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André Lavoie

Publications and source records attributed to André Lavoie.

16 recordsLinked to original sources
PubMed2006

Statistical validation of the Glasgow Coma Score.

BACKGROUND: To validate the predictive value of the Glasgow Coma Score (GCS) and find the best way to model the score in a logistic regression model predicting mortality. METHODS: Analyses were based on 20,494 patients from the trauma registries of three urban Level I trauma centers in the province of Quebec, Canada. The predictive value of the GCS and its components was evaluated in logistic regression models predicting in-hospital mortality with measures of discrimination and calibration. The performance of the GCS with no transformation and as an ordered categorical variable was compared with two transformation techniques: fractional polynomials and spline regression. RESULTS: The GCS had excellent discrimination (area under Receiving Operator Characteristic Curve=0.833 95% confidence interval=0.820-0.846) but fairly poor calibration (Pearson's Chi-squared statistic=122 on 11 df). The eye component added no predictive information to the verbal and motor components in the whole sample but was important in certain sub-populations. Using the three components separately, rather than the sum, did not improve the predictive model. Fractional polynomial transformation of the GCS improved calibration and spline regression performed even better. GCS modeled as an ordered categorical variable performed badly both in terms of discrimination and calibration. CONCLUSIONS: The GCS in its present form is an efficient predictor of in-hospital mortality, which could benefit from statistical transformation in logistic regression models when the accuracy of estimated probabilities of mortality is important. The common use of GCS categories for modeling mortality leads to loss of information and should be discarded.

Aged↗
PubMed2006

Paying the price of excluding patients from a trauma registry.

BACKGROUND: The goal of this study was to evaluate the impact of different trauma registry exclusion criteria on the assessment of trauma populations and outcome. METHODS: All patients admitted to a Canadian regional trauma center from April 1, 1993 to March 31, 2002 with a diagnosis of trauma (ICD-9 codes 800 to 959) were reviewed. TOTAL included everyone. REGISTRY included only patients meeting any of four criteria: death during hospital stay, transfer received from another hospital, admission to the intensive care unit, or hospital stay of 3 days or more. NOHIP excluded patients with isolated hip fracture. REG/NOHIP combined both. ISS12 and ISS15 excluded patients with ISS <12 and 15, respectively. RESULTS: There were 6,839 trauma patients. The percentage of excluded patients by group was: REGISTRY, 21.2%; NOHIP, 14.7%; REG/NOHIP, 34.9%; ISS12, 75%; and ISS15, 80.3%. Median length of stay was 7 days. Exclusions represented a total number of hospitalization days varying from 1.9% to 65.5% of TOTAL. Mortality was 6.9% for TOTAL, 8.6% for REGISTRY (p < 0.001), 5.7% for NOHIP (p = 0.009), 7.5% for REG/NOHIP (p=NS), 16.1% for ISS12 (p < 0.001), and 20.4% for ISS15 (p < 0.001). In groups with exclusions, transfer to long-term care varied from 0.14% to 23.5% in the excluded patients. For rehabilitation, these percentages varied from 0.14% to 17.6%. CONCLUSIONS: Registry exclusion criteria significantly alter the apparent severity of injury and resource utilization. The use of divergent exclusion criteria in the analysis of trauma registry data may be misleading.

Adult↗
PubMed2006

A simple fall in the elderly: not so simple.

BACKGROUND: The goal of this study was to evaluate the burden of falls in the elderly in a Canadian tertiary trauma center. METHODS: Patients admitted to Charles-LeMoyne Hospital with a low velocity fall (LVF) from April 1, 1993 to March 31, 2000 were individually reviewed. Elderly was defined as age 65 years and older. A region was considered to be injured if Abbreviated Injury Scale was greater than or equal to 2. RESULTS: There were 2,333 patients with LVF, 41.4% of all blunt trauma admissions. Median Injury Severity Score was 9 for elderly compared with 5 for young (p < 0.001). Injuries were significantly more frequent to head, face, thorax, and lower limbs in the elderly. Mortality (13.4% versus 0.9%; p < 0.001), length of stay (median = 15 versus 3 days; p < 0.001) and long-term care facility reference (19.3% versus 1.1%, p < 0.001) were significantly higher in the elderly. CONCLUSIONS: LVF is a frequent cause of admission for trauma in the elderly. Despite the apparent benign nature of the mechanism, LVF is associated with more severe injuries and worse outcome.

