Development and validation of a new ICD-10-based trauma mortality prediction scoring system using a Japanese national inpatient database

Development and validation of early prediction models for new-onset functional impairment of patients with trauma at hospital discharge

BACKGROUND

Early identification of individuals at risk of functional impairment after trauma is crucial for the timely clinical decision-making and intervention to improve reintegration into the society. This study aimed to develop and validate models for predicting new-onset functional impairment after trauma using predictors that are routinely collected within 2 days of hospital admission.

METHODS

In this multicenter retrospective cohort study of acute care hospitals in Japan, we identified adult patients with trauma with independence in carrying out activities of daily living before hospitalization, treated in the intensive or high-dependency care unit, and survived for at least 2 days between April 2008 and September 2023. The primary outcome was functional impairment defined as Barthel Index ≤60 at hospital discharge. In the internal validation data set (between April 2008 and August 2022), using the routinely collected 129 candidate predictors within 2 days of admission, we trained and tuned the four conventional and machine learning models with repeated random subsampling cross-validation. We measured the performance of these models in the temporal validation data set (between September 2022 and September 2023). We also computed the importance of each predictor variable in our model.

RESULTS

We identified 8,529 eligible patients. Functional impairment at discharge was observed in 41% of the patients (n = 3,506/8,529). In the temporal validation data set, all four models showed moderate discrimination ability, with areas under the curve above 0.79, and extreme gradient boosting showing the best performance (0.83). In the variable importance analyses, age was the most important predictor, followed by consciousness, severity score, cervical spinal cord injury, mild dementia, and serum albumin level at admission.

CONCLUSION

We successfully developed early prediction models for patients with trauma with new-onset functional impairment at discharge that achieved high predictive performance using routinely collected data within 2 days of hospital admission.

LEVEL OF EVIDENCE

Prognostic/Epidemiological; Level II.

Intracranial Pressure Monitoring in Children With Severe Traumatic Brain Injury: A Propensity Score Matching Analysis Using a Nationwide Inpatient Database in Japan

BACKGROUND AND OBJECTIVES

Clinical benefits of intracranial pressure (ICP) monitoring in the management of children with severe traumatic brain injury (TBI) are not universally agreed upon. We investigated the association between ICP monitoring and outcomes in children with severe TBI using a nationwide inpatient database.

METHODS

This observational study used the Japanese Diagnostic Procedure Combination inpatient database from July 1, 2010, to March 31, 2020. We included patients younger than 18 years, admitted to the intensive care unit or high-dependency unit with severe TBI. Patients who died or were discharged on the day of admission were excluded. One-to-four propensity score matching was performed to compare patients who underwent ICP monitoring on the day of admission with those who did not. The primary outcome was in-hospital mortality. Mixed-effects linear regression analysis compared outcomes and estimated the interaction between ICP monitoring and subgroups in matched cohorts.

RESULTS

Of the 2116 eligible children, 252 received ICP monitoring on the day of admission. One-to-4 propensity score matching selected 210 patients who had ICP monitoring on admission day and 840 patients who did not. In-hospital mortality was significantly lower in patients who underwent ICP monitoring than those who did not (12.7% vs 17.9%; within-hospital difference, -4.2%; 95% CI, -8.1% to -0.4%). There was no significant difference in the proportion of unfavorable outcomes (Barthel index <60 or death) at discharge, proportion of enteral nutrition at discharge, length of hospital stay, and total hospitalization cost. Subgroup analyses demonstrated a quantitative interaction between ICP monitoring and the Japan Coma Scale ( P < .001).

CONCLUSION

ICP monitoring was associated with lower in-hospital mortality in children with severe TBI. Our results demonstrated the clinical benefits of ICP monitoring in managing pediatric TBI. The advantages of ICP monitoring may be amplified in children who exhibit the most severe disturbances of consciousness.

