Assuming squared error loss, we show that finding unbiased estimators and Bayes estimators can be... more Assuming squared error loss, we show that finding unbiased estimators and Bayes estimators can be treated as using a pair of linear operators that operate between two Hilbert spaces. We note that these integral operators are adjoint and then investigate some consequences of this fact.
Background. Dimension reduction methods do not always reduce their underlying indicators to a sin... more Background. Dimension reduction methods do not always reduce their underlying indicators to a single dimension. Furthermore, such methods are usually based on optimality criteria that require discarding some information. The joint probability density functions (joint pdf or JPD) can be considered as unidimensional indices. We compare such JPD indices with some traditional scoring methods.Methods. We introduced unidirectionality and co-directionality as basic requirements for a joint pdf to become an index. we then provided an argument to demonstrate its maximal informativeness property. Using all possible joint pdf conditional specifications, we estimated the JPD index. We then applied the method to two data sets: first, on the 7 Brief Pain Inventory Interference scale (BPI-I) items obtained from 8,889 US Veterans with chronic pain and, second, on a novel measure based on administrative data, the Manifestations of Psychiatric Severity Index (MoPSI), for 912 US Veterans who had appli...
Quality improvement professionals have to decide whether a change has led to improvement. This is... more Quality improvement professionals have to decide whether a change has led to improvement. This is typically done through testing the statistical significance of the findings. In this article, we explore controversies surrounding statistical significance testing with attention to contemporary criticism of bad practice resulting from the misuse of statistical significance testing. Most statistical significance tests use tests (eg, F, χ 2) with known distributions with the P values used as the main evidence to evaluate whether tests are statistically significant. The primary conclusion of this article is that the P value alone as a measure of statistical significance does not give sufficient information about testing of hypotheses. When it is coupled with other measures, however, such as the point estimation of the effect size and the use of a confidence interval around it, the combination of these statistics can provide a more thorough explanation of statistical testing. This article offers recommendations for process improvement investigators as to when to appropriately apply and not to apply statistical significance testing.
Observational studies assessing causal or non-causal relationships between an explanatory measure... more Observational studies assessing causal or non-causal relationships between an explanatory measure and an outcome can be complicated by hosts of confounding measures. Large numbers of confounders can lead to several biases in conventional regression based estimation. Inference is more easily conducted if we reduce the number of confounders to a more manageable number. We discuss use of sufficient dimension reduction (SDR) summaries in estimating covariate balanced comparisons among multiple populations. SDR theory is related to the dimension reduction considered in regression theory. SDR summaries share much with sufficient statistics and encompass propensities. A specific type of SDR summary can wholly replace the original covariates with no loss of information or efficiency. Estimators with minimal expected loss can be based on these SDR summaries rather than all of the covariates.
A simple geometric representation of Bayes and unbiased rules for squared error loss is provided.... more A simple geometric representation of Bayes and unbiased rules for squared error loss is provided. Some orthogonality relationships between them and the functions they are estimating are proved. Bayes estimators are shown to be behave asymptotically like unbiased estimators.
medRxiv (Cold Spring Harbor Laboratory), Jul 12, 2023
doi: medRxiv preprint NOTE: This preprint reports new research that has not been certified by pee... more doi: medRxiv preprint NOTE: This preprint reports new research that has not been certified by peer review and should not be used to guide clinical practice.
