US Veterans Health Administration Research Articles

Physicians and Specialties in the Veterans Health Administration’s Community Care Network

This cross-sectional study of data from the US Veterans Health Administration examines the availability of services provided through community care networks by specialty and clinical characteristics.

Needs for Successful Engagement in Telemedicine Among Rural Older US Veterans and Their Caregivers: Qualitative Study.

Telemedicine is an important option for rural older adults who often must travel far distances to clinics or forgo essential care. In 2014, the Geriatric Research, Education, and Clinical Centers (GRECC) of the US Veterans Health Administration (VA) established a national telemedicine network called GRECC Connect. This network increased access to geriatric specialty care for the 1.4 million rural VA-enrolled veterans aged 65 years or older. The use of telemedicine skyrocketed during the COVID-19 pandemic, which disproportionately impacted older adults, exacerbating disparities in specialty care access as overburdened systems shut down in-person services. This surge presented a unique opportunity to study the supports necessary for those who would forgo telemedicine if in-person care were available. In spring 2021, we interviewed veterans and their informal caregivers to (1) elicit their experiences attempting to prepare for a video visit with a GRECC Connect geriatric specialist and (2) explore facilitators and barriers to successful engagement in a telemedicine visit. We conducted a cross-sectional qualitative evaluation with patients and their caregivers who agreed to participate in at least 1 GRECC Connect telemedicine visit in the previous 3 months. A total of 30 participants from 6 geographically diverse GRECC Connect hub sites agreed to participate. Semistructured interviews were conducted through telephone or the VA's videoconference platform for home telemedicine visits (VA Video Connect) per participant preference. We observed challenges and, when needed, provided real-time technical support to facilitate VA Video Connect use for interviews. All interviews were recorded with permission and professionally transcribed. A team of 5 researchers experienced in qualitative research analyzed interview transcripts using rapid qualitative analysis. From 30 participant interviews, we identified the following 4 categories of supports participants described regarding successful engagement in telemedicine, as defined by visit completion, satisfaction, and willingness to engage in telemedicine in the future: (1) caregiver presence to facilitate technology setup and communication; (2) flexibility in visit modality (eg, video from home or a clinic or telephone); (3) technology support (eg, determining device compatibility or providing instruction and on-demand assistance); and (4) assurance of comfort with web-based communication, including orientation to features like closed captioning. Supports were needed at multiple points before the visit, and participants stressed the importance of eliciting the varying needs and preferences of each patient-caregiver dyad. Though many initially agreed to a telemedicine visit because of pandemic-related clinic closures, participants were satisfied with telemedicine and willing to use it for other types of health care visits. To close gaps in telemedicine use among rural older adults, supports must be tailored to individuals, accounting for technology availability and comfort, as well as availability of and need for caregiver involvement. Comprehensive scaffolding of support starts well before the first telemedicine visit.

Postoperative Outcomes Associated with the Timing of Surgery After SARS-CoV-2 Infection.

Examine the association between prior SARS-CoV-2 infection, interval from infection to surgery, and adverse surgical outcomes. Earlier series have reported worse outcomes for surgery after COVID-19 illness, and these findings have led to routinely deferring surgery seven weeks after infection. We created a retrospective cohort of patients from US Veterans Health Administration facilities nationwide, April 2020-September 2022, undergoing surgical procedures. Primary outcomes were 90-day all-cause mortality and 30-day complications. Within surgical procedure groupings, SARS-CoV-2 infected and uninfected patients were matched in a 1:4 ratio. We categorized patients by two-week intervals from SARS-CoV-2 positive test to surgery. Hierarchical multilevel multivariable logistic regression models were used to estimate the association between infection to surgery interval versus no infection and primary endpoints. We identified 82,815 veterans undergoing eligible operations (33% general, 27% orthopedic, 13% urologic, 9% vascular), of whom 16,563 (20%) had laboratory confirmed SARS-CoV-2 infection prior to surgery. The multivariable models demonstrated an association between prior SARS-CoV-2 infection and increased 90-day mortality (odds ratio (OR) 1.42, 95% CI 1.08, 1.86) and complications (OR 1.32, 95% CI 1.11, 1.57) only for patients having surgery within 14 days of infection. ASA-stratified multivariable models showed that the associations between increased 90-day mortality (OR 1.40, 95% CI 1.12, 1.75) and complications (OR 1.73, 95% CI 1.34, 2.24) for patients having surgery within 14 days of infection were confined to those with ASA 4-5. In a contemporary surgical cohort, patients with prior SARS-CoV-2 infection only had increased post-operative mortality or complications when they had surgery within 14 days after positive test. These findings support revising timing recommendations between surgery and prior SARS-CoV-2 infection.

