A 680,000-person megastudy of nudges to encourage vaccination in pharmacies.

Encouraging vaccination is a pressing policy problem. To assess whether text-based reminders can encourage pharmacy vaccination and what kinds of messages work best, we conducted a megastudy. We randomly assigned 689,693 Walmart pharmacy patients to receive one of 22 different text reminders using a variety of different behavioral science principles to nudge flu vaccination or to a business-as-usual control condition that received no messages. We found that the reminder texts that we tested increased pharmacy vaccination rates by an average of 2.0 percentage points, or 6.8%, over a 3-mo follow-up period. The most-effective messages reminded patients that a flu shot was waiting for them and delivered reminders on multiple days. The top-performing intervention included two texts delivered 3 d apart and communicated to patients that a vaccine was "waiting for you." Neither experts nor lay people anticipated that this would be the best-performing treatment, underscoring the value of simultaneously testing many different nudges in a highly powered megastudy.

Prevalence and Cost of Care Cascades Following Low-Value Preoperative Electrocardiogram and Chest Radiograph Within the Veterans Health Administration.

BACKGROUND: Low-value care cascades, defined as the receipt of downstream health services potentially related to a low-value service, can result in harm to patients and wasteful healthcare spending, yet have not been characterized within the Veterans Health Administration (VHA). OBJECTIVE: To examine if the receipt of low-value preoperative testing is associated with greater utilization and costs of potentially related downstream health services in Veterans undergoing low or intermediate-risk surgery. DESIGN: Retrospective cohort study using VHA administrative data from fiscal years 2017-2018 comparing Veterans who underwent low-value preoperative electrocardiogram (EKG) or chest radiograph (CXR) with those who did not. PARTICIPANTS: National cohort of Veterans at low risk of cardiopulmonary disease undergoing low- or intermediate-risk surgery. MAIN MEASURES: Difference in rate of receipt and attributed cost of potential cascade services in Veterans who underwent low-value preoperative testing compared to those who did not KEY RESULTS: Among 635,824 Veterans undergoing low-risk procedures, 7.8% underwent preoperative EKG. Veterans who underwent a preoperative EKG experienced an additional 52.4 (95% CI 47.7-57.2) cascade services per 100 Veterans, resulting in $138.28 (95% CI 126.19-150.37) per Veteran in excess costs. Among 739,005 Veterans undergoing low- or intermediate-risk surgery, 3.9% underwent preoperative CXR. These Veterans experienced an additional 61.9 (95% CI 57.8-66.1) cascade services per 100 Veterans, resulting in $152.08 (95% CI $146.66-157.51) per Veteran in excess costs. For both cohorts, care cascades consisted largely of repeat tests, follow-up imaging, and follow-up visits, with low rates invasive services. CONCLUSIONS: Among a national cohort of Veterans undergoing low- or intermediate-risk surgeries, low-value care cascades following two routine low-value preoperative tests are common, resulting in greater unnecessary care and costs beyond the initial low-value service. These findings may guide de-implementation policies within VHA and other integrated healthcare systems that target those services whose downstream effects are most prevalent and costly.

Prioritizing the worries of AML patients: Quantifying patient experience using best-worst scaling.