Background: Informative response/non-response bias in survey research may skew effect size estima... more Background: Informative response/non-response bias in survey research may skew effect size estimates; however, an upper limit of tolerable bias has not been established.Objective: To use simple back-of-the-envelope calculations to estimate how much informative response/non-response bias can be introduced into a survey effort before parameter coverage is lost. Methods: We assigned attributes of military combat or sexual trauma exposure and of having/not having disability benefits for posttraumatic stress disorder (“service connection”) to a simulated population of 20,000 “Veterans.” We calculated true associations between combat and service connection and between military sexual trauma and service connection using 2X2 contingency tables and odds ratios. We simulated response/non-response bias by systematically increasing or decreasing individual cells of the 2X2 contingency tables by a factor of t between 1.01 and 2.00 (equivalent to introducing bias between 1% to 100%) across several sample sizes. We calculated new odds ratios and 95% confidence intervals for each biased contingency table, as well as the maximum possible bias for 13 response/non-response mechanisms.Results: Depending on the cell being manipulated, maximum possible response/nonresponse bias for the association between combat and service connection ranged from 10 to 260 percentage points and for the association between military sexual assault and service connection, 4 to 2,334 percentage points. For larger sample sizes (e.g., 1,000 -3,000), biases as small as 3 to 7 percentage points resulted in 95% confidence intervals that excluded the true odds ratio for some response/non-response mechanisms. Other mechanisms permitted bias of as much as 60 percentage points before parameter coverage was lost. Conclusions: Depending on which cell(s) in a 2X2 contingency table is affected, even small amounts of response/non-response bias can skew results to the point that 95% confidence intervals exclude the true odds ratio. Back-of-the-envelope techniques could help investigators identify and plan for high-risk scenarios.
Objective. To assess colorectal cancer (CRC) screening mode preferences and correlates of these p... more Objective. To assess colorectal cancer (CRC) screening mode preferences and correlates of these preferences among US veterans at average risk for CRC. Method. A cross-sectional survey of a nationally representative sample of VA patients was conducted between January 2005 and December 2006. We report preference distributions for screening modes among 2068 average-risk veterans and across patient subgroups based on personal, behavioral, and environmental factors. Independent predictors of preferences are identified through hierarchical logistic regression models. Results. Colonoscopy (37%) was the most preferred mode followed by fecal occult blood test (FOBT) (29%). The strongest predictors of preferences were previous screening experience, provider recommendation, and use of non-VA healthcare services. Participants in higher socioeconomic groups were more likely to choose colonoscopy and less likely to indicate no preference. Conclusion. Screening programs that offer only one mode fail to accommodate the preferences of a substantial proportion of patients. Within the VA, adding screening colonoscopy to programs currently offering only FOBT is likely to increase preferences for colonoscopy, as patients incorporate provider recommendations for and personal experience with colonoscopy into their preferences. This is likely to disproportionately benefit lower socioeconomic groups who do not currently have access to non-VA colonoscopy services. Published by Elsevier Inc.
Evidence-based psychotherapies for posttraumatic stress disorder (PTSD), such as cognitive proces... more Evidence-based psychotherapies for posttraumatic stress disorder (PTSD), such as cognitive processing therapy and prolonged exposure (CPT/PE), greatly reduce suffering for veterans, but many veterans fail to complete treatment. Developing a theory-based understanding of adherence is necessary to inform interventions to improve treatment retention. We developed and tested a series of scales applying the theory of planned behavior (TPB) to CPT/PE adherence. The scales were administered in mailed surveys as part of a larger mixedmethods study of veteran adherence to PE/CPT. Surveys were sent to 379 veterans who were initiating CPT/PE across four U.S. Veterans Affairs (VA) hospitals and 207 of their loved ones. Subsequent session attendance and homework compliance were coded via a review of electronic medical records. We examined item-level characteristics, factor structure, and the convergent and discriminant validity of the resultant scales. The findings support four subscales: two related to attitudes (i.e., Treatment Makes Sense and Treatment Fits Needs), one related to perceived behavioral control over participation (i.e., Participation Control), and one related to perceived family attitudes about CPT/PE participation (i.e., Subjective Norms). Scale validity was supported through significant associations with theoretically relevant constructs, including intentions to persist in CPT/PE, rs = .19-.38; treatment completion, rs = .21-.25; practical treatment barriers, rs = −.19 to −.24; and therapeutic alliance, rs = .39-.57. Cognitive behavioral, trauma-focused therapies for posttraumatic stress disorder (PTSD), such as prolonged exposure
We examined the interrelationships between and contributions of background, cognitive, and enviro... more We examined the interrelationships between and contributions of background, cognitive, and environmental factors to colorectal cancer (CRC) screening adherence. In this study, 2,416 average risk patients aged 50-75 from 24 Veterans Affairs medical facilities responded to a mailed survey with phone follow-up (response rate 81%). Survey data (attitudes, behaviors, demographics) were linked to facility (organizational complexity) and medical records data (diagnoses, screening history). Patients with a fecal occult blood test within 15 months, sigmoidoscopy or barium enema within 5.5 years, or colonoscopy within 11 years of the survey were considered adherent. Logistic regressions estimated the association between adherence and background, cognitive, and environmental factors. Deviance ratios examined interrelationships between factors. Population attributable risks (PAR) were used to identify intervention targets. The association of background factors with adherence was partially explained by cognitive and environmental factors. The association of environmental factors with adherence was partially explained by cognitive factors. Cognitive and environmental factors contributed equally to adherence. Factors with the highest PARs for non-adherence were age 50-64, less than two comorbidities, and lack of physician recommendation. Efforts to increase physician screening recommendations for younger, healthy patients at facilities with the lowest screening rates may improve CRC adherence in this setting.
