Improving the quality of reporting of randomized controlled trials. The CONSORT statement.
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Guidelines as Topic↗
Biomedical subjects
D F Stroup
Publications and source records attributed to D F Stroup.
Federal scene. Introducing Annals of Epidemiology Federal scene section.
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Centers for Disease Control and Prevention, U.S.↗
Metaanalysis for the obstetrician-gynecologist.
To provide guidance to obstetricians and gynecologists for using findings from metaanalyses in clinical practice, we describe the principles and methods of metaanalysis, including its strengths and weaknesses. Then we illustrate these principles by reviewing four metaanalyses published recently in the American Journal of Obstetrics and Gynecology by using a systematic approach to evaluation based on 15 questions. In these published metaanalyses most of the questions are addressed, but we noted an absence of attention to coding aspects in all studies. The usefulness of metaanalysis largely depends on the quality of the studies that are synthesized, the conduct of the metaanalysis, and the reporting of the methods and results. Proper use of metaanalyses requires an understanding of the strengths and weaknesses of the method and attention to the manner of reporting. The principles of metaanalysis are not complex, and the potential benefits can be enormous for patient care.
Evaluation Studies as Topic↗
The future of national public health surveillance in the United States.
Public health surveillance systems should have the capacity to collect and analyze data, disseminate data to public health programs, and regularly evaluate the effectiveness of the use of disseminated data. Unfortunately, in the United States, systems of public health surveillance are fragmented and do not adequately address either current or new potential challenges to public health. This commentary addresses components of any effort toward a national public health surveillance system and highlights examples of these components in state and national surveillance developments.
Confidentiality↗
Surveillance in environmental public health: issues, systems, and sources.
This article describes environmental public health surveillance and proposes a framework to enhance its practice in the United States. Special issues for surveillance in environmental public health are examined, and examples of existing systems useful for environmental public health practice are provided. Current and projected surveillance needs, as well as potential sources of data, are examined. The proposed framework for conducting environmental public health surveillance involves data from three points in the process by which an agent in the environment produces an adverse outcome in a host: hazards, exposures, and outcomes. Environmental health practitioners should build on efforts in other fields (e.g., infectious diseases and occupational health) to establish priorities in the surveillance of health conditions associated with exposure to environmental toxicants. For specific surveillance programs, existing data systems, as well as data gaps, should be identified. Coordinated surveillance systems can facilitate public health efforts to prevent and control disease, injury, and disability related to the interaction between people and their environment.
Environmental Exposure↗
The application of multidimensional scaling methods to epidemiological data.
This paper illustrates the use of multidimensional scaling methods (MDS) to examine space-time patterns in epidemic data. The paper begins by outlining the principles of MDS. The model is then formally specified and illustrated by application to two data sets. The first is partly a tutorial example. It uses monthly reported measles morbidity data for the 31-year period from January 1960 to December 1990, collected for the 50 states of the USA, plus New York City and the District of Columbia. These data are used to explore the various ways in which MDS may be used to identify changing spatial patterns in geographically-coded data. In addition to their tutorial use, the data are also employed to search for any substantive changes in the geographical structure of measles epidemics in the USA that may have followed the introduction of mass vaccination in 1965. New England appears to have developed an epidemic profile distinct from the rest of the USA, and there is tentative evidence of an urban-rural split in epidemic characteristics. The second data set takes annual reported measles mortality data for New Zealand and the states of Australia from 1860 to 1949. MDS is used to show how the spatial relationships among these geographical units have changed over time in response to changes in the sizes of local susceptible populations.
Australia↗
Efficacy and safety of intrapartum electronic fetal monitoring: an update.
