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Biomedical subjects

P Diehr

Publications and source records attributed to P Diehr.

At least 19 recordsLinked to original sources
PubMed2004

Lost working days, productivity, and restraint use among occupants of motor vehicles that crashed in the United States.

BACKGROUND: In 2001, 6.3 million passengers were involved in motor vehicle crashes. This study aimed to determine the number of work days lost as a result of motor vehicle crashes and factors that influenced people's return to work. METHODS: This was a retrospective, population based cohort study of occupants in motor vehicles involved in crashes from the 1993-2001 Crashworthiness Data System produced by the National Highway Traffic Safety Administration. The sample population of people aged 18-65 years included two groups: occupants who survived and were working before the crash and occupants who were injured fatally and were estimated to have been working before the crash. Multivariate linear regression was used to analyze the impact of restraint use and injury type on return to work. RESULTS: Overall, 30.1% of occupants of vehicles that crashed missed one or more days of work. A crash resulted in a mean 28.0 (95% confidence interval 15.8 to 40.1) days lost from work, including losses associated with fatalities. The 2.1 million working occupants of vehicles that crashed in 2001 lost a total of 60 million days of work, resulting in annual productivity losses of over $7.5 billion (2964 to 12 075). Unrestrained vehicle occupants accounted for $5.6 billion in lost productivity. CONCLUSIONS: Motor vehicle crashes result in large and potentially preventable productive losses that are mostly attributable to fatal injuries.

Accidents, Traffic↗
PubMed2004

A prospective study of household smoking bans and subsequent cessation related behaviour: the role of stage of change.

OBJECTIVE: To assess the degree to which smokers living with a full household ban on smoking change their cessation related behaviour. DESIGN, SETTING, AND PARTICIPANTS: Prospective cohort study; follow up of a population based cohort of 1133 smokers, identified from a 1997 telephone survey of adult Oregonians. After a median of 21 months, 565 were located and reinterviewed. MAIN OUTCOME MEASURES: Quit attempts, time until relapse, and smoking cessation, defined as seven day and 90 day sustained abstinence at follow up. RESULTS: A full ban at baseline was associated with a doubling of the odds of a subsequent quit attempt (odds ratio (OR) = 2.0, 95% confidence interval (CI), 1.0 to 3.9). Among respondents in the preparation stage at baseline (intention to quit in the next month with a quit attempt in the previous year), a full ban was associated with a lower relapse rate (hazard ratio = 0.5 (95% CI, 0.2 to 0.9)), while for those in precontemplation/contemplation (no intention to quit or intention to quit within the next six months, respectively), there was no significant association between full ban and relapse rate. For respondents in preparation, those with a full ban had over four times the odds of being in cessation for seven or more days before the follow up call (OR = 4.4 (1.1 to 18.7)), but for those in precontemplation/contemplation, full bans were unrelated to cessation. CONCLUSIONS: Full household bans may facilitate cessation among smokers who are preparing to quit by increasing quit attempts. They may also prolong time to relapse among those smokers.

Adolescent↗
PubMed2002

Longitudinal investigation of depression outcomes in primary care in six countries: the LIDO study. Functional status, health service use and treatment of people with depressive symptoms.

BACKGROUND: Screening surveys of depressive symptoms were conducted among primary care patients at six sites in different countries. The LIDO Study was designed to assess quality of life and economic correlates of depression and its treatment in culturally diverse primary health care settings. This paper describes: (1) the association between depressive symptoms and functional status, global health-related quality of life (QoL), and use of general health services across different cultural settings; and (2) among subjects with depressive symptoms, the factors associated with recent treatment for depression. METHODS: Subjects aged 18 to 75 were recruited from participating primary care facilities in Be'er Sheva (Israel), Porto Alegre (Brazil), Melbourne (Australia), Barcelona (Spain), St Petersburg (Russian Federation) and Seattle (USA). Depressive symptoms were measured using the CES-D. Also administered were the SF-12, global questions on QoL, selected demographic and social measures, and questions on recent treatment for depression, use of health care services, and lost workdays. RESULTS: A total of 18,489 patients were screened, of whom 37% overall (range 24-55%) scored > or = 16 on the CES-D and 28% (range 17-42%) scored > or = 20. Overall, 13% reported current treatment for depression (range 4 to 23%). Patients with higher depressive symptom scores had worse health, functional status, QoL, and greater use of health services across all sites. Among those with a CES-D score > or = 16, subjects reporting treatment for depression were more likely than those reporting no treatment to be dissatisfied with their health (except in St Petersburg), and to have higher depressive symptom scores. CONCLUSIONS: Higher depressive symptom scores in primary care patients were consistently associated with poorer health, functional status and QoL, and increased health care use, but not with demographic variables. The likelihood of treatment for depression was associated with perceptions of health, as well as severity of the depression.

