Don't Let the Sun Rise on Small Bowel Obstruction Without Surgical Consultation-Redefining Nonoperative Management Pathways.

Introduction: Small bowel obstruction (SBO) is a common cause of hospital admission leading to resource utilization. The majority of these patients require non-operative management (NOM) which can lead to increased length of stay (LOS), readmissions, resource utilization, and throughput delays. Early surgical consultation (SC) for SBO may improve efficiency and outcomes. Methods: We implemented an institution-wide intervention (INT) to encourage early SC (<1 day of diagnosis) for SBO patients in July 2022. A retrospective analysis was performed on all patients with SBO requiring NOM from January 2021 to June 2023, categorized into pre- and post-INT groups. The primary outcome was the number of SC's and secondary outcomes were early SC (<1 day of diagnosis), utilization of SBFT, LOS, 30-day readmission, and costs of admission. Results: A total of 670 patients were included, 438 in the pre-INT and 232 in the post-INT group. Overall, SBFT utilization was significantly higher in cases with SC (17.2% vs 41.4%, P < .001). Post-INT patients were more likely to receive SC (94.0% vs 83.3%, P < .001) and increased SBFT utilization (47.0% vs 33.6%, P = .001). Additionally, early SC improved significantly in the post-INT group (74.3% vs 65.7%, P = .03). There was no difference in LOS between groups (4.0 vs 3.8 days, P = .48). There was a trend toward decreased readmission rates in the INT group at 30 days (7.3% vs 11.0%, P = .13) and reduced direct costs in the INT group (US$/admission = 8467 vs 8708, P = .1). Conclusion: Hospital-wide interventions to increase early surgical involvement proved effective by improving early SC, increased SBFT utilization, and showed a trend towards decreased readmission rates and direct costs.

Changes in utilization of axillary dissection in women with invasive breast cancer and sentinel node metastasis after the ACOSOG Z0011 trial.

The American College of Surgeons Oncology Group Z0011 (ACOSOG Z0011) trial demonstrated no survival advantage for women with clinical T1-T2 invasive breast cancer with 1-2 positive sentinel lymph nodes (SLN) who received whole-breast radiation, and no further axillary surgery when compared to women who did undergo axillary lymph node dissection (ALND). We used the National Cancer Database (NCDB) to study changes in utilization of ALND after the publication of this trial. NCDB was queried for female patients from 2012 to 2015 who met Z0011 criteria. Patients were divided into four groups based on Commission on Cancer facility accreditation. Outcome measures include the rate of ALND (nonadherence to Z0011) and the average number of nodes retrieved with ALND. 27,635 patients were identified, with no significant differences in T stage and receptor profiles between groups. Overall rate of ALND decreased from 34.0% in 2012 to 22.7% in 2015. Nonadherence was lowest in Academic Programs (decreasing from 30.1% in 2012 to 20.5% in 2015) and was highest in Community Cancer Programs (41.2% in 2012 to 29.1% in 2015). Median number of positive SLN did not differ between groups (p = .563). Median number of nodes retrieved on ALND decreased from 9 (IQR 5-14) in 2012 to 7 (IQR 4-12) in 2015 (p < .001). In patients who met the ACOSOG Z11 trial guidelines, rates of ALND have decreased over time. However, rates of nonadherence to Z0011 are significantly higher in Community Cancer Programs compared to Academic Programs.

Variation in Intraoperative and Postoperative Utilization for 3 Common General Surgery Procedures.

OBJECTIVE: The aim of this study was to understand variation in intraoperative and postoperative utilization for common general surgery procedures. SUMMARY BACKGROUND DATA: Reducing surgical costs is paramount to the viability of hospitals. METHODS: Retrospective analysis of electronic health record data for 7762 operations from 2 health systems. Adult patients undergoing laparoscopic cholecystectomy, appendectomy, and inguinal/femoral hernia repair between November 1, 2013 and November 30, 2017 were reviewed for 3 utilization measures: intraoperative disposable supply costs, procedure time, and postoperative length of stay (LOS). Crossed hierarchical regression models were fit to understand case-mixed adjusted variation in utilization across surgeons and locations and to rank surgeons. RESULTS: The number of surgeons performing each type of operation ranged from 20 to 63. The variation explained by surgeons ranged from 8.9% to 38.2% for supply costs, from 15.1% to 54.6% for procedure time, and from 1.3% to 7.0% for postoperative LOS. The variation explained by location ranged from 12.1% to 26.3% for supply costs, from 0.2% to 2.5% for procedure time, and from 0.0% to 31.8% for postoperative LOS. There was a positive correlation (ρ = 0.49, P = 0.03) between surgeons' higher supply costs and longer procedure times for hernia repair, but there was no correlation between other utilization measures for hernia repair and no correlation between any of the utilization measures for laparoscopic appendectomy or cholecystectomy. CONCLUSIONS: Surgeons are significant drivers of variation in surgical supply costs and procedure time, but much less so for postoperative LOS. Intraoperative and postoperative utilization profiles can be generated for individual surgeons and may be an important tool for reducing surgical costs.

