Comparison of two prognostic models in trauma outcome.

BACKGROUND: The Trauma Audit and Research Network (TARN) in the UK publicly reports hospital performance in the management of trauma. The TARN risk adjustment model uses a fractional polynomial transformation of the Injury Severity Score (ISS) as the measure of anatomical injury severity. The Trauma Mortality Prediction Model (TMPM) is an alternative to ISS; this study compared the anatomical injury components of the TARN model with the TMPM. METHODS: Data from the National Trauma Data Bank for 2011-2015 were analysed. Probability of death was estimated for the TARN fractional polynomial transformation of ISS and compared with the TMPM. The coefficients for each model were estimated using 80 per cent of the data set, selected randomly. The remaining 20 per cent of the data were used for model validation. TMPM and TARN were compared using calibration curves, measures of discrimination (area under receiver operating characteristic curves; AUROC), proximity to the true model (Akaike information criterion; AIC) and goodness of model fit (Hosmer-Lemeshow test). RESULTS: Some 438 058 patient records were analysed. TMPM demonstrated preferable AUROC (0·882 for TMPM versus 0·845 for TARN), AIC (18 204 versus 21 163) and better fit to the data (32·4 versus 153·0) compared with TARN. CONCLUSION: TMPM had greater discrimination, proximity to the true model and goodness-of-fit than the anatomical injury component of TARN. TMPM should be considered for the injury severity measure for the comparative assessment of trauma centres.

The log multinomial regression model for nominal outcomes with more than two attributes.

An estimate of the risk or prevalence ratio, adjusted for confounders, can be obtained from a log binomial model (binomial errors, log link) fitted to binary outcome data. We propose a modification of the log binomial model to obtain relative risk estimates for nominal outcomes with more than two attributes (the "log multinomial model"). Extensive data simulations were undertaken to compare the performance of the log multinomial model with that of an expanded data multinomial logistic regression method based on the approach proposed by Schouten et al. (1993) for binary data, and with that of separate fits of a Poisson regression model based on the approach proposed by Zou (2004) and Carter, Lipsitz and Tilley (2005) for binary data. Log multinomial regression resulted in "inadmissable" solutions (out-of-bounds probabilities) exceeding 50% in some data settings. Coefficient estimates by the alternative methods produced out-of-bounds probabilities for the log multinomial model in up to 27% of samples to which a log multinomial model had been successfully fitted. The log multinomial coefficient estimates generally had lesser relative bias and mean squared error than the alternative methods. The practical utility of the log multinomial regression model was demonstrated with a real data example. The log multinomial model offers a practical solution to the problem of obtaining adjusted estimates of the risk ratio in the multinomial setting, but must be used with some care and attention to detail.

The prevalence of risk factors for venous thromboembolism among hospital patients.

BACKGROUND: This study provides an estimate of the prevalence of risk factors for venous thromboembolism among hospital patients. METHODS: The presence of risk factors for venous thromboembolism was determined from a retrospective review of the medical records of 1,000 randomly selected patients in 16 acute care hospitals in central Massachusetts. RESULTS: The most common risk factors for venous thromboembolism were age 40 years (59%) or more, obesity (28%), and major surgery (23%). The average number of risk factors increased with increasing age. One or more risk factors for venous thromboembolism were present in 78% of hospital patients, two or more in 48%, three or more in 19%, four or more in 6%, and five or more in 1%. CONCLUSION: Risk factors for venous thromboembolism are common among hospital patients, suggesting that prophylaxis should be widely employed. The cost-effectiveness and risk benefit of prophylaxis is well established in patients undergoing major surgery. Further studies are needed to confirm the benefit of prophylaxis in patients with nonsurgical risk factors for venous thromboembolism.

Changing clinical practice. Prospective study of the impact of continuing medical education and quality assurance programs on use of prophylaxis for venous thromboembolism.

