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Dive into the research topics where Elizabeth A. Cook is active.

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Featured researches published by Elizabeth A. Cook.


American Journal of Epidemiology | 2009

The Aftermath of Hip Fracture: Discharge Placement, Functional Status Change, and Mortality

Suzanne E. Bentler; Li Liu; Maksym Obrizan; Elizabeth A. Cook; Kara B. Wright; John Geweke; Elizabeth A. Chrischilles; Claire E. Pavlik; Robert B. Wallace; Robert L. Ohsfeldt; Michael P. Jones; Gary E. Rosenthal; Fredric D. Wolinsky

The authors prospectively explored the consequences of hip fracture with regard to discharge placement, functional status, and mortality using the Survey on Assets and Health Dynamics Among the Oldest Old (AHEAD). Data from baseline (1993) AHEAD interviews and biennial follow-up interviews were linked to Medicare claims data from 1993-2005. There were 495 postbaseline hip fractures among 5,511 respondents aged >or=69 years. Mean age at hip fracture was 85 years; 73% of fracture patients were white women, 45% had pertrochanteric fractures, and 55% underwent surgical pinning. Most patients (58%) were discharged to a nursing facility, with 14% being discharged to their homes. In-hospital, 6-month, and 1-year mortality were 2.7%, 19%, and 26%, respectively. Declines in functional-status-scale scores ranged from 29% on the fine motor skills scale to 56% on the mobility index. Mean scale score declines were 1.9 for activities of daily living, 1.7 for instrumental activities of daily living, and 2.2 for depressive symptoms; scores on mobility, large muscle, gross motor, and cognitive status scales worsened by 2.3, 1.6, 2.2, and 2.5 points, respectively. Hip fracture characteristics, socioeconomic status, and year of fracture were significantly associated with discharge placement. Sex, age, dementia, and frailty were significantly associated with mortality. This is one of the few studies to prospectively capture these declines in functional status after hip fracture.


Medical Care | 2007

Hospital episodes and physician visits: the concordance between self-reports and medicare claims.

Fredric D. Wolinsky; Thomas R. Miller; Hyonggin An; John Geweke; Robert B. Wallace; Kara B. Wright; Elizabeth A. Chrischilles; Li Liu; Claire B. Pavlik; Elizabeth A. Cook; Robert L. Ohsfeldt; Kelly K. Richardson; Gary E. Rosenthal

Background:Health services use typically is examined using either self-reports or administrative data, but the concordance between the 2 is not well established. Objective:We evaluated the concordance of hospital and physician utilization data from self-reports and claims data, and identified factors associated with disagreement. Methods:We performed a secondary analysis on linked observational and administrative data. A national sample of 4310 respondents who were 70 years old or older at their baseline interviews was used. Self-reported and Medicare claims-based hospital episodes and physician visits for 12 months before baseline were examined. Kappa statistics were used to evaluate concordance, and multivariable multinomial logistic regression was used to identify factors associated with overreporting (self-reports > claims), underreporting (self-reports < claims), and concordant-reporting (self-reports ∼ claims). Results:The concordance of hospital episodes was high (κ = 0.767 for the 2 × 2 comparison of none vs. some and κ = 0.671 for the 6 × 6 comparison of none, 1, …, 4, or 5 or more), but concordance for physician visits was low (κ = 0.255 for the 2 × 2 comparison of none versus some and κ = 0.351 for the 14 × 14 comparison of none, 1, ..., 12, and 13 or more). Multivariable multinomial logistic regression indicated that over-, under-, and concordant-reporting of hospital episodes was significantly associated with gender, alcohol consumption, arthritis, cancer, heart disease, psychologic problems, lower body functional limitations, self-rated health, and depressive symptoms. Over-, under-, and concordant-reporting of physician visits were significantly associated with age, gender, race, living alone, veteran status, private health insurance, arthritis, cancer, diabetes, hypertension, heart disease, lower body functional limitations, and poor memory. Conclusions:Concordance between self-reported and claims-based hospital episodes was high, but concordance for physician visits was low. Factors significantly associated with bidirectional (over- and underreporting) and unidirectional (over- or underreporting) error patterns were detected. Therefore, caution is advised when drawing conclusions based on just one physician visit data source.