The Role of Radical Cystectomy in Clinically Node Positive Bladder Cancer: A US Veterans Health Administration Study

IntroductionThe role of local definitive therapy in addition to systemic treatment in clinically positive regional lymph node (cN+) bladder cancer is yet to be determined. Herein, we sought to investigate the role of radical cystectomy (RC) in management of patients with cN+ bladder cancer at US Veterans Health Administration Facilities. MethodsWe identified patients diagnosed with cN+ bladder cancer between 2000-2017 using the Department of Veterans Affairs (VA) Informatics and Computing Infrastructure (VINCI). We employed a combination of database/registry coded values and chart review for data collection. To minimize mortality bias, we excluded patients who died within 90 days of diagnosis. We divided the patients into cystectomy (C) versus “no cystectomy” (NOC) cohorts. Propensity score matching was performed based on predictors of undergoing RC. Multivariable Cox models and Kaplan-Meier survival curves were used to estimate overall survival (OS) and cancer specific survival (CCS). ResultAfter matching, 158 patients were included in the C and NOC groups. In the C-group, 85(54%) patients received pre-cystectomy chemotherapy, and 73(46%) patients underwent post-cystectomy chemotherapy. In the C-group, 65(41%) patients and in the NOC-group, 66(42%) patients had clinical N1 disease (P = .77). In multivariable Cox model, undergoing RC was associated with improved OS (HR0.62; 95%CI 0.47-0.81), P < .001) and CSS (HR0.58; 95%CI 0.42-0.80; P < .001). ConclusionAs part of multimodal treatment, undergoing RC was associated with improved OS and CSS in subset of patients with cN+ bladder cancer. Prospective randomized trials are warranted to further investigate the role of local definitive therapy in this specific patient population.

US Veterans Health Administration Hepatitis C Virus (HCV) Program - A Model for National HCV Elimination though Patient-Centered Medical Homes.

US Veterans Health Administration Hepatitis C Virus (HCV) Program - A Model for National HCV Elimination though Patient-Centered Medical Homes.

Success of the US Veterans Health Administration's Hepatitis C Virus Care Continuum in the Direct-acting Antiviral Era.

Estimated hepatitis C prevalence within the Veterans Health Administration is higher than the general population and is a risk factor for advanced liver disease and subsequent complications. We describe the hepatitis C care continuum within the Veterans Health Administration January 1, 2014-December 31, 2022. We included individuals in Veterans Health Administration care 2021-2022 who were eligible for direct-acting antiviral treatment January 1, 2014-December 31, 2022. We evaluated the proportion of Veterans who progressed through each step of the hepatitis C care continuum, and identified factors associated with initiating direct-acting antivirals, achieving sustained virologic response, and repeat hepatitis C viremia. We identified 133,732 Veterans with hepatitis C viremia. Hepatitis C treatment was initiated in 107,134 (80.1%), with sustained virologic response achieved in 98,136 (91.6%). In those who achieved sustained virologic response, 1,097 (1.1%) had repeat viremia and 579 (52.8%) were retreated for hepatitis C. Veterans of younger ages were less likely to initiate treatment and achieve sustained virologic response, and more likely to have repeat viremia. Stimulant use and unstable housing were negatively associated with each step of the hepatitis C care continuum. The Veterans Health Administration has treated 80% of Veterans with hepatitis C in care 2021-2022 and achieved sustained virologic response in more than 90% of those treated. Repeat viremia is rare and is associated with younger age, unstable housing, opioid use, and stimulant use. Ongoing efforts are needed to reach younger Veterans, and Veterans with unstable housing or substance use disorders.

A Clinical Prediction Model to Assess Risk for Pancreatic Cancer Among Patients With Acute Pancreatitis.

