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At least 19 recordsLinked to original sources
PubMed1992

Can small-area analysis detect variation in surgery rates? The power of small-area variation analysis.

A variety of statistical methods can be used in small-area analysis to test whether there is more variation than would be expected by chance alone. However, the power of these methods to detect existing variation has never been studied. The authors used data regarding back surgery in Washington State to suggest several types of variation that might exist (alternative hypotheses), and then used computer simulation to determine the power, or the probability of detecting this variation. The chi-square test had the highest power of all methods considered against most alternative hypotheses. Power is higher if there are no multiple admissions, rates are higher, and counties have larger or similar population size. Problems of accounting for multiple admissions, adjustment for age and sex, choosing the optimum size of small areas, and detection of outliers also are discussed.

Age Factors↗
PubMed1992

Urban/rural and deprivational differences in incidence and clustering of childhood diabetes in Scotland.

Scottish hospital discharges were monitored during the period 1977-1983 for new cases of diabetes in children aged 18 years or under. An estimated ascertainment rate of 94% was obtained by validation against an independent register of cases. The postcode sector at the time of admission was available for 2125 (97%) of the 2183 cases, and was used as the basis for a small-area analysis of urban/rural and socioeconomic differences in incidence and to test for clustering. Incidence rates standardized for age and sex showed important differences between the 16 Scottish postcode areas. At the sector level, the standardized rate was 20% lower in urban sectors compared to rural sectors, but this could be explained by area to area differences and by socioeconomic effects within areas. In contrast, significant socioeconomic differences in incidence were evident within areas which could not be explained by urban/rural effects, the children in deprived sectors having 80% of the risk of those in other sectors. Rates were particularly low among children in deprived urban sectors. Nevertheless, significant variations in incidence remained between the 16 areas which could not be explained by either urban/rural or socioeconomic differences, indicating the existence of other important factors. Tests for clustering of cases both within postcodes sectors and across adjacent postcode sectors were also performed. Although clusters could be identified, they were no more common than would be expected by chance. Tests for space-time clustering were also negative.

Adolescent↗
PubMedDate not supplied

Area-level predictors of use of prenatal care in diverse populations.

Patterns and predictors of the use of prenatal care in Hawaii were examined by census tract, taking into account summary measures of socioeconomic status, environmental conditions, and aggregated indicators of pregnancy-related risk characteristics of mothers. The objectives of the study were to identify those census tracts with high levels of inadequate use of prenatal care services; to develop a model, based on census tract characteristics, to explain observed geographic variations in the use of prenatal care services; and to identify for further investigation specific localities with unanticipated patterns of use. Data were drawn from 1980 census reports and vital statistics live birth files for the period 1979-87. Regression analysis was used to develop a model that was able to predict 61 percent of the census tract variation in the percentages of inadequate use of prenatal care services. Increased proportions of mothers of Japanese and other Asian-descent and of adults with more than high school education were associated with low levels of inadequate use of prenatal care services. Increased proportions of high parity-for-age risk and Samoan mothers were associated with higher levels of inadequate use. Census tract maps of actual and predicted percentages and studentized residual values were used to identify areas with high and low rates of inadequate use of prenatal care services. The area-level methods used are believed applicable to health care planning in other areas with ethnically or socioculturally diverse populations.

Demography↗
PubMed1992

Explaining area variation in the use of Medicare home health services.

This study examines the determinants of area-level variation in Medicare home health use in 1985 for the entire United States, using data from Medicare Home Health Bills, the Medicare/Medicaid Automated Certification System, the Medicare Provider Analysis and Review Files, and other sources. Weighted two-stage least squares regression was used to analyze variation in the number of home health users per 1,000 enrollees and the average number of visits received per user. The data were aggregated to the Metropolitan Statistical Area and the rural part of the state, resulting in 343 units of analysis. According to the study's results, higher proportions of Medicare enrollees use home health services in areas with fewer nursing home beds per enrollee, higher hospital discharge rates, and shorter mean lengths of stay, higher Medicare reimbursement ceilings for skilled nursing home health visits, and more home health agencies per enrollee. Other things being equal, beneficiaries in New England are 40% more likely to use home health services than their counterparts in other regions with similar climates. The average number of visits received by home health users appears to be higher in areas where there are more agencies per enrollee and a higher share of agencies that are proprietary. There also appear to be large regional differences in the number of visits received per user. Our results imply that constrained access to nursing home beds is leading to higher levels of Medicare home health use and that there may be further savings from the substitution of home health services for hospital days. The study shows that Medicare reimbursement ceilings may constrain use and that access may be a problem for beneficiaries in areas with fewer agencies per enrollee. This study also points to significant regional variation in the proportion of beneficiaries who use home health services, even with controls for many different explanatory variables. Overall, our results suggest the possibility of serious limitations in access to Medicare home health services.