Trends in massive transfusion practice for trauma in Japan from 2011 to 2020: a nationwide inpatient database study

BACKGROUND

Previous studies have reported conflicting results regarding fresh frozen plasma (FFP)-to-red blood cell (RBC) ratio and platelet-to-RBC ratio on outcomes for massive transfusion for trauma. Moreover, nationwide data on massive transfusion practices for trauma in the real-world clinical setting are scarce. This study aimed to examine the nationwide practice patterns and trends in massive transfusion for trauma in Japan using a national administrative, inpatient database.

METHOD

We identified patients who underwent emergency hospitalization for trauma and received massive transfusion, defined as administration of at least 20 units of RBC within the first 2 days of admission, using the nationwide inpatient database, which covers approximately 90% of all tertiary emergency hospitals in Japan, between 2011 and 2020. Trends in the incidence and practice patterns of massive transfusion were described by calendar year. The association of practice patterns with mortality or adverse events was tested.

RESULTS

A total of 3,530,846 trauma hospitalizations were identified, of which 5247 (0.15%) received massive transfusion. A significant declining trend was observed in the incidence of massive transfusion in trauma hospitalizations from 0.24% in 2011 to 0.10% in 2020 (P for trend < 0.001). The FFP-to-RBC ratio rose significantly from 0.77 in 2011 to 1.08 in 2020 (P for trend < 0.001), while the platelet-to-RBC ratio remained virtually unchanged from 0.71 in 2011 to 0.78 in 2020 (P for trend 0.060). Massive transfusion with lower FFP-to-RBC (< 0.75) and platelets-to-RBC ratio (< 1.00) were associated with increased in-hospital mortality compared with those ≥ 1.00, while there were linear increases in adverse events with increasing FFP and platelets ratios.

CONCLUSIONS

This study demonstrated a declining trend in the incidence and a rise in higher FFP-to-RBC ratios in massive transfusion in association with patient outcomes for trauma from 2011 to 2020 in Japan.

Association Between Intensive Care Unit Admission Practices and Outcomes in Patients with Isolated Traumatic Subarachnoid Hemorrhage: A Nationwide Inpatient Database Analysis in Japan

BACKGROUND

Patients with traumatic brain injury associated with intracranial hemorrhage are commonly admitted to the intensive care unit (ICU); however, the need for ICU care for patients with isolated traumatic subarachnoid hemorrhage (tSAH) remains unclear. We aimed to investigate the association between the ICU admission practices and outcomes in patients with isolated tSAH.

METHODS

This observational study used a nationwide administrative database in Japan. We identified patients with isolated tSAH from the Japanese Diagnostic Procedure Combination inpatient database from July 1, 2010, to March 31, 2020. The primary outcome was in-hospital mortality, whereas the secondary outcomes were neurosurgical interventions, activities of daily living at discharge, and total hospitalization cost. We performed a risk-adjusted mixed-effect regression analysis to evaluate the association between hospital-level ICU admission rates and study outcomes. The ICU admission rates were categorized into quartiles: lowest, middle-low, middle-high, and highest. Moreover, we assessed the robustness of the results with a patient-level instrumental variable analysis.

RESULTS

Of the 61,883 patients with isolated tSAH treated at 962 hospitals, 16,898 (27.3%) patients were admitted to the ICU on the day of admission. Overall, 2465 (4.0%) patients died in the hospital, and 783 (1.3%) patients underwent neurosurgical interventions. There was no significant difference between the lowest and highest ICU admission quartile in terms of in-hospital mortality (3.7% vs. 4.3%; adjusted odds ratio 0.93; 95% confidence interval [CI] 0.78-1.10), neurosurgical interventions, and activities of daily living at discharge. However, the total hospitalization cost in the lowest ICU admission quartile was significantly lower than that in the highest quartile (US $3032 vs. $4095; adjusted difference US $560; 95% CI 33-1087). The patient-level instrumental variable analysis did not reveal a significant difference in in-hospital mortality between the patients who were admitted to the ICU and those who were not (risk difference 0.2%; 95% CI - 0.1 to 0.5).

CONCLUSIONS

There was no significant association between the ICU admission practices and outcomes in patients with isolated tSAH, whereas higher ICU admission rates were associated with significantly higher hospitalization costs. Our results provide an opportunity for improved health care allocation in the management of patients with isolated tSAH.