OBJECTIVE: To determine the effect of continuing medical education (CME) with and without a quality assurance component (CME+QA) on physician practices in the prevention of venous thromboembolism. METHODS: A communitywide study was performed in 15 short-stay hospitals in central Massachusetts. The study population included 3158 patients in acute-care hospitals with multiple risk factors for venous thromboembolism. Study hospitals were randomly assigned to one of two educational strategies or to a control group that received no intervention. RESULTS: The proportion of patients at high risk for venous thromboembolism who received effective methods of prophylaxis increased significantly from 29% in 1986 to 52% in 1989 (P < .001). This increase was seen in all study groups: control hospitals, 40% to 51% (P < .001); CME hospitals, 21% to 49% (P < .0001); and CME+QA hospitals, 27% to 55% (P < .0001). The increase in prophylaxis use from 1986 to 1989 was significantly greater among patients cared for in hospitals whose physicians participated in a formal CME program (an increase of 28%) than in control hospitals (an increase of 11%) (P < .001). There was no significant difference in the use of prophylaxis in hospitals whose physicians received CME+QA interventions compared with hospitals whose physicians received CME interventions alone (identical increases of 28%). CONCLUSION: A formal CME program significantly increased the frequency with which physicians prescribed prophylaxis for venous thromboembolism. We believe the key factor in our CME interventions that motivated clinicians to change their practices was the provision of hospital-specific data demonstrating a compelling need for improvement. Despite the substantial investment by hospitals in QA, traditional QA intervention appeared to provide no additional benefit. Even after extensive CME/QA interventions, prophylaxis for venous thromboembolism remained underutilized, suggesting the need to develop new approaches to changing clinical practice.

The impact of clinical trials on the use of medications for acute myocardial infarction. Results of a community-based study.

BACKGROUND: The impact of clinical trials on medical practice remains controversial, in part because of weak study designs and nonrepresentative study samples. OBJECTIVE: To assess changes in trends in medication use in the setting of acute myocardial infarction (AMI) before and after publication of two large clinical trials: the Second International Study of Infarct Survival (ISIS-2) trial that supported the use of aspirin after AMI and the Multi-center Diltiazem Postinfarction Trial that reported no overall benefit from the use of calcium antagonists after AMI. METHODS: Study patients consisted of 2114 patients hospitalized with AMI in 16 hospitals in metropolitan Worcester, Mass, during 1986, 1988, and 1990. Data were obtained from medical records. We used multivariable logistic regression models to examine the rate of change in the use of selected medications before and after trial publication, controlling for medical history, characteristics and complications of AMI, medications taken, and procedures performed during hospitalization. The dependent variable was receipt of the specific medication under investigation. RESULTS: Before publication of ISIS-2, 26% of patients with AMI received aspirin while hospitalized compared with 66% after its publication. However, in-hospital aspirin use began to rise before ISIS-2 with an immediate increase in the level of use occurring after trial publication but with no significant change in the rate of increase. Before publication of the Multicenter Diltiazem Postinfarction Trial, 57% of patients with AMI were new recipients of calcium antagonists compared with 51% after trial publication. The decrease in calcium antagonist use began after trial publication (odds ratio, 0.79 per 6-month period; 95% confidence interval, 0.71 to 0.88). CONCLUSIONS: The published results of large trials of cardiovascular therapies have had variable impact on medication use. Efforts to assess the effects of publication of new scientific information on medical care need to consider prior trends in treatment patterns and the varying contexts of medical care. They should consider both direct and indirect routes of influence.

A population-based perspective of the hospital incidence and case-fatality rates of deep vein thrombosis and pulmonary embolism. The Worcester DVT Study.

A community-wide study was conducted in 16 short-stay hospitals in metropolitan Worcester, Mass, to examine the incidence and case-fatality rates of deep vein thrombosis and pulmonary embolism in patients hospitalized between July 1, 1985, and December 31, 1986. The average annual incidence of deep vein thrombosis alone was 48 per 100,000, while the incidence of pulmonary embolism with or without deep vein thrombosis was 23 per 100,000. The incidence rates of deep vein thrombosis and pulmonary embolism increased exponentially with age. The in-hospital case-fatality rate of venous thromboembolism was 12%. Among patients discharged from the hospital, the long-term case-fatality rates were 19%, 25%, and 30% at 1, 2, and 3 years after hospital discharge. Extrapolation of the data from this population-based study suggests that there are approximately 170,000 new cases of clinically recognized venous thromboembolism in patients treated in short-stay hospitals in the United States each year, and 99,000 hospitalizations for recurrent disease. Because of the silent nature of this disease and the low rate of autopsy in the United States, the total incidence, prevalence, and mortality rates of venous thromboembolism remain elusive.

The effect of diet on weight gain in infancy.

Data from a longitudinal survey of 92 mothers and their female infants supported the hypothesis that the method of feeding had an effect on weight gain. Nutritionists visited the homes monthly during the first 6 months after parturition and obtained both dietary and anthropometric information. The infants were grouped according to the method of feeding at 2 months. A two-factor experiment with repeated measures on one factor as the experimental design was used to test for the effects of diet on weight gain, length increment, and weight/length pattern. The difference between group mean weights adjusted for birthweight was significant with .05 < P < 0.1. One difference was between infants fed formula and solids and infants fed breast milk and food supplements but not between infants fed breast milk or formula alone. No significant differences among the feeding groups were noted in length and weight/length, but there was a tendency for higher weight in relation to height in the infants fed formula and solids.

