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Biomedical subjects

Robert F Woolson

Publications and source records attributed to Robert F Woolson.

At least 19 recordsLinked to original sources
PubMed2006

Randomization in substance abuse clinical trials.

BACKGROUND: A well designed randomized clinical trial rates as the highest level of evidence for a particular intervention's efficacy. Randomization, a fundamental feature of clinical trials design, is a process invoking the use of probability to assign treatment interventions to patients. In general, randomization techniques pursue the goal of providing objectivity to the assignment of treatments, while at the same time balancing for treatment assignment totals and covariate distributions. Numerous randomization techniques, each with varying properties of randomness and balance, are suggested in the statistical literature. This paper reviews common randomization techniques often used in substance abuse research and an application from a National Institute on Drug Abuse (NIDA)-funded clinical trial in substance abuse is used to illustrate several choices an investigator faces when designing a clinical trial. RESULTS: Comparisons and contrasts of randomization schemes are provided with respect to deterministic and balancing properties. Specifically, Monte Carlo simulation is used to explore the balancing nature of randomization techniques for moderately sized clinical trials. Results demonstrate large treatment imbalance for complete randomization with less imbalance for the urn or adaptive scheme. The urn and adaptive randomization methods display smaller treatment imbalance as demonstrated by the low variability of treatment allocation imbalance. For all randomization schemes, covariate imbalance between treatment arms was small with little variation between adaptive schemes, stratified schemes and unstratified schemes given that sample sizes were moderate to large. CONCLUSION: We develop this paper with the goal of reminding substance abuse researchers of the broad array of randomization options available for clinical trial designs. There may be too quick a tendency for substance abuse researchers to implement the fashionable urn randomization schemes and other highly adaptive designs. In many instances, simple or blocked randomization with stratification on a major covariate or two will accomplish the same objectives as an urn or adaptive design, and it can do so with more simply implemented schedules and without the dangers of overmatching. Furthermore, the proper analysis, fully accounting for the stratified design, can be conducted.

Humans↗
PubMed2006

Preoperative statin treatment is associated with reduced postoperative mortality and morbidity in patients undergoing cardiac surgery: an 8-year retrospective cohort study.

BACKGROUND: Cardiac surgical procedures can be associated with significant morbidity and mortality. Recently, it has been recognized that statins might induce multiple biologic effects independent of lipid lowering that could potentially ameliorate adverse surgical outcomes. Accordingly, this study tested the central hypothesis that pretreatment with statins before cardiac surgery would reduce adverse postoperative surgical outcomes. METHODS: Demographic and outcomes data were collected retrospectively for 3829 patients admitted for planned cardiac surgery between February 1994 and December 2002. Statin pretreatment occurred in 1044 patients who were comparable with non-statin-pretreated (n = 2785) patients with regard to sex, race, and age. Primary outcomes examined included postoperative mortality (30-day) and a composite morbidity variable. RESULTS: The odds of experiencing 30-day mortality and morbidity were significantly less in the statin-pretreated group, with unadjusted odds ratios of 0.43 (95% confidence interval [CI], 0.28-0.66) and 0.72 (95% CI, 0.61-0.86), respectively. Risk-adjusted odds ratios for mortality and morbidity were 0.55 (95% CI, 0.32-0.93) and 0.76 (95% CI, 0.62-0.94), respectively, by using a logistic regression model and 0.51 (95% CI, 0.27-0.94) and 0.71 (95% CI, 0.55-0.92), respectively, in the propensity-matched model, demonstrating significant reductions in 30-day morbidity and mortality. In a subsample of patients undergoing valve-only surgery (n = 716), fewer valve-only patients treated with statins experienced mortality, although these results were not statistically significant (1.96% vs 7.5%). CONCLUSIONS: These findings indicate that statin pretreatment before cardiac surgery confers a protective effect with respect to postoperative outcomes.

