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Biomedical subjects

P R Yarnold

Publications and source records attributed to P R Yarnold.

At least 19 recordsLinked to original sources
PubMed2001

HIV-related Pneumocystis carinii pneumonia in older patients hospitalized in the early HAART era.

OBJECTIVE: To determine whether older age continues to influence patterns of care and in-hospital mortality for hospitalized persons with HIV-related Pneumocystis carinii pneumonia (PCP), as determined in our prior study from the 1980s. DESIGN: Retrospective chart review. PATIENTS/SETTING: Patients (1,861) with HIV-related PCP at 78 hospitals in 8 cities from 1995 to 1997. MEASUREMENTS: Medical record notation of possible HIV infection; alveolar-arterial oxygen gradient; CD4 lymphocyte count; presence or absence of wasting; timely use of anti-PCP medications; in-hospital mortality. MAIN RESULTS: Compared to younger patients, patients > or =50 years of age were less likely to have HIV mentioned in their progress notes (70% vs 82%, P <.001), have mild or moderately severe PCP cases at admission (89% vs 96%, P <.002), receive anti-PCP medications within the first 2 days of hospitalization (86% vs 93%, P <.002), and survive hospitalization (82% vs 90%, P <.003). However, age was not a significant predictor of mortality after adjustment for severity of PCP and timeliness of therapy. CONCLUSIONS: While inpatient PCP mortality has improved by 50% in the past decade, 2-fold age-related mortality differences persist. As in the 1980s, these differences are associated with lower rates of recognition of HIV, increased severity of illness at admission, and delays in initiation of PCP-specific treatments among older individuals--factors suggestive of delayed recognition of HIV infection, pneumonia, and PCP, respectively. Continued vigilance for the possibility of HIV and HIV-related PCP among persons > or =50 years of age who present with new pulmonary symptoms should be encouraged.

AIDS-Related Opportunistic Infections↗
PubMed2000

Human leucocyte antigens (HLA) and trimellitic anhydride (TMA) immunological lung disease.

Occupational immunological lung disease, due to low molecular weight, reactive chemicals such as trimellitic anhydride (TMA), is an emerging health problem. If there were a marker that was highly predictive of the ability of the immune system to recognize TMA as an allergen, better prevention strategies could be employed with at risk individuals. The purpose of this study is to evaluate whether human leucocyte antigen (HLA) class specificity is associated with the development of late respiratory systemic syndrome (LRSS) or asthma due to immunological sensitivity to trimellitic anhydride (TMA). This is a case control study of 17 individuals with LRSS, 12 with asthma and 22 TMA similarly exposed individuals who did not develop LRSS or asthma. Comparing the sensitized individuals (LRSS or asthma) with the non-sensitized individuals (controls), we found no difference in frequency of any HLA antigen. In summary, the lack of association of HLA antigens with LRSS or asthma due to TMA suggests that these will not be useful markers to identify at risk individuals.

Adult↗
PubMed2000

Multicenter, double-blind, placebo-controlled, multiple-challenge evaluation of reported reactions to monosodium glutamate.

BACKGROUND: The frequency of reactions reported to occur after the consumption of monosodium glutamate (MSG) is the subject of controversy. OBJECTIVE: We conducted a multicenter, multiphase, double-blind, placebo-controlled study with a crossover design to evaluate reactions reportedly caused by MSG. METHODS: In 3 of 4 protocols (A, B, and C), MSG was administered without food. A positive response was scored if the subject reported 2 or more symptoms from a list of 10 symptoms reported to occur after ingestion of MSG-containing foods within 2 hours. In protocol A 130 self-selected reportedly MSG-reactive volunteers were challenged with 5 g of MSG and with placebo on separate days (days 1 and 2). Of the 86 subjects who reacted to MSG, placebo, or both in protocol A, 69 completed protocol B to determine whether the response was consistent and dose dependent. To further examine the consistency and reproducibility of reactions to MSG, 12 of the 19 subjects who responded to 5 g of MSG but not to placebo in both protocols A and B were given, in protocol C, 2 challenges, each consisting of 5 g of MSG versus placebo. RESULTS: Of 130 subjects in protocol A, 50 (38. 5%) responded to MSG only, 17 (13.1%) responded to placebo only (P <. 05), and 19 (14.6%) responded to both. Challenge with increasing doses of MSG in protocol B was associated with increased response rates. Only half (n = 19) of 37 subjects who reacted to 5 g of MSG but not placebo in protocol A reacted similarly in protocol B, suggesting inconsistency in the response. Two of the 19 subjects responded in both challenges to MSG but not placebo in protocol C; however, their symptoms were not reproducible in protocols A through C. These 2 subjects were challenged in protocol D 3 times with placebo and 3 times with 5 g of MSG in the presence of food. Both responded to only one of the MSG challenges in protocol D. CONCLUSION: The results suggest that large doses of MSG given without food may elicit more symptoms than a placebo in individuals who believe that they react adversely to MSG. However, neither persistent nor serious effects from MSG ingestion are observed, and the responses were not consistent on retesting.

