An introduction to bayesian spatial smoothing methods for disease mapping: modeling county firearm suicide mortality rates.

This article introduces bayesian spatial smoothing models for disease mapping-a specific application of small area estimation where the full universe of data is known-to a wider audience of public health professionals using firearm suicide as a motivating example. Besag, York, and Mollié (BYM) Poisson spatial and space-time smoothing models were fitted to firearm suicide counts for the years 2014-2018. County raw death rates in 2018 ranged from 0 to 24.81 deaths per 10 000 people. However, the highest mortality rate was highly unstable, based on only 2 deaths in a population of approximately 800, and 80.5% of contiguous US counties experienced fewer than 10 firearm suicide deaths and were thus suppressed. Spatially smoothed county firearm suicide mortality estimates ranged from 0.06 to 4.05 deaths per 10 000 people and could be reported for all counties. The space-time smoothing model produced similar estimates with narrower credible intervals as it allowed counties to gain precision from adjacent neighbors and their own counts in adjacent years. bayesian spatial smoothing methods are a useful tool for evaluating spatial health disparities in small geographies where small numbers can result in highly variable rate estimates, and new estimation techniques in R software have made fitting these models more accessible to researchers.

EXPOSURE TO AMBIENT HEAT AND RISK OF SPONTANEOUS ABORTION: A CASE-CROSSOVER STUDY.

BACKGROUND: Few epidemiologic studies have examined the association of ambient heat with spontaneous abortion, a common and devastating pregnancy outcome. METHODS: We conducted a case-crossover study nested within Pregnancy Study Online, a preconception cohort study (2013-2022). We included all participants reporting spontaneous abortion (n=1,524). We defined the case window as the 7 days preceding the event and used time-stratified referent selection to select control windows matched on calendar month and day of week. Within each 7-day case and control window, we measured mean, maximum, and minimum of daily maximum outdoor air temperatures. We fit splines to examine non-linear relationships across the entire year and conditional logistic regression to estimate odds ratios (OR) and 95% CI of spontaneous abortion with increases in temperature during the warm season (May-September) and decreases during the cool season (November-March). RESULTS: We found evidence of a U-shaped association between outdoor air temperature and spontaneous abortion risk based on year-round data. When restricting to warm season events (n=657), the OR for a 10-percentile increase in the mean of lag 0-6 daily maximum temperatures was 1.1 (95% CI: 0.96, 1.2) and, for the maximum, 1.1 (95% CI: 0.99, 1.2). The OR associated with any extreme heat days (>95th county-specific percentile) in the preceding week was 1.2 (95% CI: 0.95, 1.5). Among cool season events (n=615), there was no appreciable association between lower temperatures and spontaneous abortion risk. CONCLUSION: Our study provides evidence of an association between high outdoor temperatures and incidence of spontaneous abortion.

Generalizability of heat-related health risk associations observed in a large healthcare claims database of patients with commercial health insurance.

BACKGROUND: Extreme ambient heat is unambiguously associated with higher risk of illness and death. The Optum Labs Data Warehouse (OLDW), a database of medical claims from US-based patients with commercial or Medicare Advantage health insurance, has been used to quantify heat-related health impacts. Whether results for the insured sub-population are generalizable to the broader population has to our knowledge not been documented. We sought to address this question, for the US population in California from 2012 to 2019. METHODS: We examined changes in daily rates of emergency department (ED) encounters and in-patient hospitalization encounters for all-causes, heat-related outcomes, renal disease, mental/behavioral disorders, cardiovascular disease, and respiratory disease. OLDW was the source for health data for insured individuals in California, and health data for the broader population were gathered from the California Department of Health Care Access and Information (HCAI). We defined extreme heat exposure as any day in a group of 2 or more days with maximum temperatures exceeding the county-specific 97.5 th percentile and used a space-time-stratified case-crossover design to assess and compare the impacts of heat on health. RESULTS: Average incidence rates of medical encounters differed by dataset. However, rate ratios for ED encounters were similar across datasets for all causes (ratio of incidence rate ratios (rIRR) = 0.989; 95% confidence interval (CI) = 0.973, 1.011), heat-related causes (rIRR = 1.080; 95% CI = 0.999, 1.168), renal disease (rIRR = 0.963; 95% CI = 0.718, 1.292), and mental health disorders (rIRR = 1.098; 95% CI = 1.004, 1.201). Rate ratios for inpatient encounters were also similar. CONCLUSIONS: This work presents evidence that OLDW can continue to be a resource for estimating the health impacts of extreme heat.