CONTEXT: Although patients with acute myeloid leukemia (AML) experience significant toxicities and poor outcomes, few studies have quantified patients' experience. METHODS: A community-centered approach was used to develop an AML-specific best-worst scaling (BWS) instrument involving 13 items in four domains (psychological, physical, decision-making, and treatment delivery) to quantify patient worry. A survey of patients and caregivers was conducted using the instrument. Data were analyzed using conditional logistic regression. RESULTS: The survey was completed by 832 patients and 237 caregivers. Patients were predominantly white (88%), married/partnered (72%), and in remission (95%). The median age was 55 years (range: 19-87). Median time since diagnosis was 8 years (range: 1-40). Patients worried most about "the possibility of dying from AML" (BWS score = 15.5, confidence interval [CI] [14.2-16.7]) and "long-term side effects of treatments" (14.0, CI [12.9-15.2]). Patients found these items more than twice as worrisome as all items within the domains of care delivery and decision-making. Patients were least worried about "communicating openly with doctors" (2.50, CI [1.97-3.04]) and "having access to the best medical care" (3.90, CI [3.28-4.61]). Caregiver reports were highly correlated to patients' (Spearman's ρ = 0.89) though noted significantly more worry about the possibility of dying and spending time in the hospital. CONCLUSION: This large convenience sample demonstrates that AML patients have two principal worries: dying from their disease and suffering long-term side effects from treatment. To better foster patient-centered care, therapeutic decision-making and drug development should reflect the importance of both potential outcomes. Further work should explore interventions to address these worries.

Understanding Geographic Variation in Systemic Overuse Among the Privately Insured.

BACKGROUND: Medical care overuse is a significant source of patient harm and wasteful spending. Understanding the drivers of overuse is essential to the design of effective interventions. OBJECTIVE: We tested the association between structural factors of the health care delivery system and regional differences systemic overuse. RESEARCH DESIGN: We conducted a retrospective analysis of deidentified claims for 18- to 64-year-old adults from the IBM MarketScan Commercial Claims and Encounters Database. We calculated a semiannual Johns Hopkins Overuse Index for each of the 375 Metropolitan Statistical Areas in the United States, from January 2011 to June 2015. We fit an ordinary least squares regression to model the Johns Hopkins Overuse Index as a function of regional characteristics of the health care system, adjusted for confounders and time. RESULTS: The supply of regional health care resources was associated with systemic overuse in commercially insured beneficiaries. Regional characteristics associated with systemic overuse included number of physicians per 1000 residents (P=0.001) and higher Medicare malpractice geographic price cost index (P<0.001). Regions with a higher density of primary care physicians (P=0.008) and a higher proportion of hospital-based providers (P=0.016) had less systemic overuse. Differences in hospital and insurer market power were inversely associated with systemic overuse. CONCLUSIONS: Systemic overuse is associated with observable, structural characteristics of the regional health care system. These findings suggest that interventions that aim to improve care efficiency via reductions in overuse should focus on the structural drivers of this phenomenon, rather than on the eradication of individual overused procedures.

Systemic overuse of health care in a commercially insured US population, 2010-2015.

BACKGROUND: Overuse is a leading contributor to the high cost of health care in the United States. Overuse harms patients and is a definitive waste of resources. The Johns Hopkins Overuse Index (JHOI) is a normalized measure of systemic health care services overuse, generated from claims data, that has been used to describe overuse in Medicare beneficiaries and to understand drivers of overuse. We aimed to adapt the JHOI for application to a commercially insured US population, to examine geographic variation in systemic overuse in this population, and to analyze trends over time to inform whether systemic overuse is an enduring problem. METHODS: We analyzed commercial insurance claims from 18 to 64 year old beneficiaries. We calculated a semiannual JHOI for each of the 375 Metropolitan Statistical Areas and 47 rural regions of the US. We generated maps to examine geographic variation and then analyzed each region's change in their JHOI quintile from January 2011 to June 2015. RESULTS: The JHOI varied markedly across the US. Across the country, rural regions tended to have less systemic overuse than their MSA counterparts (p < 0.01). Regional systemic overuse is positively correlated from one time period to the next (p < 0.001). Between 2011 and 2015, 53.7% (N = 226) of regions remained in the same quintile of the JHOI. Eighty of these regions had a persistently high or persistently low JHOI throughout study duration. CONCLUSIONS: The systemic overuse of health care resources is an enduring, regional problem. Areas identified as having a persistently high rate of systemic overuse merit further investigation to understand drivers and potential points of intervention.

National Trends in Billing Secure Messages as E-Visits.