We aimed to develop and validate a prediction model as the first step in a sequential screening strategy to identify acute pancreatitis (AP) individuals at risk for pancreatic cancer (PC). We performed a population-based retrospective cohort study among individuals 40 years or older with a hospitalization for AP in the US Veterans Health Administration. For variable selection, we used least absolute shrinkage and selection operator regression with 10-fold cross-validation to identify a parsimonious logistic regression model for predicting the outcome, PC diagnosed within 2 years after AP. We evaluated model discrimination and calibration. Among 51,613 eligible study patients with AP, 801 individuals were diagnosed with PC within 2 years. The final model (area under the receiver operating curve, 0.70; 95% confidence interval, 0.67-0.73) included histories of gallstones, pancreatic cyst, alcohol use, smoking, and levels of bilirubin, triglycerides, alkaline phosphatase, aspartate aminotransferase, alanine aminotransferase, and albumin. If the predicted risk threshold was set at 2% over 2 years, 20.3% of the AP population would undergo definitive screening, identifying nearly 50% of PC associated with AP. We developed a prediction model using widely available clinical factors to identify high-risk patients with PC-associated AP, the first step in a sequential screening strategy.

Survival impact of homologous recombination deficiency in veterans with cholangiocarcinoma including mutual exclusivity with pathogenic KRAS and TP53.

546 Background: Cholangiocarcinoma (CCA) has poor prognosis and limited treatment options. The US Veteran Health Administration’s (VHA) National Precision Oncology Program (NPOP) was established to characterize pathogenic drivers across the integrated VA network. Here, we summarize an important subgroup of CCA with homologous recombination deficiency (HRD) and its impact on overall survival (OS). Methods: Next-generation sequencing (NGS) was performed using FoundationOne CDx Analysis included clinicopathological, molecular alterations including, single nucleotide variants, gene amplification/loss, and gene fusion/rearrangements obtained from centralized data of the VHA’s Corporate Data Warehouse. Homologous recombination deficiency was defined by pathogenic variant mutations (MT) in ARID1A, ATM, ATR, BAP1, BRCA1, BRCA2, CDK12, CHEK2, FANC, NBN, PALB2, and RAD51. Statistical analysis was performed using Chi-squared test for concurrent gene enrichment and log-rank Kaplan-Meier analysis. Results: 483 CCA samples underwent tissue NGS as standard of care. Pathogenic variants in HRD genes included ARID1A (15.5%, n=75), BAP1 (9.5%, n=46), ATM (2.7%, n=13), PALB2 (2.3%, n=11) and BRCA (2.0%, n=10), representing 31.7% (n=153) of the population. HRD mutations were found in similar proportions of localized (31.8%) and metastatic (31.5%) clinical presentations at diagnosis. OS was not significantly different between CCA with HRD mutations (12.3 mo WT vs. 13.8 months with HRD MT, p=64). KRAS MT (n=77, 15.9% of population) did not impact OS (WT 12.3 mo v. MT 13.1 mo) including subgroup analysis stratified by HRD status. There was increased frequency in KRAS MT with HRD WT 18.5% versus HRD MT10.4% (p&lt;0.03). Additionally, there was increased frequency in TP53 MT with HRD WT 54.8% versus HRD MT 28.1% (p&lt;0.00001). TP53 MT (n=224, 46.3% of population) conferred inferior OS (WT 12.3 mo v. MT 13.1 mo) including subgroup analysis stratified by HRD status. Subgroup analysis of TP53 MT had worsened OS with concurrent HRD MT (n=39, 4.1 mo) v. HRD WT (n=158, 9.0 mo; p&lt;0.04). Conclusions: Across a diverse integrated healthcare system of Veterans, mutations associated with HRD were found to be common, however, not prognostic in OS across a diverse patient population of CCA. Further work is needed to clarify exposure to platinum containing chemotherapy. TP53 MT CCA remains a critical unmet need that drives worsened outcomes including here in patients with mutations in HRD. Future analysis should consider mutation signatures of HRD, loss in heterozygosity of HRD, and platinum exposure to further define the subgroups of CCA with mutations in HRD. [Table: see text]

Impact of Potential Case Misclassification by Administrative Diagnostic Codes on Outcome Assessment of Observational Study for People Who Inject Drugs.

Initiation of medications for opioid use disorder (MOUD) within the hospital setting may improve outcomes for people who inject drugs (PWID) hospitalized because of an infection. Many studies used International Classification of Diseases (ICD) codes to identify PWID, although these may be misclassified and thus, inaccurate. We hypothesized that bias from misclassification of PWID using ICD codes may impact analyses of MOUD outcomes. We analyzed a cohort of 36 868 cases of patients diagnosed with Staphylococcus aureus bacteremia at 124 US Veterans Health Administration hospitals between 2003 and 2014. To identify PWID, we implemented an ICD code-based algorithm and a natural language processing (NLP) algorithm for classification of admission notes. We analyzed outcomes of prescribing MOUD as an inpatient using both approaches. Our primary outcome was 365-day all-cause mortality. We fit mixed-effects Cox regression models with receipt or not of MOUD during the index hospitalization as the primary predictor and 365-day mortality as the outcome. NLP identified 2389 cases as PWID, whereas ICD codes identified 6804 cases as PWID. In the cohort identified by NLP, receipt of inpatient MOUD was associated with a protective effect on 365-day survival (adjusted hazard ratio, 0.48; 95% confidence interval, .29-.81; P < .01) compared with those not receiving MOUD. There was no significant effect of MOUD receipt in the cohort identified by ICD codes (adjusted hazard ratio, 1.00; 95% confidence interval, .77-1.30; P = .99). MOUD was protective of all-cause mortality when NLP was used to identify PWID, but not significant when ICD codes were used to identify the analytic subjects.

