses assessed by the fully-structured Composite International Diagnostic Interview Version 3.0 (CIDI) among Latino, non-Latino Black, and non-Latino White adolescents in comparison to gold standard diagnoses derived from the Schedule for Affective Disorders and Schizophrenia for School-age Children (K-SADS). Results are based on the National Comorbidity Survey Replication Adolescent Supplement, a national US survey of adolescent mental health. Clinicians re-interviewed 347 adolescent/parent dyads with the K-SADS. Sensitivity and/or specificity of CIDI diagnoses varied significantly by ethnicity/race for four of ten disorders. Modifications to algorithms sometimes reduced bias in prevalence estimates, but at the cost of reducing individual-level concordance. These findings document the importance of assessing fully-structured diagnostic instruments for differential accuracy in ethnic/racial subgroups.

Role of referrals in mental health service disparities for racial and ethnic minority youth.

OBJECTIVE: To investigate racial/ethnic differences in teachers' and other adults' identification and/or encouragement of parents to seek treatment for psychiatric problems in their children and to evaluate if and whether identification/encouragement is associated with service use. METHOD: Data on identification/encouragement to seek treatment for externalizing disorders (i.e., attention-deficit/hyperactivity disorder, oppositional-defiant disorder, and/or conduct disorder) and internalizing disorders (i.e., major depressive episode/dysthymia and/or separation anxiety disorder) and services used were obtained for 6,112 adolescents (13-17 years of age) in the National Comorbidity Survey Adolescent Supplement. Racial/ethnic differences were examined for Latinos, non-Latino blacks, and non-Latino whites. RESULTS: There were few racial/ethnic differences in rates of youth identification/encouragement and how identification/encouragement related to service use. Only non-Latino black youth with low severity internalizing disorders were less likely to be identified/encouraged to seek services compared with non-Latino white youth with the same characteristics (odds ratio [OR] = 0.4, 95% confidence interval [CI] = [0.2-0.7]). Identification/encouragement increased the likelihood of seeking services for externalizing and internalizing disorders for all youth. However, compared with their non-Latino white counterparts, non-Latino black youth who met criteria for internalizing disorders appeared less likely to have used any services (OR = 0.4, 95%, CI = 0.2-0.7), after adjusting for identification/encouragement, clinical, and sociodemographic characteristics. Non-Latino black youth with internalizing disorders and without identification/encouragement were less likely to use the specialty care sector than their non-Latino white counterparts. CONCLUSIONS: In this study of a nationally representative sample of adolescents, almost no ethnic/racial differences in identification/encouragement were found. However, identification/encouragement may increase service use for all youth.

Use and quality of mental health services for Haitian youth.

OBJECTIVE: To describe the mental health service use of Haitian, African-American, and non-Latino White youth in a community mental health setting. Groups are compared on adherence to treatment guidelines for attention-deficit/hyperactivity disorder (ADHD) and depressive disorders. DESIGN: Retrospective review of outpatient mental health charts (n = 252) from five community sites in an urban area of the Northeastern United States. We recorded the total number and treatment type of sessions during the first six months of treatment. Guideline-adherent treatments were compared and predicted after controlling for clinical need. RESULTS: Most Haitian and African-American youth stopped treatment by six months, with the majority attending less than eight sessions. One third of Haitian and African-American patients attended just one session. Haitian patients who presented with less severe symptoms and dysfunction were more likely to have single-session treatments. Guideline-adherent treatment for ADHD and depression was less likely for Haitians. Older patients were more likely to receive adequate depression treatment. Haitian youth were relatively underinsured, had more family separations documented, and received Adjustment Disorder diagnoses more often. CONCLUSIONS: Haitian youth use outpatient mental health services in similar proportion to African-American youth and at lower rates than White youth. Guideline-adherent treatment for ADHD and depression is limited by low retention in care for Black youth. Low insurance coverage is likely an important contributor to reduced use of services, especially for Haitians. These findings are discussed in the context of providing culturally sensitive mental health care to diverse communities.

