Search PubMed⌕ Search

Biomedical subjects

R L Stout

Publications and source records attributed to R L Stout.

At least 37 records · Page 2Linked to original sources
PubMed1997

Hepatitis C prevalence and the significance of liver enzyme elevations in the insurance population.

BACKGROUND: Liver enzyme elevation(s) are a common finding in the insurance applicant population. Hepatitis C infection results in histological and functional changes in the liver with both short and long term changes in serum liver enzyme levels. The prevalence of antibodies to HCV in the general population is estimated to be 4%. This paper reports on the prevalence of antibodies to HCV in the insurance applicant population and their relationship to the liver enzyme(s). RESULTS: Antibodies to HCV are present in 1.8% of a random sampling of insurance applicants. Alanine aminotransferase (ALT) elevations occur in 95.4% of all samples positive for antibodies to HCV. More than half of positive samples (56.7%) have ALT elevations of less than two time the upper range of normal. Antibody prevalence is lowest in samples with single enzyme elevation, 4.2%. In comparison, the prevalence is 16.4% in samples with all three enzymes, ALT, AST, and GGT, elevated. For maximal specificity two immunoassays, configured with different HCV antigens, should be performed sequentially on all positive applicant samples. CONCLUSION: HCV is the most prevalent, chronic viral infection in the insurance population. HCV prevalence is 40 times HIV prevalence. In an evaluation of enzyme reflex markers ALT was positive for antibodies to HCV 8.6% of the time while identifying 95.4% of HCV antibody positive applicants.

Adult↗
PubMed1997

A double-blind, placebo-controlled pilot study of carbamazepine for the treatment of alcohol dependence.

Carbamazepine, chemically related to the tricyclic antidepressants, has multiple clinical actions. It is a potent anticonvulsant, mild sedative, and mood stabilizer. It is nonaddictive and has little toxicity when clinical and laboratory monitoring is performed. It has proven efficacy in the treatment of acute alcohol withdrawal. Kindling and protracted withdrawal are the theoretical rationale for the mechanism of its action in the treatment of alcohol dependence. This 12-month double-blind placebo-controlled pilot study of 29 subjects evaluated the efficacy of carbamazepine for the treatment of alcohol dependence. Subjects were randomly assigned to either placebo or carbamazepine. A baseline assessment and bimonthly follow-up for 12 months assessed demographic variables, mood and functioning, treatment compliance, drinking behaviors, biological markers of drinking, and medication toxicity. Despite the small sample size, compliance difficulties after 4 months and a sizable drop-out rate, there were treatment effects favoring carbamazepine. Univariate analyses showed a decrease in drinks per drinking day and maximum number of heavy drinking days in a row at 2 and 4 months of follow-up. Survival analysis revealed a significant delay in time to first episode of heavy drinking, and close to a trend level of significance for time to first drink. There were significant time, but not time by treatment group, effects on multiple measures of mood. These pilot results are encouraging and support carbamazepine as a possible pharmacologic tool in the treatment of alcohol dependence.

Adult↗
PubMed1996

Determinants of research follow-up participation in an alcohol treatment outcome trial.

This study examined factors associated with research attrition in a long-term follow-up study (48 months). Researchers attempted to contact all randomized participants, not just those who completed treatment. The processes by which baseline characteristics, early treatment-research experiences, and short-term outcome affected subsequent participations were examined using logistic regression. The analyses deal primarily with refusal, the main reason for attrition. Baseline characteristics had small effects on likelihood of refusal; research engagement had some impact; but treatment participation had strong effect. Short-term outcome did not predict refusal. These findings, if generalizable, have implications for the conduct and reporting of outcome studies. By directly studying bias, rather than presuming its absence on skimpy evidence, researchers can achieve a better understanding of the strengths and limitations of outcome results.

Adult↗
PubMed1996

Replication and extension of Marlatt's taxonomy of relapse precipitants: overview of procedures and results. The Relapse Research Group.