Effects of alterations in fatty acid intake on the blood pressure of adolescents: the Exeter-Andover Project.

To judge the effect on blood pressure, the ratio of polyunsaturated to saturated fatty acids (P:S) of foods served to students at two boarding high schools was modified alternately at each school for one school year. The average P:S of the diet of males increased from 0.53 to 0.93 during the intervention whereas among females it increased from 0.64 to 0.98. Comparison of repeated systolic and diastolic blood pressure measurements near the end of the school year did not demonstrate a beneficial effect of the dietary fat changes on the blood pressure of these normotensive adolescents. Compared with the blood pressure patterns during control years, the dietary intervention resulted in slightly higher systolic (+0.88 mm Hg; 95% CI -0.66, +2.42) and diastolic (+1.23 mm Hg; 95% CI = +0.04, +2.42) blood pressure readings among males. Among females the intervention resulted in slightly lower systolic (-0.54 mm Hg; 95% CI = -1.95, +0.88) and diastolic (-0.80 mm Hg (95% CI -2.18, +0.58) blood pressure readings.

Impact of a physician intervention program to increase breast cancer screening.

In order to improve compliance with the National Cancer Institute's breast cancer screening guidelines, we developed a multifaceted intervention designed to alter physician screening practice. A pre-post test, two-community design was used. Primary care physicians in one community served as the control. Data were collected by two mailed surveys (1987 and 1990). Response rates were 61% and 64%, respectively. The physician intervention program consisted of a hospital-based continuing medical education program and an outreach component which focused on implementing a reminder system. Outcome measures were self-reported attitudinal, knowledge, and screening practices changes. In spite of an impressive change in comparison community physicians' practice, the difference in change over time in the intervention community physicians' ordering of annual mammography compared to the change in the comparison community physicians' ordering was significant (P = 0.04). The adjusted odds ratio is nearly 8. We conclude that our in-service continuing medical education program was successful in improving breast cancer screening practices among primary care physicians.

The effect of feeding on fat deposition in early infancy.

Trained nutritionists surveyed 92 female infants and their mothers in Western Massachusetts at monthly intervals from birth to age 6 months. A diet history, a three-day record of food intake and 11 anthropometric measurements were obtained at each home visit. Skinfold measurements showed an earlier plateau than in other published studies. There were no significant differences in fat thicknesses when infants were classified by method of feeding until age 2 months, but formula-fed infants with solids started before age 2 months had the largest mean skinfolds which peaked at age 3 months and then decreased and became similar to those of the other groups by age 5 months.

Infections in a coronary care unit.

All infections in patients in an active coronary care unit (CCU) over a 3-year period were analyzed to ascertain rates, outcomes, pathogens and sites of infections. Standard surveillance methods and definitions of the Center for Disease Control were used. A total of 236 infections were documented in 200 infected patients. Infection rates were 5 and 2% for total and CCU-acquired infections, respectively. CCU infections accounted for 11% of nosocomial infections that occurred within all critical care areas surveyed. Of all documented infections, 131 (56%) were community-acquired and 90 (38%) were acquired within the CCU. Lower respiratory and urinary tract infections were most frequently noted, with E. coli, S. aureus, and klebsiella-enterobacter-serratia most usually implicated. Mortality among patients with infections was 31%, compared with 8 to 12% in those who were not infected. Those with lower respiratory infections or primary bacteremias had a higher mortality rate than those with infections at other sites (p less than 0.001). Infections are seen in close to 5% of CCU patients and may adversely affect the survival rate. The mortality rate in infected patients may be 3 times higher than that in the general CCU population. This study also provides data against which other similar institutions can gauge their CCU infection rates.

Effects on blood pressure of a decrease in sodium use in institutional food preparation: the Exeter-Andover Project.

To judge the effect on blood pressure, sodium intake of students at two boarding high schools was reduced by 15-20% through changes in food purchasing and in preparation practices in the schools' kitchens. Students were not asked to change their usual eating habits. Each school served alternately as the control or intervention school for one school year. Blood pressure was monitored among 341 subjects during control years and 309 subjects during intervention years. Analysis of blood pressure differences between early in the school year and near the end of the school year, with adjustment for sex and initial blood pressure, showed the effect of the dietary intervention to be -1.7 mmHg for systolic (95% CI = -0.6, -2.9, p = 0.003) and -1.5 mmHg for diastolic pressure (95% CI = -0.6, -2.5, p = 0.002). Such modest and easily attainable changes in sodium intake, if maintained, could have a significant effect on the future risk of essential hypertension among young people.

Smoking cessation and severity of disease: the Coronary Artery Smoking Intervention Study.