Associations between Early Surgery and Postoperative Outcomes in Elderly Patients with Distal Femur Fracture: A Retrospective Cohort Study

Previous literature has provided conflicting results regarding the associations between early surgery and postoperative outcomes in elderly patients with distal femur fractures. Using data from the Japanese Diagnosis Procedure Combination inpatient database from April 2014 to March 2019, we identified elderly patients who underwent surgery for distal femur fracture within two days of hospital admission (early surgery group) or at three or more days after hospital admission (delayed surgery group). Of 9678 eligible patients, 1384 (14.3%) were assigned to the early surgery group. One-to-one propensity score matched analyses showed no significant difference in 30-day mortality between the early and delayed groups (0.5% versus 0.5%; risk difference, 0.0%; 95% confidence interval, −0.7% to 0.7%). Patients in the early surgery group had significantly lower proportions of the composite outcome (death or postoperative complications), shorter hospital stays, and lower total hospitalization costs than patients in the delayed surgery group. Our results showed that early surgery within two days of hospital admission for geriatric distal femur fracture was not associated with a reduction in 30-day mortality but was associated with reductions in postoperative complications and total hospitalization costs.

Effectiveness of surgical fixation for rib fractures in relation to its timing: a retrospective Japanese nationwide study

PURPOSE

The effectiveness of surgical rib fixation is currently controversial, partly because of differences in timing. We used a Japanese nationwide database to investigate the effectiveness of surgical rib fixation in relation to its timing.

METHODS

We used the Japanese Diagnosis Procedure Combination database to identify patients with rib fractures who underwent mechanical ventilation from 1 July 2010 to 31 March 2018. We performed overlap weight analysis to compare in-hospital outcomes between patients who had and had not undergone surgical rib fixation within 3, 6 or 10 days after admission. The primary outcomes were duration of mechanical ventilation and post-rib fixation length of hospital stay. The secondary outcomes were tracheostomy, post-admission pneumonia and all-cause 28-day in-hospital mortality.

RESULTS

We identified 8922 eligible patients. Surgical rib fixation within 3 days after admission was associated with shorter duration of mechanical ventilation (percent difference, - 42.9%; 95% confidence interval, - 57.4 to - 23.3) and shorter hospital stay (percent difference, - 19.6%; 95% confidence interval, - 31.8 to - 5.2). There were no significant differences between the groups in tracheostomy (risk difference, - 0.04; 95% confidence interval, - 0.15 to 0.07), post-admission pneumonia (risk difference, - 0.04; 95% confidence interval, - 0.13 to 0.05) or all-cause 28-day in-hospital mortality (risk difference, - 0.02; 95% confidence interval, - 0.07 to 0.03). However, there were no significant differences in any in-hospital outcomes between those who had and had not undergone rib fixation within 6 or 10 days after admission.

CONCLUSION

Early surgical rib fixation was associated with better in-hospital outcomes, whereas later surgical rib fixation was not.

Association between parenteral nutrition in the early phase and outcomes in patients with abdominal trauma undergoing emergency laparotomy: A retrospective nationwide study

BACKGROUND & AIMS

Parenteral nutrition in the early phase is often performed for patients with trauma who have undergone laparotomy. However, the clinical benefits of parenteral nutrition in the early phase in this population remain unknown. We investigated the association of parenteral nutrition in the early phase with outcomes in patients with trauma who underwent emergency laparotomy.

METHODS

Using a Japanese nationwide database from July 2010 to March 2018, we identified patients with trauma who underwent emergency laparotomy on admission to the hospital, required mechanical ventilation on admission, and did not receive enteral nutrition within 2 days after admission. We performed an overlap weights analysis to compare in-hospital outcomes between patients with and without parenteral nutrition in the early phase. The primary outcome was the duration of mechanical ventilation. The secondary outcomes were the length of hospital stay, total hospitalization cost, tracheostomy, hospital-acquired pneumonia, and all-cause 28-day in-hospital mortality.