Description of the condition Rheumatoid arthritis (RA) is an autoimmune disease characterized by ... more Description of the condition Rheumatoid arthritis (RA) is an autoimmune disease characterized by systemic inflammation (Lee 2001; Szekanecz 2007). The prevalence of RA has been estimated to be 0.5% to 1.0% in the Western world (Helmick 2008; Kvien 2004). RA often presents with signs and symptoms of joint pain, swelling, tenderness and stiffness, and joint deformities, which are due to the inflammation of the synovial lining of the joints, tendons and periarticular structures (Lee 2001). RA also leads to systemic inflammation characterized by premature atherosclerotic disease and other inflammatory se-quelae such as interstitial lung disease, pneumonitis, mononeuritis multiplex, subcutaneous nodules and vasculitis (Ku 2009; Prete 2011; Snow 2005). RA can lead to joint destruction, and has a significant impact on health-related quality of life (HRQoL) (Kvien 2005; Lubeck 2004). RA can lead to severe functional limitation and short-and long-term disability (
Functional Magnetic Resonance Imaging (fMRI) is a fundamental tool in advancing our understanding... more Functional Magnetic Resonance Imaging (fMRI) is a fundamental tool in advancing our understanding of the brain's functionality. Recently, a series of Bayesian approaches have been suggested to test for the voxel activation in different brain regions. In this paper, we propose a novel definition for the global Bayes factor to test for activation using the Radon-Nikodym derivative. Our proposed method extends the definition of Bayes factor to an infinite dimensional Hilbert space. Using this extended definition, a Bayesian testing procedure is introduced for signal detection in noisy images when both signal and noise are considered as an element of an infinite dimensional Hilbert space. This new approach is illustrated through a real data analysis to find activated areas of Brain in an fMRI data.
Veterans Health Administration (VHA) patients with substance use disorder (SUD) diagnoses incur s... more Veterans Health Administration (VHA) patients with substance use disorder (SUD) diagnoses incur significantly higher overall health care costs compared to the average annual costs of VHA patients. Because SUDs are relapsing/remitting chronic illnesses, it is important to understand how service costs shift over time in relation to active SUD treatment episodes in order to identify strategies which may enhance treatment outcomes and thereby reduce costs. The primary aim of the current study was to examine VHA health care costs derived from VHA administrative data for 330 Veterans during the years prior to and following patient entry into outpatient SUD treatment in two VHA facilities. Secondary aims were to examine the impact on treatment costs of patient diagnosis (alcohol dependence only vs. stimulant dependence) and participation in an abstinence incentive intervention. There was a significant effect of time on health care costs (p b 0.001).
Introduction: Female veterans smoke cigarettes at high rates compared with both male veterans and... more Introduction: Female veterans smoke cigarettes at high rates compared with both male veterans and nonveteran women. Proactive outreach to smokers may reduce gender disparities in cessation care. The objectives of this study were to compare baseline experiences with VA smoking cessation care for men and women and to assess for gender differences in response to a proactive outreach intervention. Methods: We conducted a post hoc subgroup analysis of a pragmatic, multisite randomized, controlled trial comparing proactive outreach with usual care (UC). Baseline experiences included physician advice to quit, satisfaction with care, and past-year treatment use. At the 1-year follow-up, treatment use, quit attempts, and 6-month prolonged abstinence for women and men randomized to proactive outreach versus UC were compared using logistic regression. Results: Baseline and follow-up surveys were returned by 138 women and 2,516 men. At baseline, women were less likely than men to report being very or somewhat satisfied with the process of obtaining smoking cessation medications in the VA (47% of women vs. 62% of men), but no less likely to report having used cessation medications from the VA in the past year (39% of women vs. 34% of men). After the intervention, phone counseling and combined therapy increased among both women and men in proactive outreach as compared with UC. At the 1-year follow-up, men in proactive outreach were significantly more likely to report prolonged abstinence than those in UC (odds ratio, 1.65; 95% CI, 1.28-2.14); results for women were in the same direction but not statistically significant (odds ratio, 1.39; 95% CI, 0.48-3.99). Conclusions: Satisfaction with cessation care in VA remains low. Proactive outreach to smokers was associated with an increased use of cessation therapies, and increased odds of achieving prolonged abstinence. A subgroup analysis by gender did not reveal significant differences in the treatment effect.
