Comparison by Race of Conservative Management for Low-Risk and Intermediate-Risk Prostate Cancers in Veterans From 2004 to 2018

Prostate Cancer Foundation Screening Guidelines for Black Men in the United States

BACKGROUND

In the United States, Black men are at highest risk for being diagnosed with and dying from prostate cancer. Given this disparity, we examined relevant data to establish clinical prostate-specific antigen (PSA) screening guidelines for Black men in the United States.

METHODS

A comprehensive literature search identified 1848 unique publications for screening. Of those screened, 287 studies were selected for full-text review, and 264 were considered relevant and form the basis for these guidelines. The numbers were reported according to PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines.

RESULTS

Three randomized controlled trials provided Level 1 evidence that regular PSA screening of men 50 to 74 years of age of average risk reduced metastasis and prostate cancer death at 16 to 22 years of follow-up. The best available evidence specifically for Black men comes from observational and modeling studies that consider age to obtain a baseline PSA, frequency of testing, and age when screening should end. Cohort studies suggest that discussions about baseline PSA testing between Black men and their clinicians should begin in the early 40s, and data from modeling studies indicate prostate cancer develops 3 to 9 years earlier in Black men compared with non-Black men. Lowering the age for baseline PSA testing to 40 to 45 years of age from 50 to 55 years of age, followed by regular screening until 70 years of age (informed by PSA values and health factors), could reduce prostate cancer mortality in Black men (approximately 30% relative risk reduction) without substantially increasing overdiagnosis.

CONCLUSIONS

These guidelines recommend that Black men should obtain information about PSA screening for prostate cancer. Among Black men who elect screening, baseline PSA testing should occur between ages 40 and 45. Depending on PSA value and health status, annual screening should be strongly considered. (Supported by the Prostate Cancer Foundation.).

Racial Differences in Germline Genetic Testing Completion Among Males With Pancreatic, Breast, or Metastatic Prostate Cancers

BACKGROUND

Germline genetic testing is a vital component of guideline-recommended cancer care for males with pancreatic, breast, or metastatic prostate cancers. We sought to determine whether there were racial disparities in germline genetic testing completion in this population.

PATIENTS AND METHODS

This retrospective cohort study included non-Hispanic White and Black males with incident pancreatic, breast, or metastatic prostate cancers between January 1, 2019, and September 30, 2021. Two nationwide cohorts were examined: (1) commercially insured individuals in an administrative claims database, and (2) Veterans receiving care in the Veterans Health Administration. One-year germline genetic testing rates were estimated by using Kaplan-Meier methods. Cox proportional hazards regression was used to test the association between race and genetic testing completion. Causal mediation analyses were performed to investigate whether socioeconomic variables contributed to associations between race and germline testing.

RESULTS

Our cohort consisted of 7,894 males (5,142 commercially insured; 2,752 Veterans). One-year testing rates were 18.0% (95% CI, 16.8%-19.2%) in commercially insured individuals and 14.2% (95% CI, 11.5%-15.0%) in Veterans. Black race was associated with a lower hazard of testing among commercially insured individuals (adjusted hazard ratio [aHR], 0.73; 95% CI, 0.58-0.91; P=.005) but not among Veterans (aHR, 0.99; 95% CI, 0.75-1.32; P=.960). In commercially insured individuals, income (aHR, 0.90; 95% CI, 0.86-0.96) and net worth (aHR, 0.92; 95% CI, 0.86-0.98) mediated racial disparities, whereas education (aHR, 0.98; 95% CI, 0.94-1.01) did not.

CONCLUSIONS

Overall rates of guideline-recommended genetic testing are low in males with pancreatic, breast, or metastatic prostate cancers. Racial disparities in genetic testing among males exist in a commercially insured population, mediated by net worth and household income; these disparities are not seen in the equal-access Veterans Health Administration. Alleviating financial and access barriers may mitigate racial disparities in genetic testing.