The Relapse Replication and Extension Project (RREP) was a multisite study to replicate and extend Marlatt's taxonomy of relapse precipitants. In addition to replicating Marlatt's original taxonomic system, three independent research teams utilized prospective designs to identify additional predictors of relapse and developed and evaluated two alternative systems for assessing high risk relapse situations. This overview describes the replication methodology, summarizes seven RREP studies completed by the three research groups, and discusses five cross-cutting conclusions emerging from the studies. These conclusions are: (1) reliability of Marlatt's taxonomic system was variable both within and across the three research sites; (2) Marlatt's taxonomic system showed little predictive validity in analyses that used pretreatment relapse data to predict post-treatment relapse, but there are important unresolved issues; (3) an alternative taxonomy provided little more predictive validity than the original taxonomy even though it measured more dimensions of relapse situations and provided greater analytic flexibility; (4) the Reasons for Drinking Questionnaire appeared to be a successful psychometric transformation of Marlatt's taxonomy, one which did demonstrate predictive validity; and (5) Marlatt's taxonomy was based on a time-intensive model of relapse prediction whereas RREP prospective analyses represented time-extensive models of relapse prediction. Coping responses are noted to be effective predictors of relapse under both models.

Adult↗
PubMed1996

The reliability of Marlatt's taxonomy for classifying relapses.

Marlatt's focus on the relapse situation has had a major impact upon research and clinical practice in treating addictions. One component of his work was the development of a taxonomy for classifying precipitants of relapse. This taxonomy has been incorporated into the nomenclature of clinicians and clinical researchers as part of an explanatory framework for understanding relapses. Despite the taxonomy's influence it has never been examined for the reliability of its use across research studies. The present study compared the reliability of independent classifications of 149 relapse episodes by trained raters at three research laboratories. Despite considerable across-laboratory training, reliability was found to be inconsistent for research purposes. It is concluded that comparability of results based on Marlatt's relapse taxonomy across independent studies must be subject to question, and assumptions necessary for the aggregation of a knowledge base are not supported. Recommendations are offered for improving the reliability of the taxonomy and the methods used to collect taxonomy data. More generally, questions regarding the value of the specific relapse categories, as well as the overall taxonomy, are raised.

Adult↗
PubMed1996

Predictive validity of Marlatt's relapse taxonomy versus a more general relapse code.

Marlatt's system for classifying relapses involves integrating information about the context of a relapse into a judgment about the most critical aspects of the situation. Constraints in this taxonomy, however, may limit its validity. On a sample of 300 subjects drawn from six treatment facilities, we compared the predictive validity of Marlatt's taxonomy with that of a coding scheme with fewer constraints. Marlatt's taxonomy does not significantly predict drinking outcome, nor does it predict time to relapse. There is weak evidence, however, that under some circumstances Marlatt's taxonomy can predict the type of relapse subsequently observed. The alternative coding system also does not seem useful for predicting drinking outcome, although a possible association was found between internal attribution and time to return to heavy drinking. The alternative system does seem to be able to detect repetitive aspects of subsequent relapse situations; lack of social interactions, family setting, anxiety and depression were most likely to repeat. It may be useful to consider these relapse attributes in treatment planning. The minimal predictive validity for both the Marlatt and the alternative relapse code may be due to weaknesses in the relatively unstructured interview used to gather the data, or to failure to assess the most critical dimensions relating to subsequent relapse.

Adult↗
PubMed1996

Gender differences in relapse situations.

Gender differences in variables relating to alcohol treatment are receiving increased attention. Most reports indicate gender differences in both intrapersonal, interpersonal and environmental trans-situational variables that relate specifically to women's drinking. This study investigates gender differences in the immediate relapse situation itself. These differences are then examined in the context of trans-situational (i.e. across time) affective and cognitive variables and social support. This report is part of a larger study designed to replicate Marlatt's taxonomy of high risk situations for relapse, and to examine alternative methods of describing relapse situations. Three hundred subjects (169 men, 131 women) were recruited from six different inpatient and outpatient programs. Subjects were asked to identify their last relapse before entering the index treatment. Details of the drinking episode itself were also obtained, e.g. number of drinking days in episode, drinking to intoxication, presence of others. Measures of state and trait affect, expectancies, and social support were also collected. There were no gender differences in Marlatt's taxonomy, or in drinking topography during relapse. At baseline, women reported drinking less, and drinking less often than men. However, women drank to intoxication more often than men. Surprisingly, men relapsed alone more often than did women. Men and women report relapsing frequently with same sex friends, and women showed a tendency to relapse in the presence of romantic partners. Men also tend to report more positive mood states during relapse than women, which is congruent with the finding that women report more depression. Severity of drinking pattern was found to be an important confounding variable in these analyses. It is suggested that gender differences found in individuals in treatment for alcohol problems may reflect societal differences between men and women, and that taking these differences into account in designing treatment programs may improve outcomes.

Adult↗
PubMed1994

Issues in the definition and measurement of drinking outcomes in alcoholism treatment research.