Posttraumatic stress disorder (PTSD) is the most prevalent psychiatric condition for which vetera... more Posttraumatic stress disorder (PTSD) is the most prevalent psychiatric condition for which veterans receive service-connected disability benefits from the U.S. Department of Veterans Affairs (VA). Historically, women have been less likely than men to obtain PTSD disability benefits. The authors examined whether these gender disparities have been redressed over time and, if not, whether appropriate clinical factors account for persisting differences. This longitudinal, observational study was based on a gender-stratified, nationally representative sample of 2,998 U.S. veterans who applied for VA disability benefits for PTSD between 1994 and 1998. The primary outcome was change in PTSD service connection over a ten-year period. Forty-two percent (95% confidence interval [CI]=38%-45%) of the women and 50% (CI=45%-55%) of the men originally denied service connection for PTSD eventually received such benefits. Only 8% (CI=7%-10%) of women and 5% (CI=4%-6%) of men lost PTSD disability status. Compared with men, women had lower unadjusted odds of gaining PTSD service connection (odds ratio [OR]=.70, CI=.55-.90) and greater unadjusted odds of losing PTSD service connection (OR=1.76, CI=1.21-2.57). Adjusting for clinical factors accounted for the gender difference in gaining PTSD service connection; adjusting for clinical factors and demographic characteristics eliminated the gender difference in loss of PTSD service connection. Gender-based differences in receipt of PTSD service connection persisted in this cohort over a ten-year period but were explained by appropriate sources of variation. Further research on possible disparities in loss of PTSD disability benefits is warranted.
The location of acute ischemic infarct can affect the clinical outcome of stroke patients. We aim... more The location of acute ischemic infarct can affect the clinical outcome of stroke patients. We aimed to develop a prognostic tool based on the topographic distribution of early ischemic changes on admission computed tomography (CT) scans. Using the albumin in acute stroke (ALIAS) trials dataset, patients with anterior circulation stroke were included for analysis. A 3-month modified Rankin scale (mRs) score > 2 defined disability/death; and ≤2 defined favorable outcome. A penalized logistic regression determined independent predictors of disability/death among components of admission CT scan Alberta Stroke Program Early CT score (ASPECTS). Follow-up 24-hour CT/MRI scans were reviewed for intracranial hemorrhage (ICH). A simplified ASPECTS (sASPECTS) was developed including the caudate, lentiform nucleus, insula, and M5 components of ASPECTS-which were independent predictors of disability/death on multivariate analysis. There was no significant difference between ASPECTS and sASPECTS in prediction of disability/death (P = .738). Among patients with sASPECTS ≥ 1, the rate of favorable outcome was higher in those with intravenous (IV) thrombolytic therapy (501/837, 59.9%) versus those without treatment (91/183, 49.7%, P = .013); whereas among patients with sASPECTS of 0, IV thrombolysis was not associated with improved outcome. Also, patients with sASPECTS of 0 were more likely to develop symptomatic ICH (odds ratio = 2.62, 95% confidence interval: 1.49-4.62), compared to those with sASPECTS ≥ 1 (P = .004). Topographic assessment of acute ischemic changes using the sASPECTS (including caudate, lentiform nucleus, insula, and M5) can predict disability/death in anterior circulation stroke as accurately as the ASPECTS; and may help predict response to treatment and risk of developing symptomatic ICH.
