Behavior of mortality indicators in small geographic areas: relative standardized mortality ratio and standardized proportional mortality ratio

One of the most commonly used indicators in mortality studies is the Standardized Mortality Ratio (SMR) being the Relative Standardized Mortality Ratio (RSMR) an indicator of the relative magnitude of the SMR for a specific cause of death. Along with these indicators, which must be calculated by using the population at risk, there is the Standardized Proportional Mortality Ratio (SPMR), an indicator which measures the excess mortality referring to the proportional mortality established for a standard population. This paper reviews the theoretic conditions described in literature as being necessary to establish a probability interval for the RSMR centered on the SPMR as well as the correlations between both indicators and the use of the SPMR as a predictor of the RSMR. The results obtained clearly show how difficult it is for these theoretic conditions to exist. However, they do suggest that the SPMR be used as a predictor of RSMR.     

The usefulness of the hospital standardized mortality ratio as an indicator of hospital mortality

In 2007, a patient safety programme was started to reduce hospital mortality in the Netherlands. The hospital standardized mortality ratio (HSMR) seems to be a promising indicator for monitoring the reduction of hospital mortality within hospitals. It is questionable, however, whether the HSMR can be used to compare the performance of hospitals. It has been shown that certain specialized procedures such as percutaneous transluminal coronary angioplasty (PTCA) and open heart surgery have an impact on the HSMR. Although this hampers a fair comparison between cardiac centres and general hospitals, the HSMR may still indicate whether a cardiac centre could improve its performance. Moreover, the impact of cardiac procedures on the HSMR is relatively modest, which shows that it is a robust indicator to monitor the intended decrease of hospital mortality on a national scale.     

Healthy life expectancy and the standardized mortality ratio for the elderly in Japan's 47 Prefectures

OBJECTIVE: To derive values for life expectancy and healthy life expectancy (number of years people are expected to live without certification as being in need of long-term care) for Japanese at 65 years of age across 47 Prefectures in Japan, based on both national death statistics and long-term care insurance data, and to analyze their relationships with the standardized mortality ratio (SMR) for the elderly aged 65 years and more. METHOD: Life expectancy was calculated using Chiang's method and healthy life expectancy using Sullivan's method. The number of years of living with long-term care needed (duration of care need) was determined by subtracting the healthy life expectancy from life expectancy. The SMR was calculated in comparison with that for the nation set at 1. The relationships between the indices were analyzed based on the Spearman rank-order correlation coefficient. RESULTS:(1) Among the 47 prefectures, healthy life expectancy at 65 years of age in 2004 for males was the longest in Nagano Prefecture (16.72 years) and the shortest in Aomori Prefecture (14.32 years). For females, it was the longest in Yamanashi Prefecture (19.18 years) and the shortest in Osaka Prefecture (16.47 years). (2) Healthy life expectancy for males and females positively correlated with life expectancy, and negatively correlated with the duration of care need and SMR. Life expectancy negatively correlated with SMR for males and females, and, for females, it positively correlated with the duration of care need as well. CONCLUSION: (1) Among the 47 prefectures, healthy life expectancy at 65 years of age in 2004 was the longest in Nagano Prefecture and the shortest in Aomori Prefecture. For females, it was the longest in Yamanashi Prefecture and the shortest in Osaka Prefecture. (2) For males and females, lowering the mortality rate as well as the prevalence of ill health with long-term care need is important for extending healthy life expectancy. For females, long life expectancy is associated with a long duration of care needed.     

Health service resources as determinants of infant death in rural Bangladesh: an empirical study

Using empirical data collected from a rural area of Bangladesh, this paper examines the relative importance of availability of health care resources on infant death. Following many health care studies, this paper hypothesizes that the likelihood of infant death is a function of accessibility to different types of health facilities and personnel. Both univariate and multivariate analyses of data indicate that the distance to a qualified physician of Western medicine exerts significant influence on infant deaths. Other variables considered are distance to Upazila Health Complex (UHC), Family Welfare Center (FWC), and non-qualified doctors.     