Certificate of Need↗
PubMed1992

Problems in the interpretation of small area analysis of epidemiological data: the case of cancer incidence in the West of Scotland.

STUDY OBJECTIVE: The aim was to examine the extent to which random variation alone will produce differences in observed incidence rates between small areas which will affect measures of spatial clustering and estimates of relative risk. DESIGN: This was a study of changes in the pattern of spatial concentration of cancer incidence over a five year time period. A comparison was made of observed incidence rates for 34 tumour sites with randomly generated values and, where possible, with expected values derived from known relative risks. SETTING: Twenty six local government districts in the West of Scotland. MAIN RESULTS: A statistically significant relationship was observed between sample size and the stability of a summary measure of spatial concentration. Almost all observed highest:mean rate ratios were within the 95% confidence interval of the simulated distribution of these values. In three cases examined, both observed and simulated highest:lowest rate ratios were larger than those expected on the basis of known exposures to risk. CONCLUSIONS: In the absence of a prior hypothesis, small area analysis of epidemiological data for periods of less than 10 years will almost always give misleading results for all but the most common diseases.

Analysis of Variance↗
PubMed1992

Testing the null hypothesis in small area analysis.

The goal of small area analysis is often to demonstrate that hospital admission rates or procedure rates vary greatly among regions, suggesting the occurrence of unnecessary admissions or procedures in some regions. Recent articles have shown that such variation may be largely due to chance, even if no underlying differences exist among the small areas; thus, it is important to test if the observed variation is larger than expected by chance. In this article we discuss how the appropriate method for testing the null hypothesis depends on the distribution of the number of admissions at the person level. If it is not possible for an individual to have more than one admission for a given procedure, the appropriate test is a simple chi-square test. If multiple admissions are possible, a modified chi-square test can be used to account for the excess variability due to multiple admissions. Failure to make the correct modification to the chi-square test in this latter case can result in spurious results. This underscores the importance of collecting data on multiple admissions in order to estimate the distribution of the number of admissions at the individual-patient level.

Analysis of Variance↗
PubMed1992

Arm pain in the workplace. A small area analysis.

In the mid-1980s, use-related arm pain was recognized as a major issue for worker health and workplace safety. National policy targeted these "cumulative trauma disorders," "overuse syndromes," and "motion illnesses" for a "special emphasis program" by the Occupational Safety and Health Administration, a federal regulatory agency. The program begins with case recognition to identify the responsible ergonomic hazards with the goal of mandating ergonomic remedies. This report is a small area analysis of the impact of this process on the US West Communications, Inc work force. US West employs some 55,000 workers in 14 states. Commencing in the mid-1980s, workers in four of these states complained of upper extremity pain and were diagnosed as suffering from conditions encompassed by the "cumulative trauma disorders" rubric. The incidence was tenfold higher in one task category, directory assistance operators. No ergonomic descriptor can account for the four endemics of arm pain in directory assistance operators. The response of the medical communities to the plight of these injured claimants varied considerably from community to community. Denver represents one extreme where the clinical judgments led to multiple surgical interventions, generated a total direct cost of some $1.5 million, and left many permanently disabled workers in their wake. This analysis raises many reservations about the validity of the "cumulative trauma disorder" hypothesis and provides an object lesson in the potential for untoward outcomes from the premature introduction of clinical hypotheses into the arena of health policy.

Adult↗
PubMed1992

Socioeconomic status and mortality revisited: an extension of the Brisbane area analysis.