Community-Academic Partnership to Assess the Role of Physical Disinvestment on Firearm Violence in Toledo, OH.

Reversing physical disinvestment, e.g., by remediating abandoned buildings and vacant lots, is an evidence-based strategy to reduce urban firearm violence. However, adoption of this strategy has been inconsistent across US cities. Our community-academic partnership sought to support adoption in Toledo, OH, USA, by generating locally relevant analyses on physical disinvestment and firearm violence. We used a spatial case-control design with matching. Physical disinvestment measures were derived from a citywide parcel foot audit conducted by the Lucas County Land Bank in summer 2021. Firearm violence outcomes were incident-level shootings data from the Toledo Police Department from October 2021 through February 2023. Shooting locations were matched to controls 1:4 on poverty rate, roadway characteristics, and zoning type. Exposures were calculated by aggregating parcels within 5-min walking buffers of each case and control point. We tested multiple disinvestment measures, including a composite index. Models were logistic regressions that adjusted for the matching variables and for potential spatial autocorrelation. Our sample included N = 281 shooting locations and N = 1124 matched controls. A 1-unit increase in the disinvestment score, equal to approximately 1 additional disrepair condition for the average parcel within the walking buffer, was associated with 1.68 times (95% CI: 1.36, 2.07) higher odds of shooting incidence. Across all other measures, greater disinvestment was associated with higher odds of shooting incidence. Our finding of a strong association between physical disinvestment and firearm violence in Toledo can inform local action. Community-academic partnership could help increase adoption of violence prevention strategies focused on reversing physical disinvestment.

Racial and ethnic differences in the association between depressive symptoms and cognitive outcomes in older adults: Findings from KHANDLE and STAR.

INTRODUCTION: Depressive symptoms are associated with higher risk of dementia, but how they impact cognition in diverse populations is unclear. METHODS: Asian, Black, Latino, or White participants (n = 2227) in the Kaiser Healthy Aging and Diverse Life Experiences (age 65+) and the Study of Healthy Aging in African Americans (age 50+) underwent up to three waves of cognitive assessments over 4 years. Multilevel models stratified by race/ethnicity were used to examine whether depressive symptoms were associated with cognition or cognitive decline and whether associations differed by race/ethnicity. RESULTS: Higher depressive symptoms were associated with lower baseline verbal episodic memory scores (-0.06, 95% CI: -0.12, -0.01; -0.15, 95% CI: -0.25, -0.04), and faster decline annually in semantic memory (-0.04, 95% CI: -0.07, -0.01; -0.10, 95% CI: -0.15, -0.05) for Black and Latino participants. Depressive symptoms were associated with lower baseline but not decline in executive function. DISCUSSION: Depressive symptoms were associated with worse cognitive outcomes, with some evidence of heterogeneity across racial/ethnic groups. HIGHLIGHTS: We examined whether baseline depressive symptoms were differentially associated with domain-specific cognition or cognitive decline by race/ethnicity. Depressive symptoms were associated with worse cognitive scores for all racial/ethnic groups across different domains examined. Higher depressive symptoms were associated with faster cognitive decline for semantic memory for Black and Latino participants. The results suggest a particularly harmful association between depressive symptoms and cognition in certain racial/ethnic groups.

The incidence of hypertension among children after renal trauma: A matched cohort analysis.

PURPOSE: To describe the intermediate-term incidence of hypertension following pediatric renal trauma relative to that in an extremity (control group) trauma cohort. METHODS: This was a single-institution matched cohort study of pediatric patients presenting to a Level I trauma center between 2010 and 2019. The primary cohort included patients who sustained renal trauma, and a comparator cohort of sex- and age-matched patients with isolated extremity fracture was identified. The primary outcome was new hypertension, and a sensitivity analysis was conducted of any elevated blood pressure (EBP). Conditional logistic regression was performed and adjusted for overweight/obese status. RESULTS: There were 62 renal trauma patients included, representing 35% of all eligible patients seen in the study period. Hypertension was not found to be more prevalent with renal trauma (OR 1.18, 95% CI: 0.41, 3.39). The incidence of hypertension (9.7-11.3%) and EBP (22.6-32.3%) was comparable between renal trauma and control groups. CONCLUSION: Despite a high incidence of EBP and hypertension in pediatric patients after renal or extremity trauma, we did not observe an association between renal trauma and postinjury hypertension. We identified no cases of malignant or symptomatic hypertension, and no surgical interventions for renovascular hypertension was performed. Our findings suggest that only select patients, rather than most renal trauma patients, may benefit from monitoring for postinjury hypertension.

