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PubMed2003

Heterogeneity in regional notification patterns and its impact on aggregate national case notification data: the example of measles in Italy.

BACKGROUND: A monthly time series of measles case notifications exists for Italy from 1949 onwards, although its usefulness is seriously undermined by extensive under-reporting which varies strikingly between regions, giving rise to the possibility of significant distortions in epidemic patterns seen in aggregated national data. RESULTS: A corrected national time series is calculated using an algorithm based upon the approximate equality between births and measles cases; under-reporting estimates are presented for each Italian region, and poor levels of reporting in Southern Italy are confirmed. CONCLUSION: Although an order of magnitude larger, despite great heterogeneity between regions in under-reporting and in epidemic patterns, the shape of the corrected national time series remains close to that of the aggregated uncorrected data. This suggests such aggregate data may be quite robust to great heterogeneity in reporting and epidemic patterns at the regional level. The corrected data set maintains an epidemic pattern distinct from that of England and Wales.

Algorithms↗
PubMed2004

When clinical description becomes statistical prediction.

This article reconsiders the issue of clinical versus statistical prediction. The term clinical is widely used to denote 1 pole of 2 independent axes: the observer whose data are being aggregated (clinician/expert vs. lay) and the method of aggregating those data (impressionistic vs. statistical). Fifty years of research suggests that when formulas are available, statistical aggregation outperforms informal, subjective aggregation much of the time. However, these data have little bearing on the question of whether, or under what conditions, clinicians can make reliable and valid observations and inferences at a level of generality relevant to practice or useful as data to be aggregated statistically. An emerging body of research suggests that clinical observations, just like lay observations, can be quantified using standard psychometric procedures, so that clinical description becomes statistical prediction.

Cognition↗
PubMed2025

Benchmark for Quantitative Global and Redox Proteomics Analysis by Combining Protein-Aggregation Capture and Data Independent Acquisition.

Oxidative damage plays a critical role in various diseases including cardiovascular and neurological disorders. Thiol redox reactions, acting as oxidative stress sensors, influence protein structure and function. Redox proteomics, based on the differential alkylation of cysteine sites followed by mass spectrometry, enables the comprehensive analysis of thiol redox status in cells and tissues. However, these approaches require extensive sample manipulation and are not compatible with data-independent acquisition techniques. Here, we introduce PACREDOX, an innovative strategy based on protein aggregation capture (PAC), and demonstrate its compatibility with library-free DIA. Compared with traditional methods such as FASILOX, PACREDOX reduces preparation time and costs while maintaining thiol and proteome coverage. To enable library-free DIA, we corrected in silico spectral libraries in DIA-NN using experimental retention time data from methylthiolated-Cys peptides. PACREDOX with DIA was benchmarked against FASILOX in a myocardial infarction model, yielding the same biological insights, while enhancing peptide and protein coverage. Our results underscore the potential and efficiency of this methodology for studying oxidative damage. Overall, PACREDOX offers an automatable, high-throughput, and cost-effective strategy for redox proteomics.

Proteomics↗
PubMed2000

[Effect of dapsone on survival in HIV infected patients: a meta- analysis of finished trials].

BACKGROUND: The aim of the study was to estimate the effect of dapsone on survival in HIVinfected patients. METHOD: The method was a metaanalysis. Data searches used MEDLINE, AIDS TRIALS, and AIDS DRUGS databases from 1983 to January 1996, clinical trials registries of appropriate collaborative research groups, abstract books of International Conferences on AIDS and infectious diseases between 1988 and 1996, references listed within selected articles and active experts in HIV infection. Were considered as eligible: randomized clinical trials, conducted in adults, with one arm evaluating dapsone as prophylactic agent for Pneumocystis Carinii Pneumonia (PCP). Each primary investigator was asked to provide the most recent aggregated study data by completing a standardized questionnaire and to provide files of individual patient data whenever possible. RESULTS: Overall, 17 trials (4343 patients) were eligible for the metaanalysis. The analysis of all available aggregated data included 16 trials (4267 patients) and showed no deleterious effect of dapsone on survival: OR=1.11, 95% Confidence Interval (CI)=0.961.29. There was no evidence of heterogeneity among studies (p=0.50). The analysis of individual data included 10 trials (3115 patients) (OR for aggregated data from those trials=1.10, CI=0. 931.29) and confirmed the absence of deleterious effect of dapsone on survival: stratified Hazard Ratio=1.12, CI=0.991.27 (logrank test: p=0.08). In this subsample, there was evidence of a deleterious effect of dapsone used as secondary prophylaxis. However, this result did not remain when the trial reporting the greatest negative effect of dapsone on survival was omitted. CONCLUSION: Dapsone may be used safely as a primary prophylactic regimen for PCP or toxoplasmosis. However, no definitive recommendation can be made for the use of dapsone as secondary PCP prophylaxis.