RESULTS

In total, 1700 adult patients were included. There were no significant associations between parenteral nutrition in the early phase and the duration of mechanical ventilation (difference, -0.4 days; 95% confidence interval, -2.9 to 2.2), length of hospital stay (difference, 1.3 days; 95% confidence interval, -5.0 to 7.5), total hospitalization cost (difference, US$ 730; 95% confidence interval, -2911 to 4370), tracheostomy (risk difference, 0.01; 95% confidence interval, -0.03 to 0.05), hospital-acquired pneumonia (risk difference, -0.01; 95% confidence interval, -0.05 to 0.03), or all-cause 28-day in-hospital mortality (risk difference, 0.02; 95% confidence interval, -0.01 to 0.06).

CONCLUSIONS

Parenteral nutrition in the early phase for patients with trauma undergoing emergency laparotomy was not associated with better in-hospital outcomes.

Early enteral nutrition in patients with severe traumatic brain injury: a propensity score-matched analysis using a nationwide inpatient database in Japan

BACKGROUND

Whether enteral nutrition (EN) should be administered early in severe traumatic brain injury (TBI) patients has not been fully addressed.

OBJECTIVE

The present study aimed to evaluate whether early EN can reduce mortality or nosocomial pneumonia among severe TBI patients.

METHODS

Using the Japanese Diagnosis Procedure Combination inpatient database from April 2014 to March 2017 linked with the Survey for Medical Institutions, we identified patients admitted for intracranial injury with Japan Coma Scale scores ≥30 (corresponding to Glasgow Coma Scale scores ≤8) at admission. We designated patients who started EN within 2 d of admission as the early EN group, and those who started EN at 3-5 d after admission as the delayed EN group. The primary outcome was in-hospital mortality. The secondary outcome was nosocomial pneumonia. Propensity score-matched analyses were performed to compare the outcomes between the 2 groups.

RESULTS

We identified 3080 eligible patients during the 36-mo study period, comprising 1100 (36%) in the early EN group and 1980 (64%) in the delayed EN group. After propensity score matching, there was no significant difference in in-hospital mortality (difference: -0.3%; 95% CI: -3.7%, 3.1%) between the 2 groups. The proportion of nosocomial pneumonia was significantly lower in the early EN group than in the delayed EN group (difference: -3.2%; 95% CI: -5.9%, -0.4%).

CONCLUSIONS

Early EN may not reduce mortality, but may reduce nosocomial pneumonia in patients with severe TBI.

The off-hour effect in severe trauma and the structure of care delivery among Japanese emergency and critical care centers: A retrospective cohort study

BACKGROUND

The association between mortality and off-hour presentation to a medical center has been studied in relation to various diseases and settings, but little is known of what the association indicates. This study explored the association in severe trauma patients among Japanese emergency and critical care centers and their association with the structural factors of the medical center.

METHODS

We conducted a retrospective cohort study using a Japanese, nationwide administrative database and the annual emergency and critical care centers evaluation report. We included patients who were seen because of trauma, were at least 15 years old, were transferred to an emergency and critical care center by ambulance, were admitted to the intensive care unit, and were discharged between April 1, 2012 and March 31, 2017. Off-hour care was defined as initial care beginning at all times except 8 am to 6 pm on weekdays and 8 am to noon on Saturdays. We evaluated this topic using the structure-process-outcome model as proposed by Donabedian. A multilevel logistic regression analysis was performed.

RESULTS

The sample included 111,266 patients from 233 emergency and critical care centers. The adjusted mortality odds ratio for off-hour care was 0.90 (95% confidence interval: 0.85-0.96; P < .001). In the off-hour care cohort, the immediate availability of an operating room and off-hours work management including shift work introduction had adjusted mortality odds ratios of 0.85 (95% confidence interval: 0.74-0.98; P = .02) and 0.85 (95% confidence interval: 0.73-0.99; P = .04), respectively.

CONCLUSION

In Japan, severe trauma patients who received off-hour care at the emergency and critical care centers had a decreased in-hospital mortality. The immediate availability of an operating room and management of off-hours work were contributing structural factors. Process factors in off-hour care need to be considered in future research on this topic. This finding may have important applicability to other countries as well.