Surgical Supply Cost Awareness Is Associated With Lower Costs: A Single-Center Experience.

Surgeons are often unfamiliar with the costs of surgical instrumentation and supplies. We hypothesized that surgeon cost feedback would be associated with a reduction in cost. A multidisciplinary team evaluated surgical supply costs for laparoscopic appendectomies of 7 surgeons (surgeons A-G) at a single-center academic institution. In the intervention, each surgeon was debriefed with their average supply cost per case, their partner's average supply cost per case, the cost of each surgical instrument/supply, and the cost of alternatives. In addition, the laparoscopic appendectomy tray was standardized to remove extraneous instruments. Pre-intervention (March 2017-February 2018) and post-intervention (March 2018-October 2018) costs were compared. Pre-intervention, the surgeons' average supply cost per case ranged from $754-$1189; when ranked from most to least expensive, surgeon A > B > C > D > E > F > G. Post-intervention, the surgeons' average supply cost per case ranged from $676 to $846, and ranked from surgeon G > D > F > C > E > B > A. Overall, the average cost per case was lower in the post-intervention group ($854.35 vs. $731.11, P < .001). This resulted in savings per case of $123.24 (14.4%), to a total annualized savings of $29 151.

Is magnetic resonance imaging becoming the new computed tomography for cervical spine clearance? Trends in magnetic resonance imaging utilization at a Level I trauma center.

BACKGROUND: Increasing evidence supports the limited use of magnetic resonance imaging (MRI) for cervical spine (C-spine) clearance following blunt trauma. We sought to characterize the utilization of MRI of the C-spine at a Level I trauma center. METHODS: All blunt trauma patients undergoing a computed tomography (CT) of the C-spine between January 2009 and December 2018 were reviewed. The CT and MRI results, demographics, clinical presentation, subspecialty consultations, and interventions were recorded. The MRI results were considered clinically significant if they resulted in cervical thoracic orthosis/halo placement or surgical intervention. Linear regression models were utilized to identify trends. RESULTS: There were 9,101 patients that underwent a CT of the C-spine, with 513 (5.6%) being positive for an acute injury. MRI was obtained for 375 (4.1%) of patients. A linear increase in the proportion of patients undergoing an MRI was noted, from 0.9% in 2009 to 5.6% in 2018 (p < 0.01). Of the 513 patients with a positive CT, 290 (56.5%) had an MRI. In 40 (13.8%) of them, the CT demonstrated a minor injury. Clinically significant MRI findings were noted only in two (5.0%) of the 40 patients, and both had a neurologic deficit on initial examination. Of the 8,588 patients with a negative CT, 85 (1.0%) underwent an MRI. Of those, 9 (10.6%) had a clinically significant MRI with all but one presenting with a neurological deficit. CONCLUSION: MRI is increasingly utilized for C-spine clearance following blunt trauma. MRI was exceedingly unlikely to demonstrate a clinically significant finding in the absence of a neurological deficit, when the CT was negative or included minor injuries. Trauma centers are encouraged to constantly evaluate their own practices and intervene with education and collaboration to limit the excessive use of unnecessary resources. LEVEL OF EVIDENCE: Therapeutic/Care Management Study, Level III or IV. Diagnostic test, level IV.

New cars on the highways: Trends in injuries and outcomes following ejection.