AIDS-Related Opportunistic Infections↗
PubMed1984

Analysis and aggregation of CMHC outcome data in a statewide evaluation system: a case report.

Several potential procedures for simplifying and aggregating treatment outcome data from CMHCs differing in outcome instrumentation and methodology are presented and illustrated. Their respective advantages, disadvantages, and suitability for various purposes are explored, and considerations in selecting a particular method or technique are discussed. Findings obtained by using these techniques to analyze treatment outcome data from nine CMHCs over a three-year period are presented. Selected results highlighting the relative importance of methodological, subject, status, diagnostic, treatment process, and service delivery variables are presented. The implications of these findings for the problems and limitations inherent in cross-CMHC comparisons are illustrated and discussed. Applications for aggregated and non-aggregated analyses are suggested, and an illustration using aggregated outcome data to identify potential predictor variables for positive outcomes is presented along with differences for various outcome groupings.

Community Mental Health Services↗
PubMed1992

Assay of embryo-derived platelet activating factor (EDPAF) by an equine platelet aggregation assay: Preliminary data concerning its presence in bovine embryo culture media.

This study was designed to establish a sensitive bioassay for bovine platelet-activating factor (PAF), to determine if the bovine embryo secretes PAF in vitro and if PAF release is correlated with the embryo's potential to establish a pregnancy. Using an equine platelet aggregation assay, lipid extracted culture media from 33 Day-7 embryos (individually cultured for 18 hours in 1 ml of Ham's F10 containing 0.4% BSA at 37 degrees C in an air: CO2 mixture of 95:5 prior to their transfer to recipient heifers) and from control media (n=15, Ham's F10+0.4% BSA incubated simultaneously without embryos) were investigated. In addition, culture media from Day-6 (n=6) and Day-1 (2-cell, n=12) bovine embryos that were cultured for 4 hours but not transferred were examined. The aggregation assay proved to be sensitive to 5 pg of PAF. The assay proved to be specific, since the PAF receptor antagonist SRI 63-441 inhibited platelet aggregation induced by culture media in dosages comparable to aggregation induced by synthetic PAF18. From the 15 Day-7 embryos that established a pregnancy 2 contained measurable amounts of PAF in their culture media. No PAF was detected in the culture media from 13 embryos that succeeded, in the 18 embryos that failed to establish a pregnancy, or in the control media. One of 6 Day-6 embryos and 3 of 12 Day-1 (2-cell) embryos secreted detectable amounts of PAF into the culture media. Although the results indicate that some bovine embryos release PAF or a PAF-like substance in vitro, PAF measurements in the culture medium seem not to be a suitable method for the evaluation of bovine embryos prior to transfer.

Journal Article↗
PubMedDate not supplied

The Wisconsin outcomes experience: baseline outcomes of the WISCVPR Web-based Outcomes Project.

PURPOSE: The measurement of outpatient cardiac rehabilitation (OCR) outcomes is now considered common practice. Unfortunately, because of the costs involved in purchasing outcomes tracking software, many programs are not able to participate in pooled outcomes analysis and benchmarking. The purpose of this report is to describe the current OCR outcomes data in the state of Wisconsin using a web-based model for outcomes data collection, data pooling, and benchmarking. METHODS: Participating OCR programs collected individual patient outcomes according to protocols developed by the Wisconsin Society for Cardiovascular and Pulmonary Rehabilitation's Outcomes Committee. Programs analyzed their data quarterly and submitted the values to a database via an Internet web site. Aggregate outcomes data from 34 programs were collected over a 27-month period. RESULTS: Aggregate data representing 5235 OCR patients are presented. The mean age for the men was 64 +/- 5 years (N = 3612; 69% of the sample). The mean age for the women was 67 +/- 6 years (N = 1623; 31% of the sample). The completion rate for the group was 89% (95%CI, 86-91). The average number of OCR sessions per patient was 22 +/- 6 over 9 +/- 3 weeks. The clinical and behavioral outcomes for this sample ranged from a median value of 88% for the percentage of patients meeting the blood pressure goal (95%CI, 87-91) to less than 5% for the percentage of patients receiving formal psychosocial counseling (95%CI, 0). The major cardiovascular event rate was 0.17 per 10,000 patient-hours. CONCLUSION: This report describes the baseline OCR outcomes obtained via a state affiliate-sponsored outcomes management program. These data show that this model of OCR outcomes measurement, collection, and interprogram analysis produces data that are comparable with those of published, controlled studies. Determining baseline characteristics of OCR outcomes data will be important in the development of benchmarks and best practice guidelines.

