Biomedical subjects

Cynthia J Coffman

Publications and source records attributed to Cynthia J Coffman.

10 recordsLinked to original sources

PubMed2006

Barriers to full colon evaluation for a positive fecal occult blood test.

BACKGROUND: Failure to appropriately evaluate a positive cancer screening test may negate the value of doing that test. The primary aim of this study was to explore the factors associated with undergoing a full colon evaluation for a positive fecal occult blood test (FOBT) in a single Veterans Affairs center. METHODS: Medical records of consecutive patients ages > or = 50 years, who had a positive screening FOBT from March 2000 to February 2001, were abstracted. Patient demographics, dates of ordering and doing follow-up test(s), and adherence with scheduled procedures were collected. The primary outcome, full colon evaluation, was defined as having a colonoscopy or double-contrast barium enema plus flexible sigmoidoscopy completed within 12 months. RESULTS: The sample (N = 538) was 98% men (58% Caucasian, 29% African-American, and 13% unknown race). Approximately 77% of the patients were referred to gastroenterology. Ultimately, only 44% underwent full colon evaluation within 12 months. Approximately 20% of the patients failed to attend a scheduled procedure. Referral to gastroenterology and adherence to follow-up appointments were associated with full colon evaluation. There was no association between African-American versus Caucasian race and full colon evaluation. CONCLUSIONS: Less than half of the patients with a positive FOBT had a full colon evaluation within 12 months. Multiple failures were identified, including lack of referral for further testing and patient nonadherence. Although the overall performance in evaluating a positive colorectal cancer screening test was poor, no racial disparity was observed.

Black or African American↗

PubMed2005

Comparison of three comorbidity measures for predicting health service use in patients with osteoarthritis.

OBJECTIVE: To compare the ability of 3 database-derived comorbidity scores, the Charlson Score, Elixhauser method, and RxRisk-V, in predicting health service use among individuals with osteoarthritis (OA). METHODS: The study population comprised 306 patients who were under care for OA in the Veterans Affairs (VA) health care system. Comorbidity scores were calculated using 1 year of data from VA inpatient and outpatient databases (Charlson Score, Elixhauser method), as well as pharmacy data (RxRisk-V). Model selection was used to identify the best comorbidity index for predicting 3 health service use variables: number of physician visits, number of prescriptions used, and hospitalization probability. Specifically, Akaike's Information Criterion (AIC) was used to determine the best model for each health service outcome variable. Model fit was also evaluated. RESULTS: All 3 comorbidity indices were significant predictors of each health service outcome (P < 0.01). However, based on AIC values, models using the RxRisk-V and Elixhauser indices as predictor variables were better than models using the Charlson Score. The model using the RxRisk-V index as a predictor was the best for the outcome of prescription medication use, and the model with the Elixhauser index was the best for the outcome of physician visits. CONCLUSION: The Rx-Risk-V and Elixhauser are suitable comorbidity measures for examining health services use among patients with OA. Both indices are derived from administrative databases and can efficiently capture comorbidity among large patient populations.

Comorbidity↗

PubMed2005

Identification of co-regulated transcripts affecting male body size in Drosophila.

Factor analysis is an analytic approach that describes the covariation among a set of genes through the estimation of 'factors', which may be, for example, transcription factors, microRNAs (miRNAs), and so on, by which the genes are co-regulated. Factor analysis gives a direct mechanism by which to relate gene networks to complex traits. Using simulated data, we found that factor analysis clearly identifies the number and structure of factors and outperforms hierarchical cluster analysis. Noise genes, genes that are not correlated with any factor, can be distinguished even when factor structure is complex. Applied to body size in Drosophila simulans, an evolutionarily important complex trait, a factor was directly associated with body size.

Animals↗

PubMed2005

Model selection in binary trait locus mapping.

Quantitative trait locus (QTL) mapping methodology for continuous normally distributed traits is the subject of much attention in the literature. Binary trait locus (BTL) mapping in experimental populations has received much less attention. A binary trait by definition has only two possible values, and the penetrance parameter is restricted to values between zero and one. Due to this restriction, the infinitesimal model appears to come into play even when only a few loci are involved, making selection of an appropriate genetic model in BTL mapping challenging. We present a probability model for an arbitrary number of BTL and demonstrate that, given adequate sample sizes, the power for detecting loci is high under a wide range of genetic models, including most epistatic models. A novel model selection strategy based upon the underlying genetic map is employed for choosing the genetic model. We propose selecting the "best" marker from each linkage group, regardless of significance. This reduces the model space so that an efficient search for epistatic loci can be conducted without invoking stepwise model selection. This procedure can identify unlinked epistatic BTL, demonstrated by our simulations and the reanalysis of Oncorhynchus mykiss experimental data.

