Author
Martha S. Bayliss
Other affiliations: Harvard University
Bio: Martha S. Bayliss is an academic researcher from Tufts Medical Center. The author has contributed to research in topics: Population & SF-36. The author has an hindex of 24, co-authored 55 publications receiving 5684 citations. Previous affiliations of Martha S. Bayliss include Harvard University.
Topics: Population, SF-36, AL amyloidosis, Migraine, Quality of life
Papers published on a yearly basis
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Journal Article•
TL;DR: Results suggest that the two summary measures may be useful in most studies and that their empiric validity, relative to the best SF-36 scale, will depend on the application.
Abstract: Physical component summary (PCS) and mental component summary (MCS) measures make it possible to reduce the number of statistical comparisons and thereby the role of chance in testing hypotheses about health outcomes. To test their usefulness relative to a profile of eight scores, results were compared across 16 tests involving patients (N = 1,440) participating in the Medical Outcomes Study. Comparisons were made between groups known to differ at a point in time or to change over time in terms of age, diagnosis, severity of disease, comorbid conditions, acute symptoms, self-reported changes in health, and recovery from clinical depression. The relative validity (RV) of each measure was estimated by a comparison of statistical results with those for the best scales in the same tests. Differences in RV among scales from the Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36) were consistent with those in previous studies. One or both of the summary measures were significant for 14 of 15 differences detected in multivariate analyses of profiles and detected differences missed by the profile in one test. Relative validity coefficients ranged from .20 to .94 (median, .79) for PCS in tests involving physical criteria and from .93 to 1.45 (median, 1.02) for MCS in tests involving mental criteria. The MCS was superior to the best SF-36 scale in three of four tests involving mental health. Results suggest that the two summary measures may be useful in most studies and that their empiric validity, relative to the best SF-36 scale, will depend on the application. Surveys offering the option of analyzing both a profile and psychometrically based summary measures have an advantage over those that do not.
1,818 citations
TL;DR: The IRT model estimated for a 'pool' of items from widely used measures of headache impact was useful in constructing an efficient, reliable, and valid 'static' short form (HIT-6) for use in screening and monitoring patient outcomes.
Abstract: Background: Migraine and other severe headaches can cause suffering and reduce functioning and productivity. Patients are the best source of information about such impact. Objective: To develop a new short form (HIT-6) for assessing the impact of headaches that has broad content coverage but is brief as well as reliable and valid enough to use in screening and monitoring patients in clinical research and practice. Methods: HIT-6 items were selected from an existing item pool of 54 items and from 35 items suggested by clinicians. Items were selected and modified based on content validity, item response theory (IRT) information functions, item internal consistency, distributions of scores, clinical validity, and linguistic analyses. The HIT-6 was evaluated in an Internet-based survey of headache sufferers (n = 1103) who were members of America Online (AOL). After 14 days, 540 participated in a follow-up survey. Results: HIT-6 covers six content categories represented in widely used surveys of headache impact. Internal consistency, alternate forms, and test–retest reliability estimates of HIT-6 were 0.89, 0.90, and 0.80, respectively. Individual patient score confidence intervals (95%) of app. ±5 were observed for 88% of all respondents. In tests of validity in discriminating across diagnostic and headache severity groups, relative validity (RV) coefficients of 0.82 and 1.00 were observed for HIT-6, in comparison with the Total Score. Patient-level classifications based in HIT-6 were accurate 88.7% of the time at the recommended cut-off score for a probability of migraine diagnosis. HIT-6 was responsive to self-reported changes in headache impact. Conclusions: The IRT model estimated for a 'pool' of items from widely used measures of headache impact was useful in constructing an efficient, reliable, and valid 'static' short form (HIT-6) for use in screening and monitoring patient outcomes.
984 citations
TL;DR: During the study period, elderly and poor chronically ill patients had worse physical health outcomes in HMOs than in FFS systems; mental health outcomes varied by study site and patient characteristics.
Abstract: Objective. —To compare physical and mental health outcomes of chronically ill adults, including elderly and poor subgroups, treated in health maintenance organization (HMO) and fee-for-service (FFS) systems. Study Design. —A 4-year observational study of 2235 patients (18 to 97 years of age) with hypertension, non—insulin-dependent diabetes mellitus (NIDDM), recent acute myocardial infarction, congestive heart failure, and depressive disorder sampled from HMO and FFS systems in 1986 and followed up through 1990. Those aged 65 years and older covered under Medicare and low-income patients (200% of poverty) were analyzed separately. Setting and Participants. —Offices of physicians practicing family medicine, internal medicine, endocrinology, cardiology, and psychiatry, in HMO and FFS systems of care. Types of practices included both prepaid group (72% of patients) and independent practice association (28%) types of HMOs, large multispecialty groups, and solo or small, single-specialty practices in Boston, Mass, Chicago, III, and Los Angeles, Calif. Outcome Measures. —Differences between initial and 4-year follow-up scores of summary physical and mental health scales from the Medical Outcomes Study 36-ltem Short-Form Health Survey (SF-36) for all patients and practice settings. Results. —On average, physical health declined and mental health remained stable during the 4-year follow-up period, with physical declines larger for the elderly than for the nonelderly (P Conclusions. —During the study period, elderly and poor chronically ill patients had worse physical health outcomes in HMOs than in FFS systems; mental health outcomes varied by study site and patient characteristics. Current health care plans should carefully monitor the health outcomes of these vulnerable subgroups.