Adult↗
PubMed2001

Cluster analysis and patterns of findings on cranial magnetic resonance imaging of the elderly: the Cardiovascular Health Study.

OBJECTIVE: To characterize patterns of findings on cranial magnetic resonance imaging (MRI) of the elderly using a statistical technique called cluster analysis. SUBJECTS AND METHODS: The Cardiovascular Health Study is a population-based, longitudinal study of 5888 people 65 years and older. Of these, 3230 underwent cranial MRI scans, which were coded for presence of infarcts and grades for white matter, ventricles, and sulci. Cluster analysis separated participants into 5 clusters based solely on patterns of MRI findings. Participants comprising each cluster were contrasted with respect to cardiovascular risk factors and clinical manifestations. RESULTS: One cluster was low on all the MRI findings (normal) and another was high on all of them (complex infarcts). Another cluster had evidence for infarcts alone (simple infarcts), whereas the last 2 clusters lacked infarcts, one having enlarged ventricles and sulci (atrophy) and the other having prominent white matter changes and enlarged ventricles (leukoaraiosis). Factors that distinguished these clusters in a discriminant analysis were age, sex, several measures of hypertension, internal carotid artery wall thickness, smoking, and prevalent claudication before the MRI. The atrophy group had the highest percentage of men and the normal group had the lowest. Cognitive and motor performance also differed across clusters, with the atrophy cluster performing better than may have been expected. CONCLUSIONS: These MRI patterns identified participants with different vascular disease risk factors and clinical manifestations. Results of these exploratory analyses warrant consideration in other populations of elderly people. Such patterns may provide clues about the pathophysiology of structural brain changes in the elderly.

Aged↗
PubMed2001

Probabilities of transition among health states for older adults.

GOAL: To estimate the probabilities of transition among self-rated health states for older adults, and examine how they vary by age and sex. METHODS: We used self-rated health (excellent, very good, good, fair, poor, dead) collected in two longitudinal studies of older adults (mean age 75) to estimate the probability of transition in 2 years. We used the estimates to project future health for selected cohorts. FINDINGS: These older adults were most likely to be in the same health state 2 years later, but a substantial proportion changed in both directions. Transition probabilities varied by initial health state, age and sex. Men were more likely than women to transition to excellent or dead. Women were more likely than men to transition to good or fair health. Although women aged 70 will have more years of life and more years of healthy life than men, they also have more years of unhealthy life, and the proportion of remaining life that is healthy is slightly higher for men. When observed and predicted years of healthy life (YHL) were compared in various subgroups, the YHL of persons with less favorable baseline characteristics was lower than predicted, and vice-versa. Differences, however, were small (about 5%). CONCLUSIONS: These transition probability estimates can be used to predict the future health of individuals or groups as a function of current age, sex, and self-rated health.

Age Factors↗
PubMed2001

Patterns of self-rated health in older adults before and after sentinel health events.

OBJECTIVES: To describe and compare patterns of change in self-rated health for older adults before death and before and after stroke, myocardial infarction, congestive heart failure, cardiac procedure, hospital admission for cancer, and hip fracture. DESIGN: "Event cohort," measuring time in months before and after the event. SETTING: Four U.S. communities. PARTICIPANTS: 5888 participants in the Cardiovascular Health Study (CHS), sampled from Medicare rolls and followed up to 8 years. Mean age at baseline was 73. MEASUREMENTS: Self-rated health, including a category for death, assessed at 6-month intervals, and ascertainment of events. METHODS: We examined the percentage that was healthy each month in the 5 years before death and in the 2 years before and after the other events, and compared the patterns to a "no event" group and to one another, using graphs and linear regression. RESULTS: For people who died, health status declined slowly until about 9 months before death, when it dropped steeply. Comparing persons equally far from death, health was unrelated to age, but men and whites were healthier than women and blacks. Health for other events declined before the event, dropped steeply at the event, showed some recovery, and then declined further after the event. About 65% to 80% of the subjects were healthy 2 years before their event, but only 35% to 65% were healthy two years afterwards. Patterns were similar although less extreme for the "no event" group. CONCLUSION: Visualizing trajectories of health helps us understand how serious health events changes health. Conclusions about change must be drawn with care because of a variety of possible biases. We have described the trajectories in detail. Work is now needed to explain, predict, and possibly prevent such changes in health.

