SEARCH · PubMed Health

Results for “Epidemiologic Methods”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 757 records · Page 42Linked to original sources

PubMed2004

Evaluation of surveillance methods for an epidemiological study of contact lens related microbial keratitis.

PURPOSE: To evaluate surveillance methods in a pilot epidemiological study of contact lens related microbial keratitis (MK) cases identified by ophthalmic practitioners in Australia and New Zealand between May and August 2003 inclusive. METHODS: Twelve ophthalmologists and 55 optometrists from rural and metropolitan locations were sent a study information pack with postal reporting forms. After 2 months, practitioners were emailed a link to a website for Internet reporting. After 4 months, practitioners were prompted by email and then by telephone if a response was not received. Passive response rates were the rate of returns after posting information and emailing the website link. Active response rates included personalized email and telephone follow-up. RESULTS: Ten cases of MK were identified by optometrists and five by ophthalmologists. The passive response rates were 79% and 58% for the first and second reporting periods, respectively. There was a lower response rate in the second reporting period compared to the first (P = 0.02). With active surveillance the response rate increased to 97% and 96%. A large proportion of optometrists (62%) and ophthalmologists (55%) used the website for at least one reporting period. Internet reporting was used by all New Zealand practitioners (5/5). CONCLUSIONS: A surveillance study to estimate the incidence of contact lens related MK in Australia and New Zealand is feasible and acceptable. Internet-based reporting offers a reliable, rapid and cost-effective means of running a large scale, international surveillance study. Active surveillance methods are necessary to enhance reporting rates.

Adolescent↗

PubMed2005

Molecular epidemiology: a multidisciplinary approach to understanding parasitic zoonoses.

Sound application of molecular epidemiological principles requires working knowledge of both molecular biological and epidemiological methods. Molecular tools have become an increasingly important part of studying the epidemiology of infectious agents. Molecular tools have allowed the aetiological agent within a population to be diagnosed with a greater degree of efficiency and accuracy than conventional diagnostic tools. They have increased the understanding of the pathogenicity, virulence, and host-parasite relationships of the aetiological agent, provided information on the genetic structure and taxonomy of the parasite and allowed the zoonotic potential of previously unidentified agents to be determined. This review describes the concept of epidemiology and proper study design, describes the array of currently available molecular biological tools and provides examples of studies that have integrated both disciplines to successfully unravel zoonotic relationships that would otherwise be impossible utilising conventional diagnostic tools. The current limitations of applying these tools, including cautions that need to be addressed during their application are also discussed.

Animals↗

PubMed2004

Teaching of neuroepidemiology in Europe: time for action.

Many epidemiological and clinical studies in Europe, especially in Eastern Europe and countries in transition, are of poor methodological quality because of lack of background knowledge in clinical epidemiology methods and study designs. The only way to improve the quality of epidemiological studies is to provide adequate undergraduate and/or postgraduate education for the health professionals and allied health professions. To facilitate this process, the European Federation of Neurological Societies (EFNS) Task Force on teaching of clinical epidemiology in Europe was set up in October 2000. Based on analyses of the current teaching and research activities in neuroepidemiology in Europe, this paper describes the Task Force recommendations aimed to improve these activities.

Education, Medical↗

PubMedDate not supplied

Simple statistical measures for analyzing categorical data.

The proportions of patients undergoing a given procedure or experiencing a specific health outcome often are important in studies of healthcare quality. Run charts are a nonstatistical method for evaluating changes in these proportions or rates over time. Simple epidemiological methods for comparing rates between two groups allow statistical comparison of rates between two time periods. The chi-square test measures the statistical significance of differences in rates between two groups. Practical aspects of the use of these statistics and interpretation of their results are discussed and illustrated in this article, with realistic examples originally prepared by the author for a drug usage evaluation study. Readers with appropriate software and hardware may request a simple spreadsheet from the author to calculate many of the analyses described in the article.

Chi-Square Distribution↗

PubMed2001

Epidemiological applications: a case report of a village epidemic of gastroenteritis.

This is a case report of an epidemic of gastroenteritis which was investigated and controlled by epidemiological methods only, before laboratory investigations could be done to confirm the original epidemiological conclusions--from contaminated home made ice-cubes. The case and process are reported in order to encourage similar uses of epidemiology by field public health practitioners, especially within the district or primary health care systems and particularly in places where laboratory support are difficult to avail. The case is used also to discuss the equipments and facilities that ought to be part of the support system for every modern field public health practitioner. These should include computers, modern communication facilities and epidemiological support systems, especially senior epidemiologists; as such senior personnel are available to junior colleagues in the other areas of specialist medical practice.