Adult↗
PubMed2000

Review of alleged reaction to monosodium glutamate and outcome of a multicenter double-blind placebo-controlled study.

Monosodium glutamate (MSG) has a long history of use in foods as a flavor enhancer. In the United States, the Food and Drug Administration has classified MSG as generally recognized as safe (GRAS). Nevertheless, there is an ongoing debate exists concerning whether MSG causes any of the alleged reactions. A complex of symptoms after ingestion of a Chinese meal was first described in 1968. MSG was suggested to trigger these symptoms, which were referred to collectively as Chinese Restaurant Syndrome. Numerous reports, most of them anecdotal, were published after the original observation. Since then, clinical studies have been performed by many groups, with varying degrees of rigor in experimental design ranging from uncontrolled open challenges to double-blind, placebo controlled (DBPC) studies. Challenges in subjects who reported adverse reactions to MSG have included relatively few subjects and have failed to show significant reactions to MSG. Results of surveys and of clinical challenges with MSG in the general population reveal no evidence of untoward effects. We recently conducted a multicenter DBPC challenge study in 130 subjects (the largest to date) to analyze the response of subjects who report symptoms from ingesting MSG. The results suggest that large doses of MSG given without food may elicit more symptoms than a placebo in individuals who believe that they react adversely to MSG. However, the frequency of the responses was low and the responses reported were inconsistent and were not reproducible. The responses were not observed when MSG was given with food.

Animals↗
PubMed2000

Substance use disorder in hospitalized severely mentally ill psychiatric patients: prevalence, correlates, and subgroups.

The prevalence and demographic and clinical correlates of lifetime substance use disorders were examined in a cohort of 325 recently hospitalized psychiatric patients (53% schizophrenia or schizoaffective disorder). Alcohol use was the most common type of substance use disorder, followed by cannabis and cocaine use. Univariate analyses indicated that gender (male), age (younger), education (less), history of time in jail, conduct disorder symptoms, and antisocial personality disorder symptoms were predictive of substance use disorders. Lifetime cannabis use disorder was uniquely predicted by marital status (never married) and fewer psychiatric hospitalizations during the previous 6 months. Optimal classification tree analysis, an exploratory, nonlinear method of identifying patient subgroups, was successful in predicting 74 percent to 86 percent of the alcohol, cannabis, and cocaine use disorders. The implications of this method for identifying specific patient subgroups and service needs are discussed.

Adult↗
PubMed2000

A new preadmission staging system for predicting inpatient mortality from HIV-associated Pneumocystis carinii pneumonia in the early highly active antiretroviral therapy (HAART) era.