Aged↗
PubMed2001

Transforming self-rated health and the SF-36 scales to include death and improve interpretability.

BACKGROUND: Most measures of health-related quality of life are undefined for people who die. Longitudinal analyses are often limited to a healthier cohort (survivors) that cannot be identified prospectively, and that may have had little change in health. OBJECTIVE: To develop and evaluate methods to transform a single self-rated health item (excellent to poor; EVGGFP) and the physical component score of the SF-36 (PCS) to new variables that include a defensible value for death. METHODS: Using longitudinal data from two large studies of older adults, health variables were transformed to the probability of being healthy in the future, conditional on the current observed value; death then has the value of 0. For EVGGFP, the new transformations were compared with some that were published earlier, based on different data. For the PCS, how well three different transformations, based on different definitions of being healthy, discriminated among groups of patients, and detected change in time were assessed. RESULTS: The new transformation for EVGGFP was similar to that published previously. Coding the 5 categories as 95, 90, 80, 30, and 15, and coding dead as 0 is recommended. The three transformations of the PCS detected group differences and change at least as well as the standard PCS. CONCLUSION: These easily interpretable transformed variables permit keeping persons who die in the analyses. Using the transformed variables for longitudinal analyses of health when deaths occur, either for secondary or primary analysis, is recommended. This approach can be applied to other measures of health.

Aged↗
PubMed2001

Selected statistical issues in group randomized trials.

Group randomized trials (GRTs) in public health research typically use a small number of randomized groups with a relatively large number of participants per group. Two fundamental features characterize GRTs: a positive correlation of outcomes within a group, and the small number of groups. Appropriate consideration of these fundamental features is essential for design and analysis. This paper presents the fundamental features of GRTs and the importance of considering these features in design and analysis. It also reviews and contrasts the main analytic methods proposed for GRTs, emphasizing the assumptions required to make these methods valid and efficient. Also discussed are various design issues, along with guidelines for choosing among them. A real data example illustrates these issues and methods.

Humans↗
PubMed2001

The effect of neighborhood-based community organizing: results from the Seattle Minority Youth Health Project.

OBJECTIVE: To evaluate the effect of a community mobilization and youth development strategy to prevent drug abuse, violence, and risky sexual activity. DATA SOURCES/STUDY SETTING: Primary surveys of youth, parents, and key neighborhood leaders were carried out at baseline (1994) and at the end of the intervention period (1997). The study took place in four intervention and six control neighborhoods in Seattle. STUDY DESIGN: The study was designed as a randomized controlled trial with neighborhood as the unit of randomization. The intervention consisted of a paid community organizer in each neighborhood who recruited a group of residents to serve as a community action board. Key variables included perceptions of neighborhood mobilization by youth, parents, and key neighborhood leaders. DATA COLLECTION/EXTRACTION METHODS: Youth surveys were self-administered during school hours. Parent and neighborhood leader surveys were conducted over the phone by trained interviewers. PRINCIPAL FINDINGS: Survey results showed that mobilization increased to the same degree in both intervention and control neighborhoods with no evidence of an overall intervention effect. There did appear to be a relative increase in mobilization in the neighborhood with the highest level of intervention activity. CONCLUSION: This randomized study failed to demonstrate a measurable effect for a community mobilization intervention. It is uncertain whether the negative finding was because of a lack of strength of the interventions or problems detecting intervention effects using individual-level closed-end surveys.

Adolescent↗
PubMed2000

Quality adjusted life years in older adults with depressive symptoms and chronic medical disorders.

We used data from a 4-year prospective study of 2,558 primary care patients age 65 and older in a large staff model health maintenance organization to examine the association of clinically significant depressive symptoms and eight other chronic medical conditions with quality adjusted life years (QALYs). We developed linear regression models to examine the association of clinically significant depressive symptoms as defined by a score of 16 or greater on the Center for Epidemiological Studies Depression Scale and eight common chronic medical disorders at baseline with QALYs over the 4-year study period. Estimates of QALYs were derived from Quality of Well-Being Scale scores at baseline, at 2-year follow-up, and at 4-year follow-up. Individuals with clinically significant depressive symptoms at baseline had significantly lower QALYs over the 4-year study period than nondepressed subjects, even after adjusting for differences in age, gender, and the eight other chronic medical conditions. In terms of the entire study population, only arthritis and heart disease were more strongly associated with QALYs than depression.