Revision Carpal Tunnel Release Following Endoscopic Compared With Open Decompression

Carpal tunnel release (CTR) technique may influence the likelihood of revision surgery. Prior studies of revision CTR following endoscopic CTR (ECTR) compared with open CTR (OCTR) have been limited by sample size and duration of follow-up. To estimate the incidence of revision CTR following ECTR compared with OCTR in a national cohort. This retrospective cohort study used data from the US Veterans Health Administration. Participants included all adults (age ≥18 years) undergoing at least 1 outpatient CTR from October 1, 1999, to May 20, 2021. Data were analyzed from May 21, 2021, to November 27, 2023. Index CTR technique. The primary outcome was time to revision CTR, defined as repeat ipsilateral CTR during the study period. Secondary outcomes were indications for revision, findings during revision, and additional procedures performed during revision. Among 134 851 wrists from 103 455 patients (92 510 [89.4%] male; median [IQR] age, 62 [53-70] years) undergoing at least 1 CTR, 1809 wrists underwent at least 1 revision at a median (IQR) of 2.5 (1.0-3.8) years. In competing-risks analysis, the cumulative incidence of revision was 1.06% (95% CI, 0.99%-1.12%) at 5 years and 1.59% (95% CI, 1.51%-1.67%) at 10 years. ECTR was associated with increased hazard of revision CTR compared with OCTR (adjusted hazard ratio [aHR], 1.56; 95% CI, 1.34-1.81; P < .001). The risk difference for revision CTR associated with ECTR compared with OCTR was 0.57% (95% CI, 0.31%-0.84%) at 5 years (number needed to harm, 176) and 0.72% (95% CI, 0.36%-1.07%) at 10 years (number needed to harm, 139). Regardless of index CTR technique, the most common indication for revision was symptom recurrence (1062 wrists [58.7%]). A reconstituted transverse carpal ligament (TCL) was more common after ECTR compared with OCTR, whereas scarring of the overlying tissues and of the median nerve itself were more common following OCTR. Incomplete transverse-carpal-ligament release was observed in 251 of the wrists undergoing revision CTR (13.94%) and was more common among revisions following ECTR (odds ratio, 1.62; 95% CI, 1.11-2.37; P = .01). In this cohort study of revision CTR in the Veterans Health Administration, ECTR was associated with increased risk of revision compared with OCTR, but the absolute risk was low regardless of technique. Intraoperative findings at revision varied significantly according to index CTR technique.

Adaption and National Validation of a Tool for Predicting Mortality from Other Causes Among Men with Nonmetastatic Prostate Cancer

BackgroundAn electronic health record–based tool could improve accuracy and eliminate bias in provider estimation of the risk of death from other causes among men with nonmetastatic cancer. ObjectiveTo recalibrate and validate the Veterans Aging Cohort Study Charlson Comorbidity Index (VACS-CCI) to predict non–prostate cancer mortality (non-PCM) and to compare it with a tool predicting prostate cancer mortality (PCM). Design, setting, and participantsAn observational cohort of men with biopsy-confirmed nonmetastatic prostate cancer, enrolled from 2001 to 2018 in the national US Veterans Health Administration (VA), was divided by the year of diagnosis into the development (2001–2006 and 2008–2018) and validation (2007) sets. Outcome measurements and statistical analysisMortality (all cause, non-PCM, and PCM) was evaluated. Accuracy was assessed using calibration curves and C statistic in the development, validation, and combined sets; overall; and by age (<65 and 65+ yr), race (White and Black), Hispanic ethnicity, and treatment groups. Results and limitationsAmong 107 370 individuals, we observed 24 977 deaths (86% non-PCM). The median age was 65 yr, 4947 were Black, and 5010 were Hispanic. Compared with CCI and age alone (C statistic 0.67, 95% confidence interval [CI] 0.67–0.68), VACS-CCI demonstrated improved validated discrimination (C statistic 0.75, 95% CI 0.74–0.75 for non-PCM). The prostate cancer mortality tool also discriminated well in validation (C statistic 0.81, 95% CI 0.78–0.83). Both were well calibrated overall and within subgroups. Owing to missing data, 18 009/125 379 (14%) were excluded, and VACS-CCI should be validated outside the VA prior to outside application. ConclusionsVACS-CCI is ready for implementation within the VA. Electronic health record–assisted calculation is feasible, improves accuracy over age and CCI alone, and could mitigate inaccuracy and bias in provider estimation. Patient summaryVeterans Aging Cohort Study Charlson Comorbidity Index is ready for application within the Veterans Health Administration. Electronic health record–assisted calculation is feasible, improves accuracy over age and Charlson Comorbidity Index alone, and might help mitigate inaccuracy and bias in provider estimation of the risk of non–prostate cancer mortality.