A common severe complication of human immunodeficiency virus (HIV) infection has been Pneumocystis carinii pneumonia (PCP). Recently, with increasing use of PCP prophylaxis and multidrug antiretroviral therapy, the clinical manifestations of HIV infection have changed dramatically and the predictors of inpatient mortality for PCP may have also changed. We developed a new staging system for predicting inpatient mortality for patients with HIV-associated PCP admitted between 1995 and 1997. Trained abstractors performed chart reviews of 1,660 patients hospitalized with HIV-associated PCP between 1995 and 1997 at 78 hospitals in seven metropolitan areas in the United States. The overall inpatient mortality rate was 11.3%. Hierarchically optimal classification tree analysis identified an ordered five-category staging system based on three predictors: wasting, alveolar-arterial oxygen gradient (AaPO(2)), and serum albumin level. The mortality rate increased with stage: 3.7% for Stage 1, 8.5% for Stage 2, 16.1% for Stage 3, 23.3% for Stage 4, and 49.1% for Stage 5. This new staging system may be useful for severity of illness adjustment in the current era while exploring current variation in HIV-associated PCP inpatient mortality rates among hospitals and across cities.

AIDS-Related Opportunistic Infections↗
PubMed2000

Improvements in outcomes of acute respiratory failure for patients with human immunodeficiency virus-related Pneumocystis carinii pneumonia.

In the early 1990s, hospital survival among patients with human immunodeficiency virus (HIV)-related Pneumocystis carinii pneumonia (PCP) and respiratory failure was poor, approximately 20%. We examined ICU use and outcomes for patients with acute respiratory failure from PCP from 1995 to 1997. We conducted a retrospective medical record review using a random sample of 71 hospitals in seven regions of the United States. Among 1,660 patients with confirmed or presumed PCP, 155 (9%) received mechanical ventilation for respiratory failure. Factors that predicted use of mechanical ventilation, independent of severity of illness on hospital admission, included African-American ethnicity and geographic location (p </= 0.002). Hospital survival for patients receiving mechanical ventilation was 38% (95% CI 30, 46). Controlling for severity of illness, patients who were on PCP prophylaxis prior to developing PCP were less likely to survive to hospital discharge (p </= 0.02). There were no significant differences in hospital survival regardless of whether patients had received less than or more than 5 d of PCP treatment prior to respiratory failure (39 versus 29%; p = 0.5). In conclusion, from 1995 to 1997, hospital survival after PCP requiring mechanical ventilation was approximately 40%. Physicians caring for patients with severe HIV-related PCP should be aware of the improvements in outcomes for this disease before making recommendations about withholding or withdrawing ventilatory support for respiratory failure.

AIDS-Related Opportunistic Infections↗
PubMed2000

IL-1beta and TNF-alpha in prostatic secretions are indicators in the evaluation of men with chronic prostatitis.

PURPOSE: Chronic Prostatitis, or Chronic Pelvic Pain Syndrome [CPPS], is a common disorder characterized by pelvic pain and varying degrees of inflammation in expressed prostatic secretions (EPS). In search of markers to more clearly define CPPS, we compared proinflammatory cytokines interleukin-1beta (IL-1beta) and tumor necrosis factor-alpha (TNF-alpha) levels in EPS from men with CPPS, to healthy men and men with Benign Prostatic Hyperplasia (BPH). METHODS: 78 men: controls (n = 16), BPH (n = 14), CPPS IIIA [>/=10 white blood cells per high power field (WBC/hpf) in EPS] (n = 18), CPPS IIIB [<10 WBC/hpf in EPS] (n = 20), and asymptomatic inflammatory prostatitis (AIP) (n = 10) were evaluated for EPS WBC, and IL-1beta and TNF-alpha by ELISA. RESULTS: IL-1beta and TNF-alpha levels in EPS were usually detectable in men with CPPS IIIA (89% and 45%, respectively) or AIP (90%; 100%), but less often in controls (31%; 17%), BPH (57%; 15%), and CPPS IIIB (35%; 15%) respectively. IL-1beta and TNF-alpha levels were higher in CPPS IIIA versus CPPS IIIB, and in AIP versus controls or BPH (p's <0.001). Cut-points for IL-1beta and TNF-alpha discriminated AIP from controls (predictive values = 94% and 83%, respectively) and CPPS IIIA from CPPS IIIB (predictive values 84% and 100%). Overall, there was a correlation between IL-1beta and TNF-alpha (p <0.003), but no correlation between WBC and IL-1beta (p <0.1) or TNF-alpha (p <0.50). CONCLUSIONS: Cytokines are frequently present and elevated in the EPS from men with CPPS IIIA and AIP and provide a novel means for identification, characterization and potential management of men with CPPS that differs from traditional methods based on WBC.