Assuming squared error loss, we show that finding unbiased estimators and Bayes estimators can be... more Assuming squared error loss, we show that finding unbiased estimators and Bayes estimators can be treated as using a pair of linear operators that operate between two Hilbert spaces. We note that these integral operators are adjoint and then investigate some consequences of this fact.
Background. Dimension reduction methods do not always reduce their underlying indicators to a sin... more Background. Dimension reduction methods do not always reduce their underlying indicators to a single dimension. Furthermore, such methods are usually based on optimality criteria that require discarding some information. The joint probability density functions (joint pdf or JPD) can be considered as unidimensional indices. We compare such JPD indices with some traditional scoring methods.Methods. We introduced unidirectionality and co-directionality as basic requirements for a joint pdf to become an index. we then provided an argument to demonstrate its maximal informativeness property. Using all possible joint pdf conditional specifications, we estimated the JPD index. We then applied the method to two data sets: first, on the 7 Brief Pain Inventory Interference scale (BPI-I) items obtained from 8,889 US Veterans with chronic pain and, second, on a novel measure based on administrative data, the Manifestations of Psychiatric Severity Index (MoPSI), for 912 US Veterans who had appli...
Quality improvement professionals have to decide whether a change has led to improvement. This is... more Quality improvement professionals have to decide whether a change has led to improvement. This is typically done through testing the statistical significance of the findings. In this article, we explore controversies surrounding statistical significance testing with attention to contemporary criticism of bad practice resulting from the misuse of statistical significance testing. Most statistical significance tests use tests (eg, F, χ 2) with known distributions with the P values used as the main evidence to evaluate whether tests are statistically significant. The primary conclusion of this article is that the P value alone as a measure of statistical significance does not give sufficient information about testing of hypotheses. When it is coupled with other measures, however, such as the point estimation of the effect size and the use of a confidence interval around it, the combination of these statistics can provide a more thorough explanation of statistical testing. This article offers recommendations for process improvement investigators as to when to appropriately apply and not to apply statistical significance testing.
Observational studies assessing causal or non-causal relationships between an explanatory measure... more Observational studies assessing causal or non-causal relationships between an explanatory measure and an outcome can be complicated by hosts of confounding measures. Large numbers of confounders can lead to several biases in conventional regression based estimation. Inference is more easily conducted if we reduce the number of confounders to a more manageable number. We discuss use of sufficient dimension reduction (SDR) summaries in estimating covariate balanced comparisons among multiple populations. SDR theory is related to the dimension reduction considered in regression theory. SDR summaries share much with sufficient statistics and encompass propensities. A specific type of SDR summary can wholly replace the original covariates with no loss of information or efficiency. Estimators with minimal expected loss can be based on these SDR summaries rather than all of the covariates.
A simple geometric representation of Bayes and unbiased rules for squared error loss is provided.... more A simple geometric representation of Bayes and unbiased rules for squared error loss is provided. Some orthogonality relationships between them and the functions they are estimating are proved. Bayes estimators are shown to be behave asymptotically like unbiased estimators.
medRxiv (Cold Spring Harbor Laboratory), Jul 12, 2023
doi: medRxiv preprint NOTE: This preprint reports new research that has not been certified by pee... more doi: medRxiv preprint NOTE: This preprint reports new research that has not been certified by peer review and should not be used to guide clinical practice.
Background: Informative response/non-response bias in survey research may skew effect size estima... more Background: Informative response/non-response bias in survey research may skew effect size estimates; however, an upper limit of tolerable bias has not been established.Objective: To use simple back-of-the-envelope calculations to estimate how much informative response/non-response bias can be introduced into a survey effort before parameter coverage is lost. Methods: We assigned attributes of military combat or sexual trauma exposure and of having/not having disability benefits for posttraumatic stress disorder (“service connection”) to a simulated population of 20,000 “Veterans.” We calculated true associations between combat and service connection and between military sexual trauma and service connection using 2X2 contingency tables and odds ratios. We simulated response/non-response bias by systematically increasing or decreasing individual cells of the 2X2 contingency tables by a factor of t between 1.01 and 2.00 (equivalent to introducing bias between 1% to 100%) across several sample sizes. We calculated new odds ratios and 95% confidence intervals for each biased contingency table, as well as the maximum possible bias for 13 response/non-response mechanisms.Results: Depending on the cell being manipulated, maximum possible response/nonresponse bias for the association between combat and service connection ranged from 10 to 260 percentage points and for the association between military sexual assault and service connection, 4 to 2,334 percentage points. For larger sample sizes (e.g., 1,000 -3,000), biases as small as 3 to 7 percentage points resulted in 95% confidence intervals that excluded the true odds ratio for some response/non-response mechanisms. Other mechanisms permitted bias of as much as 60 percentage points before parameter coverage was lost. Conclusions: Depending on which cell(s) in a 2X2 contingency table is affected, even small amounts of response/non-response bias can skew results to the point that 95% confidence intervals exclude the true odds ratio. Back-of-the-envelope techniques could help investigators identify and plan for high-risk scenarios.