BACKGROUND: Although ejections from motor vehicles are considered a marker of a significant mechanism and a predictor of severe injuries and mortality, scant recent data exist to validate these outcomes. This study investigates whether ejections increase the mortality risk following a motor vehicle crash using data that reflect the introduction of new vehicles to the streets of a large city in the United States. METHODS: The Trauma and Emergency Medicine Information System of Los Angeles County was queried for patients ≥ 16 years old admitted following a motor vehicle crash between 2002 and 2012. Ejected patients were compared to nonejected. Primary outcome was mortality. A logistic regression model was used to identify predictors of mortality and severe trauma. RESULTS: A total of 9,742 (6.8%) met inclusion criteria. Of these, 449 (4.6%) were ejected; 368 (82.0%) were passengers and 81 (18.0%) were drivers. The rate of ejection decreased linearly (6.1% in 2002 to 3.4% in 2012). Compared to nonejected patients, ejected patients were more likely to require intensive care unit admission (43.7% vs 22.1%, P < .01), have critical injuries (Injury Severity Score > 25) (24.2% vs 7.3%, P <.01), require emergent surgery (16.3% vs 8.0%, P <.01), and expire in the emergency department (3.6% vs 1.2%, P <.01). Overall mortality was 3.6%: 9.6% for ejected and 3.3% for nonejected patients (P <.01). In a logistic regression model, ejection and extrication both predicted mortality (adjusted odds ratio: 1.83, P <.01 and 1.87, P <.01, respectively). Ejection also predicted critical injuries (Injury Severity Score > 25) with adjusted odds ratio of 2.48 (P <.01). CONCLUSION: Ejections following motor vehicle crash have decreased throughout the years; however, they remain a marker of critical injuries and predictive of mortality.

Treatment at Academic Centers Increases Likelihood of Reconstruction After Mastectomy for Breast Cancer Patients.

BACKGROUND: Mastectomy rates continue to increase in women diagnosed with breast cancer (BC). There are limited data regarding reconstruction rates at academic centers (AC) versus community hospitals (CH). We aim to determine the effect of facility type on reconstruction rates. MATERIALS AND METHODS: The National Cancer Database was queried for BC patients treated with mastectomy from 2004 to 2014. Clinical characteristics and type of reconstruction were compared between treatment at AC or CH. RESULTS: A total of 860,509 patients were included. Patients treated at AC were younger (58.7 ± 12 y AC versus 61.6 ± 13 y CH; P < 0.001) and traveled farther to their treatment center (33.1 ± 122.8 miles AC versus 20 ± 75.3 miles CH; P < 0.001). Patients undergoing surgery at AC were more likely to have reconstruction than those at CH (43.7% AC versus 32.5% CH; P < 0.001). This trend remained across all reconstruction types including expander/implant-based reconstruction (immediate breast reconstruction) (14.4% AC versus 9.9% CH), autologous reconstruction (14.9% AC versus 11.7% CH), mixed reconstruction (5.2% AC versus 3.6% CH), and other reconstructions (9.2% AC versus 7.3% CH) (all P < 0.001). Patients in all age categories, across insurance statuses, and with comorbidities were more likely to receive reconstruction if treated at AC compared with CH. In multivariate analysis, having a mastectomy at AC was an independent predictor of reconstruction (adjusted odds ratio, 1.51; 95% confidence interval, 1.49-1.51; P < 0.001). CONCLUSIONS: Undergoing mastectomy at AC results in higher rate of reconstruction compared with CH.

Unexpected complicated appendicitis in the elderly diagnosed with acute appendicitis.

BACKGROUND: This study determined the prevalence of complicated appendicitis in elderly patients diagnosed preoperatively with uncomplicated appendicitis. METHODS: Patients with a preoperative diagnosis of uncomplicated appendicitis at an academic hospital from 11/2013 to 05/2017 were reviewed. Patients ≥65 years were compared to those younger. Pathology reports were categorized as either uncomplicated or complicated (COMP). The primary outcome was the prevalence of COMP appendicitis. RESULTS: The prevalence of COMP appendicitis increased with age after 20 years with an abrupt increase after 65 years. Patients ≥65 years were more likely to have COMP appendicitis (48.1% vs. 15.5%; OR: 5.1; p < 0.01) and prolonged stays (3.8 vs. 2.3 days; p < 0.01). CONCLUSION: Nearly half of elderly patients had pathologic confirmation of complicated appendicitis despite no preoperative clinical or radiographic suspicion for complicated appendicitis. Nonoperative management of acute appendicitis in the elderly may not be appropriate due to the high rate of unexpected complicated appendicitis.