Abbreviated Injury Scale↗
PubMed2006

Unification of the revised trauma score.

BACKGROUND: The Revised Trauma Score (RTS) calculated with Major Outcome Trauma Study weights (MTOS-RTS) is currently the standard physiologic severity score in trauma research and quality control. It is often confused with the Triage-RTS (T-RTS), a version that is easier to calculate but only intended for clinical triage. OBJECTIVES: To compare the accuracy of the MTOS-RTS to the RTS calculated with weights derived from the study population (POP-RTS) and the T-RTS, for predicting mortality in a trauma population. METHODS: The study population consists of 22,388 patients, drawn from the trauma registries of three Level I trauma centers. The predictive accuracy of the MTOS-RTS, POP-RTS, and the T-RTS were compared using measures of discrimination and model fit from logistic regression models. RESULTS: The MTOS-RTS, the POP-RTS, and the T-RTS had the same discrimination (Area under the Receiver Operating Curve [AUC] = 0.841). The POP-RTS and the T-RTS had a slightly better model fit than the MTOS-RTS (AIC = 8010, 8010, and 8067, respectively). The T-RTS had equal discrimination and equal or better model fit than the MTOS-RTS in the whole sample, in each of the three trauma centers and in the population of patients with severe head trauma. The T-RTS was also equivalent to the POP-RTS in all of these population sub-groups. CONCLUSIONS: The T-RTS could replace the MTOS-RTS as the standard physiologic severity score for trauma outcome prediction. The advantages of using the T-RTS over the MTOS-RTS are ease of calculation, the need for only one measure for triage and mortality prediction purposes and universal adaptation to a broad range of trauma populations.

Aged↗
PubMed2006

Two worst injuries in different body regions are associated with higher mortality than two worst injuries in the same body region.

BACKGROUND: The Injury Severity Score (ISS) accounts for only one injury in each body region. The New Injury Severity Score (NISS) considers all injuries in a body region. Despite a big difference between the two scores in patients with multiple injuries, the NISS does not offer significant improvement in mortality prediction. This paper hypothesizes that two injuries in different body regions are associated with higher mortality than two injuries in the same body region, independently of injury severity. METHODS: The population consisted of 15,200 patients with two or more injuries from the Quebec Trauma Registry, Canada, abstracted between 1998 and 2004. The two worst injuries were considered. Logistic regression analysis was used to assess the mortality odds ratio of having two worst injuries in different body regions (DR) compared with two worst injuries in the same body region (SR), while adjusting for the severity and the body region of the two worst injuries and age. RESULTS: A total of 5,869 patients (49%) had their worst injuries in DR. DR patients had 75% higher risk of mortality than SR patients (odds ratio = 1.75, 95% confidence interval = 1.42-2.15). CONCLUSION: After accounting for differing injury severity, patients with their two worst injuries in different body regions have higher mortality than those with their two worst injuries in the same region. Results suggest that the observed effect is not due to a foible in the Abbreviated Injury Scale system but rather to physiologic, clinical, or organizational elements. The results of this study should be considered in the development of future injury severity instruments and may have implications for the care of patients with multiple injuries.

Aged↗
PubMed2006

Statistical validation of the Revised Trauma Score.

BACKGROUND: To validate the accuracy of the Revised Trauma Score (RTS) and its components for predicting in-hospital mortality. METHODS: Analyses were based on 22,388 patients from the trauma registries of three urban Level I trauma centers in the province of Quebec, Canada. The accuracy of RTS coded variables for the Glasgow Coma Score (GCSc), Systolic Blood Pressure (SBPc), and Respiratory Rate (RRc) for predicting mortality was evaluated in logistic regression models with measures of discrimination and model fit and compared with Fractional Polynomial (FP) transformations of each component. RESULTS: RTS coded variables were associated with sparse data distributions and did not accurately represent the relation of GCS, SBP, and RR to mortality. FP models were always associated with significantly better discrimination (all p < 0.00001) and model fit. Survival probability estimates generated by the model with FP transformations were significantly different to those generated by the model with RTS-coded variables. CONCLUSIONS: The RTS in its present form does not accurately describe the relation of GCS, SBP, and RR to mortality. FP transformation would improve the accuracy of predicted survival probabilities used for performance evaluation and may improve control of confounding caused by of physiologic severity case mix in trauma research.