Adult↗
PubMed1999

Screening for undetected mental disorders in high utilizers of primary care services.

OBJECTIVE: To define the prevalence and detection rates of mental disorders among high utilizers as compared with typical utilizers, and to examine the effect of case-mix adjustment on these parameters. DESIGN: Cross-sectional study. SETTING: General internal medicine outpatient clinic associated with an urban, academic medical center. PATIENTS: From patients attending a general medicine clinic, 304 were selected randomly in three utilization groups, defined by number of clinic visits: (1) high utilizers; (2) case-mix adjusted high utilizers; and (3) typical utilizers (control patients). INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: The presence of any mental disorder was ascertained by the PRIME-MD screening instrument. Chart review on all patients was performed to ascertain mental disorders detected by primary care physicians. The prevalence of mood disorders was markedly higher in high utilizers (29%) than in adjusted high utilizers (15%) or controls (10%) (p <.001). Anxiety disorders were slightly, but not statistically, more prevalent in the group adjusted for case mix (16%) than in other high utilizers (12%) or controls (9%). Alcoholism was significantly more prevalent in controls (12%) than in adjusted (6%) or other high utilizers (3%) (p <.03). The discrepancy in detection rates between PRIME-MD and chart review for any mental disorder was less for high utilizers (37% vs 31%) as compared with adjusted high utilizers (31% vs 11%) or controls (24% vs 8%). CONCLUSIONS: Mood disorders are associated with a high overall burden of illness, while anxiety disorders are more predominant among outliers after case-mix adjustment. Detection rates differ substantially by utilization pattern. Screening efforts can be more appropriately targeted with knowledge of these patterns.

Adult↗
PubMed1999

A clinical and immunologic study to assess risk of TMA-induced lung disease as related to exposure.

The objective of this study was to determine whether there are trimellitic anhydride (TMA) exposure levels that are very unlikely to cause immunologically mediated respiratory disease. A 3-year clinical and immunologic survey study of 286 employees was conducted at a facility that manufactures TMA. Each employee was assigned an exposure classification from 1 (highest) to 5 (lowest). Of the 28 individuals in exposure class 1, 8 (29%) developed disease; of the 57 class 2 employees, 2 (4%) developed disease; of the 79 class 3 employees, 4 (5%) developed disease. Of the 98 class 4 employees and the 24 class 5 employees, none developed disease. Inasmuch as individuals in class 4 and 5 (TMA exposure < 0.002 mg/m3) are at low risk of developing disease due to TMA, it appears that they do not warrant routine inclusion in surveillance studies.

Adult↗
PubMed1999

Statistical methodology: VIII. Using confirmatory factor analysis (CFA) in emergency medicine research.

How many underlying characteristics (or factors) does a set of survey questions measure? When subjects answer a set of self-report questions, is it more appropriate to analyze the questions individually, to pool responses to all of the questions to form one global score, or to combine subsets of related questions to define multiple underlying factors? Factor analysis is the statistical method of choice for answering such questions. When researchers have no idea beforehand about what factors may underlie a set of questions, they use exploratory factor analysis to infer the best explanatory model from observed data "after the fact." If, on the other hand, researchers have a hypothesis beforehand about the underlying factors, then they can use confirmatory factor analysis (CFA) to evaluate how well this model explains the observed data and to compare the model's goodness-of-fit with that of other competing models. This article describes the basic rules and building blocks of CFA: what it is, how it works, and how researchers can use it. The authors begin by placing CFA in the context of a common research application-namely, assessing quality of medical outcome using a patient satisfaction survey. They then explain, within this research context, how CFA is used to evaluate the explanatory power of a factor model and to decide which model or models best represent the data. The information that must be specified in the analysis to estimate a CFA model is highlighted, and the statistical assumptions and limitations of this analysis are noted. Analyzing the responses of 1,614 emergency medical patients to a commonly-used "patient satisfaction" questionnaire, the authors demonstrate how to: 1) compare competing factor-models to find the best-fitting model; 2) modify models to improve their goodness-of-fit; 3) test hypotheses about relationships among the underlying factors; 4) examine mean differences in "factor scores"; and 5) refine an existing instrument into a more streamlined form that has fewer questions and better conceptual and statistical precision than the original instrument. Finally, the role of CFA in developing new instruments is discussed.

