Basic characteristics of radiology groups in the United States: results of a 1991-1992 census

OBJECTIVE: The American College of Radiology (ACR), the principal professional organization of United States radiologists, receives numerous requests for information on the characteristics of radiology groups. This report describes the basic characteristics of radiology groups in the United States. We defined radiology groups as any practice with two or more radiologists or radiation oncologists, including academic departments, units in multispecialty groups, and staff of government facilities. MATERIALS AND METHODS: To collect basic information on radiology groups, the ACR conducted a mail census of all identified radiology groups in the United States during late 1991 and early 1992. Follow-up was conducted by mail and telephone. To make the responses accurately representative of all radiology groups, we weighted the approximately 2000 responses to correspond to known control totals for the number of groups of each of seven size categories in each of the four census regions (Northeast, Midwest, South, and West). These control totals were obtained from the ACR's 1990 Manpower Survey, which showed a total of approximately 3200 radiology groups. RESULTS: Approximately one fourth of all groups have two radiologists, one fourth have three or four radiologists, one fourth have five to seven radiologists, and one fourth have eight or more radiologists. Academic groups were relatively large; almost 50% had 11 or more radiologists. Nonmetropolitan areas had very few large groups, and metropolitan center cities had relatively few small groups. Ninety-two percent of all groups practiced at hospitals, and 73% of all groups practiced at nonhospital offices or centers. The median number of practice sites for all groups was three, including both hospital and nonhospital sites. Eighty-eight percent of all groups provided diagnostic radiology services, 23% provided radiation oncology, 12% offered both, and 11% were oncology-only groups. Relatively many academic groups (25%) were oncology-only groups; very few radiology groups (2%) in multispecialty practices were oncology-only groups. The diagnostic radiology techniques available from the largest percentages of groups were general radiography (plain film), sonography, mammography, and CT. One eighth of academic groups that provided diagnostic services did not report providing mammography, compared with only a few percent of all groups in the United States that provided diagnostic services. CONCLUSION: Half of all groups have two to four radiologists, and this has not changed since at least 1986. A substantial percentage of groups that perform diagnostic radiology do not provide MR, interventional, or nuclear medicine services. This is particularly true of relatively small groups. These characteristics may become the source of some problems as managed care becomes more prominent and larger groups, offering a full range of services and practicing at several sites, are favored by managed care organizations that seek to contract with one group for all their radiology services.     

Using Labour Force Survey and census data to generate denominators for occupational injury rates: an application and expansion of Haggar-Guénette's method

The calculation of rates of occupational injury claims is essential to identify groups at high risk, yet limitations of denominator data have often restricted our capacity to do this. Haggar-Guénette's method of using Statistics Canada's data on paid workers from the Labour Force Survey as denominators has been expanded by incorporating information from the Census. The method is illustrated by calculating denominators for male construction industry workers within the province of Ontario. Information for paid workers employed in construction occupations was derived from the Labour Force Survey to produce denominators for those aged 15-64, overall and by 10-year age groups. Census data on the distribution of construction occupational roles were applied to produce denominators both overall, then simultaneously by age and by occupational role. Advantages and disadvantages, including the limitations or biases due to the differing sources for denominators and numerators are identified.     

Fund the 2000 census statistical samples

PURPOSE: A single-institution phase II trial of Temodal (temozolomide, SCH52365) in Chinese patients with advance nasopharyngeal carcinoma was undertaken to determine the efficacy and safety of the drug in this population. METHODS: A total of 14 patients with metastatic or locoregionally recurrent nasopharyngeal carcinoma were entered into the study. One patient was unevaluable. Temodal was given at doses of 150 or 200 mg/m2 daily on days 1-5 every 28 days. RESULTS: In all, 30 cycles of Temodal were given with no significant toxicity. All 13 (100%) evaluable patients had progressive disease after 2 (84.6%) or 4 (15.4%) courses. CONCLUSION: Temodal given on this schedule has no activity in advanced nasopharyngeal carcinoma.     

Using regression equations built from summary data in the neuropsychological assessment of the individual case.