546 citations
TL;DR: The approach described combines an overarching phenomenological theoretical framework with grounded theory data collection and analysis methods to yield PRO items and scales that have content validity.
Abstract: Recently published articles have described criteria to assess qualitative research in the health field in general, but very few articles have delineated qualitative methods to be used in the development of Patient-Reported Outcomes (PROs). In fact, how PROs are developed with subject input through focus groups and interviews has been given relatively short shrift in the PRO literature when compared to the plethora of quantitative articles on the psychometric properties of PROs. If documented at all, most PRO validation articles give little for the reader to evaluate the content validity of the measures and the credibility and trustworthiness of the methods used to develop them. Increasingly, however, scientists and authorities want to be assured that PRO items and scales have meaning and relevance to subjects. This article was developed by an international, interdisciplinary group of psychologists, psychometricians, regulatory experts, a physician, and a sociologist. It presents rigorous and appropriate qualitative research methods for developing PROs with content validity. The approach described combines an overarching phenomenological theoretical framework with grounded theory data collection and analysis methods to yield PRO items and scales that have content validity.
411 citations
TL;DR: Successful treatment of CHC improved HQL as measured by both CHC‐specific and generic measures of functional health and well being, as well as changes in HQL among treatment responders.
316 citations
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Book•
23 Sep 2019TL;DR: The Cochrane Handbook for Systematic Reviews of Interventions is the official document that describes in detail the process of preparing and maintaining Cochrane systematic reviews on the effects of healthcare interventions.
Abstract: The Cochrane Handbook for Systematic Reviews of Interventions is the official document that describes in detail the process of preparing and maintaining Cochrane systematic reviews on the effects of healthcare interventions.
21,235 citations
Book•
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TL;DR: It is possible to design n=O(Nlog(m)) nonadaptive measurements allowing reconstruction with accuracy comparable to that attainable with direct knowledge of the N most important coefficients, and a good approximation to those N important coefficients is extracted from the n measurements by solving a linear program-Basis Pursuit in signal processing.
Abstract: Suppose x is an unknown vector in Ropfm (a digital image or signal); we plan to measure n general linear functionals of x and then reconstruct. If x is known to be compressible by transform coding with a known transform, and we reconstruct via the nonlinear procedure defined here, the number of measurements n can be dramatically smaller than the size m. Thus, certain natural classes of images with m pixels need only n=O(m1/4log5/2(m)) nonadaptive nonpixel samples for faithful recovery, as opposed to the usual m pixel samples. More specifically, suppose x has a sparse representation in some orthonormal basis (e.g., wavelet, Fourier) or tight frame (e.g., curvelet, Gabor)-so the coefficients belong to an lscrp ball for 0
18,609 citations
TL;DR: Twenty cross-sectional and longitudinal tests of empirical validity previously published for the 36-item short-form scales and summary measures were replicated for the 12-item Physical Component Summary and the12-item Mental Component Summary, including comparisons between patient groups known to differ or to change in terms of the presence and seriousness of physical and mental conditions.
Abstract: Regression methods were used to select and score 12 items from the Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36) to reproduce the Physical Component Summary and Mental Component Summary scales in the general US population (n=2,333). The resulting 12-item short-form (SF-12) achieved multiple R squares of 0.911 and 0.918 in predictions of the SF-36 Physical Component Summary and SF-36 Mental Component Summary scores, respectively. Scoring algorithms from the general population used to score 12-item versions of the two components (Physical Components Summary and Mental Component Summary) achieved R squares of 0.905 with the SF-36 Physical Component Summary and 0.938 with SF-36 Mental Component Summary when cross-validated in the Medical Outcomes Study. Test-retest (2-week)correlations of 0.89 and 0.76 were observed for the 12-item Physical Component Summary and the 12-item Mental Component Summary, respectively, in the general US population (n=232). Twenty cross-sectional and longitudinal tests of empirical validity previously published for the 36-item short-form scales and summary measures were replicated for the 12-item Physical Component Summary and the 12-item Mental Component Summary, including comparisons between patient groups known to differ or to change in terms of the presence and seriousness of physical and mental conditions, acute symptoms, age and aging, self-reported 1-year changes in health, and recovery for depression. In 14 validity tests involving physical criteria, relative validity estimates for the 12-item Physical Component Summary ranged from 0.43 to 0.93 (median=0.67) in comparison with the best 36-item short-form scale. Relative validity estimates for the 12-item Mental Component Summary in 6 tests involving mental criteria ranged from 0.60 to 107 (median=0.97) in relation to the best 36-item short-form scale. Average scores for the 2 summary measures, and those for most scales in the 8-scale profile based on the 12-item short-form, closely mirrored those for the 36-item short-form, although standard errors were nearly always larger for the 12-item short-form.
14,793 citations
TL;DR: Reading a book as this basics of qualitative research grounded theory procedures and techniques and other references can enrich your life quality.
13,415 citations
TL;DR: This document summarizes current capabilities, research and operational priorities, and plans for further studies that were established at the 2015 USGS workshop on quantitative hazard assessments of earthquake-triggered landsliding and liquefaction.
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4,975 citations