Nanoparticle SERS substrates with 3D Raman-active volumes.

This Perspective reviews a new class of surface-enhanced Raman scattering (SERS) nanoparticle substrates defined by their three-dimensional (3D) confinement of localized electromagnetic fields. First, we describe the critical design parameters and recent advances in nanofabrication to create reproducible nanoparticle assemblies for SERS. Next, we highlight a promising platform-gold nanopyramids-for testing how the local arrangement of particles in an assembly affects the overall SERS response. The dimensions and optical properties of the nanopyramids can be tuned easily, and their unique anisotropic shape allows them to be organized into different particle configurations with 3D Raman-active volumes. Because of their large hot-spot volumes, this unique class of nanoparticle substrates offers an attractive alternative for ultra-sensitive sensors and trace chemical analysis.

Using the angle-dependent resonances of molded plasmonic crystals to improve the sensitivities of biosensors.

This paper describes how angle-dependent resonances from molded plasmonic crystals can be used to improve real-time biosensing. First, an inexpensive and massively parallel approach to create single-use, two-dimensional metal nanopyramidal gratings was developed. Second, although constant in bulk dielectric environments, the sensitivities (resonance wavelength shift and resonance width) of plasmonic crystals to adsorbed molecular layers of varying thickness were found to depend on incident excitation angle. Third, protein binding at dilute concentrations of protein was carried out at an angle that optimized the signal to noise of our plasmonic sensing platform. This angle-dependent sensitivity, which is intrinsic to grating-based sensors, is a critical parameter that can assist in maximizing signal to noise.

Optical Properties of Nested Pyramidal Nanoshells.

This paper describes the fabrication and characterization of nested Au pyramidal nanoshells. These particles exhibited two plasmon resonances at visible and near-infrared wavelengths that could be manipulated depending on the size of the gap between inner and outer pyramidal shells. We found that larger gaps (30 nm) exhibited much larger Raman scattering responses compared to smaller gaps (5 nm) in the nested pyramidal shells. The SERS-activity of these anisotropic particles can be optimized by adjusting the distances between the inner and outer Au shells.

Gold Nanopyramids Assembled into High-Order Stacks Exhibit Increased SERS Response.

This Letter describes how gold pyramidal nanoshells (nanopyramids) can be assembled into low- and high-order structures by varying the rate of solvent evaporation and surface wettability. Single-particle and individual-cluster dark field scattering spectra on isolated, dimers and trimers of nanopyramids were compared. We found that the short wavelength resonances blue-shifted as the particles assembled; the magnitude of this shift was greater for high-order structures. To test which assembled architecture supported a larger Raman-active volume, we compared their surface enhanced Raman scattering (SERS) response of the resonant Raman molecule methylene blue (λ(ex) = 633 nm). We discovered that high-order structures exhibited more Raman scattering compared to low-order assemblies. Finite-difference time-domain modeling of nanopyramid assemblies revealed that the highest electromagnetic field intensities were localized between adjacent particle faces, a result that was consistent with the SERS observations. Thus, the local spatial arrangement of the same number of nanoparticles in assembled clusters is an important design parameter for optimizing nanoparticle-based SERS sensors.

Pathways and correlates connecting Latinos' mental health with exposure to the United States.

OBJECTIVES: We examined potential pathways by which time in the United States may relate to differences in the predicted probability of past-year psychiatric disorder among Latino immigrants as compared with US-born Latinos. METHODS: We estimated predicted probabilities of psychiatric disorder for US-born and immigrant groups with varying time in the United States, adjusting for different combinations of covariates. We examined 6 pathways by which time in the United States could be associated with psychiatric disorders. RESULTS: Increased time in the United States is associated with higher risk of psychiatric disorders among Latino immigrants. After adjustment for covariates, differences in psychiatric disorder rates between US-born and immigrant Latinos disappear. Discrimination and family cultural conflict appear to play a significant role in the association between time in the United States and the likelihood of developing psychiatric disorders. CONCLUSIONS: Increased perceived discrimination and family cultural conflict are pathways by which acculturation might relate to deterioration of mental health for immigrants. Future studies assessing how these implicit pathways evolve as contact with US culture increases may help to identify strategies for ensuring maintenance of mental health for Latino immigrants.