Adolescent↗
PubMed2006

Consensus or data-derived anatomical severity scoring?

We aimed to compare the predictive accuracy of consensus-derived and data-derived injury severity scores when considered alone and in combination with age and physiological status. Analyses were based on 25,111 patients. The predictive validity of each severity score was evaluated in logistic regression models predicting in-hospital mortality using measures of discrimination and calibration. Data-derived scores had consistently better predictive accuracy than consensus-derived scores in univariate models (p<0.0001) but very little difference between scores was observed in models including information on age and physiological status. Data-derived scores provide more accurate mortality prediction than consensus-derived scores when only anatomic injury severity is considered but offer little advantage if age and physiological status are taken into account.

Adolescent↗
PubMed2005

The Injury Severity Score or the New Injury Severity Score for predicting intensive care unit admission and hospital length of stay?

OBJECTIVES: To compare the New Injury Severity Score (NISS) and the Injury Severity Score (ISS) as predictors of intensive care unit (ICU) admission and hospital length of stay (LOS) in an urban North American trauma population and in a subset of patients with head injuries. METHODS: The study population consisted of 23,909 patients from three urban level I trauma centres in the province of Quebec, Canada. The predictive accuracies of the NISS and the ISS were compared using Receiver Operator Characteristic (ROC) curves and Hosmer-Lemeshow (H-L) statistics for the logistic regression model of ICU admission and using r2 for the linear regression model of LOS. RESULTS: A total of 7660 (32%) patients were admitted to the ICU. Mean LOS was 8.2+/-2.5 days. In the whole sample, the NISS presented equivalent discrimination (area under ROC curve: NISS = 0.839 versus ISS = 0.843, p = 0.08) but better calibration (H-L statistic: 309 versus 611) for predicting ICU admission. In the subgroup patients with moderate to serious head injuries, the NISS was a better predictor of ICU admission in terms of both discrimination (area under ROC curve: NISS = 0.771 versus ISS = 0.747, p < 0.00001) and calibration (H-L statistic: 12 versus 21). The NISS explained more variation in LOS than the ISS for the whole sample (r2 = 0.254 versus 0.249, p = 0.0008) and in the sub-population with moderate to severe head injuries (r2 = 0.281 versus 0.263, p = 0.0002). CONCLUSIONS: The NISS is a better choice for case mix control in trauma research than the ISS for predicting ICU admission and LOS, particularly among patients with moderate to severe head injuries.

Adolescent↗
PubMed2005

A second injury in the same body region is associated with lower mortality than a second injury in a different body region.

HYPOTHESIS: A second injury in the same body region is associated with lower mortality than a second injury in a different body region, independently of injury severity and body region. METHODS: The population consisted of 15,200 patients with two or more injuries from level I trauma centers in Quebec. The mortality odds ratio of having a same-region second injury (SR) as opposed to a different-region second injury (DR) was assessed. RESULTS: Patients with a SR had 43% lower odds of mortality when compared to patients with a DR. CONCLUSION: A second injury in the same body region is associated with lower mortality than a second injury in a different body region.

Accidents, Traffic↗
PubMed2005

Comorbidity and age are both independent predictors of length of hospitalization in trauma patients.