OBJECTIVE: To compare the efficacy and safety of routine electronic fetal monitoring (EFM) of labor with intermittent auscultation, using the results of published randomized controlled trials (RCTs). DATA SOURCES: We identified RCTs by searching the MED-LINE data base for the period 1966-1994, contacting experts, and reviewing published references. METHODS OF STUDY SELECTION: Our search identified 12 published RCTs addressing the efficacy and safety of EFM; no unpublished studies were found. The studies included 58,855 pregnant women and their 59,324 infants in both high- and low-risk pregnancies from ten clinical centers in the United States, Europe, Australia, and Africa. DATA EXTRACTION AND SYNTHESIS: Data were abstracted, and their accuracy was confirmed independently. A single reviewer assessed study quality based on criteria developed by others for RCTs. Data reported from similar studies were used to calculate a combined risk estimate for each of nine outcomes. Overall, a statistically significant decrease was associated with routine EFM for a 1-minute Apgar score less than 4 (relative risk [RR] 0.82, 95% confidence interval [CI] 0.65-0.98) and neonatal seizures (RR 0.5, 95% CI 0.30-0.82). The protective effect of EFM for a 1-minute Apgar score less than 4 was apparent only in the non-United States studies, and the protective effect for neonatal seizures was evident only in studies with high-quality scores. No significant differences were observed in 1-minute Apgar scores less than 7, rate of admissions to neonatal intensive care units, and perinatal death. An increase associated with the use of EFM was observed in the rate of cesarean delivery (RR 1.33, 95% CI 1.08-1.59) and total operative delivery (RR 1.23, 95% CI 1.15-1.31). Risk of cesarean delivery was greatest in low-risk pregnancies. CONCLUSION: The only clinically significant benefit from the use of routine EFM was in the reduction of neonatal seizures. Because of the increase in cesarean and operative vaginal deliveries, the long-term benefit of this reduction must be evaluated in the decision reached jointly by the pregnant woman and her clinician to use EFM or intermittent auscultation during labor.
Female↗
Future directions for comprehensive public health surveillance and health information systems in the United States.
The authors describe a comprehensive system for public health surveillance for the United States based on a network of data systems ranging from population surveys and physician-based records to electronically linked laboratory and administrative data. They also discuss traditional uses of surveillance data, legal and ethical issues associated with using data from any surveillance system (particularly the tension between individual privacy and the public right to a healthful environment), and factors impeding the development of a comprehensive system. Just as provisional data on notifiable diseases are critical in protecting communities from disease, data from other information systems should be applied to prevention practice with the same urgency. The major barriers to a successful comprehensive, nationwide, integrated public health surveillance and information system are a lack of appreciation for the value of high-quality provisional surveillance data and a weak societal commitment to public health.
Confidentiality↗
A monitoring system to detect changes in public health surveillance data.
One task faced by public health surveillance practitioners is the timely identification of data patterns that might suggest the onset of an epidemic period. Many available techniques for analysis of surveillance data are based on sequential procedures, which predict expected numbers of cases and compare this estimate with observed values. To detect changes in the reported occurrence of a disease (increase, decrease, or change in trend), we used exponential smoothing and transformation of the difference between the observed and estimated data to calculate a function called the probability index. We illustrate this procedure using weekly provisional data for measles cases in the US reported through the National Notifiable Diseases Surveillance System to the Centers for Disease Control and Prevention (CDC). The method is potentially useful in public health surveillance to facilitate prompt intervention and prevention efforts, since it can be used at the national and regional levels without the requirement for sophisticated computing.
Communicable Disease Control↗
Breast cancer risk and duration of estrogen use: the role of study design in meta-analysis.
Recent meta-analyses of studies of the risk of breast cancer associated with hormone replacement therapy agree that little risk is associated with ever-use or short-term use of estrogen replacement. These analyses disagree, however, about the effect of long-duration estrogen use. To understand differences in the findings among the meta-analyses of the effect of long-term use, we investigated the source of heterogeneity among the included studies. We analyzed subgroups by source of controls (community vs hospital), study design (case-control vs follow-up), and types of estrogen. We also examined the effect of modeling assumptions: that before women began estrogen use, those who chose to use estrogen replacement (1) were, or (2) were not, at substantially different risk from those who chose not to use estrogen. We found a small increase in risk in all subgroups of studies except those that used hospital controls. From a homogeneous group of case-control studies using community controls that analyzed the effect of conjugated equine estrogens, we estimated that the risk of breast cancer after 10 years of estrogen use increased by at least 15% and up to 29%.
Breast Neoplasms↗
Evaluation of a method for detecting aberrations in public health surveillance data.
The detection of unusual patterns in routine public health surveillance data on diseases and injuries presents an important challenge to health workers interested in early identification of epidemics or clues to important risk factors. Each week, state health departments report the numbers of cases of about 50 notifiable diseases to the Centers for Disease Control and Prevention, and these reports are published weekly in the Morbidity and Mortality Weekly Report. A new analytic method and a horizontal bar graph were introduced in July 1989 to facilitate easy identification of unusual numbers of reported cases. Evaluation of the statistical properties of this method indicates that the results are fairly robust to nonnormality and serial correlation of the data. An epidemiologic evaluation of the method after the first 6 months showed that it is useful for detection of specific types of aberrations in public health surveillance.
Bias↗
A Bayesian approach to the detection of aberrations in public health surveillance data.
