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Biomedical subjects

Lee K Brown

Publications and source records attributed to Lee K Brown.

11 recordsLinked to original sources
PubMed2005

Antidepressant medication use and restless legs syndrome in patients presenting with insomnia.

BACKGROUND AND PURPOSE: Restless legs syndrome (RLS) is a movement disorder that frequently results in significant complaints of insomnia. Based on published case reports, it is commonly believed that RLS can be caused or exacerbated by antidepressant agents, thus complicating the treatment of depressed patients who are already prone to sleep disturbances. However, there are no systematic studies demonstrating an association between the clinical diagnosis of RLS and the use of antidepressant medication. PATIENTS AND METHODS: Retrospective chart review of 200 consecutive patients presenting for evaluation of sleep initiation insomnia at an accredited freestanding sleep disorders center that is part of an integrated health care system. RESULTS: Mean age (+/-SD) of patients was 51.1+/-14.8 years; 60% were women. Fifty-six percent carried a diagnosis of depression, 38% were being treated with antidepressant medication at presentation and 45% met clinical diagnostic criteria for RLS. There were no statistical associations, either by chi(2) analysis or odds ratios, between RLS and antidepressant use or use of any specific class of antidepressant. Positive associations with RLS were found for patients receiving treatment for hypothyroidism and those taking estrogens; a significant negative association was found for patients receiving beta adrenergic antagonists. CONCLUSIONS: Although there are anecdotal reports of antidepressant use causing or exacerbating RLS, systematic study of this issue fails to corroborate an association.

Adult↗
PubMed2004

Obstructive sleep apnea syndrome complicating oculopharyngeal muscular dystrophy.

We report a 75-year-old Spanish-American woman who received a diagnosis of oculopharyngeal muscular dystrophy after presenting with ptosis and dysphagia. She also complained of snoring and daytime somnolence, and was found to have obstructive sleep apnea (OSA) syndrome attributable to her neuromuscular disorder. This is the first report of OSA syndrome complicating typical, adult-onset oculopharyngeal muscular dystrophy, and should prompt the evaluation of other such patients for sleep-disordered breathing.

Aged↗
PubMed2003

Multilevel and continuous pleural fluid pH likelihood ratios for evaluating malignant pleural effusions.

STUDY OBJECTIVE: Expert consensus recommends testing pleural fluid for pH to assist the selection of patients with malignant pleural effusions for pleurodesis. Although published studies report an association between pleural fluid pH and patient outcomes after pleurodesis, clinicians have no definitive information on how to use pH to select patients for pleurodesis. Thus, we quantitatively assessed different methods for deriving likelihood ratios from pleural fluid pH and evaluated the potential role of pH in selecting patients for pleurodesis. DATA SOURCES: MEDLINE, systematic reviews, article reference lists, and contact with primary authors. STUDY SELECTION: Studies that assessed the impact of pleural fluid pH on survival and pleurodesis failure rates among patients with malignant pleural effusions. DATA EXTRACTION: Primary authors provided their data in electronic spreadsheets. DATA SYNTHESIS: Retrieved data sets included survival and pleurodesis failure rates for 417 patients and 433 patients, respectively. Binary, multilevel, and continuous likelihood ratios were calculated to estimate the likelihood of death within 3 months of pleurodesis or pleurodesis failure rates. Values for the likelihood ratios were compared for each of the three strategies, and relative clinical and statistical significance were assessed. Pleural fluid pH had marginal performance for identifying patients with < 3-month anticipated survival; binary likelihood ratios provided as much information as the multilevel and continuous strategies. Likelihood ratios for identifying patients likely to fail pleurodesis were clinically useful. Continuous likelihood ratios provided statistically more information as compared with the multilevel and binary strategies. CONCLUSIONS: Pleural fluid pH has marginal value for estimating death within 3 months of pleurodesis, and binary likelihood ratios (cut point </= 7.20) perform as well as the other strategies assessed. Pleural fluid pH provides more useful information for estimating the likelihood of pleurodesis failure for which continuous likelihood ratios provide the most information as compared with binary or multilevel likelihood ratios.

Data Interpretation, Statistical↗
PubMed2002

Multilevel likelihood ratios for identifying exudative pleural effusions(*).

STUDY OBJECTIVES: To determine multilevel likelihood ratios for pleural fluid tests that are commonly used to discriminate between exudative and transudative pleural effusions. DESIGN: Meta-analysis of patient-level data. PATIENT DATA: Selected studies included patients with diagnoses of exudative or transudative pleural effusions who underwent thoracentesis and laboratory analysis of their pleural fluid. MEASUREMENTS AND METHODS: Studies were identified by searching MEDLINE and related bibliographies. Data were obtained for 1,448 patients from seven primary investigators or extracted from dot plots in published reports. Likelihood ratios were calculated from extracted data stratified across ranges of test result values. RESULTS: Sufficient data were available to calculate multilevel likelihood ratios for the elements of Light's criteria (pleural fluid lactate dehydrogenase [LDH], ratio of pleural fluid to serum LDH, and ratio of pleural fluid to serum protein), pleural fluid protein, ratio of pleural fluid to serum cholesterol, pleural fluid cholesterol, and gradient of pleural fluid to serum albumin. Each of these tests provided levels of likelihood ratios through the most clinically relevant range (0 to 10). CONCLUSION: Multilevel likelihood ratios combined with a clinician's estimation of the pretest probability of an exudative effusion improve the diagnostic accuracy of discriminating between exudative and transudative pleural effusions. Likelihood ratios avoid the use of confusing terms, such as "pseudoexudates," that derive from the use of single cutoff points for pleural fluid tests.

Diagnosis, Differential↗
PubMedDate not supplied

Multilevel and continuous pleural fluid pH likelihood ratios for draining parapneumonic effusions.

BACKGROUND: Although clinical practice guidelines endorse the use of pleural fluid pH to select patients with parapneumonic effusions for pleural drainage, no studies have reported likelihood ratios for pleural fluid pH. OBJECTIVES: We derived and tested the value of continuous likelihood ratios for selecting pneumonia patients for pleural drainage. METHODS: Patient level pleural fluid pH results were obtained from a registry of primary studies that assessed the discriminative properties of pH. Multilevel likelihood ratios were calculated for four pH intervals. Continuous likelihood ratios were derived from logistic regression using discrete pH values. Binary, multilevel and continuous likelihood ratios were compared to evaluate the statistical (chi2) and clinical advantages of continuous likelihood ratios. RESULTS: Hundred and ninety-seven pleural fluid pH results were retrieved from published reports and categorized into four pH ordinal intervals. Multilevel likelihood ratios ranged from a low of 0.13 (95% CI, 0.04-0.41) for pH values >7.40 to a high of 15.80 (95% CI, 7.04-35.45) for pH values < or =7.00. Logistic regression derived the following equation for continuous likelihood ratios: exp[-7.168(measured pH - 7.207)]. Continuous likelihood ratios offered more diagnostic information both statistically (p < 0.005) and clinically compared with binary and multilevel likelihood ratios. CONCLUSIONS: Analysis of a patient registry allows the derivation of an exponential equation that calculates continuous likelihood ratios for discrete pleural fluid pH values. Continuous likelihood ratios provide more clinically and statistically significant information compared with binary and multilevel likelihood ratios for calculating posttest probabilities of the need to drain parapneumonic effusions.

Decision Support Techniques↗