Data Interpretation, Statistical↗
PubMed1999

Computers and connectivity in Illinois emergency departments.

UNLABELLED: Although the Internet has been described as "ubiquitous," little is known about the extent to which physicians have access to the Internet while providing clinical care. OBJECTIVE: To assess the extent of Internet connectivity within the clinical area of every ED within the state of Illinois. METHODS: This was a prospective observational study. Each Illinois ED listed in a published directory was called by telephone, and a responsible party was identified to provide information regarding the type and size of the ED, patient demographics, the types of personal computers (PCs) available in the ED (if any), the types of operating systems used, the availability of access to the World Wide Web (Web), and the highest speed at which an Internet connection could be established. Responses regarding the presence and types of PCs and the types of operating systems used were assessed using one-factor chi-square. Univariate and multivariate predictors of the type of PC used, the presence or absence of Web access, and the highest speed of Internet access were evaluated using optimal discriminant analysis and nonlinear classification tree analysis, respectively. RESULTS: One hundred ninety-eight of the 199 EDs in the state of Illinois (99.5%) completed the survey. Of the responding EDs, 50.5% had PCs, but only 17.6% had Web access. When Web access was available, it was most often available through a high-speed Internet connection that was faster than a dial-up modem. Most departments (68.1%) with PCs used the Windows 95 or Windows 98 operating systems. A majority (62.5%) used the Netscape browser exclusively. Larger EDs (more than six ED beds) in rural or suburban areas were more likely to have a PC compared with smaller EDs (six or fewer beds). Large EDs (more than 12 ED beds) in private tertiary care or academic hospitals were most likely to have Web access. CONCLUSIONS: Although half of Illinois EDs have PCs, only one in six has access to the Internet; thus, most emergency physicians do not have ready access to the Web from the site where they deliver clinical care.

Analysis of Variance↗
PubMed1999

Comparing three preprocessing strategies for longitudinal data. An example in functional outcomes research.

Longitudinal monitoring of individual patient data is becoming routine in physician office practice. This study compares three different methods for evaluating clinical outcomes for individual patients: raw change score analysis versus normative and ipsative statistical analyses. Two discrete samples of intermittent claudication patients making vascular surgery office visits--drawn from interventional management versus stable, routinely followed control groups--were tested four times using both generic and disease-specific functional status measures. Results indicated that the ipsative method was most consistent with several different types of a priori hypotheses that are often evaluated in analysis of repeated measures data.

Evaluation Studies as Topic↗
PubMed1998

Predicting in-hospital mortality of patients receiving cardiopulmonary resuscitation: unit-weighted MultiODA for binary data.

Widely used, linear classification functions may be derived on the basis of several different statistical paradigms. Since, regardless of choice, analysis generally yields an equation with unwieldy intercept and attribute coefficients, researchers often construct simpler scoring schemes based on unit weights. Accordingly, for applications involving entirely binary data, we discuss a simple procedure for obtaining unit-weighted (that is, we restrict attribute coefficients to the values of 0, 1 or -1) MultiODA functions that explicitly maximize classification accuracy in the training sample. We illustrate this with an application involving prediction of in-hospital mortality of patients receiving cardiopulmonary resuscitation. In training analysis of 88 patients, unit-weighted MultiODA outperformed prior scoring schemes and logistic regression analysis. Unit-weighted MultiODA also yielded superior hold-out (cross-generalizability) validity for an independent sample of 26 patients.

Cardiopulmonary Resuscitation↗
PubMed1998

Thrombotic thrombocytopenic purpura associated with ticlopidine. A review of 60 cases.