Objective. To assess colorectal cancer (CRC) screening mode preferences and correlates of these p... more Objective. To assess colorectal cancer (CRC) screening mode preferences and correlates of these preferences among US veterans at average risk for CRC. Method. A cross-sectional survey of a nationally representative sample of VA patients was conducted between January 2005 and December 2006. We report preference distributions for screening modes among 2068 average-risk veterans and across patient subgroups based on personal, behavioral, and environmental factors. Independent predictors of preferences are identified through hierarchical logistic regression models. Results. Colonoscopy (37%) was the most preferred mode followed by fecal occult blood test (FOBT) (29%). The strongest predictors of preferences were previous screening experience, provider recommendation, and use of non-VA healthcare services. Participants in higher socioeconomic groups were more likely to choose colonoscopy and less likely to indicate no preference. Conclusion. Screening programs that offer only one mode fail to accommodate the preferences of a substantial proportion of patients. Within the VA, adding screening colonoscopy to programs currently offering only FOBT is likely to increase preferences for colonoscopy, as patients incorporate provider recommendations for and personal experience with colonoscopy into their preferences. This is likely to disproportionately benefit lower socioeconomic groups who do not currently have access to non-VA colonoscopy services. Published by Elsevier Inc.
Evidence-based psychotherapies for posttraumatic stress disorder (PTSD), such as cognitive proces... more Evidence-based psychotherapies for posttraumatic stress disorder (PTSD), such as cognitive processing therapy and prolonged exposure (CPT/PE), greatly reduce suffering for veterans, but many veterans fail to complete treatment. Developing a theory-based understanding of adherence is necessary to inform interventions to improve treatment retention. We developed and tested a series of scales applying the theory of planned behavior (TPB) to CPT/PE adherence. The scales were administered in mailed surveys as part of a larger mixedmethods study of veteran adherence to PE/CPT. Surveys were sent to 379 veterans who were initiating CPT/PE across four U.S. Veterans Affairs (VA) hospitals and 207 of their loved ones. Subsequent session attendance and homework compliance were coded via a review of electronic medical records. We examined item-level characteristics, factor structure, and the convergent and discriminant validity of the resultant scales. The findings support four subscales: two related to attitudes (i.e., Treatment Makes Sense and Treatment Fits Needs), one related to perceived behavioral control over participation (i.e., Participation Control), and one related to perceived family attitudes about CPT/PE participation (i.e., Subjective Norms). Scale validity was supported through significant associations with theoretically relevant constructs, including intentions to persist in CPT/PE, rs = .19-.38; treatment completion, rs = .21-.25; practical treatment barriers, rs = −.19 to −.24; and therapeutic alliance, rs = .39-.57. Cognitive behavioral, trauma-focused therapies for posttraumatic stress disorder (PTSD), such as prolonged exposure
We examined the interrelationships between and contributions of background, cognitive, and enviro... more We examined the interrelationships between and contributions of background, cognitive, and environmental factors to colorectal cancer (CRC) screening adherence. In this study, 2,416 average risk patients aged 50-75 from 24 Veterans Affairs medical facilities responded to a mailed survey with phone follow-up (response rate 81%). Survey data (attitudes, behaviors, demographics) were linked to facility (organizational complexity) and medical records data (diagnoses, screening history). Patients with a fecal occult blood test within 15 months, sigmoidoscopy or barium enema within 5.5 years, or colonoscopy within 11 years of the survey were considered adherent. Logistic regressions estimated the association between adherence and background, cognitive, and environmental factors. Deviance ratios examined interrelationships between factors. Population attributable risks (PAR) were used to identify intervention targets. The association of background factors with adherence was partially explained by cognitive and environmental factors. The association of environmental factors with adherence was partially explained by cognitive factors. Cognitive and environmental factors contributed equally to adherence. Factors with the highest PARs for non-adherence were age 50-64, less than two comorbidities, and lack of physician recommendation. Efforts to increase physician screening recommendations for younger, healthy patients at facilities with the lowest screening rates may improve CRC adherence in this setting.