Aged↗
PubMed2000

A controlled time-series trial of clinical reminders: using computerized firm systems to make quality improvement research a routine part of mainstream practice.

OBJECTIVE: To explore the feasibility of conducting unobtrusive interventional research in community practice settings by integrating firm-system techniques with time-series analysis of relational-repository data. STUDY SETTING: A satellite teaching clinic divided into two similar, but geographically separated, primary care group practices called firms. One firm was selected by chance to receive the study intervention. Forty-two providers and 2,655 patients participated. STUDY DESIGN: A nonrandomized controlled trial of computer-generated preventive reminders. Net effects were determined by quantitatively combining population-level data from parallel experimental and control interrupted time series extending over two-month baseline and intervention periods. DATA COLLECTION: Mean rates at which mammography, colorectal cancer screening, and cholesterol testing were performed on patients due to receive each maneuver at clinic visits were the trial's outcome measures. PRINCIPAL FINDINGS: Mammography performance increased on the experimental firm by 154 percent (0.24 versus 0.61, p = .03). No effect on fecal occult blood testing was observed. Cholesterol ordering decreased on both the experimental (0.18 versus 0.1 1, p = .02) and control firms (0.13 versus 0.07, p = .03) coincident with national guidelines retreating from recommending screening for young adults. A traditional uncontrolled interrupted time-series design would have incorrectly attributed the experimental-firm decrease to the introduction of reminders. The combined analysis properly indicated that no net prompting effect had occurred, as the difference between firms in cholesterol testing remained stochastically stable over time (0.05 versus 0.04, p = .75). A logistic-regression analysis applied to individual-level data produced equivalent findings. The trial incurred no supplementary data collection costs. CONCLUSIONS: The apparent validity and practicability of our reminder implementation study should encourage others to develop computerized firm systems capable of conducting controlled time-series trials.

Adult↗
PubMed2000

The Kaiser Family Foundation Community Health Promotion Grants Program: findings from an outcome evaluation.

OBJECTIVES: To present results from an outcome evaluation of the Henry J. Kaiser Family Foundation's Community Health Promotion Grants Program (CHPGP) in the West, which represented a major community-based initiative designed to promote improved health by changing community norms, environmental conditions, and individual behavior in 11 western communities. METHODS: The evaluation design: 14 randomly assigned intervention and control communities, 4 intervention communities selected on special merit, and 4 matched controls. Data for the outcome evaluation were obtained from surveys, administered every two years at three points in time, of community leaders and representative adults and adolescents, and from specially designed surveys of grocery stores. Outcomes for each of the 11 intervention communities were compared with outcomes in control communities. RESULTS: With the exception of two intervention communities-a largely Hispanic community and a Native American reservation-we found little evidence of positive changes in the outcomes targeted by the 11 intervention communities. The programs that demonstrated positive outcomes targeted dietary behavior and adolescent substance abuse. CONCLUSIONS: Improvement of health through community-based interventions remains a critical public health challenge. The CHPGP, like other prominent community-based initiatives, generally failed to produce measurable changes in the targeted health outcomes. Efforts should focus on developing theories and methods that can improve the design and evaluation of community-based interventions.

Adolescent↗
PubMed2000

Measuring the "managedness" and covered benefits of health plans.

STUDY AIMS: (1) To develop indexes measuring the degree of managedness and the covered benefits of health insurance plans, (2) to describe the variation in these indexes among plans in one health insurance market, (3) to assess the validity of the health plan indexes, and (4) to examine the association between patient characteristics and the health plan indexes. Measures of the "managedness" and covered benefits of health plans are requisite for studying the effects of managed care on clinical practice and health system performance, and they may improve people's understanding of our complex health care system. DATA SOURCES/STUDY SETTING: As part of our larger Physician Referral Study, we collected health insurance information for 189 insurance product lines and 755 products in the Seattle, Washington metropolitan area, which we linked with the study's data for 2,277 patients recruited in local primary care offices. STUDY DESIGN: Managed care and benefit variables were constructed through content analysis of health plan information. Principal component analysis of the variables produced a managedness index, an in-network benefits index, and an out-of-network benefits index. Bivariable analyses examined associations between patient characteristics and the three indexes. PRINCIPAL FINDINGS: From the managed care variables, we constructed three provider-oriented indexes for the financial, utilization management, and network domains of health plans. From these, we constructed a single managedness index, which correlated as expected with the individual measures, with the domain indexes, with plan type (FFS, PPO, POS, HMO), with independent assessments of local experts, and with patients' attitudes about their health insurance. For benefits, we constructed an in-network benefits index and an out-of-network benefits index, which were correlated with the managedness index. The personal characteristics of study patients were associated with the managed care and benefit indexes. Study patients in more managed plans reported somewhat better health than patients in less managed plans. CONCLUSIONS: Indexes of the managedness and benefits of health plans can be constructed from publicly available information. The managedness and benefit indexes are associated with the personal characteristics and health status of study patients. Potential uses of the managed care and benefits indexes are discussed.

