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Biomedical subjects

Peter Cummings

Publications and source records attributed to Peter Cummings.

At least 19 recordsLinked to original sources
PubMed2006

Association of first- and second-generation air bags with front occupant death in car crashes: a matched cohort study.

First-generation air bags entail a decreased risk of death for most front seat occupants in car crashes but an increased risk for children. Second-generation air bags were developed to reduce the risks for children, despite the possibility of decreasing protection for others. Using a matched cohort design, the authors estimated risk ratios for death for use of each generation of air bag versus no air bag, adjusted for seat position, restraint use, sex, age, and all vehicle and crash characteristics, among 128,208 automobile occupants involved in fatal crashes on US roadways during 1990-2002. The authors then compared adjusted risk ratios (aRRs) between the two generations of air bags. Among front seat occupants, the aRR for death with a first-generation air bag was 0.90 (95% confidence interval (CI): 0.86, 0.94); the aRR with a second-generation air bag was 0.89 (95% CI: 0.79, 1.00) (p = 0.83 for comparison of aRRs). Among children under age 6 years, the aRR with a first-generation air bag was 1.66 (95% CI: 1.20, 2.30), while the aRR with a second-generation air bag was 1.10 (95% CI: 0.63, 1.93) (p = 0.20 for comparison of aRRs). The differences in aRRs between first- and second-generation air bags among other subgroups were small and not statistically significant.

Accidents, Traffic↗
PubMed2006

Misconceptions regarding case-control studies of bicycle helmets and head injury.

A number of published case-control studies have reported that bicycle helmets are associated with a reduced risk of head injury and brain injury among bicyclists who crashed. A paper in this journal offered several criticisms of these studies and of a systematic review of these studies. Many of those criticisms stem from misconceptions about the studies that have been done and about case-control studies in general. In this manuscript we review case-control study design, particularly as it applies to bicycle helmet studies, and review some aspects of the analysis of case-control data.

Accidents, Traffic↗
PubMed2006

Predicting major hemorrhage in patients with pelvic fracture.

BACKGROUND: Pelvic fractures can be an important source of major hemorrhage in victims of blunt trauma. However, no rapid and reliable noninvasive method exists for predicting which subjects will have major hemorrhage. The objective of this study is to use information available upon presentation to the trauma center to develop a clinical prediction rule to identify subjects with pelvic fracture who are at high risk of major hemorrhage. METHODS: A retrospective cohort study was performed on all subjects with pelvic fracture from blunt force mechanism at a single level one trauma center during a 4.3 year period. Chart review identified findings from initial pelvic radiographs and from emergency department care including mechanism of injury, and hemodynamic status. Major hemorrhage was defined by angiographic findings, transfusion requirement and pelvic hemorrhage volume. Logistic regression was used to formulate a clinical prediction rule to stratify subjects based on probability of major hemorrhage. RESULTS: Complete data were available on 627 of 783 eligible subjects. Predictors of major hemorrhage included emergency department hematocrit 30 or less, pulse rate of 130 or greater, displaced obturator ring fracture and pubic symphyseal wide diastasis. Combinations of predictors defined groups with probability of major hemorrhage from 1.6% to 66%. CONCLUSIONS: Probability of major pelvic fracture related hemorrhage can be estimated from initial pelvic radiograph, pulse, and hematocrit.

Adult↗
PubMed2005

Predicting time to subsequent pregnancy.

OBJECTIVES: Women in poverty may benefit from avoiding closely spaced pregnancies. This study sought to identify predictive factors that could identify women at risk for closely spaced pregnancies. METHODS: We studied 20,028 women receiving welfare (cash assistance) from Washington State. Using Cox proportional hazards methods, we estimated the effects of individual- and community-level variables on time from an index birth until a subsequent pregnancy (between June 1992 and December 1999). Prediction models developed in a random half of our data were validated in the other half. Receiver operator characteristic plots appropriate for proportional hazards models were calculated to compare the sensitivity and specificity of each model. RESULTS: At 5 years of follow-up, the most predictive model contained just individual-level variables (age, education, race, marital status, number of prior pregnancies); the area under the receiver operator characteristic curve was 0.66 (.62-.69). The addition of community-level variables (percent in poverty, with a high school degree or higher, Black, Hispanic, in an urban area; female unemployment rate; income inequality) added little predictive ability. Differences were found between women with different individual- and community-level characteristics, but the results suggest that these factors are not strong predictors of pregnancy spacing. CONCLUSIONS: Individual- and community-level characteristics are associated with interpregnancy intervals; however, we found little evidence that the selected variables predicted pregnancy interval in a useful manner.

Adolescent↗
PubMed2004

Car occupant death according to the restraint use of other occupants: a matched cohort study.

