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PubMed1993

Estimating the rate of mother-to-child transmission of HIV. Report of a workshop on methodological issues Ghent (Belgium), 17-20 February 1992. The Working Group on Mother-to-Child Transmission of HIV.

PURPOSE: In the last 8 years, numerous cohort studies have been conducted to estimate the rate of mother-to-child transmission (MTCT) of HIV. Many of these have faced problems in data collection and analysis, making it difficult to compare transmission rates between studies. This workshop on methodological aspects of the study of MTCT of HIV-1 was held in Ghent (Belgium) in February 1992. STUDY SELECTION AND DATA EXTRACTION: Fourteen teams of investigators participated, representing studies from Central (five) and Eastern Africa (three), Europe (two), Haiti (one) and the United States (three). A critical evaluation of the projects was carried out, under four headings: (1) enrollment and follow-up procedures, (2) diagnostic criteria and case definitions, (3) measurement and comparison of MTCT rates and (4) determinants of transmission. RESULTS OF DATA ANALYSIS: Reported transmission rates ranged from 13 to 32% in industrialized countries and from 25 to 48% in developing countries. However, no direct comparisons could be made because methods of calculation differed from study to study. Based on this review, a common methodology was developed. Agreement was reached on definitions of HIV-related signs/symptoms, paediatric AIDS and HIV-related deaths. A classification system of children born to HIV-1-infected mothers according to their probable HIV infection status during the first 15 months of life, allowed the elaboration of a direct method of computation of the transmission rate and of an indirect method for studies with a comparison group of children born to HIV-seronegative mothers. This standardized approach was subsequently applied to selected data sets. CONCLUSIONS: The methodology can now be applied to all studies with sufficient follow-up and comparisons made between transmission rates. This step is essential for assessing determinants of transmission and for the development of a common approach for the evaluation of interventions aimed at reducing or interrupting MTCT of HIV.

Adult↗

PubMed1996

Maximizing oxygen delivery in critically ill patients: a methodologic appraisal of the evidence.

OBJECTIVE: To systemically review the effect of interventions designed to achieve supraphysiologic values of cardiac index, oxygen delivery (DO2), and oxygen consumption (VO2) in critically ill patients. DATA SOURCES: Computerized bibliographic search of published research, citation review of relevant articles, and contact with primary investigators. STUDY SELECTION: We included all randomized clinical trials of adult intensive care unit (ICU) patients that evaluated interventions (fluids, inotropes, and vasoactive drugs) designed to achieve supraphysiologic values of cardiac index, DO2, and/or VO2. Independent review of 64 articles identified seven relevant studies of 1,016 patients. DATA EXTRACTION: We abstracted data on the population, interventions, outcomes, and methodologic quality of the studies by duplicate independent review. Agreement was high (weighed kappa 0.73); differences were resolved by consensus. DATA SYNTHESIS: Targeting therapy to achieve supraphysiologic end points in critically ill patients is associated with a nonstatistically significant trend toward decreased mortality rates (relative risk 0.86, 95% confidence intervals 0.62 to 1.20). For the two studies in which supraphysiologic goals were initiated preoperatively, the relative risk was 0.20 (95% confidence intervals 0.07 to 0.55). This value differed significantly from the combined estimate of the remaining studies, in which the intervention was started after ICU admission (relative risk 0.98, 95% confidence intervals 0.79 to 1.22; p<.01). However, there are several methodologic problems with the primary studies. In no trials were caregivers or outcome assessors blinded to treatment allocation. Only three of seven trials analyzed patients according to the group to which they were allocated. None adequately controlled for cointerventions, and there was considerable crossover between groups (patients in the control group achieved the goals of the intervention group and vice versa). CONCLUSIONS: Interventions designed to achieve supraphysiologic goals of cardiac index, DO2, and VO2 did not significantly reduce mortality rates in all critically ill patients. However, there may be a benefit in those patients in which the therapy is initiated preoperatively. Methodologic limitations weaken the inferences that can be drawn from these studies and preclude any evidence-based clinical recommendations.

Adult↗

PubMed1998

A risk based methodology for assessing the efficacy and priorities for the control of various radiation sources.

