Numerators and denominators of rates estimated on the basis of physicians' practice data.

The paper discusses selected methodological aspects of numerators and denominators derived from medical practice observations. The estimation of rates (of incidence or prevalence) on the basis of primary care practice data is apt to be influenced by several methodological factors. These are: morbidity of the local population, physician workload and expertise, diagnosis coding rules, and patient visiting behavior (Anderson, 1984). These factors tend to have an impact on the numerator. Vis-à-vis the lack of appropriate population denominators of single practices, the question is whether rate estimates may be developed for fee-for-service systems without population registration of persons with medical practices and which use these rates may be put to.

[Frequency of medical consultation as reflected in 2 representative surveys: DHP-Survey and EVaS-Study (German Cardiovascular Disease Prevention and Survey of Ambulatory Care)]. / Die Häufigkeit der ärztlichen Inanspruchnahme in Spiegel zweier Repräsentativerhebungen: DHP-Survey und EVaS-Studie.

The frequency of patient-doctor contacts in outpatient care is determined via two representative inquiries supplying complementary perspectives. They concern, on the one hand, a sample of contacts in the consultation room, and, on the other hand, contacts as stated in a population-based survey. In the 25-69 years age bracket, both surveys yielded a contact incidence of 2 to more than 5 contacts per person and quarter of a year. The figure is higher in women than in men. Both surveys agree very well if the consultation-room survey is limited to personal contacts between the doctor and the patient. The distribution of contacts over specialties is similar in both surveys. Compared to other countries, the frequency of outpatient consultations is high in the Federal Republic of Germany. Periodic surveys help to get insight into frequency and structure of medical services.

Ambulatory care: France, Federal Republic of Germany, and United States.

This study describes the results of a comparison of ambulatory medical care data for France, the Federal Republic of Germany (FRG), and the United States of America (U.S.). Data for this comparison were derived from independent national sample surveys in ambulatory care systems of the three countries in 1981-83. The French data set resulted from a sample of physicians who had been asked to document all patient-physician contacts for a specified 3-day period during 1982-83. The FRG survey of patient-physician contacts was performed in the fourth quarter of 1981 and the first quarter of 1982. Sample physicians reported for a sample of patient-physician contacts during two consecutive weekdays, the reporting periods being spread across the two calendar quarters in a balanced fashion. Survey physicians had been drawn at random from almost all ambulatory care specialties. U.S. survey data were obtained through a random sample of physicians reporting for a sample of their patient-physician contacts for a whole week, with the reporting weeks being spread across the whole year of 1981. Because regular office hours generally do not take place on weekends, Sundays were excluded in the French survey; in the FRG survey Saturdays and Sundays were excluded as reporting days. Although the French and the U.S. study universes consisted of almost all physicians practicing ambulatory medical care in the respective countries, the FRG physicians were drawn from five regions of the country systematically selected to represent the Federal Republic of Germany with respect to demographic population characteristics and physician specialty distribution. The universes of physicians and patient-physician encounters of the three national studies varied according to the ambulatory medical care systems of the respective countries. Data sets for this international comparison were derived from the respective national studies by selecting personal patient-physician contacts (in the physician's office or in the patient's home--referred to as "encounters") with eight physician specialties (general practitioners, pediatricians, obstetricians/gynecologists, internists, psychiatrists/neurologists, dermatologists, ophthalmologists, and otorhinolaryngologists). Patient variables used in the international comparison are patient age, sex, visit status, reason for encounter, and disposition. Yearly rates of personal patient-physician encounters in ambulatory medical care were estimated. Crude and age-sex standardized rates were computed for selected patient and physician characteristics.

Integrating health-related data from various sources: combining surveys, records and routine data.