BACKGROUND: Thrombotic thrombocytopenic purpura, a life-threatening multisystem disease, has been infrequently associated with use of ticlopidine, a platelet anti-aggregating agent. PURPOSE: To review 60 cases of ticlopidine-associated thrombotic thrombocytopenic purpura. DATA SOURCES: Medical records, published case reports, and case reports submitted to the U.S. Food and Drug Administration. STUDY SELECTION: Instances of ticlopidine-associated thrombotic thrombocytopenic purpura were identified. DATA SYNTHESIS: Ticlopidine had been prescribed for less than 1 month in 80% of the patients, and normal platelet counts had been found within 2 weeks of the onset of thrombotic thrombocytopenic purpura in most patients. Mortality rates were higher among patients who were not treated with plasmapheresis than among those who underwent plasmapheresis (50% compared with 24%; P < 0.05). CONCLUSIONS: Ticlopidine use may be associated with the development of thrombotic thrombocytopenic purpura, usually within 1 month of initiation of therapy. The onset of ticlopidine-associated thrombotic thrombocytopenic purpura is difficult to predict, despite close monitoring of platelet counts.

Adult↗
PubMed1998

Predicting patient satisfaction: a study of two emergency departments.

To identify perceptions that predict overall patient (dis)satisfaction with Emergency Department (ED) care, we studied responses to a survey mailed to all discharged patients over a 6-month period (Academic Hospital), and to a telephone interview of a random sample of discharged patients over a 1-year period (Community Hospital). The survey and interview both assessed overall satisfaction, as well as satisfaction with perceived waiting times, information delivery, and expressive quality of physicians, nurses, and staff. Data for 1176 patients (training sample) and 1101 patients (holdout sample) who rated overall satisfaction as either "very good" or "very poor" (Academic Hospital), and for 856 patients (training sample) and 431 patients (holdout sample) who rated overall satisfaction as either "excellent" or "poor" (Community Hospital), were retained for analysis. For both hospitals, nonlinear tree models efficiently achieved overall classification accuracy exceeding 98% in training analysis and 95% in holdout analysis (all p < .0001). The findings suggest that overall patient (dis)satisfaction with care received in the ED is nearly perfectly predictable on the basis of patient-rated expressive qualities of ED staff, particularly physicians and nurses. Interventions designed to reinforce positive (and extinguish negative) expressive health-care provider behaviors may cut the number of extremely dissatisfied patients in half.

Chicago↗
PubMed1998

A classification tree analysis of selection for discretionary treatment.

OBJECTIVES: To study treatment bias in observational outcomes research, the authors present a nonlinear classification tree model of clinical and psychosocial factors influencing selection for interventional management (lower extremity bypass surgery or angioplasty) for patients with intermittent claudication. METHODS: The study sample includes 532 patients with mild to moderate lower extremity vascular disease, without prior peripheral revascularization procedures or symptoms of disease progression. All patients were enrolled in a prospective outcomes study at the time of an initial referral visit for claudication to one of the 16 Chicago-area vascular surgery offices or clinics in 1993-95. The influence of baseline sociodemographic, clinical, and patient self-reported health status data on subsequent treatment is analyzed. Study variables were derived from lower extremity blood flow records and patient questionnaires. Follow-up home health visits were used to ascertain the frequency of lower extremity revascularization procedures within 6 months of study enrollment. Hierarchically optimal classification tree analysis (CTA) was used to obtain a nonlinear model of treatment selection. The model retains attributes with the highest sensitivity at each node based on cutpoints that maximize classification accuracy. Experimentwise Type I error is ensured at P < 0.05 by the Bonferroni method and jackknife validity analysis is used to assess model stability. RESULTS: Seventy-one of 532 patients (13.3%) underwent interventional procedures within 6 months. Ten patient attributes were used in the CTA model, which had an overall classification accuracy of 89.5% (67.6% sensitive and 92.9% specific), achieving 57.7% of the theoretical possible improvement in classification accuracy beyond chance. Eleven model prediction endpoints reflected a 33-fold difference in odds of undergoing lower extremity revascularization. CONCLUSIONS: Initial ankle-brachial index (100%), leg symptom status over the previous six months (89%), self-reported community walking distance (74%) and prior willingness to undergo a lower extremity hospital procedure (39%) were used to classify most patients in the sample. These attributes are critical control variables for a valid observational study of treatment effectiveness.

Angioplasty↗