Prostate cancer screening in African American men: a review of the evidence

BACKGROUND

Prostate cancer is the most diagnosed cancer in African American men, yet prostate cancer screening regimens in this group are poorly guided by existing evidence, given underrepresentation of African American men in prostate cancer screening trials. It is critical to optimize prostate cancer screening and early detection in this high-risk group because underdiagnosis may lead to later-stage cancers at diagnosis and higher mortality while overdiagnosis may lead to unnecessary treatment.

METHODS

We performed a review of the literature related to prostate cancer screening and early detection specific to African American men to summarize the existing evidence available to guide health-care practice.

RESULTS

Limited evidence from observational and modeling studies suggests that African American men should be screened for prostate cancer. Consideration should be given to initiating screening of African American men at younger ages (eg, 45-50 years) and at more frequent intervals relative to other racial groups in the United States. Screening intervals can be optimized by using a baseline prostate-specific antigen measurement in midlife. Finally, no evidence has indicated that African American men would benefit from screening beyond 75 years of age; in fact, this group may experience higher rates of overdiagnosis at older ages.

CONCLUSIONS

The evidence base for prostate cancer screening in African American men is limited by the lack of large, randomized studies. Our literature search supported the need for African American men to be screened for prostate cancer, for initiating screening at younger ages (45-50 years), and perhaps screening at more frequent intervals relative to men of other racial groups in the United States.

The impact of prognostic group classification on prostate cancer progression in intermediate-risk patients according to the European Association of Urology system: results in 479 patients treated with robot-assisted radical prostatectomy at a single tertiary referral center

Background

Treatment outcomes in intermediate-risk prostate cancer (PCa) may be impaired by adverse pathology misclassification including tumor upgrading and upstaging. Clinical predictors of disease progression need to be improved in this category of patients.

Objectives

To identify PCa prognostic factors to define prognostic groups in intermediate-risk patients treated with robot-assisted radical prostatectomy (RARP).

Design

Data from 1143 patients undergoing RARP from January 2013 to October 2020 were collected: 901 subjects had available follow-up, of whom 479 were at intermediate risk.

Methods

PCa progression was defined as biochemical recurrence and/or local recurrence and/or distant metastases. Study endpoints were evaluated by statistical methods including Cox's proportional hazards, Kaplan-Meyer survival curves, and binomial and multinomial logistic regression models.

Results

After a median (interquartile range) of 35 months (15-57 months), 84 patients (17.5%) had disease progression, which was independently predicted by the percentage of biopsy-positive cores ⩾ 50% and the International Society of Urological Pathology (ISUP) grade group 3 for clinical factors and by ISUP > 2, positive surgical margins and pelvic lymph node invasion for pathological features. Patients were classified into clinical and pathological groups as favorable, unfavorable (one prognostic factor), and adverse (more than one prognostic factor). The risk of PCa progression increased with worsening prognosis through groups. A significant positive association was found between the two groups; consequently, as clinical prognosis worsened, the risk of detecting unfavorable and adverse pathological prognostic clusters increased in both unadjusted and adjusted models.

Conclusion

The study identified factors predicting disease progression that allowed the computation of highly correlated prognostic groups. As the prognosis worsened, the risk of PCa progression increased. Intermediate-risk PCa needs more prognostic stratification for appropriate management.

Impact of genomic testing on urologists' treatment preference in favorable risk prostate cancer: A randomized trial

INTRODUCTION

The Oncotype Dx Genomic Prostate Score (GPS) is a 17-gene relative expression assay that predicts adverse pathology at prostatectomy. We conducted a novel randomized controlled trial to assess the impact of GPS on urologist's treatment preference for favorable risk prostate cancer (PCa): active surveillance versus active treatment (i.e., prostatectomy/radiation). This is a secondary endpoint from the ENACT trial which recruited from three Chicago hospitals from 2016 to 2019.