Cardiac Surgical Procedures↗
PubMed2006

Modafinil and cocaine interactions.

This Phase I trial evaluated the interaction between modafinil steady-state and cocaine. Twelve non-treatment seeking, cocaine dependent volunteers received four sets of randomized blinded infusions of saline, 20 mg IV cocaine, and 40 mg IV cocaine. Modafinil was given open label at 0 mg, 400 mg, or 800 mg. Modafinil combined with IV cocaine did not result in any significant hemodynamic interactions. Modafinil significantly dampened scores on Visual Analog Scale measures as compared to baseline cocaine conditions. No significant alterations in labs occurred. Further outpatient trials of modafinil appear to be warranted.

Benzhydryl Compounds↗
PubMed2006

Medical comorbidity in women and men with schizophrenia: a population-based controlled study.

BACKGROUND: Persons with persistent mental illness are at risk for failure to receive medical services. In order to deliver appropriate preventive and primary care for this population, it is important to determine which chronic medical conditions are most common. OBJECTIVE: We examined chronic medical comorbidity in persons with schizophrenia using validated methodologies. DESIGN: Retrospective analysis of longitudinal administrative claims data from Wellmark Blue Cross/Blue Shield of Iowa. PARTICIPANTS: Subjects with schizophrenia or schizoaffective disorder (N=1,074), and controls (N=726,262) who filed at least 1 claim for medical services, 1996 to 2001. MEASUREMENTS: Case subjects had schizophrenia as the most clinically predominant psychotic disorder, based on psychiatric hospitalization, psychiatrist diagnoses, and outpatient care. Controls had no claims for any psychiatric comorbidity. Using a modified version of the Elixhauser Comorbidity Index, inpatient and outpatient claims were used to determine the prevalence of 46 common medical conditions. Odds ratios (ORs) were adjusted for age, gender, residence, and nonmental health care utilization using logistic regression. RESULTS: Subjects with schizophrenia were significantly more likely to have 1 or more chronic conditions compared with controls. Adjusted OR (95% confidence interval [CI]) were 2.62 (2.09 to 3.28) for hypothyroidism, 1.88 (1.51 to 2.32) for chronic obstructive pulmonary disease, 2.11 (1.36 to 3.28) for diabetes with complications, 7.54 (3.55 to 15.99) for hepatitis C, 4.21 (3.25 to 5.44) for fluid/electrolyte disorders, and 2.77 (2.23 to 3.44) for nicotine abuse/dependence. CONCLUSIONS: Schizophrenia is associated with substantial chronic medical burden. Familiarity with conditions affecting persons with schizophrenia may assist programs aimed at providing medical care for the mentally ill.

Adult↗
PubMed2005

Mental health comorbidity patterns and impact on quality of life among veterans serving during the first Gulf War.

PURPOSE: To examine the patterns of coexisting (comorbid) mental disorders and whether comorbidity influences quality of life ratings in a sample of U.S. veterans. PATIENTS AND METHODS: The Iowa Gulf War Study Case Validation study evaluated 602 military personnel, two-thirds of whom had symptoms of depression, cognitive dysfunction, or chronic widespread pain, who were activated or on active duty sometime during the first Gulf War (GW). Mental health disorders were defined using the SCID-IV, and the Health Utilities Index Mark 3 (HUI3) was used to measure health-related quality of life (HRQoL). Comorbidity was defined as having two or more mental disorders that spanned across at least two separate categories (e.g., depressive disorders and anxiety disorders). RESULTS: Over 35% of veterans with a current mental disorder had at least one other comorbid mental disorder. Those with mental disorder comorbidity had lower HUI scores than veterans with only one or less mental disorders (mean 0.41 +/- 0.30 vs. 0.72 +/- 0.25, p < 0.0001). CONCLUSION: The co-occurrence of mental disorders that span at least two mental disorder categories is associated with impaired HRQoL in this veteran population. Early identification of mental health comorbidity may lead to interventions to enhance HRQoL among military personnel.