CONTEXT: A car occupant could be killed if struck by another occupant who was catapulted forward, backward, or sideways in a crash. OBJECTIVE: To estimate the association between death of a car occupant (the target) and restraint use by other occupants. DESIGN: Matched-pair cohort study comparing the outcomes of 2 target occupants in the same passenger car that crashed. SETTING: United States traffic crashes in 1988-2000, using data from the Fatality Analysis Reporting System. SUBJECTS: Target pairs, at least 1 of whom died: 61 834 front-seat pairs, 5278 rear-seat pairs, and 21 127 pairs on the left or right side. MAIN OUTCOME MEASURES: Adjusted risk ratio (RR) for death within 30 days of a crash. RESULTS: The risk of death was greater for a restrained front target occupant in front of an unrestrained occupant compared with a restrained front target in front of a restrained occupant (adjusted RR, 1.20; 95% confidence interval [CI], 1.10-1.31). For a restrained rear target occupant behind an unrestrained occupant compared with a restrained rear target occupant behind a restrained occupant, the adjusted RR was 1.22 (95% CI, 1.10-1.36). For a restrained side target occupant sitting next to an unrestrained occupant compared with a restrained side target occupant sitting next to a restrained occupant, the adjusted RR was 1.15 (95% CI, 1.08-1.22). Among unrestrained target occupants, the adjusted RRs were, for front targets, 1.04 (95% CI, 0.97-1.12), rear targets, 1.22 (95% CI, 1.10-1.36), and side targets, 0.85 (95% CI, 0.80-0.92). CONCLUSION: Persons who wish to reduce their risk of death in a crash should wear their own restraint and should ask others in the same car to use their restraints.

Accidents, Traffic↗
PubMed2004

Comparison of reporting of seat belt use by police and crash investigators: variation in agreement by injury severity.

PURPOSE: To evaluate agreement between police and trained investigators regarding seat belt use by crash victims, according to injury severity. METHODS: We used data from the National Accident Sampling System Crashworthiness Data System (CDS) for front seat occupants, 16 years and older, in crashes during 1993-2000. Crashworthiness Data System investigators determined belt use from vehicle inspection, interviews, and medical record information; their assessment was considered the gold standard for this analysis. Occupant severity of injury was categorized in five levels from no injuries to death. We estimated the sensitivity, specificity, and area under receiver operating characteristic curves for police reports of belt use. RESULTS: Among 48,858 occupants, sensitivity of a police report that a belt was used was 95.8% overall and varied only modestly by injury severity. Specificity of a police report that a belt was not used was 69.1% overall; it was the lowest among the uninjured (53.2%) and greatest among the dead (90.4%). The area under the curve was 0.82 (95% confidence interval 0.82-0.83) overall; this was lowest among those not injured (0.75, 95% confidence interval 0.74-0.76) and increased with injury severity to 0.91 (95% confidence interval 0.90-0.93) among those who died. CONCLUSION: Police usually classify belted crash victims as belted, regardless of injury severity. But they often classify unbelted survivors as belted when they were not. This misclassification may result in exaggerated estimates of seat belt effectiveness in some studies.

Accidents, Traffic↗
PubMed2004

Passenger seating position and the risk of passenger death or injury in traffic crashes.

OBJECTIVE: To estimate the association of passenger seat position with the risk of death and serious injury for passengers in traffic crashes. METHODS: Using 1993-2000 data from the National Highway Traffic Safety Administration's Crashworthiness Data System (CDS), the risk ratio for death and serious injury was estimated for rear seat passengers compared with front seat passengers in motor vehicle crashes. RESULTS: The adjusted risk ratio for death of passengers in the rear seat in a crash was 0.61 (95% confidence interval (CI) 0.46-0.81). Rear seat passenger position was also associated with a decrease in the risk of death and serious injury compared with the front seat passenger position: risk ratio=0.67 (95% CI 0.57-0.78). CONCLUSION: We estimated that the rear seat passenger position may reduce the risk of death in a motor vehicle crash by about 39% and reduce the risk of death or serious injury in a crash by 33%, compared with the front seat passenger position. If the associations that we report are causal, sitting in the rear seat, compared with the front seat, may prevent about 4 in 10 passenger deaths, or 3 in 10 passenger deaths and injuries, that might otherwise occur.

Accidents, Traffic↗
PubMed2004

Erectile dysfunction after a long-distance cycling event: associations with bicycle characteristics.