Warm season ambient ozone and children's health in the USA.

BACKGROUND: Over 120 million people in the USA live in areas with unsafe ozone (O3) levels. Studies among adults have linked exposure to worse lung function and higher risk of asthma and chronic obstructive pulmonary disease (COPD). However, few studies have examined the effects of O3 in children, and existing studies are limited in terms of their geographic scope or outcomes considered. METHODS: We leveraged a dataset of encounters at 42 US children's hospitals from 2004-2015. We used a one-stage case-crossover design to quantify the association between daily maximum 8-hour O3 in the county in which the hospital is located and risk of emergency department (ED) visits for any cause and for respiratory disorders, asthma, respiratory infections, allergies and ear disorders. RESULTS: Approximately 28 million visits were available during this period. Per 10 ppb increase, warm-season (May through September) O3 levels over the past three days were associated with higher risk of ED visits for all causes (risk ratio [RR]: 0.3% [95% confidence interval (CI): 0.2%, 0.4%]), allergies (4.1% [2.5%, 5.7%]), ear disorders (0.8% [0.3%, 1.3%]) and asthma (1.3% [0.8%, 1.9%]). When restricting to levels below the current regulatory standard (70 ppb), O3 was still associated with risk of ED visits for all-cause, allergies, ear disorders and asthma. Stratified analyses suggest that the risk of O3-related all-cause ED visits may be higher in older children. CONCLUSIONS: Results from this national study extend prior research on the impacts of daily O3 on children's health and reinforce the presence of important adverse health impacts even at levels below the current regulatory standard in the USA.

Firearm Experiences, Behaviors, and Norms Among Rural Adolescents.

Importance: Rural adolescents are at high risk for firearm-related injury, yet most existing prevention efforts are informed by research conducted in urban areas. Despite the need to account for rural perspectives, few studies have investigated the unique social ecological context of firearms for rural adolescents or have directly engaged with rural adolescents to understand their views on firearm use. Objective: To describe rural adolescents' firearm behaviors and perceptions of firearm-related social norms within their communities, peer groups, and families. Design, Setting, and Participants: This cross-sectional study used a convergent mixed-methods design and involved a community-based participatory research approach. Participants comprised 93 adolescents residing in rural Washington state and enrolled in a county or tribal reservation 4-H youth development program as an intermediate or senior age-level grouping (ie, aged 12-19 years). Adolescents completed a survey and participated in a semistructured focus group or interview between September 1, 2021, and September 30, 2022. Data were analyzed using descriptive and thematic analysis. Main Outcomes and Measures: Individual handgun behavior and peer, family, and community perceptions of firearm-related social norms. Results: The sample included 93 adolescents (mean [SD] age, 15.7 [1.7] years; 49 female participants [52.7%]). Approximately half of participants (52 [55.9%]) had carried a handgun at some point in their lives, with a mean (SD) age at first carry of 10.9 (3.1) years. Primary themes across quantitative and qualitative data focused on social norms (specifically, acceptable and unacceptable ways to engage with firearms, reasons for carrying firearms, and places to carry a firearm). Conclusions and Relevance: In this cross-sectional study, rural adolescents in 4-H programs generally understood acceptable and unacceptable firearm carrying behaviors, which aligned with state laws. Findings provide context for rural adolescent behaviors such as carrying a firearm predominantly for prosocial reasons (hunting, recreation, and sport) and adult behavior such as carrying for protection of person and personal property. Understanding firearm-related social norms in rural communities holds implications for firearm injury prevention efforts, especially related to enhancing training, developing norms-based prevention approaches, and tailoring efforts to rural settings.

Electroacupuncture for Pain Outcomes in a Trauma Center's Acute Pain Service: A Retrospective Observational Study.