Evaluation of implementation facilitation integrated into a national mentoring programme to improve access to evidence-based psychotherapy for post-traumatic stress disorder within the veterans health administration: a quality improvement report

Despite the resources dedicated to specialised mental healthcare for patients with post-traumatic stress disorder (PTSD) within the US Veterans Health Administration, evidence-based psychotherapies (EBPs) for PTSD have been underutilised, as...

Incident Ocular Inflammation After COVID-19 Infection in a US Veteran Population

ABSTRACT Purpose To investigate whether COVID-19 infection is a risk factor for incident ocular inflammatory disease. Design Retrospective case-crossover study. Methods The US Veterans Health Administration Corporate Data Warehouse was used to identify patients with positive COVID-19 testing and incident ocular inflammatory disease between March 2020 and May 2022. The timing of incident ocular inflammation and COVID-19 testing was assessed for each participant to determine whether positive COVID-19 testing occurred 0–60 days prior to incident ocular inflammation diagnosis (risk period) or 15–75 days after incident ocular inflammation diagnosis (control period). The main outcome measure was the odds of positive COVID-19 testing in the risk period versus control period. Results Of the 1006 patients with incident ocular inflammation and a positive COVID-19 test in the study period, the age mean ± standard deviation was 62.6 ± 9.8 years and 840 (83%) were male. The odds of COVID-19 exposure was higher in the risk than control period (odds ratio [OR], 1.56; 95% confidence interval [CI], 1.04–2.36; P = 0.03). Ocular inflammation was more likely to be bilateral in the risk period (OR, 3.97; 95% CI, 1.01–23.01; P = 0.03). Other ocular features and demographic characteristics were similar in the risk and control periods. Most cases of ocular inflammation were quiescent at the most recent eye examination. Conclusions Incident ocular inflammation is associated with COVID-19 infection, but the increased risk is small, and the ocular inflammation is typically acute.

Epidemiology of the 2022 Mpox Outbreak in the US Veterans Health Administration.

In May 2022, mpox cases were reported in nonendemic countries, including the United States. We examined mpox infections in the Veterans Health Administration (VHA). Mpox diagnostic and whole genome sequencing (WGS) results, demographics, risk factors, hospitalizations, exposures, deaths, and pharmacy and immunization data were obtained from VHA data sources (23 May 2022-31 May 2023). Of 1144 Veterans tested, 251 (21.9%) were presumptive positive for nonvariola orthopoxvirus (NVO) or confirmed positive for NVO and Monkeypox virus (MPXV). Incidence rate was 7.5 per 100 000 Veterans in care, with the highest rate observed in Veterans aged 25-34 years (13.83 cases per 100 000). Higher odds of NVO or NVO/MPXV positivity was associated with male sex; non-Hispanic Black race/ethnicity; syphilis or human immunodeficiency virus (HIV) positivity; or genital/rectal sample site, whereas older age and vaccination with JYNNEOS or vaccinia (smallpox) had lower odds. Among 209 with confirmatory testing, 90.4% reported intimate contact and/or an epidemiological link, 84.5% were men who have sex with men (MSM), 24.2% received tecovirimat, and 8.1% were hospitalized with 1 death. Eighty-six sequenced samples had evaluable WGS results. All were clade IIb, representing 10 different lineages from 20 states and the District of Columbia. Mpox affected younger, MSM, non-Hispanic Black, and HIV/syphilis-positive men among US Veterans. Viral diversity was noted across geographic regions. At-risk Veterans would benefit from vaccination and risk reduction strategies for mpox and other sexually transmitted infections.