The accurate and timely detection of unusual patterns in data from public health surveillance systems presents an important challenge to health workers interested in early identification of epidemics or clues to important risk factors. We apply the Kalman filter, a Bayesian method, to public health surveillance data collected in the United States to illustrate a methodology used to detect sudden, sustained changes in reported disease occurrence, changes in the rate of change of health event occurrence, as well as unusual reports or outliers. The method allows use of information external to reported data in forecasting expected numbers, information such as expert judgment, changes in case definition or reporting practices, or changes in the health event process. Results show good agreement with epidemiologically established patterns beginning early in the data series and demonstrated usefulness on a relatively short series. Because the method is unfamiliar to most practicing epidemiologists in public health, it should be compared with other techniques and made more "user-friendly" before general application.
Acquired Immunodeficiency Syndrome↗
Chronic obstructive pulmonary disease mortality. A role for altitude.
A map of US COPD mortality rates by state suggested that the relative hypoxia of increased altitude may be independently associated with COPD mortality. This was investigated using linear regression analysis of 1986 state-specific data on COPD mortality rates, history of cigarette consumption, and altitude. County seat altitudes and county populations were used to calculate the median altitude of state residents. We found independent significant associations between COPD and both smoking and altitude. State COPD mortality rose by 1/10(5) for every 5.4 increase in mean packs consumed per capita per year or for each 95-m increase in resident altitude. There was no association between altitude and smoking. If increased altitude does contribute to COPD mortality, persons with this disease may benefit from down-migration.
Altitude↗
Analysis of aberrations in public health surveillance data: estimating variances on correlated samples.
The detection of unusual patterns in health data presents an important challenge to health workers interested in early identification of epidemics or important risk factors. A useful procedure for detection of aberrations is the ratio of a current report to some historic baseline. This work addresses the problem of finding the variance of such a ratio when the surveillance reports are correlated. Results show that, when estimating this variance or the variance of the sample mean from a series of observations with an estimated correlation structure, bootstrap and jackknife estimates may be overly optimistic. The delta method or a classical method may be more useful when such model dependence is inappropriate.
Analysis of Variance↗
The geographic structure of measles epidemics in the northeastern United States.
The incidence of disease across geographic space often produces distinctive regional patterns. In this paper, a modeling approach to the identification of the factors that shape the patterns is presented, and a procedure for fitting the model to observed data is given. The methodology is illustrated by an application to the geographic structure of measles epidemics among 22 states of the northeastern United States, New York City, and Washington, D.C., from 1962 to 1988. The patterns identified are interpreted in terms of the spatial behavior of measles epidemics in the region, and the implications of the methodology for surveillance and control are considered.
Humans↗
The changing geographical coherence of measles morbidity in the United States, 1962-88.
Geographical coherence may be defined as the degree to which the behaviour of a time series in one geographical area corresponds with the time series behaviour in another. This paper illustrates the concept using the epidemiological time series of reported monthly measles morbidity for the states of the United States for the 27 years from January 1962 to December 1988. Over this period, as measles morbidity has declined in response to vaccination campaigns, and as the seasonal peaking of the disease in late spring has become less pronounced, the geographical coherence has altered at the national, divisional, regional and state levels. There was a steady decline in coherence from 1962 to 1980. In 1981, a dramatic reduction occurred, but there has been some recovery since. The implications for spatial forecasting models of these reducing levels of coherence are discussed.
Cross-Sectional Studies↗
Surveillance data for policy: a national and state approach.
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Chronic Disease↗
A meta-analysis of the effect of estrogen replacement therapy on the risk of breast cancer.
To quantify the effect of estrogen replacement therapy on breast cancer risk, we combined dose-response slopes of the relative risk of breast cancer against the duration of estrogen use across 16 studies. Using this summary dose-response slope, we calculated the proportional increase in risk of breast cancer for each year of estrogen use. For women who experienced any type of menopause, risk did not appear to increase until after at least 5 years of estrogen use. After 15 years of estrogen use, we found a 30% increase in the risk of breast cancer (relative risk, 1.3; 95% confidence interval [CI], 1.2 to 1.6). The increase in risk was largely due to results of studies that included premenopausal women or women using estradiol (with or without progestin), studies for which the estimated relative risk was 2.2 (CI, 1.4 to 3.4) after 15 years. Among women with a family history of breast cancer, those who had ever used estrogen replacement had a significantly higher risk (3.4; CI, 2.0 to 6.0) than those who had not (1.5; CI, 1.2 to 1.7).
Adult↗