Health care resources utilization in HIV-infected patients: creation of a data base and cost results

OBJECTIVES: To make and validate a data base that allows to collect information about clinical characteristics and use of health care services by HIV-infected patients. An additional purpose is to obtain some data about costs of health care services utilization. METHODS: We have designed an informatic data base that includes: demographic data, clinical data and health care services utilization during the follow up. One hundred and nine patients were selected from 5 different hospitals in Spain and they were followed for 6 months (from January to June 1997). Analytic accounting of one hospital and official tariffs were used to calculate costs of the health care services. RESULTS: The informatic data base designed is useful and appropriate to collect the information of these patients. The annual average cost is 2.5 millions dollars, ranging from 1 million dollars for asymptomatic patients to 3.8 millions for AIDS patients. The comparison of our results with previous studies shows an increased cost of asymptomatic patients. CONCLUSIONS: These results give a preliminary information about health care services utilization by HIV-infected patients and confirm the possibility of using the designed instrument in the future. Since HIV-infection presents an uncertain evolution and a variable prognosis, to implant a tracking system is a necessary requirement in order to obtain a fast and accurate information system about the evolution of clinical variables and their economic repercussions.     

Suitability of the health and social care resources for persons requiring long-term care in Spain: an empirical approach

The objective of this paper is to examine the suitability of specific facilities for dependent persons for meeting users' needs. A total of 1265 users of social and health facilities for dependent persons were interviewed in a study carried out in a typical southern European region with a Mediterranean welfare system: the Valencia Autonomous Region in Spain. Data were obtained on users' socio-demographic profile, health, functional dependence, cognition, social support and housing suitability. Based on these data and the institutional definitions of the specific facilities for dependent persons, the suitability index was drawn up for each facility and suitability was evaluated using discriminant analysis. The results give a high suitability index for most of the facilities (between 0.661 for Units for Home Hospitalisation and 1.000 for Units for Psychiatric Hospitalisation). But a significant percentage of patients (17% in Hospitals for Chronically Ill and Long-stay Patients) could be cared for in different facilities to the ones they actually use.     

A necessary and sufficient condition of comparability for using standardized mortality ratio (SMR)

A necessary and sufficient condition of comparability for using SMR was studied mathematically by considering the equivalence between SMR and CMF, as CMF was a perfectly comparable index. This condition was expressed by either proportionality of mortality vectors or proportionality of projected person-years to the plane spanned by mortality vectors of reference and index groups. We could obtain another expression of the condition, in which affect of distortions were easily understood, which consist of three factors: distortion of proportionality of mortality, distortion of person-years and similarity of distortions. Our results were applied to study the mortality of biliary tract cancer in Ibaraki Prefecture. Places where absolute difference between CMF and SMR exceeds some criterion (say, 0.15) were Satomi, Ushiboiri, Nihari in males and Gozenyama, Suifu and Asahi in females. All three distortion indices exceeded their upper 95% percentiles in Satomi in males.     

"Premature mortality" as an integral indicator of the quality of medical care

Retrospective expert appraisal of the causes of premature death provides the possibility for raising the quality of health care, eliminating defects in the work of polyclinics and hospitals and also consolidating the main chains of health care. Reduction of premature mortality for preventable causes can lengthen expectation of life. When assessing the quality of health care it is recommended to apply an integral indicator of premature mortality.     