Aged↗
PubMed2006

Distributed data processing for public health surveillance.

BACKGROUND: Many systems for routine public health surveillance rely on centralized collection of potentially identifiable, individual, identifiable personal health information (PHI) records. Although individual, identifiable patient records are essential for conditions for which there is mandated reporting, such as tuberculosis or sexually transmitted diseases, they are not routinely required for effective syndromic surveillance. Public concern about the routine collection of large quantities of PHI to support non-traditional public health functions may make alternative surveillance methods that do not rely on centralized identifiable PHI databases increasingly desirable. METHODS: The National Bioterrorism Syndromic Surveillance Demonstration Program (NDP) is an example of one alternative model. All PHI in this system is initially processed within the secured infrastructure of the health care provider that collects and holds the data, using uniform software distributed and supported by the NDP. Only highly aggregated count data is transferred to the datacenter for statistical processing and display. RESULTS: Detailed, patient level information is readily available to the health care provider to elucidate signals observed in the aggregated data, or for ad hoc queries. We briefly describe the benefits and disadvantages associated with this distributed processing model for routine automated syndromic surveillance. CONCLUSION: For well-defined surveillance requirements, the model can be successfully deployed with very low risk of inadvertent disclosure of PHI--a feature that may make participation in surveillance systems more feasible for organizations and more appealing to the individuals whose PHI they hold. It is possible to design and implement distributed systems to support non-routine public health needs if required.

Bioterrorism↗
PubMed2001

The World Survey of Cardiac Pacing and Implantable Cardioverter Defibrillators: calendar year 1997--Europe.

The registry of the European Working Group on Cardiac Pacing (EWGCP) is based on the European Pacemaker Identification Card originally designed in July 1978. National registration centers collect the local data and send aggregated annual data to the EWGCP. For 1997, data were obtained from 2,887 hospitals in 20 European countries representing a population of 568 million. Across all participating countries, the median value for all implanted pacemakers was 378 per million population. For initial pacemaker implants, the median value was 290 per million population. Single chamber atrial pacing was important in Denmark, the Netherlands, Poland, Slovak Republic, Spain, and Sweden for the treatment of sick sinus syndrome. Dual chamber pacing accounted for < 50% of initial implants in only 5 of 14 countries for atrioventricular block, and in only 3 of 15 countries for sick sinus syndrome. In 7 of 15 countries, unipolar ventricular leads were used in > or = 50% of cases. In 6 of 14 countries, there was > 15% use of unipolar atrial leads. Nine of 13 countries frequently used atrial active-fixation leads. For the 1997 survey, ICD data were obtained from 16 countries. The total number of ICDs per million population was a median value of 14. Initial ICD implants per million population was 11. Only 3 of 16 countries implanted a total of 30 or more ICDs per million population. Pacing and ICD practices were dependent on the availability of medical and technical resources and influenced by economic constraints inherent in health care administration and insurance coverage patterns.

Aged↗
PubMed1989

Data source automation: new technology for the management of patient-generated test results.

Self-monitoring of blood glucose is widely accepted by patients today, but its usefulness to clinicians has been seriously limited by our inability to interpret the patient-generated data. It is difficult or impossible to make optimal use of hand-kept diaries, no matter how compulsively kept. Patterns elude us, summaries are inaccurate, and large blocks of data are almost entirely ignored. To remedy these problems, data source automation--the automatic recording of data at their site of origin--is being applied to diabetes. Meters will measure blood glucose and memorize the result, date, and time of day. One system even allows the patient to record insulin dosage, exercise, and diet. The advantage of these systems lies in their potential for data management. Recognition of patterns of blood glucose concentration, easy longitudinal comparison of data, and aggregation of large data bases are all facilitated by computerized manipulation of the stored data. In-hospital use of glucose meters can have better documented quality control. It is possible to communicate data to physicians by telephone modem. Effective use of these systems, though, requires convenient software; and their acceptance in actual clinical practice must be demonstrated. But data management capabilities, as they are refined and brought into common use, could significantly improve diabetic management.