Patterns in the Use of Axillary Operations for Patients with Node-Positive Breast Cancer After Neoadjuvant Chemotherapy: A National Cancer Database (NCDB) Analysis.

BACKGROUND: The American College of Surgeons Oncology Group (ACOSOG) Z1071 and Sentinel Neoadjuvant (SENTINA) trials of sentinel node biopsy for node-positive breast cancer treated with neoadjuvant chemotherapy (NAC) demonstrated false-negative rates that varied on the basis of surgical technique. This study evaluated trends in axillary operations before and after publication of these trials. METHODS: This study analyzed patients from National Cancer Database (NCDB) with clinical T0 through T4, N1 and N2, M0 breast cancer who received NAC from 1 January 2012 to 31 December 2015 and sentinel lymph node biopsy (SNB) or axillary lymph node dissection (ALND). The patients were divided into the following groups: SNB, ALND, and (SNB + ALND). RESULTS: Of the 32,036 evaluable patients identified in this study. 5565 had SNB, 19,930 had ALND, and 6541 had SNB + ALND. Compared with the ALND group, the SNB group was younger, had more invasive ductal cancers, and had lower clinical T- and N-stage disease (p < 0.001). The patients in the SNB group had a higher rate of estrogen receptor-positive and triple-negative breast cancers, but a lower rate of human epidermal growth factor receptor 2 (HER2)-positive cancer (p < 0.001). The nodal pathologic complete response (PCR) rate, defined as no residual invasive cancer, was 66.5% in the SNB group and 33.1% in the ALND group. Since 2013, the rate of ALND has decreased from 88.7 to 77.1% in both community and academic institutions (p < 0.001). CONCLUSION: Since publication of the ACOSOG Z1071 and SENTINA trials, the national rates of ALND in node positive breast cancer treated with NAC have decreased despite reported false-negative SNB rates and lack of prospective outcome data regarding the oncologic safety of ALND omission.

Disparities in Compliance With National Guidelines for the Treatment of Malignant Pleural Mesothelioma.

BACKGROUND: Current guidelines support cancer-directed surgery, chemotherapy, or active surveillance for clinical stages 1 to 3 of epithelial malignant pleural mesothelioma (MPM). Definitive chemotherapy is recommended for sarcomatoid/biphasic histologies. Our objective is to assess compliance with recommendations, measuring their impact on overall survival. METHODS: The National Cancer Database participant user file (2004 to 2014) was queried for patients diagnosed with MPM clinical stages 1 to 3. Multivariable logistic regression model identified factors independently associated with guideline compliance. Kaplan-Meier analysis and Cox proportional hazards were used for overall survival comparison with histologic subgroup analysis. RESULTS: A total of 3419 patients with clinical stages 1 to 3 met criteria for analysis and comprised epithelial (68.5%), sarcomatoid (17.2%), and biphasic subtypes (14.3%). Cancer-directed surgery was significantly underutilized in epithelial MPM, with 29.3% having no treatment. On multivariable analysis, insurance status and facility type were the strongest predictors of guideline compliance. High-volume hospitals were the most compliant with guidelines (odds ratio 3.58, 95% confidence interval (CI), 2.34 to 5.49, P < .001). Median survival estimates for no treatment, chemotherapy alone, surgery plus chemotherapy, and trimodal therapy were 10.2, 15.4, 21.1, and 21.7 months, respectively (log rank P < .001). In epithelial MPM, a significant increase in overall survival was observed in surgery plus chemotherapy (hazard ratio 0.62, 95% CI, 0.53 to 0.73, P < .001) and trimodality (hazard ratio 0.61, 95% CI, 0.49 to 0.76, P < .001; reference: no treatment). CONCLUSIONS: There is a suboptimal compliance with national guidelines for the treatment of MPM, particularly in low-volume nonacademic settings. Adherence to recommended surgery-based multimodal therapy is associated with an overall survival improvement.

Imaging utilization affects negative appendectomy rates in appendicitis: An ACS-NSQIP study.