There is increasing concern as to whether our limited radiation protection resources are being directed to those radiation sources that produce the greatest return as measured by the cost/risk avoided. Major contributors to this problem include public perception and the lack of an accepted methodology for assigning priorities. Described in this report is a new methodology for assigning these priorities on the basis of cost per risk avoided. This methodology provides several different approaches for comparing the cost effectiveness and priority of these sources, as well as insight into the efficacy of regulatory programs. To demonstrate its application, various radiation sources, selected on the basis of providing insight into problem areas, are evaluated and compared. These resulting assessments show that the current funding and prioritization for the control of radiation sources are, in general, exactly opposite to the risk based efficacy for their control. It is hopeful that the insights resulting from these assessments will assist decision-makers in correcting this situation.

Cost-Benefit Analysis↗

PubMed1994

Methodological considerations in calculation of the trough: peak ratio.

AIM: The Food and Drug Administration in the United States has published guidelines which indicate that a minimum trough: peak ratio of 50-66% is required for the efficacy of an antihypertensive drug to be considered satisfactory in relation to its proposed dosage interval. However, these guidelines do not give any definition of the most appropriate methodology, and published data contain widely disparate values which often reflect methodological inconsistencies. This article attempts to define the principal methodological requirements for the accurate and reproducible measurement of trough and peak antihypertensive effects and for calculation of the trough: peak ratio. PROBLEMS IN CALCULATING THE TROUGH:PEAK RATIO: It is essential to take account of the antihypertensive effect of placebo, otherwise the results may be spurious. Similarly, account must be taken of the closely related circadian variability in blood pressure, which is particularly likely to compromise the interpretation of the peak effect. While the incorporation of placebo in a randomly allocated, crossover design is ideal, there are practical (and ethical) difficulties with this approach. CONCLUSIONS: Provided there is an adequate placebo run-in period (of not less than 4 weeks) and individual patients are studied under carefully standardized conditions, with multiple blood pressure recordings throughout the dose interval, it is possible by means of a sequential, placebo-active treatment design to calculate the trough: peak ratio with acceptable accuracy and reproducibility.

Antihypertensive Agents↗

PubMed2005

Endothelial function and dysfunction. Part I: Methodological issues for assessment in the different vascular beds: a statement by the Working Group on Endothelin and Endothelial Factors of the European Society of Hypertension.

An enormous number of studies in the last two decades have been devoted to investigating the role of the endothelium in cardiovascular diseases. Nonetheless, the optimal methodology for investigating the multifaceted aspects of endothelial dysfunction is still under debate. Biochemical markers, molecular genetic tests and invasive and non-invasive tools with and without pharmacological and physiological stimuli have been introduced. Furthermore newer pharmacological tools have been proposed. However, the application of these methodologies should fulfil a number of requirements in order to provide conclusive answers in this area of research. Thus, the most relevant methodological issues in the research on endothelial function and dysfunction are summarized in this paper.

Endothelium, Vascular↗

PubMed2002

A new method for estimating probability of survival in pediatric patients using revised TRISS methodology based on age-adjusted weights.

BACKGROUND: TRISS methodology estimates probability of survival (P(s)) based on coefficients derived largely from adult data. We developed a novel pediatric age-specific method to estimate P(s). METHODS: The Pennsylvania Trauma Outcome Study database was queried for pediatric patients injured between 1993 and 1996 (n = 9730). P(s) derived from the Pediatric Age-Adjusted TRISS (PAAT) methodology was generated using our Age-Specific Pediatric Trauma Score and Injury Severity Score with corresponding weights. A test data set of 7138 pediatric patients entered in the Pennsylvania Trauma Outcome Study from 1997 to 1999 was used to compute an expected number of survivors for PAAT, TRISS, and ASCOT (A Severity Characteristic of Trauma). Observed and expected survival were compared for blunt injured patients, for head injured patients, and by age category. RESULTS: PAAT showed no significant difference between observed and expected survival. TRISS and ASCOT significantly underestimated overall survival: across age groups, for blunt injuries, for head injuries, and for patients whose P(s) was less than 91%. CONCLUSION: PAAT offers a more reliable methodology than TRISS and ASCOT for comparing pediatric trauma outcomes.