The paper discusses the necessity of combining data from various sources in order to enhance their usefulness for a variety of applications. As future data use can hardly be forseen in advance, major data sets in health services should fulfill several formal requirements in order to make them suitable for future linkage. These formal requirements are that there be references to defined populations, to specific persons, to defined time periods, to specific places or regions. It would be necessary for terms, definition and classification schemes to agree between data sets which are to be linked and be in wide use. Three facets of data linkage are discussed specifically namely linking data at one level of aggregation, linking different data components, and combining data sets from different sources at several levels of aggregation. Three examples are provided, describing linkages of data from various sources for epidemiological studies and a study in health services research. They show that at this point in descriptive epidemiological studies linkage on the basis of regions is of great importance. This implies that it would be desirable for large scale data collection activities in health services to provide for a uniform representation of the geographic areas. Such uniformity would greatly enhance the linkage potential of data sets and thus their usefulness for small area and regional analyses.

[Determining the health status of a population: role and quality of survey questions]. / Die Messung des Gesundheitszustands der Bevölkerung: Rolle und Güte von Befragungsdaten.

Measuring population health levels: role and quality of interview data. Role and quality of interview data are examined with respect to their importance for the measurement of population health levels. Starting from general information requirements in health services, the contribution of population survey data is described. Interview data constitute just a subset of such survey data. When role and quality of interview survey data are to be judged, survey methods are of major importance. They not only determine the quality but also the role of health interview survey data in the framework of all information about the population's health. If this is so, efforts to improve health survey data quality should not only be directed towards improvement of traditional methodological aspects (such as sampling procedures and response rates) but also towards the implementation of prerequisites for wider usage of health interview data. This may be achieved by improving their linkage potential, by implementing uniform minimal basic data sets, by introducing identical terms and definitions and by keeping identical terms and definitions and by keeping identical survey methods (including questions) for several years in a row. Quality of health interview data is, therefore, determined by the methodological standards underlying their collection and the potential for usage of these data sets determines the role they play as part of the information about the population's health.

Health care: an international comparison of perceived morbidity, health services resources, and use.

Selected summary findings from the World Health Organization/International Collaborative Study of Medical Care Utilization are presented, based on data collected during a twelve-month period in 1968-1969 in twelve study areas in seven countries in the Americas and Europe. A household interview survey of almost 48,000 persons, representing a total population of about 15 million, elicited information on demographic characteristics, on perceptions of illness, its severity and character, and on attitudes toward and use of major components of health services. Information was also collected on the prevailing health care systems and resources available to the study population, as well as on socioeconomic characteristics of the study areas. Standardized rates for those defined as "healthy" and "functionally healthy" are quite similar across the twelve study areas, as are the rates for persons who reported being sick within two weeks. Rates for the volume of sick days within two weeks vary widely, and levels of chronicity with disability are much higher in the four continental European study areas. Rates for volume of physician contacts within two weeks vary considerably across study areas, but rates for persons with contacts are more stable, although for persons with perceived morbidity of high severity, the corresponding rates are lower in the four continental European study areas. By contrast, the rates for persons with an administrative reason for their most recent physical examination within twelve months are substantially higher in the latter. Where unmet need for a physician contact is greatest, the volume of hospital nights used is also greatest; a direct relationship between these two measures is evident without regard to the ratio of hospital beds available to the population. Wide differences are observed between the extremes of the measures of need, resources, and use employed in the study, raising questions about the ways in which resources are organized to provide services and about the effectiveness and efficiency of these services.

Medicaid, morbidity, and physician use.

Medical programs which provide services for low-income persons who have high medical needs have been criticized for high costs and have raised questions about overuse of physician services. A Baltimore SMSA household interview of use of health services permitted comparison of use of physician and preventive services controlled for morbidity by Medicaid recipients and two other income groups. Medicaid recipients were sickest and had higher physician use. They were more likely to have visits suggested by a physician, to be asked to return, and to be given injections. Physician visit rates were higher for each morbidity category, particularly for Medicaid healthy, who also used more preventive services in two weeks. Higher use of services by Medicaid recipients is accounted for by higher morbidity and increased need and demand for preventive services. Constraints on the use of physician services now most directly affect use of preventive services by those of low income without Medicaid benefits in the Baltimore SMSA.