This article reviews methodological and conceptual issues regarding the choice of drinking outcome measures in alcoholism treatment research. The following issues are discussed: Should drinking outcomes be conceptualized in terms of an underlying unitary disorder, or should provision be made for independent outcomes that cover a wide variety of dimensions? Which drinking outcomes are typically measured in treatment evaluation studies and how are they operationalized? What are the empirical associations among drinking outcome measures? If multiple outcomes are measured, which should be given primary importance? Over what period of time should treatment outcome be evaluated? What procedures can be used to detect, correct or prevent the response bias associated with verbal report methods? Because outcome measures need to fit the hypotheses and practical needs of a particular study, it is unlikely that complete standardization can be achieved across all studies. Nevertheless, given the importance of drinking outcomes and the need for economy, two primary dependent measures are recommended: (1) proportion of available drinking days abstinent; and (2) intensity of drinking, as defined by the total amount consumed (in ounces absolute alcohol) during the follow-up period divided by the number of actual drinking days. This article also proposes a strategy that may help to guide the selection of outcome measures in future research.

Alcoholism↗
PubMed1994

Ensuring balanced distribution of prognostic factors in treatment outcome research.

In comparative or matching research involving two or more treatments, the equivalence of the patient groups is of critical importance. In the past, equivalence has either been imposed by matching or balancing, or has been assured statistically by randomization. Matching and balancing, while useful in many contexts, nonetheless have important limitations, as does simple randomization. In recent years, a new tool has been developed that represents a compromise between balancing and randomization. This method, urn randomization, gives clinical investigators new options for improving the credibility of studies at a relatively modest cost. Urn randomization is randomization that is systematically based in favor of balancing. It can be used with several covariates, both marginally and jointly, producing optimal multivariate equivalence of treatment groups for large sample sizes. It preserves randomization as the primary basis for assignment to treatment and is less susceptible to experimenter bias or manipulation of the allocation process by staff than is balancing. Disadvantages include the fact that it is more difficult to implement, and that it violates the simple probability model of simple randomization. A number of research studies on addictions, including client-treatment matching trials, have used urn randomization. A summary of the mechanics of urn randomization is presented, and guidelines for its use in treatment studies are discussed.

Alcoholism↗
PubMed1994

Classical analytical methods for detecting matching effects on treatment outcome.

This article presents a classical approach for analyzing repeated measures designs with specific application to treatment matching studies. The generic treatment matching hypothesis is formulated under the multivariate general linear model, transforming the dependent variables to account for the repeated measures structure of the data. Issues of primary importance in the use of this approach (such as correcting for inflated Type I error and robustness of statistical tests to parametric assumptions) are discussed. The article concludes with an assessment of the strengths and weaknesses of this approach compared with alternative approaches.

Alcoholism↗
PubMed1994

Alternative analytical methods for detecting matching effects in treatment outcomes.

Project MATCH presented a unique opportunity for a team of statisticians, data analysts and content experts to come together and explore the strengths and weaknesses of the application of various statistical models to the data of the type being collected in this large trial. The following models were evaluated: multilevel models, event history models, multiple were structural equation modeling, time series models, ordinal repeated measures designs and generalized estimating equations. No one model was found to be the perfect solution and each seemed to have something to recommend it. Future research on these methods will shed light on many issues raised. It is hoped that alcohol researchers will find useful guidelines within this chapter as they plan and carry out their studies.

Alcoholism↗
PubMed1993

Effect of the social environment on alcohol involvement and subjective well-being prior to alcoholism treatment.

This article describes a conceptual model developed to explain abusive use of alcohol and reports results of an initial test of that conceptualization. General social support is hypothesized to affect the level of subjective well-being, while alcohol-relevant social support affects the degree of alcohol involvement. A cross-sectional test of two models derived from this formulation was made using data from 148 alcoholic clients entering treatment at a private non-profit psychiatric facility. Results indicate that a model in which no direct relationship between alcohol involvement and subjective well-being is specified provides a more parsimonious explanation of interrelationships at the time of treatment entry. Alcohol involvement is explained by alcohol-relevant affiliative and instrumental support (albeit weakly), and subjective well-being is explained by general affiliative and instrumental social support. There is virtually no interrelationship between alcohol involvement and subjective well-being once the support variables are taken into account. The findings indicate that treatment should more often incorporate others from a client's social network, using significant others first to provide general social support and later alcohol-relevant support as well. Further analyses involving samples with more heterogeneity in levels of social investment and exploring the utility of these variables for treatment matching categorization decisions are warranted.