METHODS

Ten urologists along with men with very low to favorable-intermediate risk PCa were included in the study. Participants were randomly assigned to standardized counseling with or without GPS assay. The main outcome was urologists' preference for active treatment at Visit 2 by study arm (GPS versus Control). Multivariable best-fit binary logistic regressions were constructed to identify factors independently associated with urologists' treatment preference.

RESULTS

Two hundred men (70% Black) were randomly assigned to either the Control (96) or GPS arm (104). At Visit 2, urologists' preference for prostatectomy/radiation almost doubled in the GPS arm to 29.3% (29) compared to 14.1% (13) in the Control arm (p = 0.01). Randomization to the GPS arm, intermediate NCCN risk level, and lower patient health literacy were predictors for urologists' preference for active treatment.

DISCUSSION

Limitations included sample size and number of urologists. In this study, we found that GPS testing reduced urologists' likelihood to prefer active surveillance.

CONCLUSIONS

These findings demonstrate how obtaining prognostic biomarkers that predict negative outcomes before treatment decision-making might influence urologists' preference for recommending aggressive therapy in men eligible for active surveillance.

Complex implementation factors demonstrated when evaluating cost-effectiveness and monitoring racial disparities associated with [18F]DCFPyL PET/CT in prostate cancer men

Prostate cancer (PC) staging with conventional imaging often includes multiparametric magnetic resonance (MR) of the prostate, computed tomography (CT) of the chest, abdomen, and pelvis, and whole-body bone scintigraphy. The recent development of highly sensitive and specific prostate specific membrane antigen (PSMA) positron emission tomography (PET) has suggested that prior imaging techniques may be insufficiently sensitive or specific, particularly when evaluating small pathologic lesions. As PSMA PET/CT is considered to be superior for multiple clinical indications, it is being deployed as the new multidisciplinary standard-of-care. Given this, we performed a cost-effectiveness analysis of [¹⁸F]DCFPyL PSMA PET/CT imaging in the evaluation of PC relative to conventional imaging and anti-3-[¹⁸F]FACBC (¹⁸F-Fluciclovine) PET/CT. We also conducted a single institution review of PSMA PET/CT scans performed primarily for research indications from January 2018 to October 2021. Our snapshot of this period of time in our catchment demonstrated that PSMA PET/CT imaging was disproportionately accessed by men of European ancestry (EA) and those residing in zip codes associated with a higher median household income. The cost-effectiveness analysis demonstrated that [¹⁸F]DCFPyL PET/CT should be considered as an alternative to anti-3-[¹⁸F]FACBC PET/CT and standard of care imaging for prostate cancer staging. [¹⁸F]DCFPyL PET/CT is a new imaging modality to evaluate PC patients with higher sensitivity and specificity in detecting disease than other prostate specific imaging studies. Despite this, access may be inequitable. This discrepancy will need to be addressed proactively as the distribution network of the radiotracer includes both academic and non-academic sites nationwide.

Does ADT Influence the Risk of Suicidal Ideation among US Veteran Prostate Cancer Patients Pre-Exposed to PTSD?

Post-traumatic stress disorder (PTSD) is defined as a mental health disease that has a high probability of developing among individuals who have experienced traumatic events [...].

Prognostic Value of the Intermediate-risk Feature in Men with Favorable Intermediate-risk Prostate Cancer: Implications for Active Surveillance

Background

Guidelines suggest that active surveillance (AS) may be considered for select patients with favorable intermediate-risk (fIR) prostate cancer.

Objective

To compare the outcomes between fIR prostate cancer patients included by Gleason score (GS) or prostate-specific antigen (PSA). Most patients are classified with fIR disease due to either a 3 + 4 = 7 GS (fIR-GS) or a PSA level of 10-20 ng/ml (fIR-PSA). Previous research suggests that inclusion by GS 7 may be associated with worse outcomes.

Design setting and participants

We conducted a retrospective cohort study of US veterans diagnosed with fIR prostate cancer from 2001 to 2015.