Journals of Gerontology Series A-biological Sciences and Medical Sciences | 2009

Recent Hospitalization and the Risk of Hip Fracture Among Older Americans

Fredric D. Wolinsky; Suzanne E. Bentler; Li Liu; Maksym Obrizan; Elizabeth A. Cook; Kara B. Wright; John Geweke; Elizabeth A. Chrischilles; Claire E. Pavlik; Robert L. Ohsfeldt; Michael P. Jones; Kelly K. Richardson; Gary E. Rosenthal; Robert B. Wallace

BACKGROUND We identified hip fracture risks in a prospective national study. METHODS Baseline (1993-1994) interview data were linked to Medicare claims for 1993-2005. Participants were 5,511 self-respondents aged 70 years and older and not in managed Medicare. ICD9-CM 820.xx (International Classification of Diseases, 9th Edition, Clinical Modification) codes identified hip fracture. Participants were censored at death or enrollment into managed Medicare. Static risk factors included sociodemographic, socioeconomic, place of residence, health behavior, disease history, and functional and cognitive status measures. A time-dependent marker reflecting postbaseline hospitalizations was included. RESULTS A total of 495 (8.9%) participants suffered a postbaseline hip fracture. In the static proportional hazards model, the greatest risks involved age (adjusted hazard ratios [AHRs] of 2.01, 2.82, and 4.91 for 75-79, 80-84, and > or =85 year age groups vs those aged 70-74 years; p values <.001), sex (AHR = 0.45 for men vs women; p < .001), race (AHRs of 0.37 and 0.46 for African Americans and Hispanics vs whites; p values <.001 and <.01), body mass (AHRs of 0.40, 0.77, and 1.73 for obese, overweight, and underweight vs normal weight; p values <.001, <.05, and <.01), smoking status (AHRs = 1.49 and 1.52 for current and former smokers vs nonsmokers; p values <.05 and <.001), and diabetes (AHR = 1.99; p < .001). The time-dependent recent hospitalization marker did not alter the static model effect estimates, but it did substantially increase the risk of hip fracture (AHR = 2.51; p < .001). CONCLUSIONS Enhanced discharge planning and home care for non-hip fracture hospitalizations could reduce subsequent hip fracture rates.


Chiropractic & Manual Therapies | 2007

The use of chiropractors by older adults in the United States

Fredric D. Wolinsky; Li Liu; Thomas R. Miller; John Geweke; Elizabeth A. Cook; Barry R. Greene; Kara B. Wright; Elizabeth A. Chrischilles; Claire E. Pavlik; Hyonggin An; Robert L. Ohsfeldt; Kelly K. Richardson; Gary E. Rosenthal; Robert B. Wallace

BackgroundIn a nationally representative sample of United States Medicare beneficiaries, we examined the extent of chiropractic use, factors associated with seeing a chiropractor, and predictors of the volume of chiropractic use among those having seen one.MethodsWe performed secondary analyses of baseline interview data on 4,310 self-respondents who were 70 years old or older when they first participated in the Survey on Assets and Health Dynamics Among the Oldest Old (AHEAD). The interview data were then linked to their Medicare claims. Multiple logistic and negative binomial regressions were used.ResultsThe average annual rate of chiropractic use was 4.6%. During the four-year period (two years before and two years after each respondents baseline interview), 10.3% had one or more visits to a chiropractor. African Americans and Hispanics, as well as those with multiple depressive symptoms and those who lived in counties with lower than average supplies of chiropractors were much less likely to use them. The use of chiropractors was much more likely among those who drank alcohol, had arthritis, reported pain, and were able to drive. Chiropractic services did not substitute for physician visits. Among those who had seen a chiropractor, the volume of chiropractic visits was lower for those who lived alone, had lower incomes, and poorer cognitive abilities, while it was greater for the overweight and those with lower body limitations.ConclusionChiropractic use among older adults is less prevalent than has been consistently reported for the United States as a whole, and is most common among Whites, those reporting pain, and those with geographic, financial, and transportation access.


BMC Health Services Research | 2010

Defining emergency department episodes by severity and intensity: A 15-year study of Medicare beneficiaries

Brian Kaskie; Maksym Obrizan; Elizabeth A. Cook; Michael P. Jones; Li Liu; Suzanne E. Bentler; Robert B. Wallace; John Geweke; Kara B. Wright; Elizabeth A. Chrischilles; Claire E. Pavlik; Robert L. Ohsfeldt; Gary E. Rosenthal; Fredric D. Wolinsky