Association of Japan Coma Scale score on hospital arrival with in-hospital mortality among trauma patients

Background

The Japan Coma Scale (JCS) score has been widely used to assess patients’ consciousness level in Japan. JCS scores are divided into four main categories: alert (0) and one-, two-, and three-digit codes based on an eye response test, each of which has three subcategories. The purpose of this study was to investigate the utility of the JCS score on hospital arrival in predicting outcomes among adult trauma patients.

Methods

Using the Japan Trauma Data Bank, we conducted a nationwide registry-based retrospective cohort study. Patients 16 years old or older directly transported from the trauma scene between January 2004 and December 2017 were included. Our primary outcome was in-hospital mortality. We examined outcome prediction accuracy based on area under the receiver operating characteristic curve (AUROC) and multiple logistic regression analysis with multiple imputation.

Results

A total of 222,540 subjects were included; their in-hospital mortality rate was 7.1% (n = 15,860). The 10-point scale JCS and the total sum of Glasgow Coma Scale (GCS) scores demonstrated similar performance, in which the AUROC (95% CIs) showed 0.874 (0.871–0.878) and 0.878 (0.874–0.881), respectively. Multiple logistic regression analysis revealed that the higher the JCS score, the higher the predictability of in-hospital death. When we focused on the simple four-point scale JCS score, the adjusted odds ratio (95% confidence intervals [CIs]) were 2.31 (2.12–2.45), 4.81 (4.42–5.24), and 27.88 (25.74–30.20) in the groups with one-digit, two-digit, and three-digit scores, respectively, with JCS of 0 as a reference category.

Conclusions

JCS score on hospital arrival after trauma would be useful for predicting in-hospital mortality, similar to the GCS score.

Characteristics, treatments, and outcomes among patients with abdominal aortic injury in Japan: a nationwide cohort study

Background

Abdominal aortic injury (AAI) is a life-threatening condition that occurs in only 0.1% of all trauma admissions. Because of its rarity, the clinical features of AAI remain unclear. We investigated the characteristics, treatments, and clinical outcomes among patients with AAI.

Methods

This retrospective cohort study was performed using the Japanese Diagnosis Procedure Combination database. We identified patients with a confirmed diagnosis of AAI with emergency admission from 1 July 2010 to 31 March 2017. Eligible patients were divided into three groups: those who were treated with no surgery or endovascular treatment (non-repair group), those who underwent surgery without endovascular treatment (open repair group), and those who received endovascular treatment without surgery (endovascular repair group).

Results

A total of 238 patients met the inclusion criteria during the study period. Of these, 191 (80.3%) were allocated to the non-repair group, 20 (8.4%) were allocated to the open repair group, and 27 (11.3%) were allocated to the endovascular repair group. The proportions of patients in the non-repair group from July 2010 to March 2012, April 2012 to March 2014, April 2014 to March 2016, and April 2016 to March 2017 were 93.5%, 75.9%, 80.6%, and 73.2%, respectively. The crude in-hospital mortality rate was 26.2%, 35.0%, and 18.5% in the non-repair, open repair, and endovascular repair group, respectively.

Conclusions

In this cohort, the proportion of non-repair for AAI decreased from 2010 to 2017, whereas the proportion of endovascular repair increased. Younger patients were more likely to undergo open repair, whereas older patients were more likely to undergo endovascular repair.

Volume-outcome relationship in severe operative trauma surgery: A retrospective cohort study using a Japanese nationwide administrative database

BACKGROUND

The relationship between hospital case volume and in-hospital mortality, often referred to as the volume-outcome relationship, has been studied in various types of surgery. Despite its usefulness in policymaking, it has not been reported in operative trauma surgery. This study aimed to identify the volume-outcome relationship in severe operative trauma surgery.