We tested the effectiveness of an individually delivered behavioral multicomponent smoking intervention (SI) against offering advice only (AO) to 267 patients after coronary arteriography. After 6 months, 51% of AO patients and 62% of SI patients reported abstinence. Validated rates were 34% and 45% for AO and SI patients, respectively. Logistic regression analyses, controlling for severity of illness, stage of change, and self-efficacy, among other variables, showed that, at 6 months, the SI had the most effect for patients with more severe coronary artery disease (CAD) who had been admitted with a myocardial infarction (95% confidence interval = 2.05, 124.85). At 12 months, only severity of disease mediated SI effects (95% confidence interval = 3.10, 58.00). Similar results were seen for cotinine-validated cessation. This study confirms the effectiveness of individually administered SI for more seriously ill patients with CAD and raises questions as to how to better intervene with those individuals with less severe disease.

Estimates of blood pressure variability in adolescents using an automatic blood pressure measuring device.

Knowledge of BP variability is important for BP screening and for the design of studies with BP as an outcome. We calculated estimates of the between-visit and within-visit variances from data obtained using an automated BP.device (Dinamap) in 776 students, aged 13-17 years, in the Exeter-Andover Project. Each subject had his or her BP measured three times per visit at up to 24 weekly visits. We compared these estimates of variance with those published for adolescents using a standard mercury sphygmomanometer. For subjects measured using the Dinamap, the between-visit variance was greater for SBP and the within-visit variance for both pressures was almost three times greater than for subjects measured with the standard instrument.

Effect of a community health center intervention on breast cancer screening among Hispanic American women.

OBJECTIVE: A multiple component intervention in a community health center is presented, and its effect on breast cancer screening participation by Hispanic American women between the ages of 45 and 75 years is discussed. DATA SOURCES/STUDY SETTING: In 1990, data were collected through a retrospective audit (at least as far back as 1987) of community health center medical records, as well as from a client referral log. The health center, located in a small Massachusetts city, primarily serves clients of Latino heritage. STUDY DESIGN: The study used a nonexperimental pretest-posttest intervention design to document clients' screening activities. To control for uneven length of enrollment, aging of the population, and sporadic utilization, the unit of analysis chosen for the principle study variables was an "eligible year." DATA COLLECTION: Variables of interest included screening (clinical breast exam and mammography), periodicity of screening, and compliance with referrals. PRINCIPAL FINDINGS: Postintervention, considerably greater screening mammography occurred among all age groups, more women had at least one screening mammogram during the period, more clinical breast exams included a mammogram referral, and the compliance rate improved. The rate of clinical breast exam did not significantly improve, showing a downward trend.

Comparison of patients' and their resident physicians' responses regarding smoking-cessation interventions.

PURPOSE: To investigate (1) the extent of agreement between what resident physicians and their patients report as having occurred in physician-delivered smoking interventions and (2) the ability of residents to effectively transmit information concerning smoking interventions to their patients. METHODS: A total of 263 patients and 91 residents in internal medicine or family practice completed paper-and-pencil exit interviews after a regularly scheduled clinic appointment between 1986 and 1988 at the University of Massachusetts Medical School; the residents had been trained to deliver counseling interventions. The kappa statistic was used as an index of chance-corrected agreement between the patients' and residents' responses. RESULTS: Agreement was substantial regarding whether a specific plan for the patient to stop or reduce smoking was agreed upon, whether written materials on how to quit smoking were provided, and whether nicotine-containing chewing gum was prescribed. CONCLUSIONS: There was positive agreement between the patients and their resident physicians concerning the residents' delivery of quit-smoking messages and the provision of written materials to assist in stopping. Programs must continue to be designed, for residents and for more senior physicians, so that physicians can be encouraged to incorporate smoking interventions into their practice activities.

Sources of sodium, potassium, and energy in the diets of adolescents.

Analysis of food diaries of 200 students in two boarding high schools indicated that 30% of their average daily sodium intake was contributed by bakery foods and ready-to-eat cereals. The next most important source of sodium (24%) was a category made up of food adjuncts, snack-type foods, soups, and beverages. The largest proportion of sodium in most foods had been added during food manufacture or preparation. Salt added at the table contributed less than 1% of the sodium in the diets of the teenagers. All students did not eat foods from all categories on their day of recording; 70% or more ate bakery products, dairy foods, food adjuncts, and meat, fish, poultry, and eggs. Changes in recipe formulations can decrease sodium content for a variety of bakery products, cereals, mixed dishes, snack-type foods, soups, and processed meats. It is therefore possible to make large reductions in dietary sodium without disturbing other nutrient values.