Adult↗
PubMed2005

Factors associated with advanced liver disease in adults with alpha1-antitrypsin deficiency.

BACKGROUND & AIMS: Alpha 1 -antitrypsin deficiency (AAT) is an autosomal recessive disease that affects 1 in 2500 persons and might lead to cirrhosis. Our study aim was to characterize the liver disease in AAT and identify factors associated with advanced liver disease. METHODS: A cohort of the Alpha-1 Foundation Registry who reported liver disease was surveyed with a liver disease questionnaire to obtain information related to liver disease, liver transplantation, and AAT phenotype. RESULTS: One hundred sixty-five of the 2175 participants in the registry reported a history of jaundice or liver disease, and 139 (84.2%) completed the questionnaire. Of these, 71.3% were PiZZ, 18.0% were PiMZ, and 5.7% did not know their phenotype. Analysis of 104 participants with a known age of diagnosis included 30 participants diagnosed with liver disease before 18 years, of whom 15 had advanced liver disease defined as liver transplantation or listed for liver transplantation. No differences in age, age at diagnosis, gender, race, phenotype, or infant jaundice were identified. Seventy-four participants were diagnosed after age 18 years, of whom 25 had advanced liver disease. In this group, advanced liver disease was associated with male gender ( P = .006) and a greater mean body mass index ( P = .01), but not with race, Pi phenotype, infant jaundice, diabetes, or hypercholesterolemia. Viral hepatitis was more frequently reported in the nontransplant group (34.7% vs 8.0%, P = .01), and the mean daily alcohol use was significantly greater in this group ( P = .04). CONCLUSIONS: Our results suggest that male gender and obesity but not alcohol or viral hepatitis predispose to advanced liver disease in adults with AAT.

Adult↗
PubMed2005

Dietary magnesium and C-reactive protein levels.

OBJECTIVE: Current dietary guidelines recommend adequate intake of magnesium (310-420 mg daily) in order to maintain health and lower the risk of cardiovascular disease. Recent evidence from animal and clinical studies suggests that magnesium may be associated with inflammatory processes. The objective of this study was to determine whether dietary magnesium consumption is associated with C-reactive protein (CRP), a marker of inflammation, in a nationally representative sample. METHODS: Analysis of adult (> or =17 years) participants in a cross-sectional nationally representative survey (National Health and Nutrition Examination Survey 1999-2000 [NHANES]) who were not taking magnesium or magnesium-containing supplements. The primary outcome measure was high sensitivity CRP (elevated > or =3.0 mg/L). RESULTS: Among US adults, 68% consumed less than the recommended daily allowance (RDA) of magnesium, and 19% consumed less than 50% of the RDA. After controlling for demographic and cardiovascular risk factors, adults who consumed or =RDA (Odds Ratio [OR] for intake <50% RDA = 1.75, 95% Confidence Interval [CI] 1.08-2.87). Adults who were over age 40 with a BMI >25 and who consumed <50% RDA for magnesium were 2.24 times more likely to have elevated CRP (95% CI 1.13-4.46) than adults > or =RDA. CONCLUSIONS: Most Americans consume magnesium at levels below the RDA. Individuals with intakes below the RDA are more likely to have elevated CRP, which may contribute to cardiovascular disease risk.

Adolescent↗
PubMed2005

Adjusting O'Brien's test to control type I error for the generalized nonparametric Behrens-Fisher problem.

O'Brien (1984, Biometrics 40, 1079-1087) introduced a simple nonparametric test procedure for testing whether multiple outcomes in one treatment group have consistently larger values than outcomes in the other treatment group. We first explore the theoretical properties of O'Brien's test. We then extend it to the general nonparametric Behrens-Fisher hypothesis problem when no assumption is made regarding the shape of the distributions. We provide conditions when O'Brien's test controls its error probability asymptotically and when it fails. We also provide adjusted tests when the conditions do not hold. Throughout this article, we do not assume that all outcomes are continuous. Simulations are performed to compare the adjusted tests to O'Brien's test. The difference is also illustrated using data from a Parkinson's disease clinical trial.