Outcome measurements and statistical analysis

We compared the incidence of metastatic disease, prostate cancer-specific mortality (PCSM), all-cause mortality (ACM), and receipt of definitive treatment between fIR-PSA and fIR-GS patients managed with AS. Outcomes were compared with those of a previously published cohort of patients with unfavorable intermediate-risk disease using cumulative incidence function and Gray's test for statistical significance.

Results and limitations

The cohort included 663 men; 404 had fIR-GS (61%) and 249 fIR-PSA (39%). There was no evidence of difference in the incidence of metastatic disease (8.6% vs 5.8%, p = 0.77), receipt of definitive treatment (77.6% vs 81.5%, p = 0.43), PCSM (5.7% vs 2.5%, p = 0.274), and ACM (16.8% vs 19.1%, p = 0.14) between the fIR-PSA and fIR-GS groups at 10 yr. On multivariate regression, unfavorable intermediate-risk disease was associated with higher rates of metastatic disease, PCSM, and ACM. Limitations included varying surveillance protocols.

Conclusions

There is no evidence of difference in oncological and survival outcomes between men with fIR-PSA and fIR-GS prostate cancer undergoing AS. Thus, presence of GS 7 disease alone should not exclude patients from consideration of AS. Shared decision-making should be utilized to optimize management for each patient.

Patient summary

In this report, we compared the outcomes of men with favorable intermediate-risk prostate cancer in the Veterans Health Administration. We found no significant difference between survival and oncological outcomes.

Five-Year Prospective Observational Study of African-American Men on Active Surveillance for Prostate Cancer Demonstrates Race Is Not Predictive of Oncologic Outcomes

INTRODUCTION

This study aimed to evaluate if race impacted outcomes or risk of disease progression in men on active surveillance (AS) for prostate cancer. We present the results from our majority African-American cohort of men in an equal access setting over a 5-year follow-up period.

PATIENTS AND METHODS

All patients who elected AS for prostate cancer at the Southeast Louisiana Veterans Health Care System are entered into a prospectively managed observational database. Patients were divided into groups based on self-reported race. Grade group progression was defined as pathologic upgrading above International Society of Urological Pathology Grade Group 1 disease on subsequent biopsies following diagnostic biopsy. All tests were 2 sided using a significance of .05.

RESULTS

A total of 228 men met inclusion criteria in the study, including 154 non-Hispanic African American and 74 non-Hispanic Caucasian American men, with a median follow-up of 5 years from the initiation of AS. Race was not predictive of Gleason grade progression, AS discontinuation, or biochemical recurrence on Cox multivariate analysis (HR = 1.01, 0.94, 0.85, P = .96, .79, .81, respectively). On Kaplan-Meier analysis at 5 years, African-American progression-free, AS discontinuation free, and overall survival probability was comparable to their Caucasian American counterparts (P > .05 for all).

CONCLUSIONS

Active surveillance is a safe treatment option for low and very low risk prostate cancer, regardless of race. African-American and Caucasian-American men did not have any significant difference in Gleason grade group progression in our cohort with 5-year follow-up.

Prostate cancer risk in men of differing genetic ancestry and approaches to disease screening and management in these groups

Prostate cancer is the second most common solid tumour in men worldwide and it is also the most common cancer affecting men of African descent. Prostate cancer incidence and mortality vary across regions and populations. Some of this is explained by a large heritable component of this disease. It has been established that men of African and African Caribbean ethnicity are predisposed to prostate cancer (PrCa) that can have an earlier onset and a more aggressive course, thereby leading to poorer outcomes for patients in this group. Literature searches were carried out using the PubMed, EMBASE and Cochrane Library databases to identify studies associated with PrCa risk and its association with ancestry, screening and management of PrCa. In order to be included, studies were required to be published in English in full-text form. An attractive approach is to identify high-risk groups and develop a targeted screening programme for them as the benefits of population-wide screening in PrCa using prostate-specific antigen (PSA) testing in general population screening have shown evidence of benefit; however, the harms are considered to weigh heavier because screening using PSA testing can lead to over-diagnosis and over-treatment. The aim of targeted screening of higher-risk groups identified by genetic risk stratification is to reduce over-diagnosis and treat those who are most likely to benefit.