Adolescent↗

PubMed1978

A new planning methodology to assess the impact of the health care system on health status.

This article summarizes a new methodology recently developed by the Rand Corporation which permits health planners to assess the impact of the local health care system on the health status of the population. The methodology, in algorithm form, should assist health planners in developing objectives and actions related to the occurrence of selected health status indicators and should be amenable to health care interventions. Emphasis has been placed on developing a simplified, approximate analysis that health planners will find both feasible and effective. No detailed mathematic analyses are called for. The data required are, in most instances, readily obtainable. The algorithm is a methodology by which HSAs can investigate determinants of health status, identify breakdowns in the health care system, and specify needed improvements in the system. The goal of these algorithms is to assist HSAs to obtain valid and sufficiently detailed data that will provide a basis for monitoring breakdowns in the health care system and to improve planning decisions aimed at preventing such breakdowns. This should, in turn, affect population health status in the planning area.

Breast Neoplasms↗

PubMed1997

Clinical quality measurement. Comparing chart review and automated methodologies.

OBJECTIVES: This study investigates the use of data from automated systems within a large managed care plan to create indicators of clinical quality. METHODS: Measures from the first year of Health Plan Employer Data and Information Set, HEDIS 2.0, are used to compare chart review and automated analysis methodologies. The contributions of various data systems in creating clinical quality measures are evaluated. RESULTS: Chart review data usually are better for creating clinical quality indicators, although the level of agreement between the two methodologies often is quite high. Computerized patient record systems are found to be the most reliable automated data source, and automated claims are found to be the least reliable. This study's findings suggest that automated encounter systems may provide relatively reliable data. CONCLUSIONS: Managed care plans may not want to rely on automated data alone for clinical quality measurement. The results reported here support the use of combined methodologies such as the "hybrid" method, which utilizes both automated and chart-review data.

Bias↗

PubMed1997

Quantitative methods in research on complementary and alternative medicine. A methodological manifesto. NIH Office of Alternative Medicine.

OBJECTIVES: This article summarizes the deliberations of the Quantitative Methods Working Group convened by the National Institutes of Health (NIH) in support of the NIH Office of Alternative Medicine. METHODS: The working group was charged with identifying methods of study design and data analysis that can be applied to empirical research on complementary and alternative medicine. This charge was broad and inclusive and addressed the evaluation of alternative therapies, the investigation of the basic science of complementary medical systems, studies of health promotion and disease prevention, and health services research. RESULTS: The working group produced a "methodological manifesto," a summary list of seven recommended methodological guidelines for research on alternative medicine. These recommendations emphasize the robustness of existing research methods and analytic procedures despite the substantive unconventionality of alternative medicine. CONCLUSIONS: Contrary to the assertions of many researchers and alternative practitioners, established methodologies (eg, experimental trials, observational epidemiology, social survey research) and data-analytic procedures (eg, analysis of variance, logistic regression, multivariate modeling techniques) are quite satisfactory for addressing the majority of study questions related to alternative medicine, from clinical research on therapeutic efficacy to basic science research on mechanisms of pathogenesis and recovery.

Clinical Trials as Topic↗

PubMed1999

Choices of methodology in pharmacoeconomics studies.

OBJECTIVES: The goal of this paper is to evaluate the comparative value of economic methodologies in assessing the benefit of a new cytoprotective agent (amifostine) delivered before cisplatin/cyclophosphamide in the treatment of ovarian cancer. BACKGROUND: Data from a randomized controlled multinational multicenter ovarian cancer trial were used as the basis for a retrospective pharmacoeconomic analysis. Trial results demonstrated amifostine had no significant effect on oncolytic efficacy, but side effect profiles improved for febrile neutropenia (absolute risk reduction [ARR] 11%), neurotoxicity (ARR 11%), and nephrotoxicity (ARR 26%). Although, the methodology most commonly used in this type of analysis is cost utility (CU), we investigated a "willingness to pay" (WTP) approach. RESEARCH DESIGN SUBJECTS: Four pharmacy managers were given an informal telephone interview to assess their preferences. Two managers understood, and preferred, the CU data. The others, who had no education or training on CU principles, preferred WTP data. All managers understood the outputs from WTP studies. RESULTS/MEASURES: WTP for reductions in febrile neutropenia, neurotoxicity, and nephrotoxicity were collected from 50 healthy volunteers and measured against the cost of delivering the new therapy. Results revealed WTP values of $141 per year for reductions in febrile neutropenia, $86 per year for reductions in neurotoxicity, and $71 per year for reductions in nephrotoxicity. The base case analysis showed that amifostine was cost neutral ($350 net cost, CI = -850 to +1551). CONCLUSIONS: The results were well-received by decision-makers. This manager survey illustrates that the methodologic choice should be determined not only by the nature of the comparison, but also by the stakeholder the data is meant to influence.