Background: Evidence for acupuncture to treat pain is growing. Electrostimulation of acupuncture needles (electroacupuncture) is common for pain and is thought to augment the therapeutic effect. Objectives: To examine the association of pain outcomes after a single acupuncture session with electrostimulation included (EA) compared with no electrostimulation included (NEA). Methods: A retrospective observational study was conducted using electronic health records of acupuncture sessions for adults with acute pain under the care of an acute pain service. Paired t-test and linear regression were used to report pain intensity changes after a single acupuncture session and by including EA. Ordered logistic regression was used to report categorical pain relief. Logistic regression was used to explore the odds of adding EA and the patient's age, gender, and pretreatment pain. Results: From July 24, 2017, through November 9, 2020, 465 acupuncture sessions recorded EA (n = 194), or NEA (n = 271). Acupuncture, independent of EA status, reduced pain intensity by a mean 2.5 points. EA was associated with a mean 0.38-point reduction in pain intensity more than NEA (confidence interval [95% CI]: -0.75 to -0.01). Among sessions reporting categorical pain relief (n = 415), higher relief was more likely with EA (odds ratio = 2.16, 95% CI: 1.52-3.08). There was no association between EA and the patient's age, gender, and pretreatment pain intensity. Conclusions: After a single acupuncture session, both EA and NEA reduced pain intensity. Higher categorical pain relief was reported with EA, though the clinical meaning is uncertain. Future research should focus on well-defined populations for electroacupuncture and factors for including electrostimulation.

School Handgun Carrying Among Youth Growing Up in Rural Communities.

PURPOSE: To characterize school handgun carrying and violence risk factors among rural youth. METHODS: Using a sample of rural youth (n = 1995), we quantified the proportion who carried a handgun to school, carried but not to school, and did not carry across grades 7-12 and endorsed risk factors for violence in individual, peer, school, and community domains. RESULTS: Overall, 3% (95% confidence interval [CI]: 2%-4%) of youth ever carried to school; 15% (95% CI: 14%-16%) carried but not to school; and 82% (95% CI: 80%-84%) never carried. Violence risk factors (e.g., attacking someone) were more commonly endorsed by youth who carried to school (84%; 95% CI: 73%-95%) than those who carried but not to school (51%; 95% CI: 44%-58%) and did not carry (23%; 95% CI: 20%-26%). DISCUSSION: Carrying a handgun to school in rural areas is not common; however, it is associated with risk factors for violence. Understanding violence risk factors among youth who carry handguns to school could inform violence prevention programs in rural areas.

Effect of the Communities That Care Prevention System on Adolescent Handgun Carrying: A Cluster-Randomized Clinical Trial.

Importance: There is little information on upstream community-based interventions that reduce the prevalence of handgun carrying among adolescents, especially those growing up in rural areas. Objective: To test whether Communities That Care (CTC), a community-based prevention system focusing on risk and protective factors for behavioral problems early in life, reduces handgun carrying prevalence among adolescents growing up in rural areas. Design, Setting, and Participants: Community-randomized trial of 24 small towns in 7 states assigned randomly to the CTC or control group with outcomes assessed from 2003 to 2011. Participants were youths attending public schools in grade 5 who received consent from their parents to participate (77% of the eligible population) and were repeatedly surveyed through grade 12 with 92% retention. Analyses were conducted from June to November 2022. Interventions: A coalition of community stakeholders received training and technical assistance to install CTC, used local epidemiologic data to identify elevated risk factors and low protective factors for adolescent behavioral problems, and implemented tested preventive interventions for youth, their families, and schools. Main Outcomes and Measures: Handgun carrying (never vs at least once) operationalized in 2 ways: (1) prevalence of past-year handgun carrying, and (2) cumulative prevalence of handgun carrying from grade 6 through grade 12. Results: Overall, the 4407 study participants' mean (SD) age was 12 (.4) years in both CTC (2405 participants) and control (2002 participants) communities in grade 6; about one-half of participants in each group were female (1220 [50.7 %] in the CTC group and 962 [48.1%] in the control group). From grade 6 through grade 12, 15.5% of participants in CTC communities and 20.7% of those in control communities reported carrying a handgun at least once. Youths in CTC communities were significantly less likely to report handgun carrying at a given grade than those in control communities (odds ratio [OR], 0.73; 95% CI, 0.65-0.82). The most pronounced effects were observed in grade 7 (OR, 0.70; 95% CI, 0.42-0.99), grade 8 (OR, 0.58; 95% CI, 0.41-0.74), and grade 9 (OR, 0.65; 95% CI, 0.39-0.91). Cumulatively from grade 6 through grade 12, youths in CTC communities were significantly less likely to report handgun carrying at least once than those in control communities (OR, 0.76; 95% CI, 0.70-0.84). Overall, CTC reduced the prevalence of past-year handgun carrying by 27% at a given grade and by 24% cumulatively through grade 12. Conclusions and Relevance: In this study, CTC reduced the prevalence of adolescent handgun carrying in participating communities. Trial Registration: ClinicalTrials.gov Identifier: NCT01088542.

