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A new classification of head injury based primarily on information gleaned from the initial computerized tomography (CT) scan is described. It utilizes the status of the mesencephalic cisterns, the degree of midline shift in millimeters, and the presence or absence of one or more surgical masses. The term "diffuse head injury" is divided into four subgroups, defined as follows: Diffuse Injury I includes all diffuse head injuries where there is no visible pathology; Diffuse Injury II includes all diffuse injuries in which the cisterns are present, the midline shift is less than 5 mm, and/or there is no high-or mixed-density lesion of more than 25 cc; Diffuse Injury III includes diffuse injuries with swelling where the cisterns are compressed or absent and the midline shift is 0 to 5 mm with no high-or mixed-density lesion of more than 25 cc; and Diffuse Injury IV includes diffuse injuries with a midline shift of more than 5 mm and with no high-or mixed-density lesion of more than 25 cc. There is a direct relationship between these four diagnostic categories and the mortality rate. Patients suffering diffuse injury with no visible pathology (Diffuse Injury I) have the lowest mortality rate (10%), while the mortality rate in patients suffering diffuse injury with a midline shift (Diffuse Injury IV) is greater than 50%. When used in conjunction with the traditional division of intracranial hemorrhages (extradural, subdural, or intracerebral), this categorization allows a much better assessment of the risk of intracranial hypertension and of a fatal or nonfatal outcome. This more accurate categorization of diffuse head injury, based primarily on the result of the initial CT scan, permits specific subsets of patients to be targeted for specific types of therapy. Patients who would appear to be at low risk based on a clinical examination, but who are known from the CT scan diagnosis to be at high risk, can now be identified. KEY WOROSTraumatic Coma Data Bank 9 head injury 9 coma 9 intracranial pressure 9 computerized tomography 9 grading system N 'EUROSURGEONS and others interested in treating head-injured patients have traditionally categorized head injury on the basis of focal or nonfocal lesions or, more recently, on the basis of diffuse versus focal or mass lesions. ~' 2 These categorizations, while helpful in subdividing head injury into two major groups, have significant limitations in terms of prognosis. It is generally recognized that patients with diffuse injury have a lower mortality rate than do patients with mass lesions. However, this type of pooling of patient data might mask groups of patients with diffuse injury who are at risk from intracranial hypertension and who in fact have a high mortality rate.A general lack of recognition of the importance of $14 J. Neurosurg. / Volume 75/

and Stroke initiated the Stroke Data Bank, which is a multicenter project to prospectively collect data on the clinical course and sequelae of stroke. Additional objectives were to provide information that would enable a standard diagnostic clinical evaluation, to identify prognostic factors, and to provide planning data for future studies. A brief description of the structure and methods precede the baseline characterization of 1,805 patients enrolled in the Stroke Data Bank between July 1983 and June 1986. Two thirds of these patients were admitted within 24 hours after stroke onset. Medical history, neurologic history, and hospitalization summaries are presented separately for the following stroke subtypes: infarction, unknown cause; embolism from cardiac source; infarction due to atherosclerosis; lacune; parenchymatous or intracerebral hemorrhage; subarachnoid hemorrhage; and other. The utility and limitations of these data are discussed. (Stroke 1988;19:547-554) S troke is the third leading cause of death in the United States; only coronary heart disease and cancer are more prevalent causes of death. In 1985, there were 153,050 deaths attributed to cerebrovascular diseases and a crude death rate of 64.1 per 100,000 resident population.1 Cerebrovascular diseases are also a major cause of chronic disability, affecting millions of Americans. In 1978, the National Institute of Neurological and Communicative Disorders and Stroke (NINCDS) initiated a data bank project to provide prospectively and consistently recorded information on stroke to address some of the many unresolved research issues in cerebrovascular disease. The Stroke Data Bank (SDB) had four major objec- Received August 10, 1987; accepted November 17, 1987. tives: 1) to obtain information on the clinical course and outcome of stroke, 2) to provide information that would enable a standard diagnostic clinical evaluation, 3) to identify factors predictive of outcome following stroke, and 4) to provide planning data for future controlled, randomized, clinical trials in the treatment of stroke patients. The purpose of our report is to provide a comprehensive description of the project background, design, and methods and a description of the patients enrolled. Additional details (including copies of the data collection forms) are available in the SDB Manual of Operations.2 Previous communications have reported on the pilot phase, 3 reliability studies, 4 -5 and nursing implications 6 of this project. The primary analytic publications from the main phase of the SDB are now in preparation. Design and Methods Project OrganizationCooperative clinical projects require an organizational structure that will both facilitate efficient operation and at the same time provide a mechanism to ensure participation of all collaborators in the decisionmaking process. Toward these goals, the organizational structure developed for the SDB fostered careful and uniform adherence to the procedures for data collection and effective communication and cooperation among the va...