BACKGROUND: Length of hospitalization is a good indicator of resource utilization. Older patients are increasingly suffering trauma, and comorbid medical conditions are also increasing. Our objective was to determine the separate and combined effect of these 2 factors on length of hospital stay for trauma patients in a tertiary trauma centre. METHODS: All 994 consecutive trauma patients surviving to hospital discharge between Apr. 1, 2000, and Mar. 31, 2001, were identified. Patient characteristics, injury severity and length of hospitalization were obtained from the hospital trauma registry. Each medical record was then reviewed for completeness of information and assessment of comorbid conditions. A multivariate linear regression model was developed to predict logarithmic length of stay from age and presence of a cormorbid condition while adjusting for the Injury Severity Score (ISS). RESULTS: The mean age of the patients was 49.7 (range from 14-100) years and median ISS was 9 (range from 1-50). At least 1 comorbid condition was present in 321 (32%) patients. Mean length of hospital stay was 15.3 days. The proportion of patients with a comorbid condition increased steadily with age, from 8.7% before the age of 55 years to 92% at 85 or more years of age (p < 0.001). According to the multivariate model, the presence of comorbidity, age and ISS were all independent predictors of hospital stay (p < 0.001). When applied to patients with the mean ISS value of 9, the model showed an increase in length of hospitalization for patients with a comorbid condition over those without; (3.6 v. 13.1 d for patients < 55 and > or = 85 yr respectively). Length of hospital stay increased particularly with neurologic and pulmonary problems. CONCLUSIONS: Comorbidity and age were both independently significant predictors of length of hospitalization over and beyond that which is expected based on the severity of the injuries. With an aging population, this phenomenon should severely affect resource utilization in trauma centres in the near future. Researchers should take account of both age and comorbidity in order to compare trauma populations.

Adolescent↗
PubMed2005

Multiple imputation of the Glasgow Coma Score.

BACKGROUND: To investigate whether multiple imputation (MI) of missing Glasgow Coma Scale (GCS) values generates more accurate GCS frequency distributions and less biased parameter estimates in logistic regression models predicting mortality than the standard procedure of excluding observations with missing GCS values. METHODS: The study population consisted of 5,065 patients with complete GCS information from the trauma registry of a Level 1 trauma center. Missing GCS values were imposed on the data set, and the performance of MI (extrapolating missing GCS from a data prediction model) and of deleting all data observations with missing GCS (list-wise deletion) were evaluated. GCS and Trauma and Injury Severity Score (TRISS) frequency distributions and parameter estimates were compared with true values from the original data set. RESULTS: GCS and TRISS frequency values generated by MI were much more accurate than those generated by list-wise deletion. GCS and TRISS parameter estimates generated by MI all had acceptable bias and coverage rates when compared with true values. List-wise deletion provided biased parameter estimates for the GCS, the Revised Trauma Score, and the Injury Severity Score. CONCLUSION: MI is a valid solution to the problem of missing GCS data in trauma research. It allows the conservation of precious data observations and leads to unbiased estimates in consequent analyses. Analyses, which exclude observations with missing GCS data, provide biased results.

Biomedical Research↗
PubMed2004

Impact of transfer delays to rehabilitation in patients with severe trauma.

OBJECTIVE: To measure the effect on rehabilitation outcomes of administrative delays in transferring patients from a level I trauma center to inpatient rehabilitation. DESIGN: Retrospective cohort study. SETTINGS: Level I trauma center and an inpatient rehabilitation center in Quebec, Canada. PARTICIPANTS: A total of 289 patients with severe trauma admitted to inpatient rehabilitation from a level I trauma center between 1994 and 1999. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Length of stay (LOS) in rehabilitation, motor and cognitive function at discharge from rehabilitation, interruptions in rehabilitation, and disposition at discharge. RESULTS: Shorter administrative delays were associated with shorter rehabilitation LOS (P<.01) improved cognitive function (P=.02) and had a negative but statistically nonsignificant association with motor function at discharge. No effect was observed for rehabilitation interruptions or dispositions at discharge. CONCLUSIONS: Transferring trauma patients more quickly to inpatient rehabilitation can affect rehabilitation outcomes positively. It can also lead to an economy of resource use in both acute and rehabilitation settings.

Adolescent↗
PubMed2004

The New Injury Severity Score: a more accurate predictor of in-hospital mortality than the Injury Severity Score.