Using the methodology of an earlier study of socioeconomic mortality gradients, we partitioned Brisbane City into five strata of equal size on the basis of suburb scores derived from aggregate socioeconomic census data. Numbers of deaths by stratum, age, sex and cause were obtained from mortality files. For almost all causes, mortality gradients had not changed between 1976-1979 and 1980-1987. A new category, medically-preventable death under age 65, had lower rates in higher-ranking suburbs. Potential years of life lost (PYLL) per unit of population, age-standardised, were also computed by stratum and cause. External causes of death were the main contributors to PYLL among men, with a strong socioeconomic gradient, while neoplasms were most important among women, with little evidence of a social class effect. It is estimated that, in urban Australia, the annual number of additional deaths under age 65 due to socioeconomic circumstances is over 2000 for males and over 1000 for females. This study provides a baseline against which the programs of health advancement initiated in the mid-1980s may be evaluated, or conversely, the effects of societal changes assessed.

Adolescent↗
PubMed1992

The association of maternal and socioeconomic characteristics in metropolitan Adelaide with medical, obstetric and labour complications and pregnancy outcomes.

Multiple regression analysis was used to measure associations of maternal age, race, gravidity, marital status and socioeconomic status with medical problems and pregnancy outcomes. The study population comprised all singleton births to residents of metropolitan Adelaide (in South Australia) during 1988 that were included in the State's perinatal statistics collection. The results indicate that in metropolitan Adelaide, low socioeconomic status is related to a higher risk profile of mothers and babies. It also highlights that there is a strong association of divorce and separation with medical problems and an adverse pregnancy outcome. Poorer outcomes are also seen in never married women, teenage women, older women, non-Caucasian women and primigravid women. These poorer outcomes in older women and primigravidas include higher risks of low birth-weight and prematurity of their babies. The study also demonstrates that groups that are less likely to have choice of obstetric care, eg. teenage women, non-Caucasian women, and women of low socioeconomic status, have a lower odds of obstetric intervention as characterized by nonspontaneous labour and elective Caesarean section.

Adult↗
PubMed1992

Is magnitude of co-payment effect related to income? Using census data for health services research.

This study: (1) describes and evaluates a method for estimating household income using home addresses in conjunction with census data, and (2) uses this method in a study designed to determine if the introduction of copayments caused primary care office visit rates to decrease more for lower income enrollees than for higher income enrollees of a large health maintenance organization (HMO). Each step in the process of linking income estimates for small census units (block groups) to specific home addresses is described and the validity and precision of these estimates is assessed through comparisons of estimated income with self-reported income for residents of the Puget Sound area of Washington state. Although subject to considerable measurement error, this approach provided valid income estimates. This method was then used to estimate the incomes of over 20,000 households of HMO enrollees in a controlled study of the relationship between copayment effect on visit rates and enrollee income. Copayments were found to have a similar effect on higher and lower income enrollees.

Adult↗
PubMed1992

The Small Area Health Statistics Unit: a national facility for investigating health around point sources of environmental pollution in the United Kingdom.

STUDY OBJECTIVE: The Small Area Health Statistics Unit (SAHSU) was established at the London School of Hygiene and Tropical Medicine in response to a recommendation of the enquiry into the increased incidence of childhood leukaemia near Sellafield, the nuclear reprocessing plant in West Cumbria. The aim of this paper was to describe the Unit's methods for the investigation of health around point sources of environmental pollution in the United Kingdom. DESIGN: Routine data currently including deaths and cancer registrations are held in a large national database which uses a post code based retrieval system to locate cases geographically and link them to the underlying census enumeration districts, and hence to their populations at risk. Main outcome measures were comparison of observed/expected ratios (based on national rates) within bands delineated by concentric circles around point sources of environmental pollution located anywhere in Britain. MAIN RESULTS: The system is illustrated by a study of mortality from mesothelioma and asbestosis near the Plymouth naval dockyards during 1981-87. Within a 3 km radius of the docks the mortality rate for mesothelioma was higher than the national rate by a factor of 8.4, and that for asbestosis was higher by a factor of 13.6. CONCLUSIONS: SAHSU is a new national facility which is rapidly able to provide rates of mortality and cancer incidence for arbitrary circles drawn around any point in Britain. The example around Plymouth of mesothelioma and asbestosis demonstrates the ability of the system to detect an unusual excess of disease in a small locality, although in this case the findings are likely to be related to occupational rather than environmental exposure.

