Contributions of incidence and case fatality to mortality from bladder cancer in the south Thames Regions

Measures of prevalence: which healthcare registers are applicable?

Aims: This study analyses the applicability of some of the registers used within the healthcare system for estimations of disease prevalence .The study focuses on the diagnoses of asthma, diabetes mellitus, chronic bronchitis/emphysema, hypertensive disease, and cerebrovascular disease. Methods: The study population comprised all inhabitants ( n=20,037) in the municipality of Tierp on 31 December 1996. Diagnostic information was collected from primary healthcare and occupational healthcare in the municipality of Tierp and from inpatient and outpatient units at the hospitals in Uppsala County. The proportion of registered patients in the different registers was calculated in relation to the total number of patients who had been registered during 1996 with the selected diagnoses . Results: In the primary healthcare register, between 67% ( cerebrovascular disease) and 85% ( asthma) of all patients with selected diagnoses could be identified. A search on the inpatient care register ( Hospital Discharge Register) led to the identification of between 8% ( hypertensive disease) and 53% ( cerebrovascular disease) of the patients. Conclusions: For all of the examined diagnoses, most patients could be identified in the primary healthcare register. Register data from both primary healthcare and inpatient and outpatient care at hospital are needed to make reasonable estimates of prevalence.

Studies of avoidable factors influencing death: a call for explicit criteria

OBJECTIVE

To analyse studies evaluating cases of potentially "avoidable" death.

DESIGN

The definitions, sources of information, and methods were reviewed with a structured protocol. The different types of avoidable factors,--that is, deficiencies in medical care that may have contributed to death--were categorised. The presence of explicit classifications and standards was examined. basic criteria for quality of the studies were defined and the numbers of studies fulfilling these criteria were assessed.

SETTING AND PARTICIPANTS

65 studies, published during 1988-93 in peer reviewed medical journal for which the title, or abstract, or both indicated that they had analysed potentially avoidable factors influencing death. Studies analysing aggregated data only, were not included.

RESULTS

Only one third of the studies fulfilled basic quality criteria,--namely, that the avoidable factors examined should be defined and the sources of information and people responsible for the judgements presented. The definitions used comprised two levels, one stating that there had been errors in management (process) and the other that the errors may have contributed to the deaths (outcome). Only 15% of the studies explicitly defined what type of factors they had looked for and 8% referred to specified standards of care.

CONCLUSIONS

Studies of avoidable factors influencing death may have considerable potential as part of a system of improving medical care and reducing avoidable mortality. At present, however, the results from different studies are not comparable, due to differences in materials and methods. There is a need to improve the quality of the studies and to define standardised explicit definitions and classifications.

Components of small area variation in death rates: a method applied to data from Sweden

STUDY OBJECTIVES

The study aimed to develop and evaluate a method for small area analysis of different non-random components of the variation in death rates. The method was applied to incidence and mortality data for selected malignant neoplasms in 26 administrative health areas in Sweden.

DESIGN

Variation in mortality and incidence rates for malignant neoplasms of the trachea, bronchus, and lung; colon; rectum; and cervix uteri in the 26 health areas were analysed after standardisation for age. In addition, the systematic and random components of variance were estimated. The systematic component of variance in mortality was divided into two additive components-one component was dependent on the variation in the corresponding incidence rates and the other remained after adjustment for incidence. SETTING AND PARTICIPANT: All cases diagnosed between 1972 and 1983 and all deaths between 1974 and 1985 for selected malignant neoplasms in Swedish citizens and other residents in Sweden, aged between 0 and 64 years, were analysed.

MAIN RESULTS

Much of the observed variation in mortality was explained by the estimated random variation. For malignant neoplasms of the trachea, bronchus, and lung the systematic variation in mortality was mainly explained by the variation in incidence. For cancer of the cervix uteri, alone, there was significant systematic variation of moderate magnitude that was not explained by the incidence rates.

CONCLUSIONS

These methods made it possible to divide the observed variance in mortality into different components. Random effects and variance in incidence rates were found to be of great importance when analysing the variance in death rates between health areas. By studying different systematic components of variation it is possible to identify fields for in depth studies on the quality of prevention and treatment.