Racial and Ethnic Differences in the Association between Depressive Symptoms and Cognitive Outcomes in Older Adults: Findings from KHANDLE and STAR.

INTRODUCTION: Depressive symptoms are associated with higher risk of dementia but how they impact cognition in diverse populations is unclear. METHODS: Asian, Black, LatinX, or White participants (n=2,227) in the Kaiser Healthy Aging and Diverse Life Experiences (age 65+) and the Study of Healthy Aging in African Americans (age 50+) underwent up to three waves of cognitive assessments over four years. Multilevel models stratified by race/ethnicity were used to examine whether depressive symptoms were associated with cognition or cognitive decline and whether associations differed by race/ethnicity. RESULTS: Higher depressive symptoms were associated with lower baseline verbal episodic memory scores (-0.06, 95%CI: -0.12, -0.01; -0.15, 95%CI: -0.25, -0.04), and faster decline annually in semantic memory (-0.04, 95%CI: -0.07, -0.01; -0.10, 95%CI: -0.15, -0.05) for Black and LatinX participants. Depressive symptoms were associated with lower baseline but not decline in executive function. DISCUSSION: Depressive symptoms were associated with worse cognitive domains, with some evidence of heterogeneity across racial/ethnic groups.

Analysis of Daily Ambient Temperature and Firearm Violence in 100 US Cities.

Importance: Firearm violence is a leading public health crisis in the US. Understanding whether and how ambient temperature is associated with firearm violence may identify new avenues for prevention and intervention. Objective: To estimate the overall and regional association between hotter temperatures and higher risk of firearm violence in the US. Design, Setting, and Participants: This cross-sectional study used distributed lag nonlinear models, controlling for seasonality and long-term time trends by city and pooled results overall and by climate region. The most populous cities in the US with the highest number of assault-related firearm incidence (ie, shootings) from 2015 to 2020 were analyzed. Data analysis was performed from October 2021 to June 2022. Exposures: Maximum daily temperature by city. Main Outcomes and Measures: The primary outcome was the number of assault-related firearm shootings by city. Results: A total of 116 511 shootings in 100 cities were included in this analysis. The pooled analysis estimated that 6.85% (95% CI, 6.09%-7.46%) of all shootings were attributable to days hotter than city-specific median temperatures. This equates to 7973 total shootings (95% CI, 7092-8688 total shootings) across the 100 cities over the 6-year study period, although the number of total persons injured or killed would be higher. Estimated risk of firearm incidents increased almost monotonically with higher temperatures, with a local peak at the 84th percentile of the temperature range corresponding to a relative risk of 1.17 (95% CI, 1.12-1.21) compared with the median temperature. However, even moderately hot temperatures were associated with higher risk of shootings. Although significant, there was low heterogeneity between cities (I2 = 11.7%; Cochran Q test, P = .02), indicating regional or climate-specific variation in the daily temperature and incident shootings relationship. Conclusions and Relevance: These findings underscore the importance of heat adaptation strategies broadly throughout the year to reduce shootings, rather than focusing on only the hottest days.

Survey of Washington clinicians' willingness to use and preferences related to extreme risk protection orders.

Extreme Risk Protection Orders (ERPOs) temporarily restrict access to firearms if an individual is deemed a significant risk of harm to themselves or others. Some states allow clinicians to initiate ERPO petitions for their patients and a new Justice Department model statute recommends clinicians should be eligible petitioners. Washington clinicians cannot currently file ERPOs independently. This article presents the results of an electronic survey of all actively licensed Washington physicians and advanced registered nurse practitioners in 2021 to gauge clinicians' familiarity, willingness, barriers, facilitators, and preferences for initiating ERPOs by counselling a patient or patient's family, contacting law enforcement, or filing independently. 3021 Clinicians responded. 75.2% were not familiar with ERPOs but reported being willing to counsel patients about ERPOs if they encountered a patient at substantial risk of harm to themselves (96%) or others (97%). Counselling was the preferred approach to filing; however, approximately 75% would be willing to file independently if allowed. Lack of knowledge about ERPOs was the most reported barrier and training the most common facilitator for all initiation approaches. Having a trained social worker to refer patients (81.5%), an ERPO liaison to law enforcement (70.9%), or coordinator to assist with filing (71.3%) was highly desired. Survey response rates were: 13.5% for physicians, 17.2% for nurse practitioners. Washington clinicians are willing to use ERPOs for their patients, but they need training. Counselling was the preferred initiation approach, and there was a strong preference for a social worker or ERPO coordinator to assist in counseling and filing.