This study assesses US trends in e-visit billing using national all-payer claims.

Regional Supply of Medical Resources and Systemic Overuse of Health Care Among Medicare Beneficiaries.

BACKGROUND: Overuse of health care resources has been identified as the leading contributor to waste in the US health care system. OBJECTIVE: To explore health care system factors associated with regional variation in systemic overuse of health care resources as measured by the Johns Hopkins Overuse Index (JHOI) which aggregates systemic overuse of 20 health care services. DESIGN: Using Medicare fee-for-service claims data from beneficiaries age 65 or over in 2008, we calculated the JHOI for the 306 hospital referral regions in the United States. We used ordinary least squares regression and multilevel models to estimate the association of JHOI scores and characteristics of regional health care delivery systems listed in the Area Health Resource File and Dartmouth Atlas. KEY RESULTS: Regions with a higher density of primary care physicians had lower JHOI scores, indicating less systemic overuse (P < 0.001). Regional characteristics associated with higher JHOI scores, indicating more systemic overuse, included number per 1000 residents of acute care hospital beds (P = 0.002) and of hospital-based anesthesiologists, pathologists, and radiologists (P = 0.02). CONCLUSIONS: Regional variations in health care resources including the clinician workforce are associated with the intensity of systemic overuse of health care. The role of primary care doctors in reducing health care overuse deserves further attention.

VALUE AND PERFORMANCE OF ACCOUNTABLE CARE ORGANIZATIONS: A COST-MINIMIZATION ANALYSIS.

OBJECTIVES: Determine the relationship between quality of an accountable care organization (ACO) and its long-term reduction in healthcare costs. METHODS: We conducted a cost minimization analysis. Using Centers for Medicare and Medicaid cost and quality data, we calculated weighted composite quality scores for each ACO and organization-level cost savings. We used Markov modeling to compute the probability that an ACO transitioned between different quality levels in successive years. Considering a health-systems perspective with costs discounted at 3 percent, we conducted 10,000 Monte Carlo simulations to project long-term cost savings by quality level over a 10-year period. We compared the change in per-member expenditures of Pioneer (early-adopters) ACOs versus Medicare Shared Savings Program (MSSP) ACOs to assess the impact of coordination of care, the main mechanism for cost savings. RESULTS: Overall, Pioneer ACOs saved USD 641.24 per beneficiary and MSSP ACOs saved USD 535.59 per beneficiary. By quality level: (a) high quality organizations saved the most money (Pioneer: USD 459; MSSP: USD 816); (b) medium quality saved some money (Pioneer: USD 222; MSSP: USD 105); and (c) low quality suffered financial losses (Pioneer: USD -40; MSSP: USD -386). CONCLUSIONS: Within the existing fee-for-service healthcare model, ACOs are a mechanism for decreasing costs by improving quality of care. Higher quality organizations incorporate greater levels of coordination of care, which is associated with greater cost savings. Pioneer ACOs have the highest level of integration of services; hence, they save the most money.

Observational Analysis of a Generalized, Health Plan-led Community Health Worker Intervention in Medicaid.

INTRODUCTION/OBJECTIVES: In 2018, a Medicaid managed care plan launched a new community health worker (CHW) initiative in several counties within a state, designed to improve the health and quality of life of members who could benefit from additional services. The CHW program involved telephonic and face-to-face visits from CHWs who provided support, empowerment, and education to members, while identifying and addressing health and social issues. The primary objective of this study was to evaluate the impact of a generalized (not disease-specific), health plan-led CHW program on overall healthcare use and spending. METHODS: This retrospective cohort study used data from adult members who received the CHW intervention (N = 538 participants) compared to those who were identified for participation but were unable to be reached (N = 435 nonparticipants). Outcomes measures included healthcare utilization, including scheduled and emergency inpatient admissions, emergency department (ED) visits, and outpatient visits; and healthcare spending. The follow-up period for all outcome measures was 6 months. Using generalized linear models, 6-month change scores were regressed on baseline characteristics to adjust for between-group differences (eg, age, sex, comorbidities) and an indicator for group. RESULTS: Program participants experienced a greater increase in outpatient evaluation and management visits (0.09 per member per month [PMPM]) than the comparison group during the first 6 months of the program. This greater increase was observed across in-person (0.07 PMPM), telehealth (0.03 PMPM), and primary care (0.06 PMPM) visits. There was no observed difference in inpatient admissions, ED utilization or allowed medical spending and pharmacy spending. CONCLUSIONS: A health plan-led CHW program successfully increased multiple forms of outpatient utilization in a historically disadvantaged population of patients. Health plans may be particularly well positioned to finance, sustain, and scale programs that address social drivers of health.