METHODS

A retrospective cohort study was conducted using a risk adjustment method based on the International Classification of Diseases 10th Revision Codes in a Japanese nationwide administrative database. Patients discharged from July 1, 2010, to March 31, 2015, who underwent severe operative trauma surgery, defined as having a mortality rate equal to or greater than 10%, were included. A logistic regression model with random effects was used for analysis. Annual hospital case volume was categorized into 4 groups: <6 (reference group), 6 to 11, 12 to 17, and ≥18. Subgroup analysis on head and torso trauma surgery was conducted.

RESULTS

The study population consisted of 18,382 patients from 964 hospitals. Overall mortality was 19.7%. The adjusted odds ratio for mortality did not reduce significantly in the higher hospital case volume category. Subgroup analysis revealed that the adjusted odds ratio reduced significantly in the subgroup of torso surgery (<6 cases/y [reference] vs ≥6 cases/y; adjusted odds ratio, 0.55; 95% confidence interval, 0.42-0.73), but not in the operative head trauma surgery subgroup.

CONCLUSION

A volume-outcome relationship was not identified in severe operative trauma surgery but was observed in the operative torso trauma surgery subgroup.

Physician-manned prehospital emergency care in tertiary emergency centers in Japan

Aim

Use of a physician‐manned prehospital emergency medical service (EMS) has recently become widespread in Japan. Understanding the epidemiology of critically ill patients is essential for planning national and regional physician‐manned prehospital EMS systems. However, current knowledge on patients receiving physician‐manned prehospital EMS is sparse. The present study aimed to determine the clinical features of critically ill patients with and without physician‐manned prehospital EMS, using a national inpatient database in Japan.

Methods

Using the Japanese Diagnosis Procedure Combination inpatient database, we identified all hospitalized patients transported to tertiary emergency centers by physician‐manned EMS or EMS without a physician from April 2014 to March 2015. We collected data on patient characteristics, in‐hospital mortality, admission diagnoses, advanced life support interventions, and incidence of critical illnesses.

Results

We identified 497,911 hospitalized patients transported to tertiary emergency centers by EMS. Of these, 15,507 (3%) patients were hospitalized by physician‐manned EMS. The majority of admission diagnoses in the physician‐manned EMS group were classified “diseases of the circulatory system” (45%) and “injury, poisoning and certain other consequences of external causes” (34%). The rates of in‐hospital mortality, advanced life support interventions, and critical illnesses in the physician‐manned EMS group were 22%, 51%, and 53%, respectively. The median incidences of hospitalized patients by physician‐manned EMS, advanced life support interventions, and critical illnesses were 12, 137, and 205 per 100,000 persons per year in facilities with physician‐manned EMS, respectively.

Conclusion

Our study indicates that physician‐manned EMS is dispatched to a relatively small proportion of critically ill patients in Japan.

Outcomes of patients receiving a massive transfusion for major trauma

BACKGROUND

The benefits of high transfusion ratios (plasma to red blood cells and platelets to red blood cells) on survival in injured patients who receive massive transfusions remain uncertain. This study aimed to assess the association between transfusion ratios and adverse events and survival in patients undergoing massive transfusion for major trauma.

METHODS

A retrospective observational study was conducted on patients who had major trauma using a Japanese national administrative database. The associations between transfusion ratios and outcomes (in-hospital mortality and incidence of adverse events) were analysed using a non-linear logistic generalized additive model (GAM). In a logistic generalized estimating equation model, adjusted for patient and hospital-level confounders, transfusion ratios were included as continuous or categorical variables (low, transfusion ratio 0·75 or less; intermediate, over 0·75 to 1·25; high, over 1·25).

RESULTS

Some 1777 patients were included in the analysis, of whom 602 died in hospital. GAM plots of the transfusion ratios for in-hospital mortality demonstrated a downward convex unimodal curve. In-hospital mortality was similar with increasing transfusion ratios for plasma (adjusted odds ratio (OR) 1·13, 95 per cent c.i. 0·82 to 1·55; P = 0·446) and platelets (adjusted OR 0·84, 0·66 to 1·08; P = 0·171). Both plasma to red blood cell ratio (adjusted OR 1·77, 1·32 to 2·37; P < 0·001) and platelet to red blood cell ratio (adjusted OR 1·71, 1·35 to 2·15; P < 0·001) were significantly associated with a higher incidence of adverse events. No significant differences in in-hospital mortality were observed between the three transfusion categories (low, medium and high).