Asbestosis↗
PubMed1992

Hospital variations in adverse patient outcomes.

Careful review of the literature suggests that the conceptual problem in analyzing hospitals' quality of care is the difficulty of identifying problem domains of hospital care. An appropriate measurement model using multiple indicators of hospital quality problems is developed and evaluated. Adverse patient outcomes reflecting the quality problems are compiled from a peer review organization's generic screen indicators for 85 acute care hospitals. Predictor variables of adverse outcomes include bed size, number of high-technology services offered, case mix, severity of patients treated, ownership, case mix, severity of patients treated, ownership, net profit, market share, efficiency, teaching status, and metropolitan size. The findings show that hospital characteristics exert limited effects on adverse outcomes. Efficiency and average length of stay are the only statistically significant factors that explain the variation in adverse outcomes.

Hospital Mortality↗
PubMed1992

Variations in asthma hospitalizations and deaths in New York City.

BACKGROUND: Recent reports have identified New York City as having asthma mortality rates that are substantially higher than expected based on US rates. This study investigates the problems of asthma morbidity and mortality in New York City. METHODS: Data on asthma hospitalizations (1982 to 1986) and deaths (1982 to 1987) among persons aged 0 to 34 years were studied. Descriptive and multivariate techniques were used to examine differences in rates among subgroups and across geographic areas. RESULTS: The average annual hospitalization rate was 39.2 per 10,000; the mortality rate was 1.2 per 100,000. Hospitalization and death rates among Blacks and Hispanics were 3 to 5.5 times those of Whites. Large geographic variations in hospitalizations and mortality occurred. Asthma hospitalization and mortality rates were highly correlated (r = .67), with the highest rates concentrated in the city's poorest neighborhoods. Household income, percentage of population Black, and percentage of population Hispanic were significant predictors of area hospitalization rates (adjusted R2 = .75). CONCLUSION: These findings provide a basis for focusing investigations of the causes of variations in asthma outcomes and targeting interventions to reduce the disproportionate morbidity and mortality borne by poor and minority populations.

Abstracting and Indexing↗
PubMed1992

Realizing the potential of practice pattern profiling.

In January 1992, the Physician Payment Review Commission held a conference to learn about the appropriateness of present uses of profiling of practice patterns, and to identify what will be required to realize the full potential of this technique in the future. The conference addressed the data needs of profiling, the development of valid and relevant profiles, the impact of profiles on medical practice, and controversies surrounding public access to profiling information and the uses to which profiling has been put. This paper, based in part on that conference, reviews the basic concepts that underlie profiling and describes the roles that profiling can play in quality improvement, assessment of provider performance, and utilization review. It uses case studies to illustrate the types of problems that have arisen in actual usage and discusses what will be required to resolve them. The final section describes the roles that profiling can play in achieving the goals of health care reform, and concludes with what is needed in data and infrastructure development to improve the quality and usefulness of profiling.

Data Collection↗
PubMed1992

Mortality of iron foundry workers. II. Analysis by work area.

Plantwide analyses of the mortality experience of 8147 foundrymen revealed excesses for several diseases including lung cancer. Using indirect measures of smoking, it appeared that most, if not all, of the excess of lung cancer deaths could be explained by smoking habits. To explore further the possible association between these mortality excesses and foundry exposures, jobs were grouped into six work areas on the basis of similarities in production processes. The findings of analyses by work areas support the inferences from plantwide observations. No evidence was found of a relationship between lung cancer and foundry exposures. The pattern of mortality from emphysema and cerebrovascular disease in the different work areas paralleled that of lung cancer, suggesting that mortality from these diseases may have been influenced by a common etiologic agent, probably tobacco smoke. The data also reveal possible associations between metal pattern-making and colon cancer, silica or metal dust and stomach cancer, and carbon monoxide and ischemic heart disease.

Adult↗