PURPOSE: We conducted a prospective cohort study to examine the relationship between bicycle characteristics and the occurrence of erectile dysfunction. MATERIALS AND METHODS: Subjects consisted of 463 cyclists completing a cycling event of at least 320 km who were free of erectile dysfunction before their event. RESULTS: The cumulative incidence of erectile dysfunction after the ride was 4.2% (95% confidence interval [CI] 2.4%-6.8%) and 1.8% (95% CI 0.7%-3.8%) 1 week and 1 month after the event, respectively. Bicycle characteristics associated with an increased risk of erectile dysfunction included a mountain bicycle compared with a road bicycle (risk ratio [RR] 4.1, 95% CI 1.6-12.5), and the relative height of the handlebars parallel with or higher than the saddle compared with the relative handlebar height lower than the saddle (RR 3.0, 95% CI 1.1-9.3). Perineal numbness during the ride was experienced by 31% of the cyclists and was associated with erectile dysfunction (RR 4.4, 95% CI 1.6-12.7). Saddle cutouts were associated with an increased risk of erectile dysfunction among those who experienced numbness (RR 6.0, 95% CI 1.3-27.1), but the association was reversed among those who did not report numbness (RR 0.3, 95% CI 0.0-2.5). CONCLUSIONS: If the associations described are causal, then cyclists on a long-distance ride may be able to decrease the risk of erectile dysfunction by riding a road bicycle instead of a mountain bicycle, keeping handlebar height lower than saddle height and using a saddle without a cutout if perineal numbness is experienced.

Adult↗
PubMed2004

Association of hospital trauma designation with admission patterns of injured children.

BACKGROUND: Little is known about the influence of regionalization of trauma care on pediatric trauma care delivery. The purpose of this study was to estimate whether formal adoption of a statewide trauma system was associated with hospital admission patterns of injured children. METHODS: A longitudinal study of children who were residents of Washington State during 1989 to 1999 was conducted. The main outcome measure was hospital admission for trauma. RESULTS: During the 11-year period, there were 24,955 admissions. Admission rates of injured children to pediatric-designated trauma hospitals decreased by 20%, rates at adult-designated hospitals decreased by 60%, and rates at nondesignated hospitals decreased by 66%. Introduction of the trauma system in 1994 was associated with a 12% increase in admission rates to pediatric-designated hospitals, little change (+1%) in admission rates to adult-designated centers, and an 11% decrease in admissions at nondesignated hospitals. CONCLUSION: Trauma designation in Washington was associated with a shift in admissions from nondesignated hospitals to pediatric trauma hospitals.

Adolescent↗
PubMed2004

The association of third molars with mandibular angle fractures: a meta-analysis.

OBJECTIVE: To estimate the relative risk of mandibular angle fractures among people with a lower third molar compared with those without a lower third molar. METHODS: Data for a case-control meta-analysis were obtained by performing a literature search in MEDLINE and EMBASE to identify suitable observational studies. To be included, studies had to present data on patients with mandibular fractures, incorporate cross-classified information about the presence of a lower third molar and indicate whether the fracture was a mandibular angle fracture on the ipsilateral side. RESULTS: Six studies, involving 3,002 patients with mandibular fractures, met the inclusion criteria. Crude relative risk estimates for an angle fracture, comparing patients with a third molar with those without, ranged from 1.2 to 12.7. There was evidence of heterogeneity across the 6 studies (p = 0.001), but when 2 studies with less methodologic rigour were excluded, a test of homogeneity was no longer statistically significant (p = 0.22). The estimated relative risk across the remaining 4 studies was 2.4 (95% CI 1.9 to 3.0). CONCLUSIONS: The presence of a lower third molar may double the risk of an angle fracture of the mandible. This could have a bearing on any clinical decision on whether to extract the molar.

Adult↗
PubMed2003

Association between acute and chronic graft-versus-host disease and bronchiolitis obliterans organizing pneumonia in recipients of hematopoietic stem cell transplants.

Bronchiolitis obliterans organizing pneumonia (BOOP) has been reported following hematopoietic stem cell (HSC) transplantation, but the clinical features and risk factors for this disorder have not been well characterized. This case-control study of 49 patients with histologic BOOP and 161 control subjects matched by age and year of transplantation describes the clinical features and analyzes the risk factors for BOOP following HSC transplantation. Data on clinical features and outcome were collected by chart review. Odds ratios, estimating the relative risk of BOOP in allogeneic HSC recipients, were calculated by conditional logistic regression with adjustment for potential confounding factors. Clinical features of BOOP in this population were similar to idiopathic BOOP and BOOP occurring in other disease settings. There was an association between acute and chronic graft-versus-host disease (GVHD) and the subsequent development of BOOP (odds ratios, 3.8 [95% CI, 1.2 to 12.3] and 3.1 [95% CI, 1.1 to 9.2], respectively). Patients with BOOP were more likely to have acute GVHD involving the skin (odds ratio, 4.6; P =.005) and chronic GVHD involving the gut (odds ratio, 6.6; P =.018) and oral cavity (odds ratio, 5.9; P =.026). This study shows that histologic BOOP following HSC transplantation has clinical features that resemble idiopathic BOOP and is strongly associated with prior acute and chronic GVHD. These results have important implications for the care of patients who develop respiratory symptoms after HSC transplantation and may help elucidate the pathogenesis of idiopathic BOOP.

Acute Disease↗