Regression equations have many useful roles in neuropsychological assessment. This article is based on the premise that there is a large reservoir of published data that could be used to build regression equations; these equations could then be used to test a wide variety of hypotheses concerning the functioning of individual cases. This resource is currently underused because (a) not all neuropsychologists are aware that equations can be built with only basic summary data for a sample and (b) the computations involved are tedious and prone to error. To overcome these barriers, the authors set out the steps required to build regression equations from sample summary statistics and the further steps required to compute the associated statistics for drawing inferences concerning an individual case. The authors also develop, describe, and make available computer programs that implement the methods. Although caveats attach to the use of the methods, these need to be balanced against pragmatic considerations and against the alternative of either entirely ignoring a pertinent data set or using it informally to provide a clinical "guesstimate." (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Trends of the biological monitoring measurements from 1991 to 1995]

Partial amendments to the Japanese Regulation on the Prevention of Lead Poisoning and that of Organic Solvent Poisoning were made in 1989. As a result, the measurement of blood lead and urinary delta-aminolevulinic acid (delta-ALA) became indispensable items of the occupational health examination for workers who handle lead. Also, the measurement of urinary metabolites of workers who handle eight kinds of organic solvents (xylene, N,N-dimethylformamide, styrene, tetrachloroethylene, 1,1,1-trichloroethane, trichloroethylene, toluene, and normal-hexane) became mandatory. The results of the biological monitoring mentioned above are classified into one of three categories, that is, distribution 1, 2 and 3, according to the concentration of the determinants. In this paper, the incidence of distribution 1, 2 and 3 of each determinant is reported and its change from 1991 to 1995 is discussed. The incidence of distribution 3 was 0.1-5.0% in each determinant. Although the ratio of distribution 1, 2 and 3 seems to have been almost the same for 5 years some determinants decreased their percentage of distribution 3. It is important to utilize the biological monitoring results for the improvement of working environments and working styles, and health management.     

Using systems performance data for ambulance management

The ambulance service is an important component in the emergency medical system of a community. The availability of performance information on several aspects of the ambulance system may improve ambulance management. The location of new ambulance stations, selection of the destination hospital for urgent cases, scheduling of crew changes, and evaluation of crew performance can be approached through an examination of existing data. Management use of such an information system by the Victorian Civil Ambulance Service in Melbourne, Australia is included in the discussion.     

Using claims data to monitor hospital utilization

Controlling provider use is a continuing problem for health care insurers. This paper describes a Blue Cross and Blue Shield of Michigan system that places primary responsibility for inpatient admissions on participating hospitals and uses a dual monitoring approach. Expensive annual samples that review medical records against published criteria constitute the basic test of compliance. An inexpensive indicator is developed quarterly using automated universal claims review. Statistical methodology, costs, and savings for both monitors are described. The claims monitor uses diagnosis related group (DRG) characteristics to estimate the percentage of inappropriate utilization from historical values for the patient group.     

Family history score as a predictor of breast cancer mortality: prospective data from the Cancer Prevention Study II, United States, 1982-1991

A consistent predictor of a woman's risk for breast cancer is a family history of the disease. Most studies of family history and breast cancer have used the number of affected relatives in the family to calculate relative risk, but they have not considered the heterogeneity of the familial risk for breast cancer in a systematic way. With the use of data from a large prospective mortality study of US adults, the authors compared simple classification of family history of breast cancer (yes/no) to the method of using a quantitative family history score method, which takes into account the effects of family structure, age, and birth cohort as predictors of breast cancer mortality. After 9 years of follow-up, 1,428 cases of fatal breast cancer were observed among 453,073 women with complete information on number and age of siblings and family history. With the use of the family history score, about one-third of women with a positive family history of breast cancer were at no higher risk for breast cancer mortality than those without a family history of the disease. As a quantitative measure of relative risk for each family, family history score gave a better fit to the data, and it provided an incremental improvement of predictive accuracy of developing fatal breast cancer. Family history score can also be used as a categorical variable to stratify families. This allows researchers to focus on which risk groups would benefit from conducting further genetic analysis and to test the effects of genetic factors, environmental exposure, and gene-environment interactions on the etiology of the development of breast cancer.     

Using the normal quantile plot to explore meta-analytic data sets.

In a meta-analysis, graphical displays can be used to check statistical assumptions for numerical procedures and they can be used to discover important patterns in the data. The authors propose the normal quantile plot as a preferred alternative to the funnel plot for such purposes. The normal quantile plot, like the funnel plot, can be used to investigate whether all studies come from a single population and to search for publication bias. However, the normal quantile plot is easier to interpret than the funnel plot, especially when it includes 95% confidence bands. In addition, the normal quantile plot can be used to check the normality assumption for numerical procedures. The funnel plot cannot be used for this latter purpose. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Using a repeated measures ANOVA to analyze the data from a pretest-posttest design: A potentially confusing task.