Mediation analysis with principal stratification.

In assessing the mechanism of treatment efficacy in randomized clinical trials, investigators often perform mediation analyses by analyzing if the significant intent-to-treat treatment effect on outcome occurs through or around a third intermediate or mediating variable: indirect and direct effects, respectively. Standard mediation analyses assume sequential ignorability, i.e. conditional on covariates the intermediate or mediating factor is randomly assigned, as is the treatment in a randomized clinical trial. This research focuses on the application of the principal stratification (PS) approach for estimating the direct effect of a randomized treatment but without the standard sequential ignorability assumption. This approach is used to estimate the direct effect of treatment as a difference between expectations of potential outcomes within latent subgroups of participants for whom the intermediate variable behavior would be constant, regardless of the randomized treatment assignment. Using a Bayesian estimation procedure, we also assess the sensitivity of results based on the PS approach to heterogeneity of the variances among these principal strata. We assess this approach with simulations and apply it to two psychiatric examples. Both examples and the simulations indicated robustness of our findings to the homogeneous variance assumption. However, simulations showed that the magnitude of treatment effects derived under the PS approach were sensitive to model mis-specification.

Nested Markov compliance class model in the presence of time-varying noncompliance.

SUMMARY: We consider a Markov structure for partially unobserved time-varying compliance classes in the Imbens-Rubin (1997, The Annals of Statistics 25, 305-327) compliance model framework. The context is a longitudinal randomized intervention study where subjects are randomized once at baseline, outcomes and patient adherence are measured at multiple follow-ups, and patient adherence to their randomized treatment could vary over time. We propose a nested latent compliance class model where we use time-invariant subject-specific compliance principal strata to summarize longitudinal trends of subject-specific time-varying compliance patterns. The principal strata are formed using Markov models that relate current compliance behavior to compliance history. Treatment effects are estimated as intent-to-treat effects within the compliance principal strata.

Disparities in defining disparities: statistical conceptual frameworks.

Motivated by the need to meaningfully implement the Institute of Medicine's (IOM's) definition of health care disparity, this paper proposes statistical frameworks that lay out explicitly the needed causal assumptions for defining disparity measures. Our key emphasis is that a scientifically defensible disparity measure must take into account the direction of the causal relationship between allowable covariates that are not considered to be contributors to disparity and non-allowable covariates that are considered to be contributors to disparity, to avoid flawed disparity measures based on implausible populations that are not relevant for clinical or policy decisions. However, these causal relationships are usually unknown and undetectable from observed data. Consequently, we must make strong causal assumptions in order to proceed. Two frameworks are proposed in this paper, one is the conditional disparity framework under the assumption that allowable covariates impact non-allowable covariates but not vice versa. The other is the marginal disparity framework under the assumption that non-allowable covariates impact allowable ones but not vice versa. We establish theoretical conditions under which the two disparity measures are the same and present a theoretical example showing that the difference between the two disparity measures can be arbitrarily large. Using data from the Collaborative Psychiatric Epidemiology Survey, we also provide an example where the conditional disparity is misled by Simpson's paradox, whereas the marginal disparity approach handles it correctly.

Family Cohesion and its Relationship to Psychological Distress among Latino Groups.

This paper presents analyses of a representative sample of US Latinos (N=2540) to investigate whether family cohesion moderates the effects of cultural conflict on psychological distress. The results for the aggregated Latino group suggests a significant association between family cohesion and lower psychological distress and the combination of strong family cohesion with presence of family cultural conflict was associated with higher psychological distress. However, this association differed by Latino groups. We found no association for Puerto Ricans, Cuban results were similar to the aggregate group, family cultural conflict in Mexicans was associated with higher psychological distress, while family cohesion in Other Latinos was associated with higher psychological distress. Implications of these findings are discussed to unravel the differences in family dynamics across Latino subethnic groups.