Abstracting and Indexing↗
PubMed1999

Increasing response rates for mailed surveys of Medicaid clients and other low-income populations.

Mailing surveys to low-income populations is often avoided because of concern about low response rates. In this study, the authors used a mailed survey of a low-income population to test whether $1.00 or $2.00 cash-response incentives were worth the expense and whether 2-day priority mail ($2.90 postage) would yield a sufficiently higher response rate than certified mail ($1.52 postage) to justify its cost. In 1994, 2,243 randomly selected families in subsidized health care programs in Pierce County, Washington, were randomly sent no incentive, $1.00, or $2.00 in the first of three mailings. For the third mailing, nonrespondents were randomly assigned to receive either certified or 2-day priority mail. After 4 weeks, the response rates were 36.7%, 48.1%, and 50.3% for the no-incentive, $1.00, and $2.00 groups, respectively. After three mailings, the cost per response was the lowest for the group that received $1.00. The response rate for the certified mailing (28.1%) was significantly higher than the rate for the more expensive priority mailing (21.7%). No incentive-related bias was detected. The authors concluded that the most efficient protocol for this low-income population was to use a $1.00 incentive in the first mailing and a certified third mailing.

Aged↗
PubMed1999

Explaining community-level variance in group randomized trials.

Between-community variance or community-by-time variance is one of the key factors driving the cost of conducting group randomized trials, which are often very expensive. We investigated empirically whether between-community variance could be reduced by controlling individual- and/or community-level covariates and identified these covariates from four large community-based group randomized trials or surveys: the Working Well Trial; Kaiser Adolescent Survey; Kaiser Adults Survey; and the Eating Patterns Study. We found that adjusting for covariates will often substantially reduce the between-community variance component. Therefore investigators could block the communities according to these covariates, or adjust for these covariates to improve the power of community trials. We found that the community-by-time variance components are always near zero in these data sets, especially for the surveys where a cohort was followed over time. The covariate adjustment had less impact on reducing the community-by-time variance for the cohort samples than for the cross-sectional samples. This suggests that blocking may not be necessary for the design of the group randomized trials where the change from baseline is of primary interest. The Working Well Trial data were used to illustrate this point.

Adolescent↗
PubMed1999

Survival versus years of healthy life: which is more powerful as a study outcome?

Studies of interventions that are intended to improve patients' health are often evaluated with survival as the primary outcome, even when a measure adjusted for quality of survival, such as years of healthy life (YHL), would seem more appropriate. The purpose of this article is to determine whether studies based on survival are more or less powerful than studies based on YHL in clinical trials where either measure might be appropriate. We used data from the Cardiovascular Health Study (CHS) to estimate the sample size that would be needed in studies of 156 different health conditions, for the two outcome measures. The median sample size for a 5-year study was 687 if survival was the endpoint and 484 for YHL. YHL usually required lower sample sizes than survival, although survival was more powerful for some health conditions. We also found that lengthy studies, and studies with many follow-up measures per person, did not have appreciably higher power than less intensive studies. We conclude that clinical investigations in which the goal is to improve health may often be performed more efficiently with YHL rather than survival as the primary outcome measure. Such studies can be short in duration, with relatively few measures per person of health status.

Aged↗
PubMed1999

Primary care physicians' participation in managed care networks.

The study described in this article explored the relationships between primary care physician characteristics and patterns of managed care affiliation in a single region. Secondary data sources were used to investigate the affiliations of all primary care physicians in King County, Washington (Seattle and environs) with 29 managed care products in 1996. Descriptive findings indicate that specialty, board certification, and experience all are associated with the managed care affiliations held by physicians. Differences between managed care product provider lists suggest that there are different strategies for the design and management of provider networks.

Case Management↗