BackgroundEpisodes of Emergency Department (ED) service use among older adults previously have not been constructed, or evaluated as multi-dimensional phenomena. In this study, we constructed episodes of ED service use among a cohort of older adults over a 15-year observation period, measured the episodes by severity and intensity, and compared these measures in predicting subsequent hospitalization.MethodsWe conducted a secondary analysis of the prospective cohort study entitled the Survey on Assets and Health Dynamics among the Oldest Old (AHEAD). Baseline (1993) data on 5,511 self-respondents ≥70 years old were linked to their Medicare claims for 1991-2005. Claims then were organized into episodes of ED care according to Medicare guidelines. The severity of ED episodes was measured with a modified-NYU algorithm using ICD9-CM diagnoses, and the intensity of the episodes was measured using CPT codes. Measures were evaluated against subsequent hospitalization to estimate comparative predictive validity.ResultsOver 15 years, three-fourths (4,171) of the 5,511 AHEAD participants had at least 1 ED episode, with a mean of 4.5 episodes. Cross-classification indicated the modified-NYU severity measure and the CPT-based intensity measure captured different aspects of ED episodes (kappa = 0.18). While both measures were significant independent predictors of hospital admission from ED episodes, the CPT measure had substantially higher predictive validity than the modified-NYU measure (AORs 5.70 vs. 3.31; p < .001).ConclusionsWe demonstrated an innovative approach for how claims data can be used to construct episodes of ED care among a sample of older adults. We also determined that the modified-NYU measure of severity and the CPT measure of intensity tap different aspects of ED episodes, and that both measures were predictive of subsequent hospitalization.


BMC Geriatrics | 2009

A 12-year prospective study of stroke risk in older Medicare beneficiaries

Fredric D. Wolinsky; Suzanne E. Bentler; Elizabeth A. Cook; Elizabeth A. Chrischilles; Li Liu; Kara B. Wright; John Geweke; Maksym Obrizan; Claire E. Pavlik; Robert L. Ohsfeldt; Michael P. Jones; Robert B. Wallace; Gary E. Rosenthal

Background5.8 M living Americans have experienced a stroke at some time in their lives, 780K had either their first or a recurrent stroke this year, and 150K died from strokes this year. Stroke costs about


Clinical Infectious Diseases | 2015

Increased Statin Prescribing Does Not Lower Pneumonia Risk

Linnea A. Polgreen; Elizabeth A. Cook; John M. Brooks; Yuexin Tang; Philip M. Polgreen

66B annually in the US, and also results in serious, long-term disability. Therefore, it is prudent to identify all possible risk factors and their effects so that appropriate intervention points may be targeted.MethodsBaseline (1993–1994) interview data from the nationally representative Survey on Assets and Health Dynamics among the Oldest Old (AHEAD) were linked to 1993–2005 Medicare claims. Participants were 5,511 self-respondents ≥ 70 years old. Two ICD9-CM case-identification approaches were used. Two approaches to stroke case-identification based on ICD9-CM codes were used, one emphasized sensitivity and the other emphasized specificity. Participants were censored at death or enrollment into managed Medicare. Baseline risk factors included sociodemographic, socioeconomic, place of residence, health behavior, disease history, and functional and cognitive status measures. A time-dependent marker reflecting post-baseline non-stroke hospitalizations was included to reflect health shocks, and sensitivity analyses were conducted to identify its peak effect. Competing risk, proportional hazards regression was used.ResultsPost-baseline strokes occurred for 545 (9.9%; high sensitivity approach) and 374 (6.8%; high specificity approach) participants. The greatest static risks involved increased age, being widowed or never married, living in multi-story buildings, reporting a baseline history of diabetes, hypertension, or stroke, and reporting difficulty picking up a dime, refusing to answer the delayed word recall test, or having poor cognition. Risks were similar for both case-identification approaches and for recurrent and first-ever vs. only first-ever strokes. The time-dependent health shock (recent hospitalization) marker did not alter the static model effect estimates, but increased stroke risk by 200% or more.ConclusionThe effect of our health shock marker (a time-dependent recent hospitalization indicator) was large and did not mediate the effects of the traditional risk factors. This suggests an especially vulnerable post-hospital transition period from adverse effects associated with both their underlying health shock (the reasons for the recent hospital admission) and the consequences of their treatments.


Medical Care | 2014

Geographic variation in statin use for complex acute myocardial infarction patients: evidence of effective care?