Suicidal risk and management in borderline personality disorder.

This paper reviews recent advances in our understanding of suicidality in borderline personality disorder (BPD), with a focus on suicide risk assessment, guidelines for treatment, and medicolegal concerns. Relevant material on distinctions between suicide completers and suicide attempters, contributions of published American Psychiatric Association Guidelines, the controversial role of hospitalization, and management strategies regarding litigation is addressed. Despite accumulating data on suicidality in BPD, the current state of knowledge offers only partial clues to help identify the BPD patients most at risk of death by suicide, and offers a limited armamentarium of treatment targeted to suicide prevention, creating discomfort in clinicians and fears regarding litigation in the event of a successful suicide. Promising new interventions include less resource-intensive psychotherapies as well as brief crisis intervention.

Assessment of Care Cascades Following Low-Value Prostate-Specific Antigen Testing Among Veterans Dually Enrolled in the US Veterans Health Administration and Medicare Systems.

Importance: Older US veterans commonly receive health care outside of the US Veterans Health Administration (VHA) through Medicare, which may increase receipt of low-value care and subsequent care cascades. Objective: To characterize the frequency, cost, and source of low-value prostate-specific antigen (PSA) testing and subsequent care cascades among veterans dually enrolled in the VHA and Medicare and to determine whether receiving a PSA test through the VHA vs Medicare is associated with more downstream services. Design, Setting, and Participants: This retrospective cohort study used VHA and Medicare administrative data from fiscal years (FYs) 2017 to 2018. The study cohort consisted of male US veterans dually enrolled in the VHA and Medicare who were aged 75 years or older without a history of prostate cancer, elevated PSA, prostatectomy, radiation therapy, androgen deprivation therapy, or a urology visit. Data were analyzed from December 15, 2020, to October 20, 2022. Exposures: Receipt of low-value PSA testing. Main Outcomes and Measures: Differences in the use and cost of cascade services occurring 6 months after receipt of a low-value PSA test were assessed for veterans who underwent low-value PSA testing in the VHA and Medicare compared with those who did not, adjusted for patient- and facility-level covariates. Results: This study included 300 393 male US veterans at risk of undergoing low-value PSA testing. They had a mean (SD) age of 82.6 (5.6) years, and the majority (264 411 [88.0%]) were non-Hispanic White. Of these veterans, 36 459 (12.1%) received a low-value PSA test through the VHA, which was associated with 31.2 (95% CI, 29.2 to 33.2) additional cascade services per 100 veterans and an additional $24.5 (95% CI, $20.8 to $28.1) per veteran compared with the control group. In the same cohort, 17 981 veterans (5.9%) received a PSA test through Medicare, which was associated with 39.3 (95% CI, 37.2 to 41.3) additional cascade services per 100 veterans and an additional $35.9 (95% CI, $31.7 to $40.1) per veteran compared with the control group. When compared directly, veterans who received a PSA test through Medicare experienced 9.9 (95% CI, 9.7 to 10.1) additional cascade services per 100 veterans compared with those who underwent testing within the VHA. Conclusions and Relevance: The findings of this cohort study suggest that US veterans dually enrolled in the VHA and Medicare commonly experienced low-value PSA testing and subsequent care cascades through both systems in FYs 2017 and 2018. Care cascades occurred more frequently through Medicare compared with the VHA. These findings suggest that low-value PSA testing has substantial downstream implications for patients and may be especially challenging to measure when care occurs in multiple health care systems.