Adaptation, Psychological↗
PubMed1992

The relationship between craving, anxiety, and other symptoms in opioid withdrawal.

Craving and anxiety share many similar attributes including comparable responses to pharmacological agents. To better characterize the relationship among craving, anxiety, and other opioid withdrawal signs and symptoms, we examined 32 opioid-dependent subjects undergoing clonidine-assisted opioid withdrawal. A 13-item analog scale measured subjective withdrawal symptoms. Statistical analyses of separate subscale items, using craving as the dependent variable, showed that the highest positive correlations occur for craving and anxiety. The high correlation between craving and anxiety suggests common mechanisms underlying both.

Anxiety↗
PubMed1990

Renal effects of ibuprofen, piroxicam, and sulindac in patients with asymptomatic renal failure. A prospective, randomized, crossover comparison.

STUDY OBJECTIVE: To evaluate the effects of three chemically distinct nonsteroidal anti-inflammatory drugs (NSAIDs) on renal function in patients with asymptomatic, mild but stable chronic renal failure. DESIGN: Prospectively randomized, triple-crossover study with at least 1-month washout between each of three treatment periods. SETTING: Inpatient and outpatient clinical research center of a university teaching hospital. PATIENTS: Convenience sample of 12 women with serum creatinine levels between 130 and 270 mumols/L (1.5 and 3.0 mg/dL). Mean glomerular filtration rate +/- standard error was 0.36 +/- 0.03 mL/s.m2 (37 +/- 3 mL/min.1.73 m2); mean effective renal plasma flow was 1.6 +/- 0.18 mL/s.m2 (166 +/- 19 mL/min.1.73 m2). INTERVENTIONS: Patients received ibuprofen, 800 mg three times daily; piroxicam, 20 mg daily; and sulindac, 200 mg twice daily for 11 days. Treatment was discontinued if serum creatinine rose by 130 mumols/L (1.5 mg/dL) or serum potassium exceeded 6 mmol/L (6 mEq/L). MEASUREMENTS AND MAIN RESULTS: Three patients met our criteria for stopping ibuprofen by day 8; however, all patients completed piroxicam and sulindac therapy. When the three patients in whom ibuprofen was withdrawn were rechallenged with ibuprofen, 400 mg three times daily, two again developed evidence of acute renal deterioration. All three regimens suppressed renal prostaglandin production. CONCLUSIONS: These findings indicate that a brief course of ibuprofen, a compound widely used on a nonprescription basis, may result in acute renal failure in patients with asymptomatic, mild chronic renal failure. Additional studies are needed to assess the risk of piroxicam and sulindac in patients with more pronounced renal impairment and in patients receiving longer courses of therapy, which, according to our data, may result in drug accumulation.

Adult↗
PubMed1989

Sulindac kinetics and effects on renal function and prostaglandin excretion in renal insufficiency.

The purpose of this study was to evaluate the pharmacokinetics of sulindac, a purported "renal sparing" nonsteroidal anti-inflammatory drug, and its effects on renal function and prostaglandin excretion in patients with reduced glomerular filtration rate. Twelve female patients (glomerular filtration rate 37 +/- 4 mL/min) were treated with sulindac 200 mg bid for 11 days. Urinary PGE2, 6-keto-PGF1 alpha and serum thromboxane (TxB2) generation were measured by radioimmunoassay (RIA) following extraction on C-18 columns. Glomerular filtration rate and effective renal plasma flow were measured by 99TC-DPTA and 131I-para-aminohippuric acid clearance. In six patients serum and urine levels of sulindac and its metabolites were measured by high-pressure liquid chromatography (HPLC). Sulindac was rapidly absorbed and converted to sulindac sulfide with peak levels 2 hours after a single dose, but steady state levels were not reached prior to drug discontinuation. Sulindac sulfide AUC (0-5 hours micrograms min/mL) progressively increased from 382 to 3,030 on day 11. It did not appear in the urine. Baseline urinary PGE2 and 6-keto-PGF1 alpha excretion were 23.8 +/- 5.6 and 18.9 +/- 2.7 ng/hr respectively and were reduced by 68% and 47% by day 4 of therapy. TxB2 generation fell by 34% after one dose and by 67% by day 11. There was a significant increase in serum creatinine from 1.88 +/- 0.13 mg/dl before treatment to 2.16 +/- 0.15 mg/dL (P less than .05) after eleven days.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Platelets↗