Description of the condition Rheumatoid arthritis (RA) is an autoimmune disease characterized by ... more Description of the condition Rheumatoid arthritis (RA) is an autoimmune disease characterized by systemic inflammation (Lee 2001; Szekanecz 2007). The prevalence of RA has been estimated to be 0.5% to 1.0% in the Western world (Helmick 2008; Kvien 2004). RA often presents with signs and symptoms of joint pain, swelling, tenderness and stiffness, and joint deformities, which are due to the inflammation of the synovial lining of the joints, tendons and periarticular structures (Lee 2001). RA also leads to systemic inflammation characterized by premature atherosclerotic disease and other inflammatory se-quelae such as interstitial lung disease, pneumonitis, mononeuritis multiplex, subcutaneous nodules and vasculitis (Ku 2009; Prete 2011; Snow 2005). RA can lead to joint destruction, and has a significant impact on health-related quality of life (HRQoL) (Kvien 2005; Lubeck 2004). RA can lead to severe functional limitation and short-and long-term disability (
Functional Magnetic Resonance Imaging (fMRI) is a fundamental tool in advancing our understanding... more Functional Magnetic Resonance Imaging (fMRI) is a fundamental tool in advancing our understanding of the brain's functionality. Recently, a series of Bayesian approaches have been suggested to test for the voxel activation in different brain regions. In this paper, we propose a novel definition for the global Bayes factor to test for activation using the Radon-Nikodym derivative. Our proposed method extends the definition of Bayes factor to an infinite dimensional Hilbert space. Using this extended definition, a Bayesian testing procedure is introduced for signal detection in noisy images when both signal and noise are considered as an element of an infinite dimensional Hilbert space. This new approach is illustrated through a real data analysis to find activated areas of Brain in an fMRI data.
Veterans Health Administration (VHA) patients with substance use disorder (SUD) diagnoses incur s... more Veterans Health Administration (VHA) patients with substance use disorder (SUD) diagnoses incur significantly higher overall health care costs compared to the average annual costs of VHA patients. Because SUDs are relapsing/remitting chronic illnesses, it is important to understand how service costs shift over time in relation to active SUD treatment episodes in order to identify strategies which may enhance treatment outcomes and thereby reduce costs. The primary aim of the current study was to examine VHA health care costs derived from VHA administrative data for 330 Veterans during the years prior to and following patient entry into outpatient SUD treatment in two VHA facilities. Secondary aims were to examine the impact on treatment costs of patient diagnosis (alcohol dependence only vs. stimulant dependence) and participation in an abstinence incentive intervention. There was a significant effect of time on health care costs (p b 0.001).
Introduction: Female veterans smoke cigarettes at high rates compared with both male veterans and... more Introduction: Female veterans smoke cigarettes at high rates compared with both male veterans and nonveteran women. Proactive outreach to smokers may reduce gender disparities in cessation care. The objectives of this study were to compare baseline experiences with VA smoking cessation care for men and women and to assess for gender differences in response to a proactive outreach intervention. Methods: We conducted a post hoc subgroup analysis of a pragmatic, multisite randomized, controlled trial comparing proactive outreach with usual care (UC). Baseline experiences included physician advice to quit, satisfaction with care, and past-year treatment use. At the 1-year follow-up, treatment use, quit attempts, and 6-month prolonged abstinence for women and men randomized to proactive outreach versus UC were compared using logistic regression. Results: Baseline and follow-up surveys were returned by 138 women and 2,516 men. At baseline, women were less likely than men to report being very or somewhat satisfied with the process of obtaining smoking cessation medications in the VA (47% of women vs. 62% of men), but no less likely to report having used cessation medications from the VA in the past year (39% of women vs. 34% of men). After the intervention, phone counseling and combined therapy increased among both women and men in proactive outreach as compared with UC. At the 1-year follow-up, men in proactive outreach were significantly more likely to report prolonged abstinence than those in UC (odds ratio, 1.65; 95% CI, 1.28-2.14); results for women were in the same direction but not statistically significant (odds ratio, 1.39; 95% CI, 0.48-3.99). Conclusions: Satisfaction with cessation care in VA remains low. Proactive outreach to smokers was associated with an increased use of cessation therapies, and increased odds of achieving prolonged abstinence. A subgroup analysis by gender did not reveal significant differences in the treatment effect.