Use and Cost of Low-Value Health Services Delivered or Paid for by the Veterans Health Administration.

Importance: Within the Veterans Health Administration (VA), the use and cost of low-value services delivered by VA facilities or increasingly by VA Community Care (VACC) programs have not been comprehensively quantified. Objective: To quantify veterans' overall use and cost of low-value services, including VA-delivered care and VA-purchased community care. Design, Setting, and Participants: This cross-sectional study assessed a national population of VA-enrolled veterans. Data on enrollment, sociodemographic characteristics, comorbidities, and health care services delivered by VA facilities or paid for by the VA through VACC programs were compiled for fiscal year 2018 from the VA Corporate Data Warehouse. Data analysis was conducted from April 2020 to January 2022. Main Outcomes and Measures: VA administrative data were applied using an established low-value service metric to quantify the use of 29 potentially low-value tests and procedures delivered in VA facilities and by VACC programs across 6 domains: cancer screening, diagnostic and preventive testing, preoperative testing, imaging, cardiovascular testing and procedures, and other procedures. Sensitive and specific criteria were used to determine the low-value service counts per 100 veterans overall, by domain, and by individual service; count and percentage of each low-value service delivered by each setting; and estimated cost of each service. Results: Among 5.2 million enrolled veterans, the mean (SD) age was 62.5 (16.0) years, 91.7% were male, 68.0% were non-Hispanic White, and 32.3% received any service through VACC. By specific criteria, 19.6 low-value services per 100 veterans were delivered in VA facilities or by VACC programs, involving 13.6% of veterans at a total cost of $205.8 million. Overall, the most frequently delivered low-value service was prostate-specific antigen testing for men aged 75 years or older (5.9 per 100 veterans); this was also the service with the greatest proportion delivered by VA facilities (98.9%). The costliest low-value services were spinal injections for low back pain ($43.9 million; 21.4% of low-value care spending) and percutaneous coronary intervention for stable coronary disease ($36.8 million; 17.9% of spending). Conclusions and Relevance: This cross-sectional study found that among veterans enrolled in the VA, more than 1 in 10 have received a low-value service from VA facilities or VACC programs, with approximately $200 million in associated costs. Such information on the use and costs of low-value services are essential to guide the VA's efforts to reduce delivery and spending on such care.

Time to address disparities in care by appointment time.

Quality of care systematically decreases over the course of the day. Ensuring that patients seen later in the day receive the same care as patients seen first thing in the morning has broad clinical and economic implications for our health care system. In this article, we outline feasible near-term solutions to direct clinicians and patients toward consistently better primary care decisions, throughout the day. These insights could be adapted to address similar challenges in other health care settings.

The impact of global budget payment reform on systemic overuse in Maryland.

BACKGROUND: Medical overuse is a leading contributor to the high cost of the US health care system and is a definitive misuse of resources. Elimination of overuse could improve health care efficiency. In 2014, the State of Maryland placed the majority of its hospitals under an all-payer, annual, global budget for inpatient and outpatient hospital services. This program aims to control hospital use and spending. OBJECTIVE: To assess whether the Maryland global budget program was associated with a reduction in the broad overuse of health care services. METHODS: We conducted a retrospective analysis of deidentified claims for 18-64 year old adults from the IBM MarketScan® Commercial Claims and Encounters Database. We matched 2 Maryland Metropolitan Statistical Areas (MSAs) to 6 out-of-state comparison MSAs. In a difference-in-differences analysis, we compared changes in systemic overuse in Maryland vs the comparison MSAs before (2011-2013) and after implementation (2014-2015) of the global budget program. Systemic overuse was measured using a semiannual Johns Hopkins Overuse Index. RESULTS: Global budgets were not associated with a reduction in systemic overuse. Over the first 1.5 years of the program, we estimated a nonsignificant differential change of -0.002 points (95%CI, -0.372 to 0.369; p = 0.993) relative to the comparison group. This result was robust to multiple model assumptions and sensitivity analyses. CONCLUSIONS: We did not find evidence that Maryland hospitals met their revenue targets by reducing systemic overuse. Global budgets alone may be too blunt of an instrument to selectively reduce low-value care.

