Biomedical subjects

Greg Samsa

Publications and source records attributed to Greg Samsa.

4 recordsLinked to original sources

PubMed2005

Combining information from multiple data sources to create multivariable risk models: illustration and preliminary assessment of a new method.

A common practice of metanalysis is combining the results of numerous studies on the effects of a risk factor on a disease outcome. If several of these composite relative risks are estimated from the medical literature for a specific disease, they cannot be combined in a multivariate risk model, as is often done in individual studies, because methods are not available to overcome the issues of risk factor colinearity and heterogeneity of the different cohorts. We propose a solution to these problems for general linear regression of continuous outcomes using a simple example of combining two independent variables from two sources in estimating a joint outcome. We demonstrate that when explicitly modifying the underlying data characteristics (correlation coefficients, standard deviations, and univariate betas) over a wide range, the predicted outcomes remain reasonable estimates of empirically derived outcomes (gold standard). This method shows the most promise in situations where the primary interest is in generating predicted values as when identifying a high-risk group of individuals. The resulting partial regression coefficients are less robust than the predicted values.

Journal Article↗

PubMed2004

A new instrument for measuring anticoagulation-related quality of life: development and preliminary validation.

BACKGROUND: Anticoagulation can reduce quality of life, and different models of anticoagulation management might have different impacts on satisfaction with this component of medical care. Yet, to our knowledge, there are no scales measuring quality of life and satisfaction with anticoagulation that can be generalized across different models of anticoagulation management. We describe the development and preliminary validation of such an instrument - the Duke Anticoagulation Satisfaction Scale (DASS). METHODS: The DASS is a 25-item scale addressing the (a) negative impacts of anticoagulation (limitations, hassles and burdens); and (b) positive impacts of anticoagulation (confidence, reassurance, satisfaction). Each item has 7 possible responses. The DASS was administered to 262 patients currently receiving oral anticoagulation. Scales measuring generic quality of life, satisfaction with medical care, and tendency to provide socially desirable responses were also administered. Statistical analysis included assessment of item variability, internal consistency (Cronbach's alpha), scale structure (factor analysis), and correlations between the DASS and demographic variables, clinical characteristics, and scores on the above scales. A follow-up study of 105 additional patients assessed test-retest reliability. RESULTS: 220 subjects answered all items. Ceiling and floor effects were modest, and 25 of the 27 proposed items grouped into 2 factors (positive impacts, negative impacts, this latter factor being potentially subdivided into limitations versus hassles and burdens). Each factor had a high degree of internal consistency (Cronbach's alpha 0.78-0.91). The limitations and hassles factors consistently correlated with the SF-36 scales measuring generic quality of life, while the positive psychological impact scale correlated with age and time on anticoagulation. The intra-class correlation coefficient for test-retest reliability was 0.80. CONCLUSIONS: The DASS has demonstrated reasonable psychometric properties to date. Further validation is ongoing. To the degree that dissatisfaction with anticoagulation leads to decreased adherence, poorer INR control, and poor clinical outcomes, the DASS has the potential to help identify reasons for dissatisfaction (and positive satisfaction), and thus help to develop interventions to break this cycle. As an instrument designed to be applicable across multiple models of anticoagulation management, the DASS could be crucial in the scientific comparison between those models of care.

Administration, Oral↗

PubMed2002

Incorporating genetic susceptibility feedback into a smoking cessation program for African-American smokers with low income.

PURPOSE: Markers of genetic susceptibility to tobacco-related cancers could personalize harms of smoking and motivate cessation. Our objective was to assess whether a multicomponent intervention that included feedback about genetic susceptibility to lung cancer increased risk perceptions and rates of smoking cessation compared with a standard cessation intervention. EXPERIMENTAL DESIGN: Our design was a two-arm trial with eligible smokers randomized in a 1:2 ratio to Enhanced Usual Care or Biomarker Feedback (BF). Surveys were conducted at baseline, 6, and 12 months later. The setting was an inner city community health clinic. African-American patients who were current smokers (n = 557) were identified by chart abstraction and provider referral. All smokers received a self-help manual and, if appropriate, nicotine patches. Smokers in the BF arm also were offered a blood test for genotyping the GST(3) gene (GSTM1), sent a test result booklet, and called up to four times by a health educator. Prevalent abstinence was assessed by self-report of having smoked no cigarettes in the prior 7 days at the 6- and 12-month follow-ups and sustained abstinence, i.e., not smoking at either follow-up or in-between. RESULTS: Smoking cessation was greater for the BF arm than the Enhanced Usual Care arm (19% versus 10%, respectively; P < 0.006) at 6 months but not at 12 months. CONCLUSIONS: Smokers agreed to genetic feedback as part of a multicomponent cessation program. Although the program increased short-term cessation rates compared with standard intervention, genetic feedback of susceptibility may not benefit smokers with high baseline risk perceptions.

Adult↗

PubMedDate not supplied

Exploring the association between perceived risks of smoking and benefits to quitting: who does not see the link?

This report explored associations between different measures of smokers' perceived risks of smoking and benefits to quitting and the extent to which these associations varied by demographic and other characteristics for 144 smokers. We hypothesized greater perceived risk of smoking would be associated with greater perceived benefits to quitting and would be strongest among smokers who were concerned about health effects of smoking and motivated to quit. Results indicated smokers' perceived themselves at risk for lung cancer regardless if they continued or quit smoking and was strongest for smokers who were older and minimized the importance of reducing lung cancer risk. There was a weak correlation between perceived risk for lung cancer when compared to nonsmokers and perception that quitting smoking would reduce lung cancer risk and was weakest for African Americans, lighters smokers, and smokers with higher intrinsic relative to extrinsic motivation for cessation. In conclusion, these subgroup differences in the relationship between perceptions of risks and benefits could be important to consider to increase the relevance and motivational potency of smoking cessation interventions.

Adult↗