Genetic Factors Associated with Prostate Cancer Conversion from Active Surveillance to Treatment

Men diagnosed with low-risk prostate cancer (PC) are increasingly electing active surveillance (AS) as their initial management strategy. While this may reduce the side effects of treatment for prostate cancer, many men on AS eventually convert to active treatment. PC is one of the most heritable cancers, and genetic factors that predispose to aggressive tumors may help distinguish men who are more likely to discontinue AS. To investigate this, we undertook a multi-institutional genome-wide association study (GWAS) of 5,222 PC patients and 1,139 other patients from replication cohorts, all of whom initially elected AS and were followed over time for the potential outcome of conversion from AS to active treatment. In the GWAS we detected 18 variants associated with conversion, 15 of which were not previously associated with PC risk. With a transcriptome-wide association study (TWAS), we found two genes associated with conversion (MAST3, p = 6.9×10-7 and GAB2, p = 2.0×10-6). Moreover, increasing values of a previously validated 269-variant genetic risk score (GRS) for PC was positively associated with conversion (e.g., comparing the highest to the two middle deciles gave a hazard ratio [HR] = 1.13; 95% Confidence Interval [CI]= 0.94-1.36); whereas, decreasing values of a 36-variant GRS for prostate-specific antigen (PSA) levels were positively associated with conversion (e.g., comparing the lowest to the two middle deciles gave a HR = 1.25; 95% CI, 1.04-1.50). These results suggest that germline genetics may help inform and individualize the decision of AS-or the intensity of monitoring on AS-versus treatment for the initial management of patients with low-risk PC.

Factors Associated with Time to Conversion from Active Surveillance to Treatment for Prostate Cancer in a Multi-Institutional Cohort

PURPOSE

We examined the demographic and clinicopathological parameters associated with the time to convert from active surveillance to treatment among men with prostate cancer.

MATERIALS AND METHODS

A multi-institutional cohort of 7,279 patients managed with active surveillance had data and biospecimens collected for germline genetic analyses.

RESULTS

Of 6,775 men included in the analysis, 2,260 (33.4%) converted to treatment at a median followup of 6.7 years. Earlier conversion was associated with higher Gleason grade groups (GG2 vs GG1 adjusted hazard ratio [aHR] 1.57, 95% CI 1.36-1.82; ≥GG3 vs GG1 aHR 1.77, 95% CI 1.29-2.43), serum prostate specific antigen concentrations (aHR per 5 ng/ml increment 1.18, 95% CI 1.11-1.25), tumor stages (cT2 vs cT1 aHR 1.58, 95% CI 1.41-1.77; ≥cT3 vs cT1 aHR 4.36, 95% CI 3.19-5.96) and number of cancerous biopsy cores (3 vs 1-2 cores aHR 1.59, 95% CI 1.37-1.84; ≥4 vs 1-2 cores aHR 3.29, 95% CI 2.94-3.69), and younger age (age continuous per 5-year increase aHR 0.96, 95% CI 0.93-0.99). Patients with high-volume GG1 tumors had a shorter interval to conversion than those with low-volume GG1 tumors and behaved like the higher-risk patients. We found no significant association between the time to conversion and self-reported race or genetic ancestry.

CONCLUSIONS

A shorter time to conversion from active surveillance to treatment was associated with higher-risk clinicopathological tumor features. Furthermore, patients with high-volume GG1 tumors behaved similarly to those with intermediate and high-risk tumors. An exploratory analysis of self-reported race and genetic ancestry revealed no association with the time to conversion.

Active surveillance for intermediate-risk prostate cancer in African American and non-Hispanic White men

BACKGROUND

The safety of active surveillance (AS) for African American men compared with non-Hispanic White (White) men with intermediate-risk prostate cancer is unclear.