Amifostine↗

PubMed1998

Methodologic issues in low back pain research in primary care.

STUDY DESIGN: Narrative review and discussion of the selected literature. OBJECTIVES: To discuss some important methodologic challenges in low back pain research in primary care. SUMMARY OF BACKGROUND DATA: Many methodologic problems must be confronted when conducting low back pain research. Some of these problems are back pain specific or specific to the primary care setting. METHODS: Methodologic problems related to four research issues will be discussed: study designs, definition of low back pain, determinants of low back pain, and outcome assessment. RESULTS: Two fundamentally different study designs are frequently used in low back pain research, namely observational studies and experimental studies. The definition of low back pain is typically restricted to a highly variables self-reported symptom, the sensation of pain in the back. There clearly is a need for an evidence-based classification system for low back pain. Because a tenable theoretical framework is lacking, it is difficult to know which determinants of low back pain should be quantified. Low back pain studies focus usually on health-related quality-of-life outcome parameters. The identification of the minimum clinically relevant changes for the most important outcome instruments needs further consideration. CONCLUSIONS: In years to come, low back pain researchers are challenged to overcome some of these (and other) problems to enhance the quality of low back pain research in primary care.

Clinical Trials as Topic↗

PubMed1986

Q methodology: relevance and application to nursing research.

Q methodology is a unique research tradition with an epistemology and technique that is much more than the Q-sort form of instrumentation used to gather data. Developed to explore and understand the richness of human subjectivity, Q methodology, with its emphasis on the individual, is relevant to many substantive areas of scientific inquiry within nursing. This article presents an overview of the technique and delineates special considerations for implementing Q methodological investigations.

Adult↗

PubMed1997

Constructivism: a naturalistic methodology for nursing inquiry.

This article will explore the philosophical underpinnings of the constructivist research paradigm. Despite its increasing popularity in evaluative health research studies there is limited recognition of constructivism in popular research texts. Lincoln and Guba's original approach to constructivist methodology is outlined and a detailed framework for nursing research is offered. Fundamental issues and concerns surrounding this methodology are debated and differences between method and methodology are highlighted.

Data Interpretation, Statistical↗

PubMed2005

Applying clinical significance methodology to alcoholism treatment trials: determining recovery outcome status with individual- and population-based measures.

BACKGROUND: The current analysis applies clinical significance methodology to alcoholism treatment outcome research using data available from Project MATCH. Because of its high internal validity and its inclusion of multiple measures assessing multiple outcome dimensions, MATCH was considered an ideal study to explore the utility of this methodology. METHODS: Data reported here are from a total of 1,726 participants enrolled in either aftercare (n = 774) or outpatient (n = 952) arms of the study. First, a cutoff score was determined differentiating functional versus dysfunctional status on three outcome measures: percent days abstinent (PDA), mean drinks per drinking day (DDD) and negative consequences of alcohol use. Second, the reliable change in pre- to post-treatment scores on these three measures was calculated. RESULTS: The results reported herein support the importance of distinguishing between statistical and clinical significance of outcomes. During three months post-treatment, approximately one-half of the treated patients were "recovered" (i.e., both functional and reliably changed) with respect to both PDA (i.e., 51%) and negative consequences of drinking (i.e., 47%); however, only about one-third of individuals remained recovered throughout the full one-year follow-up period (i.e., 33% on PDA and 35% on negative consequences). These individual-based change outcomes compared similarly to a population-based indicator of heavy drinking. Alternatively, only about one-quarter of participants were recovered using two distinct criteria for mean DDD (i.e., 23-29%), and even fewer participants remained recovered on mean DDD over the full one-year follow-up period (i.e., about 14-18%). CONCLUSIONS: Based on study limitations, more work is required to make clinical significance methodology practically useful to alcoholism treatment trials including more precise definitions of functional status and relative change as well as better interpretation of the inter-relationship between multiple measures assessing multiple outcome domains.