CONCLUSION

In this study, transfusion strategies with high plasma to red blood cell and platelet to red blood cell ratios did not have survival benefits, but were associated with an increase in adverse events.

Development and validation of an ICD-10-based disability predictive index for patients admitted to hospitals with trauma

BACKGROUND

There was no established disability predictive measurement for patients with trauma that could be used in administrative claims databases. The aim of the present study was to develop and validate a diagnosis-based disability predictive index for severe physical disability at discharge using the International Classification of Diseases, 10th revision (ICD-10) coding.

METHODS

This retrospective observational study used the Diagnosis Procedure Combination database in Japan. Patients who were admitted to hospitals with trauma and discharged alive from 01 April 2010 to 31 March 2015 were included. Pediatric patients under 15 years old were excluded. Data for patients admitted to hospitals from 01 April 2010 to 31 March 2013 was used for development of a disability predictive index (derivation cohort), while data for patients admitted to hospitals from 01 April 2013 to 31 March 2015 was used for the internal validation (validation cohort). The outcome of interest was severe physical disability defined as the Barthel Index score of <60 at discharge. Trauma-related ICD-10 codes were categorized into 36 injury groups with reference to the categorization used in the Global Burden of Diseases study 2013. A multivariable logistic regression analysis was performed for the outcome using the injury groups and patient baseline characteristics including patient age, sex, and Charlson Comorbidity Index (CCI) score in the derivation cohort. A score corresponding to a regression coefficient was assigned to each injury group. The disability predictive index for each patient was defined as the sum of the scores. The predictive performance of the index was validated using the receiver operating characteristic curve analysis in the validation cohort.

RESULTS

The derivation cohort included 1,475,158 patients, while the validation cohort included 939,659 patients. Of the 939,659 patients, 235,382 (25.0%) were discharged with severe physical disability. The c-statistics of the disability predictive index was 0.795 (95% confidence interval [CI] 0.794-0.795), while that of a model using the disability predictive index and patient baseline characteristics was 0.856 (95% CI 0.855-0.857).

CONCLUSIONS

Severe physical disability at discharge may be well predicted with patient age, sex, CCI score, and the diagnosis-based disability predictive index in patients admitted to hospitals with trauma.

Impact of hospital volume on mortality in patients with severe torso injury

BACKGROUND

Whether a positive volume-outcome relationship exists in the context of trauma remains controversial. Heterogeneity in the definition of hospital volume in previous studies is one of the main reasons for this inconclusiveness. We investigated whether hospital volume is associated with mortality in patients with severe torso injury using two different definitions of hospital volume.

MATERIALS AND METHODS

This retrospective cohort study used the Diagnosis Procedure Combination database in Japan. Patients who were admitted to tertiary emergency centers with severe torso injury and underwent emergency surgery or interventional radiology treatment for the torso injury upon admission from April 1, 2010 to March 31, 2014 were included. Hospital volume was defined as the annual number of admissions with severe torso injury (HV-torso) or the annual number of total trauma admissions (HV-all). The main outcome was 28-d mortality. Multivariable logistic regression models fitted with generalized estimating equations were used to evaluate relationships between hospital volume and 28-d mortality.

RESULTS

Overall, 7725 patients were included. The 28-d mortality rate was 15.3%. The HV-torso was significantly associated with reduced 28-d mortality (adjusted odds ratio = 0.59; 95% confidence interval = 0.44-0.79). However, there was no significant association between the HV-all and mortality (adjusted odds ratio = 1.02; 95% confidence interval = 0.72-1.46).

CONCLUSIONS

The HV-torso was significantly associated with reduced mortality in patients with severe torso injury. In contrast, the HV-all had no significant relationship with their mortality. Regionalization of trauma care for severe torso injury may be beneficial for patients with severe torso injury.