Rates of Routine Cancer Screening and Diagnosis Before vs After the COVID-19 Pandemic.

This cross-sectional study analyzes patterns in the rates of routine screening and diagnosis for breast, cervical, and colorectal cancer before and after the COVID-19 pandemic.

Developing and piloting an instrument to prioritize the worries of patients with acute myeloid leukemia.

BACKGROUND: Acute myeloid leukemia (AML) is a rapidly progressing blood cancer for which new treatments are needed. We sought to promote patient-focused drug development (PFDD) for AML by developing and piloting an instrument to prioritize the worries of patients with AML. PATIENTS AND METHODS: An innovative community-centered approach was used to engage expert and community stakeholders in the development, pretesting, pilot testing, and dissemination of a novel best-worst scaling instrument. Patient worries were identified through individual interviews (n=15) and group calls. The instrument was developed through rigorous pretesting (n=13) and then piloted among patients and caregivers engaged in this study (n=25). Priorities were assessed using best-worst scores (spanning from +1 to -1) representing the relative number of times that items were endorsed as the most and the least worrying. All findings were presented at a PFDD meeting at the US Food and Drug Administration (FDA) that was attended by >80 stakeholders. RESULTS: The final instrument included 13 worries spanning issues such as decision making, treatment delivery, physical impacts, and psychosocial effects. Patients and caregivers most prioritized worries about dying from their disease (best minus worst [BW] score=0.73), long-term side effects (BW=0.28), and time in hospital (BW=0.25). CONCLUSION: Community-centered approaches are valuable in designing and executing PFDD meetings and associated quantitative surveys to document the experience of patients. Expert and community stakeholders welcomed the opportunity to share their experiences with the FDA and strongly endorsed implementing this survey nationally.

Factors Influencing Overuse of Breast Cancer Screening: A Systematic Review.

BACKGROUND: Excessive breast cancer screening with mammography or other modalities often burdens patients with false-positive results and costs. Yet, screening patients beyond the age at which they will benefit or at too frequent intervals persists. This review summarizes the factors associated with overuse of breast cancer screening. METHODS: We searched Medline and Embase from January 1998 to March 2017 for articles addressing the overuse of breast cancer screening and hand-searched the reference lists of included articles. Studies were included if they were written in English, pertained to a U.S. population, and identified a factor associated specifically with overuse of breast imaging. Paired reviewers independently screened abstracts, extracted data, and assessed quality. RESULTS: We included 15 studies: 3 cohort, 5 cross-sectional, 6 surveys, and 1 in-depth interview. White women (non-Hispanic) were less vulnerable than other racial groups to overuse in 3 of 5 studies. Physician specialty was consistently associated with screening overuse in three of three studies. Abundant access to primary care and a patient desire for screening were associated with breast cancer screening overuse. Lower self-confidence, lower risk taking tendencies, higher perception of conflict in expert recommendations, and a belief in screening effectiveness were clinician traits associated with overuse of screening in the surveys. CONCLUSIONS: The literature supports that liberal access to care and clinicians' recommendations to screen, possibly influenced by conflicting guidelines, increase excessive breast cancer screening. Overuse might conceivably be reduced with more concordance across guidelines, physician education, patient involvement in decision-making, thoughtful insurance restrictions, and limitations on the supply of services; however, these will need careful testing regarding their impact.