✓ This study describes the relationship between raised intracranial pressure (ICP), hypotension, and outcome from severe head injury. The study is based on information derived from the Traumatic Coma Data Bank where ICP records from a relatively large number of patients were available to help delineate the major factors influencing outcome. From the total data base of 1030 patients, 428 met minimum monitoring duration criteria for inclusion in the present analysis. Outcome was classified according to the Glasgow Outcome Scale score determined at 6 months postinjury. Arrays of comparably defined summary measures describing the patient's course were considered for ICP, blood pressure (BP), central perfusion pressure, and therapy intensity level. For instance, the array of ICP summary descriptors included the proportion of ICP readings greater than x, for x = 0 to 80 mm Hg by increments of 5 mm Hg. A total of 187 candidate summary descriptors were considered. A stepwise ordinal logistic regression was used to select the subset of candidate summary descriptors that best explained the 6-month outcome. As established previously, age, admission motor score, and abnormal pupils were each highly significant in explaining outcome. Beyond these factors, the proportion of hourly ICP readings greater than 20 mm Hg was next selected and was also highly significant in explaining outcome (p < 0.0001). In addition to the ICP factor, the cutoff point of 20 mm Hg was selected by the procedure as most indicative of outcome. With these four factors modeled, the next selected factor was the proportion of hourly BP readings less than 80 mm Hg. Again, the BP factor was highly significant in explaining outcome (p < 0.0001). As with the ICP factor, the BP cutoff point of 80 mm Hg was objectively selected as most indicative of outcome. In summary, the incidence of mortality and morbidity resulting from severe head trauma is strongly related to raised ICP and hypotension measured during the course of ICP management. Moreover, these ICP and BP factors provide a better indication of outcome than the similarly defined factors of central perfusion pressure or therapy intensity level.

The time of onset of ischemic stroke was determined for 1,167 of 1,273 patients during the collection of data by four academic hospital centers between June 30, 1983, and June 30, 1986. More strokes occurred in awake patients from 10:00 AM to noon than during any other 2-hour interval. The incidence of stroke onset declined steadily during the remainder of the day and early evening. The onset of stroke is least likely to occur in the late evening, before midnight.

When designing a clinical trial to test the equality of survival distributions for two treatment groups, the usual assumptions are exponential survival, uniform patient entry, full compliance, and censoring only administratively at the end of the trial. Various authors have presented methods for estimation of sample size or power under these assumptions, some of which allow for an R-year accrual period with T total years of study, T greater than R. The method of Lachin (1981, Controlled Clinical Trials 2, 93-113) is extended to allow for cases where patients enter the trial in a nonuniform manner over time, patients may exit from the trial due to loss to follow-up (other than administrative), other patients may continue follow-up although failing to comply with the treatment regimen, and a stratified analysis may be planned according to one or more prognostic covariates.

OBJECTIVEThe Diabetes Prevention Program (DPP) and its Outcomes Study (DPPOS) demonstrated that either intensive lifestyle intervention or metformin could prevent type 2 diabetes in high-risk adults for at least 10 years after randomization. We report the 10-year within-trial cost-effectiveness of the interventions.RESEARCH DESIGN AND METHODSData on resource utilization, cost, and quality of life were collected prospectively. Economic analyses were performed from health system and societal perspectives.RESULTSOver 10 years, the cumulative, undiscounted per capita direct medical costs of the interventions, as implemented during the DPP, were greater for lifestyle ($4,601) than metformin ($2,300) or placebo ($769). The cumulative direct medical costs of care outside the DPP/DPPOS were least for lifestyle ($24,563 lifestyle vs. $25,616 metformin vs. $27,468 placebo). The cumulative, combined total direct medical costs were greatest for lifestyle and least for metformin ($29,164 lifestyle vs. $27,915 metformin vs. $28,236 placebo). The cumulative quality-adjusted life-years (QALYs) accrued over 10 years were greater for lifestyle (6.81) than metformin (6.69) or placebo (6.67). When costs and outcomes were discounted at 3%, lifestyle cost $10,037 per QALY, and metformin had slightly lower costs and nearly the same QALYs as placebo.CONCLUSIONSOver 10 years, from a payer perspective, lifestyle was cost-effective and metformin was marginally cost-saving compared with placebo. Investment in lifestyle and metformin interventions for diabetes prevention in high-risk adults provides good value for the money spent.

We determined the prevalence of dementia in 927 patients with acute ischemic stroke aged years in the Stroke Data Bank cohort based on the examining neurologist's best judgment Diagnostic agreement among examiners was 68% (K=034). Of 726 testable patients, 116 (16%) were demented. Prevalence of dementia was related to age but not to sex, race, handedness, educational level, or employment status before the stroke. Previous stroke and previous myocardial infarction were related to prevalence of dementia although hypertension, diabetes mellitus, atrial fibrillation, and previous use of antithrombotic drugs were not Prevalence of dementia was most frequent in patients with infarcts due to large-artery atherosclerosis and in those with infarcts of unknown cause. Computed tomographic findings related to prevalence of dementia included infarct number, infarct site, and cortical atrophy. Among 610 patients who were not demented at stroke onset, we used methods of survival analysis to determine the incidence of dementia occurring during the 2-year follow-up. Incidence of dementia was related to age but not sex. Based on logistic regression analysis, the probability of new-onset dementia at 1 year was 5.4% for a patient aged 60 years and 10.4% for a patient aged 90 years. With a multivariate proportional hazards model, the most important predictors of incidence of dementia were a previous stroke and the presence of cortical atrophy at stroke onset (Stroke 1990-^1:858-866) C erebrovascular disease is considered to be the second most common cause of dementia; 20%-25% of cases of dementia are due to stroke, and another 10%-15% are attributed to a combination of vascular and Alzheimer's disease.