BACKGROUND: Negative appendectomy rates (NAR) historically ranged from 15 to 25%, but have decreased recently. METHODS: Using the 2016 ACS-NSQIP database, we identified patients who underwent appendectomies for appendicitis. Patients with and without appendicitis on pathology were compared. Multivariate analysis was used to identify predictors of negative appendectomies. RESULTS: 11,841 patients underwent appendectomies, with a NAR of 4.5%. Utilization rates of US, CT and MRI were 14.9%, 86.1%, and 1.1%. NAR's of US, CT, and MRI were 9.7%, 2.5%, and 7.1%, and 19.2% for patients without imaging. An ultrasound consistent with appendicitis has a NAR of 4.8%; adding a CT decreases it to 0.6%. Predictors of NA include females, smoking, no imaging, and ultrasounds. Factors with lower odds of NA include leukocytosis, sepsis, and CTs. CONCLUSIONS: The NAR in the 2016 ACS-NSQIP population is 4.5%. CTs are the most frequently used imaging modality and have the lowest NAR. Obtaining a CT in addition to an ultrasound is associated with lower NAR. This should be further explored with a cost-benefit analysis between multiple imaging studies versus negative appendectomies.

Does the Approach Matter? Comparing Survival in Robotic, Minimally Invasive, and Open Esophagectomies.

BACKGROUND: Our objective was to determine how surgical approach impacts overall survival and postoperative outcomes when comparing robotic-assisted minimally invasive esophagectomy (RAMIE), minimally invasive esophagectomy (MIE), and open esophagectomy (OE). METHODS: The National Cancer Database was queried for patients diagnosed with pathologic Stage 0 to III esophageal cancer from 2010 to 2015. Primary outcome measures evaluated were length of stay, 30-day unplanned readmissions, mortality rates at 30 and 90 days, and overall survival rates. The surgical cohorts underwent 1:1 propensity score matching, and Kaplan-Meier survival estimates were compared by surgical approach. Cox proportional hazards regression was utilized to estimate factors associated with overall survival. RESULTS: Of 5,553 patients that met criteria, 28.4% were MIE, 7.8% RAMIE, and 63.8% OE. From 2010 to 2015, an increasing trend was seen for both minimally invasive approaches, with MIE surpassing the number of OEs. Unplanned 30-day readmissions and 30-day and 90-day mortality rates were not significantly different between the different groups. Median length of stay was significantly shorter in MIE (9 [interquartile range (IQR), 8 to 14] days) and RAMIE (9 [IQR, 7 to 14] days), compared with OE (10 [IQR, 8 to 15] days; p < 0.001). MIE and RAMIE had comparable survival rates compared with OE, with no significant differences in median overall survival estimates after propensity score matching (log-rank p = 0.603), with a trend for increased survival in MIE (adjusted hazard ratio, 0.97; 95% confidence interval, 0.89 to 1.06; p = 0.530) and RAMIE (hazard ratio, 0.81; 95% confidence interval, 0.69 to 0.95; p = 0.012). Both minimally invasive approaches had a significantly higher median lymph node counts (MIE: 15 [IQR, 9 to 22]; RAMIE: 17 [IQR, 11 to 24]; OE: 13 [IQR, 8 to 20]), which may highlight important differences in postoperative upstaging. CONCLUSIONS: Trends in MIE use is surpassing the open approach. Minimally invasive approaches are becoming the preferred approach, with noninferior long-term results compared with OEs. A significantly higher lymph node yield was seen for RAMIE and MIE.

Firearm legislation, gun violence, and mortality in children and young adults: A retrospective cohort study of 27,566 children in the USA.

BACKGROUND: Firearm violence results in the death of thousands of children in the US annually. The effects of firearm legislation on gun violence are published but widely contested. MATERIALS AND METHODS: The Kid's Inpatient Database from 2000 to 2009 were queried to capture hospitalizations of children diagnosed with a firearm-related injury. Cases were categorized into five levels of firearm legislation strictness by Brady State Scorecard. Trends of injuries were explored in terms of legislative strength, age, and race. RESULTS: 27,566 children analyzed in the study. Most were adolescents aged 15-19 (87.3%), male (89.7%), and black (53.7%). The proportion of accidental injuries increased relative to state law leniency (R2 = 0.90), with highest percentage in lenient states (33.2%) compared to strict (16.7%). The proportion of suicide attempts were higher in states with lenient laws (4.4%) compared to strict (1.3%). Accidents were inversely related to age (59.3% in ages 0-4 compared to 22.0% in adolescents), while assaults were positively related to age (31.6% in ages 0-4 compared to 66.6% in adolescents). Whites were most likely to present with accidental injuries (44.6%), and Blacks and Hispanics with assaults (68.2% and 75.6%). Race (p = 0.009), age (p < 0.001), and firearm injury type (p = 0.001) were associated with mortality; Hispanics (OR 1.36, 95% CI: 1.03-1.78), children age 5-9 (2.03, 1.30-3.17) and suicide attempts (15.6, 11.6-20.9) had higher odds of in-hospital mortality. CONCLUSIONS: Firearm-related injuries types in hospitalized children are associated with age, race, and state level legislation. Accidents are most prevalent in young children, Whites, and states with lenient gun laws, while suicide attempts are more common in adolescents, Whites, and states with lenient gun laws. Suicide attempts are also associated with the greatest odds of in-hospital mortality. To address firearm violence, consideration should be given to legislation that promote safe gun storage behaviors and restrict firearm accessibility to children.