The pretest-posttest control group design (or an extension of it) is a highly prestigious experimental design. A popular analytic strategy involves subjecting the data provided by this design to a repeated measures analysis of variance (ANOVA). Unfortunately, the statistical results yielded by this type of analysis can easily be misinterpreted, since the score model underlying the analysis is not correct. Examples from recently published articles are used to demonstrate that this statistical procedure has led to (a) incorrect statements regarding treatment effects, (b) completely redundant reanalyses of the same data, and (c) problems with respect to post hoc investigations. 2 alternative strategies-gain scores and covariance-are discussed and compared. (19 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Retrospective analysis of census data on general practitioners who qualified in South Asia: who will replace them as they retire?

OBJECTIVES: To determine the number and geographical distribution of general practitioners in the NHS who qualified medically in South Asia and to project their numbers as they retire. DESIGN: Retrospective analysis of yearly data and projection of future trends. SETTING: England and Wales. SUBJECTS: General practitioners who qualified medically in the countries of Bangladesh, India, Pakistan, and Sri Lanka and who were practising in the NHS on 1 October 1992. MAIN OUTCOME MEASURES: Proportion and age of general practitioners who qualified in South Asia by health authority; the Benzeval and Judge measure of population need at the health authority level. RESULTS: 4192 of 25 333 (16.5%) of all unrestricted general practitioners practising full time on 1 October 1992 qualified in South Asian medical schools. The proportion varied by health authority from 0.007% to 56.5%. Roughly two thirds who were practising in 1992 will have retired by 2007; in some health authorities this will represent a loss of one in four general practitioners. The practices that these doctors will leave seem to be in relatively deprived areas as measured by deprivation payments and a health authority measure of population need. CONCLUSION: Many general practitioners who qualified in South Asian medical schools will retire within the next decade. The impact will vary greatly by health authority. Those health authorities with the greatest number of such doctors are in some of the most deprived areas in the United Kingdom and have experienced the most difficulty in filling vacancies. Various responses will be required by workforce planners to mitigate the impact of these retirements.     

Using hierarchical linear modeling to analyze grouped data.

This article discusses how to use a random coefficient modeling technique known as hierarchical linear modeling to analyze data collected within groups. The article describes how to use this technique to examine group- and individual-level phenomena, including examination of how individual-level relationships vary as a function of group characteristics. A comparison of hierarchical linear modeling with more traditional, ordinary-least-squares techniques and a presentation of how to implement analyses to test specific hypotheses are included. Included are brief discussions of pertinent issues such as the impact of different centering options, the analysis of categorical variables, distinctions between random and fixed effects, and balanced and unbalanced designs. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Using confidence intervals for graphically based data interpretation.

As a potential alternative to standard null hypothesis significance testing, we describe methods for graphical presentation of data--particularly condition means and their corresponding confidence intervals--for a wide range of factorial designs used in experimental psychology. We describe and illustrate confidence intervals specifically appropriate for between-subject versus within-subject factors. For designs involving more than two levels of a factor, we describe the use of contrasts for graphical illustration of theoretically meaningful components of main effects and interactions. These graphical techniques lend themselves to a natural and straightforward assessment of statistical power. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Pulmonary fibrosis and lung cancer in the United States: analysis of the multiple cause of death mortality data, 1979 through 1991

BACKGROUND: Hepatocyte growth factor (HGF) plays a key role in the regulation of liver regeneration after hepatocyte damage. Changes in HGF production reflect the status of the regeneration process. METHODS: Serum concentrations of HGF and energy substrates were measured during and after liver transplantation in 30 recipients. RESULTS: In the patients with compromised grafts (group A) HGF concentrations were persistently high after reperfusion, whereas in the patients with well-functioning grafts (group B), HGF concentrations decreased rapidly and remained low 4 hours after reperfusion. The patients in group A who died had persistently high concentrations of HGF. The surviving patients with reversible primary graft dysfunction in group A exhibited low concentrations 48 hours after reperfusion. The decrease in HGF concentration preceded the decrease in aspartate aminotransferase concentration. The metabolic parameters that reflect carbohydrate metabolism by the graft paralleled the changes in HGF. CONCLUSIONS: HGF may be more sensitive and specific in predicting early graft function than prothrombin time, ratio, aspartate aminotransferase, or arterial ketone body ratio. The determination of HGF levels after liver transplantation may yield valuable information for evaluating early graft function and making an early decision to repeat a graft procedure in an acutely ill patient.