Disease Outbreaks↗

PubMedDate not supplied

Comparison of methods to assess coronary heart disease prevalence in South Asians.

BACKGROUND: Migrants from the Indian subcontinent (South Asian migrants) in the United Kingdom have high mortality from coronary heart disease (CHD) in comparison to the indigenous population. Few studies have assessed the prevalence of CHD in South Asians, and the applicability of conventional survey methods in this population is not known. In this pilot random population survey of South Asian men and women living in West London, the prevalence of CHD as judged by the Rose questionnaire, past cardiac history, cardiologist and resting electrocardiogram were compared. METHODS: Subjects aged 30-64 years from randomly selected households were invited for a cardiological assessment. A lay person administered the Rose questionnaire and recorded the past cardiac history. A cardiologist also made an independent assessment and a 12-lead electrocardiogram was recorded and analysed according to the Minnesota code. RESULTS: Three hundred and seventy-six individuals (192 men and 184 women) were assessed. The prevalence of angina in men and women, respectively, was 3.1% and 4.9% by the Rose questionnaire; 2.6% and 2.2% by past cardiac history; and 4.2% and 0.5% according to the cardiologist. The prevalence of myocardial infarction in men and women, respectively, was 5.2% and 2.2% by the Rose questionnaire, 3.6% and zero by past cardiac history and 3.6% and 0.5% by the cardiologist. Q/QS codes were present in 1.6% men and 0.5% women and ischaemic codes in 13% men and 14% women. Ischaemic changes were not associated with any cardiac history in 72% of men and 92% of women. For a diagnosis of CHD in men, there was poor agreement between the Rose questionnaire and either the past cardiac history or the cardiologist's assessment, but moderate agreement between the past cardiac history and the cardiologist. Agreement was poor between all three methods for a positive diagnosis of CHD in women. CONCLUSION: Current accepted epidemiological methods for assessing CHD prevalence may be inaccurate in South Asians, especially women. Electrocardiogram abnormalities suggestive of ischaemia are common in South Asians and are usually not associated with evidence of CHD. Thus, their value as indicators of CHD is questionable.

Adult↗

PubMed2003

Paleoepidemiology: is there a case to answer?

Paleopathology is the study of disease, physiological disruptions and impairment in the past. After two centuries of mainly descriptive studies, efforts are being made towards better methodological approaches to the study of diseases in human populations of ancient times whose remains are recovered by archaeology. Paleoepidemiology can be defined as an interdisciplinary area that aims to develop more suitable epidemiological methods, and to apply those in current use, to the study of disease determinants in human populations in the past. In spite of the limits of funerary or other archaeological series of human remains, paleoepidemiology tries to reconstruct past conditions of disease and health in those populations and its relation to lifestyle and environment. Although considering the limits of studying populations of deceased, most of them represented exclusively by bones and teeth, the frequency of lesions and other biological signs of interest to investigations on health, and their relative distribution in the skeletal remains by age and sex, can be calculated, and interpreted according to the ecological and cultural information available in each case. Building better models for bone pathology and bone epidemiology, besides a more complex theoretical frame for paleoepidemiological studies is a big job for the future that will need the incorporation of methods and technology from many areas, including the tools of molecular biology.

Archaeology↗

PubMed1998

[Tuberculosis in AIDS patients: the contribution of an analysis of the restriction fragment length polymorphism of Mycobacterium tuberculosis isolates].

BACKGROUND: In this report we study tuberculosis transmission in HIV infected patients using molecular epidemiological methods. PATIENTS AND METHODS: We have studied 60 M. tuberculosis isolates from 30 HIV infected cases, and their clinical-epidemiological data. Susceptibility to tuberculostatic agents and electrophoretic patterns using RFLPs (restriction fragment length polymorphisms) method were evaluated. Dice's coefficient was used for the similarity analysis. RESULTS: Over 73% studied patients were included in clusters using RFLPs analysis. This data show that nearly 60% of the tuberculosis cases in our area have a recent transmission. Forty per cent of these cases were included in the main cluster. The frequency of tuberculostatic-resistant strains in HIV infected patients was similar to the that of observed in other patients. We did not find correlation between RFLPs clusters and clinical-epidemiological data. CONCLUSIONS: Tuberculosis transmission in HIV-positive patients using RFLPs as molecular marker shows that 60% of the cases are caused by recently acquired strains. We did not find multi-drug resistant strains in our isolates. However due to the high transmissibility of these circulating clones, control disease measures in this group of risk population are required.