Mortality among US veterans with a physician-documented diagnosis of pyruvate kinase deficiency

ABSTRACT Real-world studies of pyruvate kinase (PK) deficiency and estimates of mortality are lacking. This retrospective observational study aimed to identify patients with PK deficiency and compare their overall survival (OS) to that of a matched cohort without PK deficiency. Patients with ≥1 diagnosis code related to PK deficiency were selected from the US Veterans Health Administration (VHA) database (01/1995–07/2019); patients with a physician-documented diagnosis were included (PK deficiency cohort; index: date of first diagnosis code related to PK deficiency). Patients in the PK deficiency cohort were matched 1:5 to patients from the general VHA population (non-PK deficiency cohort; index: random visit date during match’s index year). OS from index was compared between the two cohorts. Eighteen patients in the PK deficiency cohort were matched to 90 individuals in the non-PK deficiency cohort (both cohorts: mean age 57 years, 94% males; median follow-up 6.0 and 8.0 years, respectively). At follow-up, patients in the non-PK deficiency cohort had significantly longer OS than the PK deficiency cohort (median OS: 17.1 vs. 10.9 years; hazard ratio: 2.3; p = 0.0306). During their first-year post-index, 75% and 40% of the PK deficiency cohort had laboratory-confirmed anemia and iron overload, respectively. Among patients who died, cause of death was highly heterogeneous. These results highlight the increased risk of mortality and substantial clinical burden among patients with PK deficiency. While the intrinsic characteristics of the VHA database may limit the generalizability of the results, this is the first real-world study to characterize mortality in patients with PK deficiency.

Monoclonal Gammopathy of Undetermined Significance and Risk of Cardiovascular Disease in US Veterans

Background: Monoclonal gammopathy of undetermined significance (MGUS) has been associated with worse overall survival. The cause of this association is unclear but may result from increased risk of cardiovascular disease (CVD) events. Population-based studies have demonstrated associations between MGUS and CVD, but these were in largely Non-Hispanic White (NHW) populations. As such, we aim to examine the association between MGUS and CVD risk in the US Veterans Health Administration (VHA) which has the largest population of non-Hispanic Black patients (NHB). Additionally, this database can capture patient outcomes with an extensive electronic medical record system. The identification of a novel risk factor for CVD will improve our ability to prevent CVD events further. Methods: This was a population-based retrospective cohort study of US Veterans using linked data from the national Veterans Health Administration and Medicare. Veterans free from CVD events were included in the analytic cohort and were followed from age 50 until they either develop CVD, they expire, or the date 12/31/2022 is reached. Veterans who died or were lost to follow up within 3 years after age 50 were excluded. The exposure is presumed MGUS diagnosis before CVD event or ever. The MGUS diagnosis was captured by a natural language processing (NLP) algorithm (previously developed by our group) based on the presence of a monoclonal protein less than 3 gm/dL and bone marrow plasma cells less than 10%. The outcome of interest was CVD event after age 50 which was identified with International Classification of Diseases (ICD)-9 and -10 codes atherosclerotic cardiovascular diseases and congestive heart failure. A multivariable logistic regression adjusting for sex, race/ethnicity, region of residence, income level, marital status, type 2 diabetes before CVD diagnosis or ever, and BMI at age 50 was performed to estimate odds ratios (ORs) and 95% confidence intervals (CIs). Results: The analytic cohort contained 523,604 Veterans: 503,098 without MGUS, among whom 25.8% developed CVD and 20,506 with MGUS, among whom, 40% developed CVD (p&amp;lt;0.0001). The CVD events included heart failure with 18.6% (n=3,804) in the MGUS group and 8.7% (n=43,955) in the group without MGUS (p&amp;lt;0.0001). The mean age of MGUS (n=20,506) was 69.2 years and 66.8 in patients who had a CVD event (n=137,918). Compared to individuals without MGUS, individuals with MGUS had a higher proportion of being male (95.5 versus 86.5%, p&amp;lt;0.0001), non-Hispanic Black (29.7 versus 22.0%, p&amp;lt;0.0001), non-Hispanic White (55.2 versus 50.0%, p&amp;lt;0.0001), divorced/separated/widowed (36.2 versus 19.6%, p&amp;lt;0.0001), single/never married (10.6 versus 6.0%, p&amp;lt;0.0001), diabetes mellitus (38.4 versus 22.0%, p&amp;lt;0.001). The odds ratio of having a CVD in the setting of MGUS was 1.23 (95% CI: 1.19-1.26). Conclusions: MGUS was associated with an increased risk of diagnosis of cardiovascular disease for individuals aged 50 years or older. Clinicians should consider evaluation of patients with MGUS for CVD risk factors. Further studies are required to evaluate whether addressing modifiable CVD risk factors is associated with decreased risk of developing CVD in MGUS patients.