OBJECTIVE: The purpose of this study was to determine whether the New Injury Severity Score (NISS) is a better predictor of mortality than the Injury Severity Score (ISS) in general and in subgroups according to age, penetrating trauma, and body region injured. METHODS: The study population consisted of 24,263 patients from three urban Level I trauma centers in the province of Quebec, Canada. Discrimination and calibration of NISS and ISS models were compared using receiver operator characteristic (ROC) curves and Hosmer-Lemeshow statistics. RESULTS: NISS showed better discrimination than ISS (area under the ROC curve = 0.827 vs. 0.819; p = 0.0006) and improved calibration (Hosmer-Leme-show = 62 vs. 112). The advantage of the NISS over the ISS was particularly evident among patients with head/neck injuries (area under the ROC curve = 0.819 vs. 0.784; p < 0.0001; Hosmer-Lemeshow = 59 vs. 350). CONCLUSION: The NISS is a more accurate predictor of in-hospital death than the ISS and should be chosen over the ISS for case-mix control in trauma research, especially in certain subpopulations such as head/neck-injured patients.

Adolescent↗
PubMed2004

Clinical factors predicting fractures associated with an anterior shoulder dislocation.

OBJECTIVES: To identify risk factors for fractures associated with an anterior shoulder dislocation treated in an emergency department (ED). METHODS: A retrospective case-control study over five years of patients with an anterior shoulder dislocation was accomplished in a university-affiliated ED. Chart review identified possible predictors of fractures. Comparing the profile of patients having a clinically important fracture associated with their shoulder dislocation (cases) with those sustaining a noncomplicated dislocation (controls) provided the outcome measure. RESULTS: A total of 334 patients were included in the study. Eighty-five (25.5%) had a clinically important fracture-dislocation, and the remaining 249 (74.5%) sustained a noncomplicated shoulder dislocation. Chi-square, logistic regression, and recursive partitioning analysis showed three significant factors for the presence of fracture-dislocation: 1) age 40 years or older, 2) a first episode of dislocation, and 3) mechanism of injury (i.e., a fall greater than one flight of stairs, a fight/assault episode, or a motor vehicle crash). A multiple logistic regression model estimated the significant adjusted odds ratios (and their 95% confidence intervals [95% CIs]) for each of the three factors: 5.18 (95% CI = 2.74 to 9.78), 4.23 (95% CI = 1.82 to 9.87), and 4.06 (95% CI = 1.95 to 8.48), respectively. A predictive model using any one of the three factors reached a sensitivity of 97.7% (95% CI = 91.8% to 99.4%), a specificity of 22.9% (95% CI = 18.1% to 28.5%), and a negative predictive value of 96.6% (95% CI = 88.3% to 99.6%). CONCLUSIONS: Three risk factors predict clinically important fractures that are associated with shoulder dislocation: age, first episode, and mechanism of dislocation. A prospective validation may lead to standardized use of prereduction radiographs of the shoulder in the ED.

Accidental Falls↗
PubMed2003

Multicenter Canadian study of prehospital trauma care.

OBJECTIVE: To evaluate whether the type of on-site care a trauma patient receives affects outcome. SUMMARY BACKGROUND DATA: The controversy regarding the prehospital care of trauma patients between Advanced Life Support (ALS) and Basic Life Support (BLS) is ongoing. Due to this unresolved controversy, as well as historical, cultural, and political factors, there are significant variations with respect to the type of prehospital care available for trauma patients. METHODS: This prospective cohort study compared three types of prehospital trauma care systems: Montreal, where physicians provide ALS (MD-ALS); Toronto, where paramedics provide ALS (PMD-ALS); and Quebec City, where emergency medical technicians provide BLS only (EMT-BLS). The study took advantage of this variation to evaluate the association between the type of on-site care and mortality in patients with major life-threatening injuries. All patients were treated at highly specialized tertiary (level I) trauma hospitals. The main outcome measure was death as a result of injury. Follow-up was to hospital discharge. RESULTS: The overall mortality rates by type of on-site personnel were physicians 35%, paramedics 24%, and EMTs 18%. For patients with major but survivable trauma, the overall mortality rates were physicians 32%, paramedics 28%, and EMTs 26%. The overall mortality rate of patients receiving only BLS at the scene was 18% compared to 29% for patients receiving ALS. For the subgroup of patients with major but survivable injuries, the mortality rates were 30% for ALS and 26% for BLS. The adjusted increased risk for mortality in patients receiving ALS at the scene was 21%. CONCLUSIONS: In urban centers with highly specialized level I trauma centers, there is no benefit in having on-site ALS for the prehospital management of trauma patients.

Adult↗