AIDS-Related Opportunistic Infections↗

PubMed2000

[An epidemiological study on acute diarrhea during a filed exercise in PLA unit in an area in southern China].

OBJECTIVE: To explore the epidemiological characteristics and risk factors of acute diarrheal disease during a filed exercise. METHODS: Epidemiological study of a certain artillery acute diarrheal disease during a filed exercise and multiple linear stepwise regression analysis, multiple stepwise discriminate analysis were used. RESULTS: Result showed that the incidence rate of training troops was significantly higher than that of the local troops at the corresponding period (7.32% vs 0.98% P<0.05). The incidence rate among officers was significantly lower than that of the soldiers (0.99% vs 8.20% P<0.05). The incidence rate was significantly higher at the beginning of assemble for training but smooth and steady afterwards with several outbreaks. There was highly significant difference in the incidence rate of 39 companies. Regression and discrimination analysis suggested that the incidence rate was correlated with the density of flies and average boiled water volume provided everyday. The correct classifying rate of the discrimination was 91.9% in total. CONCLUSION: These results provided a basis for prevention of acute diarrheal disease during filed exercise of military action.

Acute Disease↗

PubMed1999

The neonatal "sepsis work-up": personal reflections on the development of an evidence-based approach toward newborn infections in a managed care organization.

"Rule out sepsis" may be the most common discharge diagnosis among infants admitted to the neonatal intensive care unit. Although the frequency of sepsis, meningitis, and other confirmed bacterial infections has remained constant (between 1 and 5/1000 live births) for many years, the number of infants evaluated and treated is much higher. Each year in the United States, as many as 600 000 infants experience at least one evaluation for suspected bacterial infection during the birth hospitalization. The number treated is estimated at 130 000 to 400 000 per year. Despite massive overtreatment, delayed diagnosis still occurs. The Kaiser Permanente Medical Care Program (KPMCP) considers developing and implementing an evidence-based approach to "rule out sepsis," a research and operational priority. To achieve these goals, it is essential to consider two key aspects of the problem. First, it is important to adopt a phenomenologic approach that takes clinicians' personal experience into account. This must include reflection on those aspects of experience often considered "irrational" or "subjective." Second, incorporation of a phenomenologic approach needs to be tempered with sound epidemiologic methods. If one considers these two aspects-physician experience and sound epidemiology-it is clear that much of the existing literature on "rule out sepsis" is of limited utility. Consequently, the KPMCP has conducted its own studies. These are aimed at characterizing the "sepsis work-up," developing electronic datasets that would permit clinicians to simulate various strategies, and developing techniques for ongoing electronic monitoring. This article summarizes the approach taken by the KPMCP Division of Research. It describes the results of a pilot study as well as the development and use of a dedicated neonatology outcomes database, the Kaiser Permanente Neonatal Minimum Data Set (NMDS). The NMDS database includes the Score for Neonatal Acute Physiology and permits ongoing monitoring of sepsis "work-ups" as well as confirmed cases of neonatal infection. The article also describes how the experience from the pilot as well as the NMDS was incorporated in the design of a much larger study on "rule out sepsis." Finally, the article describes some important theoretic issues affecting decision rule development and the use of computer simulations in neonatology. These issues are 1) how one handles possible overanalysis of a dataset; 2) how one handles data points that are unstable (eg, the absolute neutrophil count, which can vary considerably depending on age and sampling conditions); and 3) the limitations of decision rules based on computer simulations.

Bacterial Infections↗

PubMed1999

An indirect method for the estimation of osteoporotic fractures from injury and fracture profiles.

Study objective was to develop a valid epidemiological method for the estimation of osteoporotic fracture risk, using administrative databases and accounting for variable baseline risks of injury. Design is the secondary analysis of inpatient and outpatient utilization data. A baseline injury risk was estimated by the incidence of primary utilization of medical services for soft tissue injuries (ICD-9 diagnostic codes 910-929), and the risk profile was compared after normalization with the overall primary utilization rate for fractures (ICD-9 diagnostic codes 800-829). The setting is a county with approximately 100,000 inhabitants in the former East Germany. Participants were all inhabitants of the county who had a physician contact (inpatient or outpatient) during 1987-1988, as well as hospital inpatients for all of Germany in 1989. The number of fractures increased with age, especially in women, when compared to the number of fractures expected from the incidence of soft tissue injury. Similar patterns were identified in hospitalization data from East and West Germany. Estimating the prevalence of osteoporosis directly from certain "osteoporotic" fracture types associated with higher age is potentially biased, since it neglects the underlying risk of injury. Our model distinguished the osteoporotic fracture risk as the excess risk over an expected injury-related fracture risk for a given age and sex, and may allow a more valid quantification of osteoporotic fractures in different populations.