METHODS

The authors identified patients with modified National Comprehensive Cancer Network favorable ("low-intermediate") and unfavorable ("high-intermediate") intermediate-risk prostate cancer diagnosed between 2001 and 2015 and initially managed with AS in the Veterans Health Administration database. They analyzed definitive treatment, disease progression, metastases, prostate cancer-specific mortality (PCSM), and all-cause mortality by using cumulative incidences and multivariable competing-risks (disease progression, metastasis, and PCSM) or Cox (all-cause mortality) regression.

RESULTS

The cohort included 1007 men (African Americans, 330 [32.8%]; Whites, 677 [67.2%]) followed for a median of 7.7 years; 773 (76.8%) had low-intermediate-risk disease, and 234 (23.2%) had high-intermediate-risk disease. The 10-year cumulative incidences of definitive treatment were not significantly different (African Americans, 83.5%; 95% confidence interval [CI], 78.5%-88.7%; Whites, 80.6%; 95% CI, 76.6%-84.4%; P = .17). Among those with low-intermediate-risk disease, there were no significant differences in the 10-year cumulative incidences of disease progression (African Americans, 46.8%; 95% CI, 40.0%-53.3%; Whites, 46.9%; 95% CI, 42.1%-51.5%; P = .91), metastasis (African Americans, 7.1%; 95% CI, 3.7%-11.8%; Whites, 10.8%; 95% CI, 7.6%-14.6%; P = .17), or PCSM (African Americans, 3.8%; 95% CI, 1.6%-7.5%; Whites, 3.8%; 95% CI, 2.0%-6.3%; P = .69). In a multivariable regression including the entire cohort, African American race was not associated with increased risks of definitive treatment, disease progression, metastasis, PCSM, or all-cause mortality (all P > .30).

CONCLUSIONS

Outcomes in the Veterans Affairs Health System were similar for African American and White men treated for low-intermediate-risk prostate cancer with AS.

Social determinants do not affect access to specialized epilepsy care in veterans

INTRODUCTION

It is well established that sociodemographic and neighborhood determinants impact access to healthcare. Veterans with epilepsy (VWE) face unique challenges that may limit access to specialized epilepsy care, though institutional initiatives have aimed to minimize disparities. We assessed the extent to which surrogate markers of access to quality care in VWE were impacted by sociodemographic and neighborhood determinants.

METHODS

The sample included 180 VWE. Surrogate markers included time between initial diagnosis and admission to epilepsy monitoring unit (EMU) (time to referral, TTR), and the number of CT, MRI, and EEGs conducted prior to initial EMU evaluation. Sociodemographic and neighborhood determinants included age, sex, race, education, neighborhood advantage, rural status, distance from home to the nearest VAMC, and number of service connection (SC) conditions. Significant correlations across variables of interest were entered into a linear regression. Group differences between social factors were assessed for early and late TTR groups (based on 1st and 4th quartiles).

RESULTS

The mean TTR was 12 years (SD ± 13.18). Longer TTR was correlated to older age (p < 0.001) and fewer SC conditions (p = 0.03). None of the other factors were significantly correlated to TTR. Older age significantly predicted longer TTR on regression. The earlier TTR group was younger, had more SC conditions, lived closer to a VAMC, and was more likely to be female. Greater geographic distance was correlated with fewer CT scans (p = 0.01). A greater number of MRIs was correlated with older age (p = 0.04). Younger age (p < 0.01) and greater education (p = 0.01) were correlated with more SC.

CONCLUSION

Access to epilepsy care among VWE was largely unimpacted by social determinants, with the exception of older age leading to longer TTR. The TTR in VWE was considerably shorter than has been reported in the literature for civilian patients. The Veterans Health Administration model of care may harbor certain advantages in epilepsy treatment.