Posttraumatic stress disorder (PTSD) is the most prevalent psychiatric condition for which vetera... more Posttraumatic stress disorder (PTSD) is the most prevalent psychiatric condition for which veterans receive service-connected disability benefits from the U.S. Department of Veterans Affairs (VA). Historically, women have been less likely than men to obtain PTSD disability benefits. The authors examined whether these gender disparities have been redressed over time and, if not, whether appropriate clinical factors account for persisting differences. This longitudinal, observational study was based on a gender-stratified, nationally representative sample of 2,998 U.S. veterans who applied for VA disability benefits for PTSD between 1994 and 1998. The primary outcome was change in PTSD service connection over a ten-year period. Forty-two percent (95% confidence interval [CI]=38%-45%) of the women and 50% (CI=45%-55%) of the men originally denied service connection for PTSD eventually received such benefits. Only 8% (CI=7%-10%) of women and 5% (CI=4%-6%) of men lost PTSD disability status. Compared with men, women had lower unadjusted odds of gaining PTSD service connection (odds ratio [OR]=.70, CI=.55-.90) and greater unadjusted odds of losing PTSD service connection (OR=1.76, CI=1.21-2.57). Adjusting for clinical factors accounted for the gender difference in gaining PTSD service connection; adjusting for clinical factors and demographic characteristics eliminated the gender difference in loss of PTSD service connection. Gender-based differences in receipt of PTSD service connection persisted in this cohort over a ten-year period but were explained by appropriate sources of variation. Further research on possible disparities in loss of PTSD disability benefits is warranted.
The location of acute ischemic infarct can affect the clinical outcome of stroke patients. We aim... more The location of acute ischemic infarct can affect the clinical outcome of stroke patients. We aimed to develop a prognostic tool based on the topographic distribution of early ischemic changes on admission computed tomography (CT) scans. Using the albumin in acute stroke (ALIAS) trials dataset, patients with anterior circulation stroke were included for analysis. A 3-month modified Rankin scale (mRs) score > 2 defined disability/death; and ≤2 defined favorable outcome. A penalized logistic regression determined independent predictors of disability/death among components of admission CT scan Alberta Stroke Program Early CT score (ASPECTS). Follow-up 24-hour CT/MRI scans were reviewed for intracranial hemorrhage (ICH). A simplified ASPECTS (sASPECTS) was developed including the caudate, lentiform nucleus, insula, and M5 components of ASPECTS-which were independent predictors of disability/death on multivariate analysis. There was no significant difference between ASPECTS and sASPECTS in prediction of disability/death (P = .738). Among patients with sASPECTS ≥ 1, the rate of favorable outcome was higher in those with intravenous (IV) thrombolytic therapy (501/837, 59.9%) versus those without treatment (91/183, 49.7%, P = .013); whereas among patients with sASPECTS of 0, IV thrombolysis was not associated with improved outcome. Also, patients with sASPECTS of 0 were more likely to develop symptomatic ICH (odds ratio = 2.62, 95% confidence interval: 1.49-4.62), compared to those with sASPECTS ≥ 1 (P = .004). Topographic assessment of acute ischemic changes using the sASPECTS (including caudate, lentiform nucleus, insula, and M5) can predict disability/death in anterior circulation stroke as accurately as the ASPECTS; and may help predict response to treatment and risk of developing symptomatic ICH.
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Papers by Siamak Noorbaloochi