Animals↗

PubMed2005

Estimating the occurrence of amyotrophic lateral sclerosis among Gulf War (1990-1991) veterans using capture-recapture methods.

OBJECTIVE: Using data from a recent report that indicated a 2-fold higher risk of amyotrophic lateral sclerosis (ALS) among veterans of the 1991 Gulf War, we applied capture-recapture methodology to estimate possible under-ascertainment of ALS cases among deployed and non-deployed military personnel who were on active duty during that war. STUDY DESIGN AND SETTING: One of the most serious concerns facing field epidemiological investigations is that of case ascertainment bias, particularly when it is differential among the study groups. Capture-recapture methods, however, have promise as an approach to assessing the impact of case ascertainment bias in such studies. To overcome potential limitations of any one approach, three different estimation methods were used: log-linear models, sample coverage, and ecological models, to obtain a comprehensive view of under-ascertainment bias in these populations. RESULTS: All three approaches indicated differential undercount of ALS cases with modest under-ascertainment likely to have occurred among non-deployed military personnel, but little under-ascertainment among the deployed. After correcting the rates for under-ascertainment, the age-adjusted risk of ALS remained elevated among military personnel who had been deployed to S.W. Asia during the 1991 Gulf War, confirming the earlier report. CONCLUSIONS: Capture-recapture methods are a useful approach to assessing the magnitude of case ascertainment bias in epidemiological studies from which ascertainment-adjusted estimates of rates and relative risks can be calculated.

Adult↗

PubMed2005

Hormone therapy does not affect depression severity in older women.

OBJECTIVE: Although estrogens are thought to have a beneficial effect on menopausal symptoms, the role of estrogen in the etiology and treatment of depression in older women remains unclear. The authors examined the relationship between hormone therapy (HT) use and depressive symptom severity. METHODS: Authors report the findings from a cross-sectional analysis of baseline data from the Improving Mood: Promoting Access to Collaborative Treatment (IMPACT) Study, using data from 1,160 women age 60 years and older. RESULTS: Women who were taking HT were likely to be younger, White, married, and to have had at least some college education. They were also more likely to report good or better health and to have taken antidepressant medications in the past 3 months. Although HT use was associated with more severe depressive symptoms in the unadjusted analysis, it was not associated with depression severity in adjusted analyses. Although there was a trend for a differential effect of college education with HT use on depression scores, no significant interaction was found between HT and race. CONCLUSION: There was no evidence to suggest that women HT users differ from non-HT users in depressive symptom severity.

Aged↗

PubMed2004

One-year follow-up study of blood pressure and dietary patterns in dietary approaches to stop hypertension (DASH)-sodium participants.

BACKGROUND: We conducted a 12-month follow-up study on participants in the Dietary Approaches to Stop Hypertension (DASH)-Sodium trial to determine the impact of the DASH diet and 150, 100, or 50 mmol/day of sodium after discontinuation of the feeding intervention. METHODS: Upon completion of the trial, 56 of the 113 participants at the clinical center at Duke University entered a longitudinal observational study. Measurements including 24-h ambulatory systolic and diastolic blood pressure (BP), weight, and 24-h urinary electrolytes were obtained at 1, 6, and 12 months after completion of the DASH-Sodium trial. Block food frequency questionnaires were completed at the 12-month visit. Linear mixed-effects regression models were used to analyze the effect of the diet and sodium intake on longitudinal changes in BP during the final feeding period. RESULTS: The DASH participants significantly increased their intakes of fruits or juices and vegetables at 12 months. Control participants had no change in DASH food group intake. Both groups increased sodium intake. Among control participants, systolic and diastolic BP increased 5.33 (95% confidence interval [CI] 0.28, 10.37) and 3.20 mm Hg (95% CI 0.25, 6.16), respectively. Among DASH participants, systolic and diastolic BP increased 3.12 (95% CI -0.44, 6.68) and 0.79 mm Hg (95% CI -1.15, 2.72), respectively. There was a significant effect of the final sodium level by diet on the change in SBP over time (P = .04 for three-way interaction among diet, time of visit, and sodium). CONCLUSIONS: After the feeding intervention, DASH diet participants ate more fruits/vegetables and had sustained reductions in BP despite increased sodium intake.

Adult↗

PubMed2004

The impact of environmental tobacco smoke on women's risk of dying from heart disease: a meta-analysis.