Association of raltegravir use with long-term health outcomes in HIV-infected patients: an observational post-licensure safety study in a large integrated healthcare system.

BACKGROUND: Raltegravir became the first integrase inhibitor to gain FDA approval; but with limited evidence documenting long-term risks in real world care, especially for major health outcomes of interest. OBJECTIVE: Assess raltegravir safety in clinical practice within an integrated health system. METHODS: We conducted a cohort study of HIV-infected adults within Kaiser Permanente California from 2005 to 2013. We compared patients initiating raltegravir during the study period with two groups; a historical cohort (started new antiretroviral regimen [ART] 2005-2007) and a concurrent cohort that did not initiate raltegravir (2007-2013). We used multivariate Cox proportional hazard regression to obtain hazard ratios (HR) for pre-specified incident health outcomes, employing propensity scores to adjust for potential confounding. RESULTS: The population included 8,219 HIV-infected adults (raltegravir cohort N = 1,757; 4,798 patient-years), with greater years known HIV-infected among raltegravir patients. The raltegravir cohort had increased HR for AIDS-defining (HR 2.69 [1.53-4.71]; HR 1.85 [1.21-2.82]) and non-AIDS-defining malignancies (HR 2.26 [1.29-3.94]; HR 1.88 [1.26-2.78]) relative to both comparison cohorts. Compared to the historical cohort we found no significant difference in all-cause mortality; the raltegravir cohort experienced increased HR for all-cause mortality compared to concurrent (HR 1.53 [1.02-2.31]). Raltegravir appeared protective of lipodystrophy when compared to the historical cohort but associated with increased incidence compared to concurrent. There were no significant differences in the incidence of hepatic, skin, or cardiovascular events. CONCLUSIONS: The potentially elevated risk for malignancy and mortality with raltegravir and residual confounding merits further investigation. We demonstrate the value of observational cohorts for monitoring post-licensure medication safety.

Determinants of the overuse of imaging in low-risk prostate cancer: A systematic review.

BACKGROUND: The overuse of radiologic services, where imaging tests are provided in circumstances where the propensity for harm exceeds the propensity for benefit, comprises a risk to patient safety and a burden on health care systems. Advanced imaging in the staging of low-risk prostate cancer is considered an overused procedure by many professional societies, yet the determinants that drive this phenomenon are not fully appreciated. METHODS: We systematically searched published literature within MEDLINE and Embase from January 1998 to March 2017. We searched for studies conducted in the United States that contain original data and describe determinants associated with the overuse of imaging in low-risk prostate cancer. Paired reviewers independently screened abstracts, assessed quality, and extracted data. We synthesized the identified determinants as patient-level, clinician-level, or system-level factors of overuse. RESULTS: A total of 14 articles were included; the 13 empirical studies defined overuse as being the use of imaging that was discordant with clinical guidelines. Patient- and system-related factors were most commonly described as being associated with overuse; clinician-level determinants were examined infrequently. Older patient age (n = 5), more patient comorbidities (n = 7), and characteristics related to geography (n = 6), higher regional income (n = 6), and less education (n = 5) were the most consistently identified statistically significant determinants of overuse. Meaningful differences were detected between health care settings; large integrated health care systems provided less variable care and had lower rates of overuse. Clinical indicators related to prostate cancer were inconsistently associated with overuse. CONCLUSION: Many patient- and system-related determinants were identified as contributing to the overuse of advanced imaging to stage low-risk prostate cancer. Overuse may be the consequence of systematized clinician behavior and be relatively invariant of patient characteristics. The identified system-level determinants suggest that payment models that are not tied to volume or that reward, enhanced care co-ordination may curb overuse. We propose further examination of physician-level determinants and implore researchers to rank the relative importance of the identified factors and to test their influence through experimental and quasi-experimental methods.