2938. Hepatitis C Virus Care Continuum in the Direct-acting Antiviral Era within the US Veterans Health Administration

Abstract Background Estimated hepatitis C prevalence within the Veterans Health Administration is higher than the general population and is a risk factor for advanced liver disease and its associated complications. We describe the hepatitis C care continuum within the Veterans Health Administration between January 1, 2014 and December 31, 2022. Methods Individuals in Veterans Health Administration care 2021-2022 who were eligible for direct-acting antiviral treatment between January 1, 2014 and December 31, 2022 comprised our cohort. We evaluated the proportion of Veterans who progressed through each step of the hepatitis C care continuum, and identified factors associated with initiating direct-acting antivirals, achieving sustained virologic response, and repeat hepatitis C viremia after achieving sustained virologic response. Results We identified 133,732 Veterans with hepatitis C viremia during our study timeframe. Hepatitis C treatment was initiated in 107,134 (80.1%), with sustained virologic response achieved in 98,136 (91.6%). In those who achieved sustained virologic response, 1,097 (1.1%) had subsequent repeat viremia and 579 (52.8%) were retreated for hepatitis C. Veterans of younger ages were less likely to initiate treatment and achieve sustained virologic response, and more likely to have repeat viremia. Stimulant use and unstable housing were negatively associated with each step of the hepatitis C care continuum.Table 1:Characteristics of Veterans with HCV ViremiaTable 2:Factors Associated with DAA Treatment Initiation in those with HCV ViremiaFigure 1:Overview of the VHA Hepatitis C Care Continuum as of December 31, 2022 Conclusion The Veterans Health Administration has treated 80% of Veterans with hepatitis C with direct-acting antiviral therapy since its approval in 2014 and achieved sustained virologic response in more than 90% of those treated. Repeat viremia is rare and is associated with younger age, unstable housing, opioid use, and stimulant use. Ongoing efforts are needed to reach younger Veterans, and Veterans with unstable housing or substance use disorders. Disclosures All Authors: No reported disclosures

899. Epidemiology of the 2022 Mpox Outbreak in the US Veterans Health Administration (VHA)

Abstract Background Mpox, an orthopoxvirus zoonotic disease, is endemic to Africa. In May 2022, cases were reported concurrently in endemic and non-endemic countries, including the US. WHO and DHHS subsequently declared Mpox a public health emergency. Herein, we examine Mpox in the Veterans Health Administration (VHA). Methods Mpox diagnostic and whole genome sequencing (WGS) results, demographics, hospitalizations, deaths, diagnosis codes, exposure information, pharmacy and immunization data were obtained from VHA data sources and/or chart review (5/23/22-4/11/23). Association of risk factors with Mpox was determined using multivariable logistic regression. Results Of 1,034 Veterans tested, 251 (24%) were orthopox positive in 32 states (peaking in August 2022), with 50.2% HIV+ and 32.7% with other concurrent sexually transmitted infections (STIs). Significant associated Mpox risk factors included: male gender, age &amp;lt; 55 years, non-Hispanic Black race/ethnicity, and HIV positivity. Among 193 with confirmed Mpox, 90% reported intimate contact and/or an epi link to another Mpox case; 83% were men who have sex with men (MSM); 24% received Tecovirimat; and 11% were hospitalized with no deaths attributable to Mpox. 13% had reported or documented smallpox vaccine(s) &amp;gt;2 weeks prior to exposure (primarily as active duty) and an additional 14 (7%) received JYNNEOS &amp;lt; 2 weeks prior to presentation (or precise date not recorded). Review of 80 patients with evaluable WGS results found all were clade IIb, representing 10 different lineages from 18 states and District of Columbia. Serial WGS samples (n=3) evaluated after Tecovirimat regimens revealed no drug resistance. Since July 2022, over 4,300 Veterans have received at least 1 dose of smallpox/Mpox vaccine with over 6,700 doses having been administered at a VA facility. Conclusion The Mpox outbreak primarily affected younger, MSM, non-Hispanic Black race and HIV+ males among those in VHA care. Although some were vaccinated, the protective effect may have been diminished, or it was received too close to the exposure to provide adequate protection. Viral diversity was noted across geographic regions. Veterans with risk factors would benefit from vaccination and risk reduction strategies for Mpox and other STIs. Disclosures All Authors: No reported disclosures