Long-term depression incidence and associated mortality among African American and White prostate cancer survivors

BACKGROUND

Depression is common after a diagnosis of prostate cancer and may contribute to poor outcomes, particularly among African Americans. The authors assessed the incidence and management of depression and its impact on overall mortality among African American and White veterans with localized prostate cancer.

METHODS

The authors used the Veterans Health Administration Corporate Data Warehouse to identify 40,412 African American and non-Hispanic White men diagnosed with localized prostate cancer from 2001 to 2013. Patients were followed through 2019. Multivariable logistic regression was used to measure associations between race and incident depression, which were ascertained from administrative and depression screening data. Cox proportional hazards models were used to measure associations between incident depression and all-cause mortality, with race-by-depression interactions used to assess disparities.

RESULTS

Overall, 10,013 veterans (24.5%) were diagnosed with depression after a diagnosis of prostate cancer. Incident depression was associated with higher all-cause mortality (adjusted hazard ratio [aHR], 1.27; 95% confidence interval [CI], 1.23-1.32). African American veterans were more likely than White veterans to be diagnosed with depression (29.3% vs 23.2%; adjusted odds ratio [aOR], 1.15; 95% CI, 1.09-1.21). Among those with depression, African Americans were less likely to be prescribed an antidepressant (30.4% vs 31.7%; aOR, 0.85; 95% CI, 0.77-0.93). The hazard of all-cause mortality associated with depression was greater for African American veterans than White veterans (aHR, 1.32 [95% CI, 1.26-1.38] vs 1.15 [95% CI, 1.07-1.24]; race-by-depression interaction P < .001).

CONCLUSIONS

Incident depression is common among prostate cancer survivors and is associated with higher mortality, particularly among African American men. Patient-centered strategies to manage incident depression may be critical to reducing disparities in prostate cancer outcomes.

A machine learning approach to identify distinct subgroups of veterans at risk for hospitalization or death using administrative and electronic health record data

Background

Identifying individuals at risk for future hospitalization or death has been a major priority of population health management strategies. High-risk individuals are a heterogeneous group, and existing studies describing heterogeneity in high-risk individuals have been limited by data focused on clinical comorbidities and not socioeconomic or behavioral factors. We used machine learning clustering methods and linked comorbidity-based, sociodemographic, and psychobehavioral data to identify subgroups of high-risk Veterans and study long-term outcomes, hypothesizing that factors other than comorbidities would characterize several subgroups.

Methods and findings

In this cross-sectional study, we used data from the VA Corporate Data Warehouse, a national repository of VA administrative claims and electronic health data. To identify high-risk Veterans, we used the Care Assessment Needs (CAN) score, a routinely-used VA model that predicts a patient’s percentile risk of hospitalization or death at one year. Our study population consisted of 110,000 Veterans who were randomly sampled from 1,920,436 Veterans with a CAN score≥75^th percentile in 2014. We categorized patient-level data into 119 independent variables based on demographics, comorbidities, pharmacy, vital signs, laboratories, and prior utilization. We used a previously validated density-based clustering algorithm to identify 30 subgroups of high-risk Veterans ranging in size from 50 to 2,446 patients. Mean CAN score ranged from 72.4 to 90.3 among subgroups. Two-year mortality ranged from 0.9% to 45.6% and was highest in the home-based care and metastatic cancer subgroups. Mean inpatient days ranged from 1.4 to 30.5 and were highest in the post-surgery and blood loss anemia subgroups. Mean emergency room visits ranged from 1.0 to 4.3 and were highest in the chronic sedative use and polysubstance use with amphetamine predominance subgroups. Five subgroups were distinguished by psychobehavioral factors and four subgroups were distinguished by sociodemographic factors.

Conclusions

High-risk Veterans are a heterogeneous population consisting of multiple distinct subgroups–many of which are not defined by clinical comorbidities–with distinct utilization and outcome patterns. To our knowledge, this represents the largest application of ML clustering methods to subgroup a high-risk population. Further study is needed to determine whether distinct subgroups may benefit from individualized interventions.