Adolescent↗

PubMed1988

The proband method in psychiatric epidemiology: a bias associated with differences in family size.

Psychiatric epidemiology has traditionally employed both census and proband-based methods to determine the population prevalence of psychiatric disorders. In this article we outline a potential bias in the proband method. With this method, the probability of ascertainment for an individual depends on the number of available relatives. If the average size of families containing one or more affected individuals (RA) differs from the average size of families with no affected individuals (RU), then the ratio of the prevalence estimated by the proband method to the true prevalence is approximately [(RA - 1)/(RU - 1)]. For certain psychiatric disorders associated with decreased family size (e.g. schizophrenia), the underestimation of prevalence by the proband method may be non-trivial.

Epidemiologic Methods↗

PubMed2002

Effect of changes in surgical practice on the rate and detection of nosocomial infections: a prospective analysis.

The practice of surgery is being performed increasingly on an outpatient basis. How these changes have influenced the nosocomial infection rate and the ability of standard, Center for Disease Control (CDC)-designed surveillance techniques to detect these infections is unknown. The goal of this study was to determine whether recent changes in surgical care have led to an increased nosocomial infection rate based on number of discharges and whether current surveillance techniques are adequate to detect these complications. Data were collected prospectively on all nosocomial infections over a 1-year period on the general surgery, trauma, and transplant units at a university hospital, as independently observed by both the study team [surgical auditors (SA)] and CDC-trained infection control practitioners (ICP). The patient study group had a high acuity of illness (for 516 episodes of infection, mean APACHE II score of 15.4, 45% intensive care unit-bound, mortality of 16%). The overall infection rate per 100 discharges was 23.8 for SA and 12.2 for ICP (P < 0.001 by chi2), higher than historical reports. SA detected significantly more surgical site infections, pneumonias, and non-Clostridium difficile-related gastrointestinal infections. These relative rates of detection, however, were similar to those described previously in prior studies using similar methodologies. The nosocomial infection rate in surgical patients, based on number of discharges, appears to be increasing, perhaps due to increased inpatient acuity of illness. Current epidemiological methods provide estimates of infection rates with effectiveness similar to that reported in previous epidemiological studies but fail to recognize many infections otherwise identified by surgeons dedicated to infection control.

Centers for Disease Control and Prevention, U.S.↗

PubMed2004

Effect of environment on extremely severe road traffic crashes: retrospective epidemic analysis during 2000-2001.

OBJECTIVE: To make an epidemiological analysis of the effect of environment on extremely severe road traffic crashes (RTCs). METHODS: Epidemiologic data of extremely severe RTCs associated with environmental factors, including weather, topography, road conditions and other traffic conditions in Mainland China during 2000-2001, were collected and analyzed. RESULTS: (1) During 2000-2001, there were 3365 extremely severe RTCs with 13666 deaths, 12204 injuries and a direct economical loss of 136 million RMB. (2) Most extremely severe RTCs occurred in fine weather days and in the daytime. The high occurrence sites were plain areas, horizontal and straight roads, Grade B and C roads, ordinary road segment, and asphalt, smooth and mixed roads. (3) Compared with other RTCs, extremely severe RTCs were more likely to happen under following conditions: on cloudy, snowing, misty and blustering days; in hill and mountainous areas; on crooked and sloping roads; on freeway, Grade A, B, and C roads; mixed roads; ordinary, bridge, narrow and transitional roads; sand and dirt-roads; without traffic control measures; night without lighting. (4) Extremely severe RTCs of mountainous area or crooked and sloping roads were most severe in terms of deaths and injures per crash. CONCLUSIONS: Extremely severe RTCs are closely related with environmental factors. Rational road programming, enhancing road establishment and improving road conditions are probably effective measures to reduce the road traffic injuries.

Accidents, Traffic↗

PubMed1988

Review of methods of identification of high caries risk groups and individuals. Fédération Dentaire Internationale Technical Report No. 31.