Algorithms↗
PubMed2005

Incarceration and veterans of the first Gulf War.

OBJECTIVE: This study investigated the prevalence of incarceration and the association with deployment among veterans of the first Persian Gulf War (GW). METHODS: A structured telephone interview of military personnel from Iowa deployed to the Persian Gulf and a comparison sample of nondeployed military personnel was conducted. The interview consisted of validated questions, validated instruments, and investigator-derived questions to assess relevant medical and psychiatric conditions. A total of 4,886 subjects were randomly drawn from one of four study domains, i.e., GW regular military, GW National Guard/Reserve, non-GW regular military, or non-GW National Guard/Reserve. Symptoms of medical conditions, psychiatric disorders, and health care utilization were the main outcome measures. RESULTS: Nearly one-quarter (845 of 3,695 subjects, 22.9%) had been incarcerated at some point before the interview ("ever incarcerated"). Ever incarcerated veterans had a higher frequency of psychiatric and medical comorbidity and higher rates of health care utilization. Ever incarcerated status was associated with male gender, enlisted rank, lower educational levels, low levels of military preparedness, discharge from service, cigarette smoking, antisocial traits, court martial and/or other military discipline, having seen a mental health professional, and having used illegal drugs. GW veterans who participated in combat had a modestly higher risk for incarceration after the GW than did noncombatants (odds ratio, 1.6; 95% confidence interval, 1.0-2.5). CONCLUSIONS: Military recruits with a history of incarceration more often displayed problematic behaviors, more often developed psychiatric/medical conditions, and had high rates of health care utilization. A history of incarceration may be a behavioral marker for substance abuse, antisocial behavior, and mental illness. Importantly, GW deployment carried no increased risk of subsequent incarceration overall.

Adult↗
PubMed2004

Statistical design considerations for pilot studies transitioning therapies from the bench to the bedside.

Pilot studies are often used to transition therapies developed using animal models to a clinical setting. Frequently, the focus of such trials is on estimating the safety in terms of the occurrence of certain adverse events. With relatively small sample sizes, the probability of observing even relatively common events is low; however, inference on the true underlying event rate is still necessary even when no events of interest are observed. The exact upper limit to the event rate is derived and illustrated graphically. In addition, the simple algebraic expression for the confidence bound is seen to be useful in the context of planning studies.

Editorial↗
PubMed2004

Can we predict early recurrence in acute stroke?

BACKGROUND: The prevention of early recurrent stroke, which worsens outcomes after a cerebral infarction, is a major objective for acute stroke therapy. The ability to predict which patients are at risk for early recurrence would be useful for both the management and design of clinical trials. METHODS: Using the prospective database with the 1,266 stroke patients admitted in the TOAST study, we analyzed all the patients who had suffered either a transient ischemic attack (TIA) or a recurrent stroke within 3 months after stroke, and their possible association with 20 selected clinical variables. Both univariate and stepwise regression analyses were performed. RESULTS: Sixty-two patients (4.9%) had a second stroke, and 47 patients (3.7%) had at least one TIA. No particular high-risk period was observed. Early recurrent stroke was associated with the large artery atherosclerosis subtype. A prior history of TIA increased the odds for recurrent stroke (OR = 2.52; 1.16-5.46) or poststroke TIA (OR = 3.46; 1.59-7.48). In addition, patients who had a TIA after the stroke had a 17% chance of having an early recurrent stroke, as compared with 4.4% among those that did not (p = 0.001). CONCLUSION: Our present ability to identify patients at risk for early recurrence based on baseline clinical features remains limited. While the presence of TIA before or after the stroke denotes a subgroup of acute stroke patients at higher risk for early recurrence in the first 3 months, no other factors reliably identify high-risk patients.