OBJECTIVE: To review systematically and analyze the association between environmental tobacco smoke (ETS) exposure and the risk of dying from heart disease in women. METHODS: We searched the English-language literature using MEDLINE (1966-April 2004), CINAHL, PsychInfo, and bibliographies of selected studies. We included studies that specifically addressed the association of ETS and heart disease mortality in women and had adequate controls and retrievable risk estimates. We looked for either cohort studies or randomized controlled trials. Studies were evaluated independently by two of the authors. Nine cohort studies were finally selected for analysis. We estimated the summary relative risk (RR) and associated 95% confidence intervals (95% CI) using a random-effects model. RESULTS: Mean follow-up periods for these cohorts ranged from 6 to 39 years. Among non-smoking women, exposure to ETS was associated with a 15% increase in the risk of dying from heart disease compared with nonsmoking women not exposed to ETS (RR = 1.15, 95% CI 1.03-1.28, p < 0.05). CONCLUSIONS: Among nonsmoking women, exposure to passive smoke increases the risk of dying from heart disease. In accordance with the newly developed guidelines by the American Heart Association for prevention of cardiovascular disease (CVD) in women, we recommend counseling women on reducing or avoiding ETS exposure.

Cohort Studies↗

PubMed2003

Intersection tests for single marker QTL analysis can be more powerful than two marker QTL analysis.

BACKGROUND: It has been reported in the quantitative trait locus (QTL) literature that when testing for QTL location and effect, the statistical power supporting methodologies based on two markers and their estimated genetic map is higher than for the genetic map independent methodologies known as single marker analyses. Close examination of these reports reveals that the two marker approaches are more powerful than single marker analyses only in certain cases. Simulation studies are a commonly used tool to determine the behavior of test statistics under known conditions. We conducted a simulation study to assess the general behavior of an intersection test and a two marker test under a variety of conditions. The study was designed to reveal whether two marker tests are always more powerful than intersection tests, or whether there are cases when an intersection test may outperform the two marker approach.We present a reanalysis of a data set from a QTL study of ovariole number in Drosophila melanogaster. RESULTS: Our simulation study results show that there are situations where the single marker intersection test equals or outperforms the two marker test. The intersection test and the two marker test identify overlapping regions in the reanalysis of the Drosophila melanogaster data. The region identified is consistent with a regression based interval mapping analysis. CONCLUSION: We find that the intersection test is appropriate for analysis of QTL data. This approach has the advantage of simplicity and for certain situations supplies equivalent or more powerful results than a comparable two marker test.

Animals↗

PubMed2003

Is specialty care associated with improved survival of patients with congestive heart failure?

BACKGROUND: Implementation of the complex treatment strategies that have been shown to improve survival of patients with congestive heart failure (CHF) may require certain expertise. We wanted to examine the association between pattern of outpatient care and survival of patients with CHF. METHODS: In a retrospective cohort study conducted with national Veterans Health Administration (VHA) databases, we examined the association between the pattern of outpatient care and survival in 11,661 patients discharged from VA hospitals between October 1, 1991, and September 30, 1992, with the primary diagnosis of CHF (cohort 1). Patients were divided into 4 groups, on the basis of their pattern of outpatient care over a 12-month period after discharge: 1) general medicine clinic visits only (GM-only); 2) cardiology clinic visits only (CARD-only); 3) general medicine and cardiology (MIXED) clinic visits; and 4) neither general medicine nor cardiology clinic visits (no-GM/CARD). We used the Cox proportional hazards model to evaluate 1-year survival, controlling for clinical and demographic factors. Consistency of our results was examined by performing identical analysis on a cohort of patients discharged from VHA hospitals between October 1, 1994, and September 30, 1995 (cohort 2, n = 10,141). RESULTS: The overall 1-year mortality rate was 23% in the primary cohort. The unadjusted mortality rate was highest for patients in the no-GM/CARD follow up (29%) and lowest for patients in the MIXED group (19%). By use of the MIXED group as reference and adjusting for important clinical and demographic factors, the risk of death (risk ratio [95% CI]) was 1.12 (0.94-1.34) in the CARD-only group, 1.26 (1.15-1.38) in the GM-only group, and 1.48 (1.28-1.72) in the no-GM/CARD group. Cohort-2 results were consistent with cohort 1 for most covariates, and significant survival differences were again found between GM-only and the MIXED group (1.25 [1.14-1.37]). CONCLUSIONS: We found an improved survival associated with cardiologist care and a mixture of general practitioner and cardiologist care compared with general practitioner care. The pattern of outpatient care may therefore be important for the survival of patients with CHF.

Aged↗