John M. Brooks; Elizabeth A. Cook; Cole G. Chapman; Puttarin Kulchaitanaroaj; Ea Chrischelles; S Welch; Jennifer G. Robinson

BACKGROUND Investigators have attributed protective effects of statins against pneumonia and other infections. However, these reports are based on observational data where treatments are not assigned randomly. We aimed to determine if the protective effects of statins against pneumonia are due to nonrandom treatment assignment. METHODS We built a cohort consisting of 124 695 Medicare beneficiaries diagnosed with an acute myocardial infarction (AMI) for which we had complete claims data. We considered patients who survived at least 30 days post-AMI (full sample), or who survived for 1 year post-AMI (survivors). First, we used ordinary least squares (OLS) and logit models to determine if receiving a statin was protective against pneumonia. Second, to control for nonrandom treatment assignment, we performed an instrumental variables analysis using geographic treatment rates as an instrument. All models included patient demographics, medications, diagnoses, length of hospital stay, and out-of-pocket drug costs as covariates. Our outcome measure was a pneumonia diagnosis during the 1 year following AMI. RESULTS A total of 76 994 patients (61.9%) filled a statin prescription, and 19 078 (15.3%) were diagnosed with pneumonia. Using OLS, the statin coefficient was -0.016 (P < .001), indicating that statins are associated with a reduction in pneumonia. Using instrumental variables, we find that statin prescriptions are not associated with a reduction in pneumonia. For the full sample, statin coefficients ranged from -0.001 to -0.01 (P > .6). CONCLUSIONS For patients with AMI, the protective effect of statins against pneumonia is most likely the result of nonrandom treatment assignment (ie, a healthy-user bias).


Journal of Midwifery & Women's Health | 2014

Formulating evidence-based guidelines for certified nurse-midwives and certified midwives attending home births

Elizabeth A. Cook; Melissa D. Avery; Melissa H. Frisvold

Background:Despite strong evidence to designate statin use for secondary prevention of cardiovascular disease (CVD) as “effective care,” observational studies show that many patients with CVD do not receive statins. This suggests that statin prescribing decisions for complex CVD patients are preference sensitive. Objectives:The aim of this study was to evaluate local area variation in statin prescribing for subsets of complex patients after acute myocardial infarction (AMI) to assess whether current statin prescribing patterns fit profiles of either “effective care” or “preference-sensitive care.” Research Design and Subjects:This was a retrospective cohort study of 124,618 Medicare patients with fee-for-service parts A, B, and D benefits who were hospitalized with AMI in 2008 or 2009 with no evidence of AMI in the past 12 months. Measures:Patient complexity was defined by the presence of diabetes, heart failure, and chronic kidney disease in the year before AMI admission. Local area practice styles for “no statin,” “lower-intensity statins,” and “high-intensity statins” were measured using the driving area for clinical care method. Statin prescribing rates for complex patient subsets were contrasted across patients grouped by local areas practice styles. Results:Lower statin treatment rates were observed for patients with complex conditions, especially among those with heart failure. However, substantial local area variation in statin prescribing is observed across all complex patient groups. Conclusions:Despite guidelines promoting the use of statins for secondary prevention for CVD patients, substantial local area variation suggests that patient and provider beliefs and preferences weigh heavily in statin prescribing decisions.


Journal of Clinical Epidemiology | 2013

What is the Effect of Area Size When Using Local Area Practice Style as an Instrument

John M. Brooks; Yuexin Tang; Cole G. Chapman; Elizabeth A. Cook; Elizabeth A. Chrischilles

INTRODUCTION Implementing national home birth guidelines for certified nurse-midwives (CNMs) and certified midwives (CMs) in the United States may facilitate a common approach to safe home birth practices. Guidelines are evidence-based care recommendations for specified clinical situations that can be modified by individual providers to meet specific client needs. METHODS Following a review of home birth guidelines from multiple countries, a set of home birth practices guidelines for US CNMs/CMs was drafted. Fifteen American Midwifery Certification Board, Inc. (AMCB)-certified home birth midwives who participate in the American College of Nurse-Midwives (ACNM) home birth electronic mailing list considered the use of such a document in their practices and reviewed and commented on the guidelines. RESULTS The proposed guidelines addressed client screening, informed consent, antepartum care, routine intrapartum care, obstetric complications and hospital transports, postpartum care, neonatal care, gynecologic care, primary care, peer reviews, recordkeeping, and physician collaboration. The reviewers had varying assessments as to whether the guidelines reflected international standards and current best evidence. The primary concern expressed was that an adoption of national guidelines could compromise provider autonomy. DISCUSSION Incorporation of evidence-based guidelines is an ACNM standard and was recommended by the Home Birth Consensus Summit. Clinical practice guidelines are informed by current evidence and supported by experts in a given discipline. Implementation of guidelines ensures optimal patient care and is becoming increasingly central to reimbursement and to medicolegal support. A set of practice guidelines based on current best evidence and internationally accepted standards was developed and reviewed by an interested group of US CNMs/CMs. Further discussion with home birth midwives and other stakeholders about the development and implementation of home birth guidelines is needed, especially in light of this projects finding of less support for national home birth guidelines among the reviewers subsequent to versus prior to their review of the draft guidelines.

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John M. Brooks

University of South Carolina

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