Acute Disease↗
PubMed2004

Is esophagoscopy alone sufficient for patients with reflux symptoms?

BACKGROUND: Unsedated esophagoscopy with ultrathin endoscopes is a valuable screening modality for Barrett's esophagus, but the stomach and the duodenum cannot be examined completely with the smallest and best tolerated of these endoscopes. There are no data as to how often disease in the stomach and the duodenum would be missed when using this screening strategy. Our hypothesis is that patients with reflux symptoms, in the absence of daily abdominal pain, nausea, or history of ulcer, were unlikely to have clinically significant gastroduodenal disease. METHODS: Patients scheduled for upper endoscopy at a single outpatient endoscopy unit in a tertiary referral center were screened. The inclusion criterion was reflux symptoms as the primary indication for upper endoscopy. Patients with another valid indication were excluded. A detailed history was recorded and symptom questionnaire completed for each patient before endoscopy; these data were compared with the endoscopy findings. RESULTS: A total of 175 patients were included. Indications for upper endoscopy were the following: worsening symptoms (n=74), ongoing reflux despite therapy (n=27), and long-standing reflux (n=74). Major esophageal findings were discovered in 95 patients. In 10 patients, major gastric or duodenal findings were detected as follows: erosive gastritis (n=8), gastric ulcer (n=2), duodenal ulcer (n=2), erosive duodenitis (n=2), and duodenal polyp (n=1). Daily abdominal pain (p=0.014) or possibly daily nausea (p=0.028 unadjusted, 0.197 adjusted) was associated with major gastric/duodenal disease. Patients without daily abdominal pain, nausea, or a history of gastric/duodenal ulcer were much less likely to have major disease (0.9%) than patients with one of these predictors (13.2%, p=0.00097). CONCLUSIONS: Daily abdominal pain and nausea, in combination with a history of ulcer disease, are strong predictors of major gastric or duodenal disease. Patients with reflux without these predictors are highly unlikely to have a major disease involving the stomach or duodenum, and are suitable candidates for esophagoscopy alone.

Adult↗
PubMed2004

Gulf War veterans with anxiety: prevalence, comorbidity, and risk factors.

BACKGROUND: Veterans of the first Gulf War have higher rates of medical and psychiatric symptoms than nondeployed military personnel. METHODS: To assess the prevalence of and risk factors for current anxiety disorders in Gulf War veterans, we administered a structured telephone interview to a population-based sample of 4886 military personnel from Iowa at enlistment. Participants were randomly drawn from Gulf War regular military, Gulf War National Guard/ Reserve, non-Gulf War regular military, and non-Gulf War National Guard/Reserve. Medical and psychiatric conditions were assessed through standardized interviews and questionnaires in 3695 subjects (76% participation). Risk factors were assessed using multivariate logistic regression models. RESULTS: Veterans of the first Gulf War reported a markedly higher prevalence of current anxiety disorders than nondeployed military personnel (5.9% vs. 2.8%; odds ratio = 2.1; 95% confidence interval = 1.3-3.1), and their anxiety disorders are associated with co-occurring psychiatric disorders. Posttraumatic stress disorder, panic disorder, and generalized anxiety disorder were each present at rates nearly twice expected. In our multivariate model, predeployment psychiatric treatment and predeployment diagnoses (posttraumatic stress disorder, depression, or anxiety) were independently associated with current anxiety disorder. Participation in Gulf War combat was independently associated with current posttraumatic stress disorder, panic disorder, and generalized anxiety disorder. CONCLUSIONS: Current anxiety disorders are relatively frequent in a military population and are more common among Gulf War veterans than nondeployed military personnel. Predeployment psychiatric difficulties are robustly associated with the development of anxiety. Healthcare providers and policymakers need to consider panic disorder and generalized anxiety disorder, in addition to posttraumatic stress disorder, to ensure their proper assessment, treatment, and prevention in veteran populations.