Autoanalysis↗
PubMed2004

Impacts of informal caregiver availability on long-term care expenditures in OECD countries.

OBJECTIVE: To quantify the effects of informal caregiver availability and public funding on formal long-term care (LTC) expenditures in developed countries. DATA SOURCE/STUDY SETTING: Secondary data were acquired for 15 Organization for Economic Cooperation and Development (OECD) countries from 1970 to 2000. STUDY DESIGN: Secondary data analysis, applying fixed- and random-effects models to time-series cross-sectional data. Outcome variables are inpatient or home heath LTC expenditures. Key explanatory variables are measures of the availability of informal caregivers, generosity in public funding for formal LTC, and the proportion of the elderly population in the total population. DATA COLLECTION/EXTRACTION METHOD: Aggregated macro data were obtained from OECD Health Data, United Nations Demographic Yearbooks, and U.S. Census Bureau International Data Base. PRINCIPAL FINDINGS: Most of the 15 OECD countries experienced growth in LTC expenditures over the study period. The availability of a spouse caregiver, measured by male-to-female ratio among the elderly, is associated with a $28,840 (1995 U.S. dollars) annual reduction in formal LTC expenditure per additional elderly male. Availability of an adult child caregiver, measured by female labor force participation and full-time/part-time status shift, is associated with a reduction of $310 to $3,830 in LTC expenditures. These impacts on LTC expenditure vary across countries and across time within a country. CONCLUSIONS: The availability of an informal caregiver, particularly a spouse caregiver, is among the most important factors explaining variation in LTC expenditure growth. Long-term care policies should take into account behavioral responses: decreased public funding in LTC may lead working women to leave the labor force to provide more informal care.

Adult↗
PubMed1988

Multivariate diallel analysis of ethanol withdrawal symptoms in mice.

Mice from five highly inbred strains were crossed in a complete diallel design. Five hundred and fifty-five offspring were given a liquid diet containing ethanol as their sole food source for 9 days in an attempt to induce dependence. At 6 hr postwithdrawal on day 10, the mice were given a battery of physiological and behavioral measures designed to assess the symptoms of withdrawal. Littermate data were aggregated separately by sex and the aggregate litter mean data was employed in a multivariate extension of Hayman's diallel analysis. Hypothesis sums of squares and cross-products were tested against pooled-within-cell sums of squares and cross-products using Wilk's lambda as a criterion. For each sex, a highly significant additive effect was found, with some evidence for dominance effects as well, suggesting the raw materials are present for successful genetic selection. There was some evidence for dominance effects as well, but no evidence for maternal and other reciprocal effects was found for the set of seven measures. Composites derived from the additive and general dominance hypotheses correlation matrices and error correlation matrix were compared with a composite index currently being used in a multivariate selection study of ethanol dependence. Total ethanol consumption during the exposure period was positively correlated with low dependence between strains, and negatively correlated with measures of low dependence within cells.

Alcohol Drinking↗
PubMed1993

Aggregation bias and the use of regression in evaluating models of human performance.

Regression analyses are increasingly being used to provide confirmatory evidence for models of human performance. The amount of information made available to judge these models is reduced because clearly established standards in the techniques of performing and reporting regression analyses are lacking. This paper addresses two primary problems in regression analysis: aggregation of data and the aggregation of variables into composite models. We provide examples of the misuse of regression techniques and recommend ways in which the amount of information made available to evaluate the model being tested can be maximized in analysis and reporting.

Bias↗
PubMed2001

Comparison of four composite deprivation indices and two census variables in predicting dental caries in 12-year-old children in Wales.