Adult↗

PubMed2004

Advances in statistical methodology and their application in critical care.

PURPOSE OF REVIEW: To review some of the major advances in statistical methodology of the past two decades and their application to investigations in critical care. RECENT FINDINGS: The introduction of new technologies and the ready availability of advanced computer resources have led to significant developments in statistical methodology. These include the development of computationally intensive methods, improved methods for modeling correlated outcome data, and new methods for handling missing data. Although many of these tools are available in standard statistical software, they remain underutilized in the medical literature. SUMMARY: By becoming familiar with advances in statistical methodology, researchers and clinicians can enhance collaboration with their statistical colleagues, toward the goal of better study design and analysis.

Critical Care↗

PubMed2005

Common methodological flaws in economic evaluations.

Economic evaluations are increasingly being used by those bodies such as government agencies and managed care groups that make decisions about the reimbursement of health technologies. However, several reviews of economic evaluations point to numerous deficiencies in the methodology of studies or the failure to follow published methodological guidelines. This article, written for healthcare decision-makers and other users of economic evaluations, outlines the common methodological flaws in studies, focussing on those issues that are likely to be most important when deciding on the reimbursement, or guidance for use, of health technologies. The main flaws discussed are: (i) omission of important costs or benefits; (ii) inappropriate selection of alternatives for comparison; (iii) problems in making indirect comparisons; (iv) inadequate representation of the effectiveness data; (v) inappropriate extrapolation beyond the period observed in clinical studies; (vi) excessive use of assumptions rather than data; (vii) inadequate characterization of uncertainty; (viii) problems in aggregation of results; (ix) reporting of average cost-effectiveness ratios; (x) lack of consideration of generalizability issues; and (xi) selective reporting of findings. In each case examples are given from the literature and guidance is offered on how to detect flaws in economic evaluations.

Cost-Benefit Analysis↗

PubMed2004

Methodologic issues in research on religion and health.

This study examines several methodologic issues in research on religion and health, including the measurement of the concept of religion, research designs, sampling, and statistical controls for assessing the "net" effects of religion on health outcomes. It briefly discusses differences in analytical perspectives that have contributed to the debate about the effects of religion on health. The authors review some of the methodologic problems of past research in this area of study and address what needs to be done to enhance the quality of the research. The authors conclude that the research methodology used in studies of religion and health has improved over time and that it continues to do so.

Epidemiologic Methods↗

PubMed2001

Advanced database methodology for the Collation of Connectivity data on the Macaque brain (CoCoMac).

The need to integrate massively increasing amounts of data on the mammalian brain has driven several ambitious neuroscientific database projects that were started during the last decade. Databasing the brain's anatomical connectivity as delivered by tracing studies is of particular importance as these data characterize fundamental structural constraints of the complex and poorly understood functional interactions between the components of real neural systems. Previous connectivity databases have been crucial for analysing anatomical brain circuitry in various species and have opened exciting new ways to interpret functional data, both from electrophysiological and from functional imaging studies. The eventual impact and success of connectivity databases, however, will require the resolution of several methodological problems that currently limit their use. These problems comprise four main points: (i) objective representation of coordinate-free, parcellation-based data, (ii) assessment of the reliability and precision of individual data, especially in the presence of contradictory reports, (iii) data mining and integration of large sets of partially redundant and contradictory data, and (iv) automatic and reproducible transformation of data between incongruent brain maps. Here, we present the specific implementation of the 'collation of connectivity data on the macaque brain' (CoCoMac) database (http://www.cocomac.org). The design of this database addresses the methodological challenges listed above, and focuses on experimental and computational neuroscientists' needs to flexibly analyse and process the large amount of published experimental data from tracing studies. In this article, we explain step-by-step the conceptual rationale and methodology of CoCoMac and demonstrate its practical use by an analysis of connectivity in the prefrontal cortex.

Animals↗