Adult↗
PubMed2003

Antimicrobial resistance trends and outbreak frequency in United States hospitals.

We assessed resistance rates and trends for important antimicrobial-resistant pathogens (oxacillin-resistant Staphylococcus aureus [ORSA], vancomycin-resistant Enterococcus species [VRE], ceftazidime-resistant Klebsiella species [K-ESBL], and ciprofloxacin-resistant Escherichia coli [QREC]), the frequency of outbreaks of infection with these resistant pathogens, and the measures taken to control resistance in a stratified national sample of 670 hospitals. Four hundred ninety-four (74%) of 670 surveys were returned. Resistance rates were highest for ORSA (36%), followed by VRE (10%), QREC (6%), and K-ESBL (5%). Two-thirds of hospitals reported increasing ORSA rates, whereas only 4% reported decreasing rates, and 24% reported ORSA outbreaks within the previous year. Most hospitals (87%) reported having implemented measures to rapidly detect resistance, but only approximately 50% reported having provided appropriate resources for antimicrobial resistance prevention (53%) or having implemented antimicrobial use guidelines (60%). The most common resistant pathogen in US hospitals is ORSA, which accounts for many recognized outbreaks and is increasing in frequency in most facilities. Current practices to prevent and control antimicrobial resistance are inadequate.

Anti-Bacterial Agents↗
PubMed2003

Percutaneous injury, blood exposure, and adherence to standard precautions: are hospital-based health care providers still at risk?

To examine factors associated with blood exposure and percutaneous injury among health care workers, we assessed occupational risk factors, compliance with standard precautions, frequency of exposure, and reporting in a stratified random sample of 5123 physicians, nurses, and medical technologists working in Iowa community hospitals. Of these, 3223 (63%) participated. Mean rates of hand washing (32%-54%), avoiding needle recapping (29%-70%), and underreporting sharps injuries (22%-62%; overall, 32%) varied by occupation (P<.01). Logistic regression was used to estimate the adjusted odds of percutaneous injury (aOR(injury)), which increased 2%-3% for each sharp handled in a typical week. The overall aOR(injury) for never recapping needles was 0.74 (95% CI, 0.60-0.91). Any recent blood contact, a measure of consistent use of barrier precautions, had an overall aOR(injury) of 1.57 (95% CI, 1.32-1.86); among physicians, the aOR(injury) was 2.18 (95% CI, 1.34-3.54). Adherence to standard precautions was found to be suboptimal. Underreporting was found to be common. Percutaneous injury and mucocutaneous blood exposure are related to frequency of sharps handling and inversely related to routine standard-precaution compliance. New strategies for preventing exposures, training, and monitoring adherence are needed.

Blood-Borne Pathogens↗
PubMed2003

Effectiveness of a nationally implemented smoking cessation guideline on provider and patient practices.

BACKGROUND: The Agency for Health Care Policy and Research (AHCPR) smoking cessation guideline outlines a set of recommendations for physicians to follow in daily practice. However, the effectiveness of this guideline has not been reported. The goal of this project was to evaluate the effect of the AHCPR smoking cessation guideline on provider practices with smokers and on patient smoking rates. METHODS: Patient survey and chart review data from 138 Veterans Administration (VA) acute care medical centers with outpatient facilities were examined. Data were available from both sources in 1996, 1997, and 1998. At the midpoint of this period (1997), the VA recommended the AHCPR smoking cessation clinical practice guideline for implementation throughout the VA healthcare system. RESULTS: From 1996 to 1998, both the chart audit and the patient survey showed a significant increase in the percentage of patients in the VA who were counseled about smoking and a significant decrease in the percentage of patients who smoke. CONCLUSIONS: Because the VA tied the guideline implementation to report cards and other performance-enhancing measures, guideline adherence may have been maximized in this setting. These findings suggest that healthcare systems should take an integrated approach to guideline implementation.

Adult↗