Predictors of Failure to Rescue After Esophagectomy.

BACKGROUND: Failure to rescue (FTR), defined as death after a major complication, is a metric increasingly being used to assess quality of care. Risk factors associated with FTR after esophagectomy have not been previously studied. METHODS: The American College of Surgeons National Surgical Quality Improvement Program database was queried for patients who underwent esophagectomy with gastric conduit between 2010 and 2014. Patients with at least one major postoperative complication were grouped according to inhospital mortality (FTR group) and survival to discharge (SUR group). A stepwise logistic regression model was used to identify predictors of FTR. RESULTS: A total of 1,730 patients comprised the study group, with 102 (5.9%) in the FTR group and 1,628 (94.1%) in the SUR group. The FTR patients were older (69.0 versus 64.0 years, p < 0.0001) compared with the SUR patients. There were no differences in sex, body mass index, preoperative weight loss, smoking status, operation type, or surgeon specialty between the two groups. Age greater than 75 years (adjusted odds ratio 2.68, p < 0.0001), black race (adjusted odds ratio 2.75, p = 0.001), American Society of Anesthesiologists class 4 or 5 (adjusted odds ratio 1.82, p = 0.02), and the occurrence of pneumonia, respiratory failure, acute renal failure, sepsis, or acute myocardial infarction were predictive of FTR based on multivariable logistic regression. CONCLUSIONS: Nearly 6% of patients who have a major complication after esophagectomy do not survive to discharge. Age greater than 75 years, black race, American Society of Anesthesiologists class 4 or 5, and complications related to major infection or organ failure predict FTR. Further research is necessary to investigate how these factors affect survival after complications in order to improve rescue efforts.

Reconstruction among patients undergoing mastectomy: the effect of surgical deserts.

BACKGROUND: Surgical deserts (SDs) are defined as the geographic maldistribution of general surgeons of six or less per 100,000 population in underserved/rural counties. Disparities have been reported in breast cancer outcomes; however, the effect of SDs remains unknown. We sought to examine the effect of SDs on breast reconstruction (BR) after mastectomy and the differences between patients in both the cohorts. METHODS: Using the Nationwide Inpatient Sample database years 2007-2011, we identified International Classification of Diseases 9th edition codes for breast cancer, mastectomy, and BR in California. SDs were identified using the American College of Surgeons Health Policy Research Institute workforce atlas. Data included patient demographics and socioeconomic status, and the primary outcome was the rates of BR. RESULTS: A total of 9325 mastectomy patients, with or without BR, were identified. Of this, 12.8% patients were in SDs, whereas 87.2% patients were in nonsurgical deserts (NSDs). Overall, 35.8% of patients received BR, whereas 64.2% did not. Of the patients in SDs, only 14% received BR, whereas in NSDs, 39% received BR. On multivariate analysis, SD patients were significantly less likely to receive BR than NSD patients (odds ratio [95% confidence interval], 0.29 [0.24-0.35]; P < 0.001). SDs had higher rates of low household income, Medicare insurance, and comorbidities. NSDs had higher rates of high household income, Health Maintenance Organization/private insurance, and lower rates of comorbidities. CONCLUSIONS: Patients in SDs are significantly less likely to receive BR. This disparity may be magnified because of differences in demographics and income levels, and decreased access to reconstructive surgeons. Interventions aimed at decreasing disparities caused by SDs are needed.