The search for methods of predicting dental caries activity began during the last century. The purpose of this review was to update the report on methods of caries prediction which resulted from the 1977 workshop, sponsored by the National Institutes of Health, Washington, DC, and also to identify the methods most likely to provide effective prediction of caries risk which should be given high priority in future research. The factors that need to be considered in assessing the value of a method of predicting caries risk are the correlation coefficient between the predictions and the final caries scores and in particular an assessment of the ability of the method to recognize subjects who will develop caries (sensitivity) and to exclude those who will not (specificity). The predictive power of the method should also be known. There is, however, the risk that when predictive tests are applied to a population with decreasing caries prevalence the number classified as false positive could be increased. This may limit the cost-effectiveness of preventive technique. The requirements of a good method of predicting dental caries are that the method should be simple, inexpensive and rapid and should identify subjects who will become diseased and exclude subjects who will remain healthy. To date, a wide variety of factors have been considered in the search for an effective method of predicting caries risk, but only a few have had some success. Certain epidemiological methods have shown reasonable sensitivity but less specificity. Measures in this category include specific indicator surfaces and DMFT increment in the previous year. Among the more useful specific tests have been mutans streptococci and lactobacillus counts and measurement of saliva buffering capacity. Other methods that show some promise include the physical measurement of incipient carious lesions of enamel. The measurement of possible determinants of a multifactorial disease is extremely difficult and regardless of which single method has been tried the authors have usually concluded that it is difficult to develop a reliable method of identifying caries susceptible individuals from the method. To a lesser extent the same conclusions have been applied to methods for identifying risk groups. There does, however, appear to have been little research in which a combination of tests or methods have been used, particularly combinations of tests that involve different scientific disciplines.(ABSTRACT TRUNCATED AT 400 WORDS)

Demography↗

PubMed1986

Reporting radiographic methods in dental epidemiologic and experimental studies.

A number of technical and methodologic factors govern the quality of the radiographic image. The purpose of the present paper is to analyze the attention paid to these factors in epidemiologic studies and clinical trials. The description of radiographic methods in a sample of scientific reports was reviewed. It is concluded that the descriptions are generally sparse. They seem to be of an erratic character, and the data described are not selected according to their significance. Factors governing object coverage, image density and contrast, image geometry, and readability are discussed in relation to the descriptions analyzed. Recommendations for relevant and informative descriptions enabling the reader to evaluate and control the results of an investigation are presented.

Clinical Trials as Topic↗

PubMed2003

Multilocus sequence typing reveals a lack of diversity among Escherichia coli O157:H7 isolates that are distinct by pulsed-field gel electrophoresis.

Escherichia coli O157:H7 is a major cause of foodborne illness in the United States. Pulsed-field gel electrophoresis (PFGE) is the molecular epidemiologic method mostly commonly used to identify food-borne outbreaks. Although PFGE is a powerful epidemiologic tool, it has disadvantages that make a DNA sequence-based approach potentially attractive. Multilocus sequence typing (MLST) analyzes the internal fragments of housekeeping genes to establish genetic relatedness between isolates. We sequenced selected portions of seven housekeeping genes and two membrane protein genes (ompA and espA) of 77 isolates that were diverse by PFGE to determine whether there was sufficient sequence variation to be useful as an epidemiologic tool. There was no DNA sequence diversity in the sequenced portions of the seven housekeeping genes and espA. For ompA, all but five isolates had sequence identical to that of the reference strains. E. coli O157:H7 has a striking lack of genetic diversity in the genes we explored, even among isolates that are clearly distinct by PFGE. Other approaches to identify improved molecular subtyping methods for E. coli 0157:H7 are needed.

DNA, Bacterial↗

PubMed1988

[Polyarterial pathology. Epidemiological aspects].

Polyarterial arteriosclerosis is a problem facing more and more clinicians because of the technical advances in exploration and revascularization methods. Epidemiologic data are rare in this field except for Framingham's study. We are reporting here the results of a French epidemiologic study regarding a representative sample of a group of 11,000 active men and women, with age ranging between 25 and 65 years. Methodologic difficulties cannot be avoided, but a minimal estimation may be expressed: polyarterial pathology represents approximately 15 p. cent of the pathology in each case. Polyarterial pathology is as prevalent as monoarterial pathology with a 10 years delay between the two sexes. Coronary diseases are the most frequent and represent the initial location in two-thirds of the cases. The same risk factors are found, but their chronology is different: more than ever, age is an essential factor since there is a ten years difference. Hyperglycaemia in men, overweight in women are major factors as important as tobacco abuse in men, arterial hypertension and dyslipidemia in both sexes. Finally the type A behavior seems to occupy an even larger role in polyarterial patients of both sexes.

Adult↗