OBJECTIVE: To compare the explanatory power of four composite indices of social economic status in their ability to predict dental caries experience. BASIC RESEARCH DESIGN: A secondary analysis of Welsh BASCD survey data using ward aggregated dental data, census variables and composite measures of deprivation. CLINICAL SETTING: Examinations took place in schools. PARTICIPANTS: All 12-year-old children examined in the 1996/97 survey. MAIN OUTCOME MEASURES: The explanatory variables were Jarman index, Welsh Underprivileged Area score (WUPA), Carstairs and Townsend indices and the outcome measure was mean DMFT. RESULTS: The amount of the mean DMFT explained by the explanatory variables ranged from 62.9% with Welsh Underprivileged Area score (WUPA) in Bro Taf Health Authority to 4.2% with the Jarman index in Dyfed-Powys health authority. Of the constituent parts of the composite variables only the percentage with no car appeared in the 'top three' variables in all but one of six models. CONCLUSIONS: The composite indices explained very different amounts of the variation in mean DMFT between the different health authorities. It would be unwise to rely on any one as a method of predicting which sections of the population would be likely to have dental disease.

Child↗
PubMedDate not supplied

Relative fees and the utilization of physicians' services in Canada.

STUDY QUESTION: The study objective is to estimate the relationship between changes in the relative fee physicians receive for a procedure and the utilization of the procedure. DATA SOURCES/STUDY SETTING: The study uses claims-based, procedure-specific, quarterly, aggregate utilization data for physicians in three specialties and four provinces in Canada for the period 1977-1989. STUDY DESIGN: The unit of analysis is an individual procedure. Multi-variate regression methods for cross-sectional/times-series data are applied to estimate the utilization-fee relationship while controlling for supply- and demand-side determinants of utilization. PRINCIPAL FINDINGS: There is no evidence of a strong, uniform utilization response among the 11 procedures analyzed. The results include a mixture of significant and non-significant fee coefficients, and among the significant coefficients, a mixture of signs is observed. The results are consistent with utility-maximizing behaviour by physicians rather than with profit-maximizing behaviour. CONCLUSIONS: The fact that the direction and degree of the utilization effect associated with changing fees is procedure-specific has direct implications for our ability to develop effective policies to modify physician behaviour that are based primarily on financial incentives, particularly those based on manipulating fees. The study also highlights the limitations of analyses based on aggregate data and suggests methodological approaches that have potential to overcome some of these limitations to fill gaps in our current knowledge.

Canada↗
PubMed1999

Simultaneous analysis of individual and aggregate responses in psychometric data using multilevel modeling.

Psychometric data on risk perceptions are often collected using the method developed by Slovic, Fischhoff, and Lichtenstein, where an array of risk issues are evaluated with respect to a number of risk characteristics, such as how dreadful, catastrophic or involuntary exposure to each risk is. The analysis of these data has often been carried out at an aggregate level, where mean scores for all respondents are compared between risk issues. However, this approach may conceal important variation between individuals, and individual analyses have also been performed for single risk issues. This paper presents a new methodological approach using a technique called multilevel modelling for analysing individual and aggregated responses simultaneously, to produce unconditional and unbiased results at both individual and aggregate levels of the data. Two examples are given using previously published data sets on risk perceptions collected by the authors, and results between the traditional and new approaches compared. The discussion focuses on the implications of and possibilities provided by the new methodology.

Humans↗
PubMed2003

The effect of choosing different units of analysis when estimating risk of presence of dental caries in the primary dentition.

BACKGROUND: Data on caries are usually collected with the tooth surface or the tooth as the unit, but subsequently analysed by aggregating the data at the level of the individual. AIMS: To evaluate how different units of analysis may affect the result of the statistical analyses in a study of the association between deciduous dental caries and a set of risk factors. METHOD: 293 children (mean age: 7.5 yrs) from two primary schools in Dar es Salaam, Tanzania were examined. Thus the study design was cross-sectional. Logistic regression analysis was used to determine the association between caries experience and nutritional status, socioeconomic background, and microbiological and salivary characteristics using the subject, the tooth, and the tooth surface as unit of analysis, allowing for the fact that teeth and surfaces within the same individual must be considered non-independent. RESULTS: When aggregated data were used, point estimates were larger in some instances. The precision of the estimates increased considerably when the tooth as compared to the individual was used as the unit of analysis. No or limited gain in precision was obtained when the tooth surface as compared to the tooth was used as unit of analysis. CONCLUSIONS: The choice of unit of analysis may strongly influence the result of the statistical analyses and thus the conclusion of an investigation.

Buffers↗