医院标准化死亡比指标建设及应用的国际经验与启示

死亡类指标是反映医疗质量和安全的重要指标,医院标准化死亡比指标已被很多国家作为重要的质量工具以衡量医院的医疗质量。本文通过文献综述,系统梳理和对比了苏格兰、英格兰、美国马萨诸塞州、澳大利亚、荷兰和加拿大6个国家/地区的医院标准化死亡比指标构建经验及其应用情况,并对我国建设该指标的可行性、建设方法以及指标应用方面提出建议。     

Study of coverage of confidence intervals for the standardized mortality ratio in studies with missing death certificates

This paper assesses the coverage probability of commonly used confidence intervals for the standardized mortality ratio (SMR) when death certificates are missing. It also proposes alternative confidence interval approaches with coverage probabilities close to .95. In epidemiology, the SMR is an important measure of risk of disease mortality (or incidence) to compare a specific group to a reference population. The appropriate confidence interval for the SMR is crucial, especially when the SMR is close to 1.0 and the statistical significance of the risk needs to be determined. There are several ways to calculate confidence intervals, depending on a study characteristics (ie, studies with small number of deaths, studies with small counts, aggregate SMRs based on several countries or time periods, and studies with missing death certificates). This paper summarizes the most commonly used confidence intervals and newly applies several existing approaches not previously used for SMR confidence intervals. The coverage probability and length of the different confidence intervals are assessed using a simulation study and different scenarios. The performance of the confidence intervals for the lung cancer SMR and all other cancer SMR is also assessed using the dataset of French and Czech uranium miners. Finally, the most appropriate confidence intervals to use under different study scenarios are recommended.     

Health services resources and their relation to mortality from causes amenable to health care intervention: a cross-national study

Gross national product has been found to be negatively associated with age-specific mortality, and the prevalence of medical doctors positively associated with mortality in younger age groups. We studied the relationship between mortality and its determinants among people aged 64 years or less in 25 developed countries. Age-adjusted mortality rates from causes of death amenable to interventions by health services were calculated for the period 1975-8, and, likewise, rates from partly amenable causes, non-amenable causes, and violent causes of death. In regression analysis, log mortality from amenable causes was significantly negatively associated with gross domestic product (GDP) but not with the numbers of medical doctors, nurses and midwives, hospital beds, alcohol consumption, tobacco consumption, or military expenditure. It is argued that cross-sectional comparisons disguise the effects of health services on mortality.     

Variance estimation and confidence intervals for the standardized mortality ratio with application to the assessment of a cancer screening program

The effect of a cancer screening program can be measured through the standardized mortality ratio (SMR) statistic. The numerator of the SMR is the observed number of deaths from the screened disease among participants in the screening program, whereas the denominator of the SMR is an estimate of the expected number of deaths in these participants under the assumption that the screening program has no effect. In this article, we propose a variance estimator for the denominator of the SMR when this expected number of deaths is estimated with Sasieni's method. We give both a general formula for this variance as well as formulas for specific disease incidence and survival estimators. We show how this new variance estimator can be used to build confidence intervals for the SMR. We investigate the coverage properties of various types of confidence intervals by simulation and find that intervals that make use of the proposed variance estimator perform well. We illustrate the method by applying it to the Québec Breast Cancer Screening program.     

Mortality studies of machining fluid exposure in the automobile industry I: A standardized mortality ratio analysis.

Machining fluids are widely used in a variety of common industrial metalworking operations to lubricate and cool both the tool and the working surfaces. Previous studies have suggested elevated respiratory, digestive, and skin cancers in exposed populations. This cohort study was initiated to assess whether long-term exposure to machining fluids in the course of machining, grinding, and other cutting operations is associated with excess cancer mortality. The cohort includes more than 45,000 automobile production workers from 3 plants, almost 1 million years of follow-up, over 10,000 deaths, and an extensive exposure assessment component. Standardized mortality ratios (SMRs) have been estimated for each of the 3 plants, using both U.S. as well as local populations as reference. Relative risks of 1.2-3.1 have been observed for several specific respiratory and digestive cancers of a priori interest, including cancer of the stomach, large intestine, pancreas, lung, and larynx. In addition, elevated risks for leukemia and asthma were noted. Future exposure-response analyses will provide the opportunity to identify relatively modest excesses in cause-specific mortality risk associated with exposure to specific types (straight, soluble, or synthetic), additives, or components of machining fluids.