Trajectories of Handgun Carrying in Rural Communities From Early Adolescence to Young Adulthood.

Importance: Characterizing patterns of handgun carrying among adolescents and young adults can inform programs to reduce firearm-related harm. Longitudinal patterns of handgun carrying among rural adolescents have not been identified. Objectives: To assess specific points of intervention by characterizing patterns of handgun carrying by youths in rural communities from early adolescence to young adulthood and to quantify how age at initiation, duration, and frequency of carrying differ across identified patterns. Design, Setting, and Participants: This cohort study uses the control group of the community-randomized trial of the Communities That Care prevention system, conducted among public school students in 12 rural communities across 7 states. Participants self-reported their handgun carrying at 10 data collection points from 12 to 26 years of age (2005-2019). Data were analyzed from January to July 2021. Main Outcomes and Measures: Handgun carrying in the past 12 months. Latent class growth analysis was used to estimate handgun carrying trajectories. Results: In this longitudinal rural sample of 2002 students, 1040 (51.9%) were male; 532 (26.6%) were Hispanic, Latino, Latina, or Latinx; 1310 (65.4%) were White; and the highest level of educational attainment of either parent was a high school degree or less for 649 students (32.4%). The prevalence of handgun carrying in the last 12 months ranged from 5.3% (95 of 1795) to 7.4% (146 of 1969) in adolescence and increased during the mid-20s (range, 8.9% [154 of 1722] to 10.9% [185 of 1704] from 23 to 26 years of age). Among the participants who reported handgun carrying at least once between 12 and 26 years of age (n = 601 [30.0%]), 320 (53.2%) reported carrying a handgun in only 1 wave. Latent class growth analysis indicated 6 longitudinal trajectories: never or low probability of carrying (1590 [79.4%]), emerging adulthood carrying (166 [8.3%]), steadily increasing carrying (163 [8.1%]), adolescent carrying (53 [2.6%]), declining carrying (24 [1.2%]), and high probability and persistent carrying (6 [0.3%]). The earliest mean (SD) age at initiation of handgun carrying occurred in both the adolescent and declining carrying groups at the ages of 12.6 (0.9) and 12.5 (0.7) years, respectively. More than 20% of some groups (emerging adulthood [age 26 years: 49 of 154 (31.8%)], steadily increasing [age 26 years: 37 of 131 (28.2%)], declining [age 13 years: 7 of 23 (30.4%)], and high probability and persistent carrying [age 15 years: 3 of 6 (50.0%)]) reported carrying 40 times or more in the past year by the age of 26 years. Conclusions and Relevance: This study found distinct patterns of handgun carrying from adolescence to young adulthood in rural settings. Findings suggest that promoting handgun safety in rural areas should start early. Potential high-risk trajectories, including carrying at high frequencies, should be the focus of future work to explore the antecedents and consequences of handgun carrying in rural areas.

King-Devick testing and concussion recovery time in collegiate athletes.

OBJECTIVES: To assess whether the King-Devick (KD) test is useful as a prognostic test for prolonged concussion symptoms by examining the relationship between a) change in performance on KD test from baseline to within two days post-injury and b) the absolute KD time at post-concussion testing, with an outcome of time to return to play (RTP). DESIGN: Prospective Cohort Study. METHODS: Collegiate varsity athletes in the Concussion Assessment, Research, and Education (CARE) Consortium completed baseline and post-injury King-Devick tests from 2014 to 2018. Two exposures were evaluated: 1) change in KD score from baseline to within two days post-injury and 2) absolute KD score within two days post-injury, adjusted for baseline KD. We used Cox proportional hazards models to analyze the relationships between these exposures and time to RTP post-concussion. RESULTS: A total of 309 concussion injuries were included. Median baseline KD score was 40.0 s (IQR: 35.8, 45.2). Median post-injury KD score was 45.8 s (IQR: 39.8, 57.1). Median number of days until RTP in this cohort was 11 (IQR: 8, 17). Post-injury KD score adjusted for baseline KD had a stronger association with time to RTP duration (HR: 0.99 (0.98, 1.00), p = 0.03) than the difference in KD score from baseline to post-injury (HR: 0.99 (0.99, 1.00), p = 0.07). CONCLUSIONS: Higher post-injury KD scores are associated with longer RTP. The association between KD post-concussion test and longer RTP warrants further investigation to assess the utility of the KD for prognostication in a clinical setting.