Unstable Housing and Mortality Among US Veterans Receiving Dialysis

Housing status is an important health determinant, yet little is known about unstable housing among individuals receiving dialysis. To determine factors associated with unstable housing among US veterans receiving dialysis and to estimate the association of unstable housing with risk of death. This retrospective cohort study used data from the US Veterans Health Administration (VHA) and the US Renal Data System for patients who initiated dialysis between October 1, 2012, and December 31, 2018. Veterans were included if they used VHA outpatient services and completed 1 or more unstable housing screenings within a 3-year period before starting dialysis. Data analysis was conducted from January 24 to June 16, 2023. Unstable housing was defined as self-report of not having stable housing within the past 2 months or having concerns about stable housing in the next 2 months. The main outcome was all-cause mortality. Characteristics associated with unstable housing at the time of dialysis initiation were examined. The multivariate Fine and Gray cumulative incidence model was used, treating transplant as a competing risk and age as an effect modifier, to examine the risk of death associated with unstable housing. This study included 25 689 veterans, with a median age of 68 (IQR, 62-74) years. Most participants were men (98%), and more than half (52%) were White. There were 771 veterans (3%) with a positive screen for unstable housing within a 3-year period before starting dialysis. Compared with veterans with stable housing, those with unstable housing were younger (mean [SD] age, 61 [8] vs 68 [10] years), were more likely to be Black (45% vs 32%) or Hispanic (9% vs 7%), and were more likely to start dialysis with a central venous catheter (77% vs 66%), receive in-center hemodialysis (96% vs 91%), and have non-Medicare insurance (53% vs 28%). Factors associated with unstable housing included Hispanic ethnicity, non-arteriovenous fistula vascular access, lack of predialysis nephrology care, and non-Medicare insurance. Veterans with unstable housing had higher all-cause mortality (adjusted hazard ratio [AHR], 1.20 [95% CI, 1.04 to 1.37] for a median age of 68 years), and risks increased with age (P = .01 for interaction). In age-stratified analyses, unstable housing was associated with higher mortality among veterans aged 75 to 85 years (AHR, 1.64 [95% CI, 1.18 to 2.28]), but associations were not observed for other age groups. In this cohort study of veterans receiving dialysis, unstable housing experienced before starting dialysis was associated with increased risk of all-cause mortality, and risks increased with age. Further efforts are needed to understand the experiences of older adults with unstable housing and to estimate the scope of unstable housing among all individuals receiving dialysis.

Investigation of the role of perceived access to primary care in mediating and moderating racial and ethnic disparities in chronic disease control in the veterans health administration.

To examine the role of patient-perceived access to primary care in mediating and moderating racial and ethnic disparities in hypertension control and diabetes control among Veterans Health Administration (VA) users. We performed a secondary analysis of national VA user administrative data for fiscal years 2016-2019. Our primary exposure was race or ethnicity and primary outcomes were binary indicators of hypertension control (<140/90 mmHg) and diabetes control (HgbA1c < 9%) among patients with known disease. We used the inverse odds-weighting method to test for mediation and logistic regression with race and ethnicity-by-perceived access interaction product terms to test moderation. All models were adjusted for age, sex, socioeconomic status, rurality, education, self-rated physical and mental health, and comorbidities. We included VA users with hypertension and diabetes control data from the External Peer Review Program who had contemporaneously completed the Survey of Healthcare Experience of Patients-Patient-Centered Medical Home. Hypertension (34,233 patients) and diabetes (23,039 patients) samples were analyzed separately. After adjustment, Black patients had significantly lower rates of hypertension control than White patients (75.5% vs. 78.8%, p < 0.01); both Black (81.8%) and Hispanic (80.4%) patients had significantly lower rates of diabetes control than White patients (85.9%, p < 0.01 for both differences). Perceived access was lower among Black, Multi-Race and Native Hawaiian and Other Pacific Islanders compared to White patients in both samples. There was no evidence that perceived access mediated or moderated associations between Black race, Hispanic ethnicity, and hypertension or diabetes control. We observed disparities in hypertension and diabetes control among minoritized patients. There was no evidence that patients' perception of access to primary care mediated or moderated these disparities. Reducing racial and ethnic disparities within VA in hypertension and diabetes control may require interventions beyond those focused on improving patient access.