Rigorous new approach to constructing a gold standard for validating new diagnostic criteria, as exemplified by the eosinophilia-myalgia syndrome

BACKGROUND

Constructing diagnostic criteria, a common problem in clinical medicine, is particularly difficult for diseases that lack a pathognomonic "gold standard." To develop an improved strategy for constructing such criteria, we used the eosinophilia-myalgia syndrome as an example. The goal, for research classifications, was to construct validated clinically sensible criteria and to develop improved methods that can be used for other disorders.

METHODS

Using a "pattern-based" approach with data from several separate sources, a committee of investigators first prepared and informally tested criteria for the diagnosis of eosinophilia-myalgia syndrome. A gold standard challenge set of reports of cases and noncases was independently generated and separately validated by an external panel of clinical experts. The criteria were then tested using the gold standard set, and interobserver variability and diagnostic accuracy were determined.

RESULTS

Interobserver variability showed the following mean proportionate agreements: 98.7% for the presence of specific criteria elements, 99% to 100% for diagnosis, and 97% to 98% for diagnostic pattern. kappa Values were correspondingly high. Diagnostic accuracy showed sensitivity at 88%, specificity at 97%, and overall accuracy at 92%.

CONCLUSIONS

The proposed criteria are accurate and reproducible, and can be used in future clinical investigations of the eosinophilia-myalgia syndrome. The new strategy and methods developed for this challenge can be valuable for solving analogous problems in constructing criteria for other clinical disorders.

The dimensions of service quality for hospitals: development and use of the KQCAH scale

Using a combination of qualitative and quantitative research methodologies, this study identifies the dimensions of hospital service quality, operationalizes the dimensions, and develops an instrument to measure patient satisfaction. This instrument, the Key Quality Characteristics Assessment for Hospitals (KQCAH) scale, was developed using input from 12 hospital administrators, over 100 hospital employees, and 23 recent patients and family members.

Antibiotic use in Ontario facilities that provide chronic care

OBJECTIVE

To determine the incidence and variability of antibiotic use in facilities which provide chronic care and to determine how often clinical criteria for infection are met when antibiotics are prescribed in these facilities.

DESIGN

A prospective, 12-month, observational cohort study.

SETTING

Twenty-two facilities which provide chronic care in southwestern Ontario.

PARTICIPANTS

Patients who were treated with systemic antibiotics over the study period.

MEASUREMENTS

Characteristics of antibiotic prescriptions (name, dose, duration, and indication) and clinical features of randomly selected patients who were treated with antibiotics.

RESULTS

A total of 9,373 courses of antibiotics were prescribed for 2,408 patients (66% of all patients in study facilities). The incidence of antibiotic prescriptions in the facilities ranged from 2.9 to 13.9 antibiotic courses per 1,000 patient-days. Thirty-six percent of antibiotics were prescribed for respiratory tract infections, 33% for urinary infections, and 13% for skin and soft tissue infections. Standardized surveillance definitions of infection were met in 49% of the 1,602 randomly selected patients who were prescribed antibiotics. Diagnostic criteria for respiratory, urinary, and skin infection were met in 58%, 28%, and 65% of prescriptions, respectively. One third of antibiotic prescriptions for a urinary indication were for asymptomatic bacteriuria. Adverse reactions were noted in 6% of prescriptions for respiratory and urinary infections and 4% of prescriptions for skin infection.

CONCLUSIONS

Antibiotic use is frequent and highly variable amongst patients who receive chronic care. Reducing antibiotic prescriptions for asymptomatic bacteriuria represents an important way to optimize antibiotic use in this population.

Life-sustaining treatment and assisted death choices in depressed older patients

OBJECTIVES

The major purpose of this study was to examine the effect of depressed mood in older, medically ill, hospitalized patients on their preferences regarding life-sustaining treatments, physician-assisted suicide (PAS), and euthanasia and to determine the degree to which financial constraints affected their choices.

DESIGN

Cross-sectional study.

SETTING

General medical hospital.

PARTICIPANTS

One hundred fifty-eight medically hospitalized, nondemented patients age 60 or older, mean age 74.1 (range 60-94). The sample was divided, based on Center for Epidemiologic Studies-Depression (CES-D) scores, into a depressed group (n = 71) and a nondepressed control group.

MEASUREMENTS

Subjects underwent a structured interview evaluating their life-sustaining treatment choices and whether they would accept or refuse PAS or euthanasia under a variety of hypothetical conditions. These choices were reevaluated with the introduction of financial impact. In addition, assessment included measures of depression, suicide, cognition, social support, functioning, and religiosity.

RESULTS

Depression was found to be highly associated with acceptance of PAS and euthanasia in most hypothetical clinical scenarios in addition to patients' current condition. Compared with nondepressed people, depressed respondents were 13 times as likely to accept PAS when considering their current condition (95% confidence interval [CI] 1.68-110.98), and over twice as likely to accept PAS when facing a hypothetical terminal illness or coma. Depression alone was weakly associated with life-sustaining treatment choices but, when financial impact was introduced, significantly more depressed subjects refused treatment options they had previously desired than did nondepressed subjects. The presence of suicidal ideation, even passive ideation, was strongly predictive of life-sustaining treatment refusals and increased interest in PAS and euthanasia. Depression's effect on acceptance of PAS was confirmed by logistic regression, which also showed that religious coping was significantly correlated with less interest in PAS in two hypothetical scenarios. CONCLUSION. Depressed subjects and even subjects with subtle, passive suicidal ideation were markedly more interested in PAS and euthanasia than nondepressed subjects in hypothetical situations. Depressed subjects were also particularly vulnerable to rejecting treatments if financial consequences might have resulted.

Apathy in neurologic disorders

Recent research has greatly increased our understanding of the clinical phenomenology and etiology of apathy as a distinct clinical symptom and syndrome. Several rating scales have been developed that assist in making a diagnosis of apathy. Apathy has received increasing attention as an important source of functional disability that should be considered when assessing and treating patients with neurologic disease.

Antiphospholipid syndrome and perioperative hemostatic management of cardiac valvular surgery

Hemostatic aspects of antiphospholipid syndrome (APS) present unique challenges to clinicians and laboratory personnel alike, particularly in the perioperative period. These challenges are especially evident in patients requiring cardiac valve replacement surgery. However, the literature outlining the optimal approach in such patients is limited. We present the case of a 25-year-old woman with severe aortic regurgitation as a result of APS with particular reference to the precautions necessary during perioperative care. Particularly important are the prevention of thrombotic or hemorrhagic complications, management of associated thrombocytopenia, and laboratory methods of perioperative anticoagulation monitoring in the setting of prolonged clotting times.

Genetic modification of survival in tissue-specific knockout mice with mitochondrial cardiomyopathy

We recently described a mouse model that reproduces important pathophysiological features of mitochondrial DNA (mtDNA) mutation diseases. The gene for mouse mitochondrial transcription factor A, Tfam (also called mtTFA), a nucleus-encoded key regulator of mtDNA expression, was targeted with loxP sites (Tfam(loxP)) and disrupted in vivo by transgenic expression of cre-recombinase from the muscle creatinine kinase (Ckmm) promoter. This promoter is active from embryonic day 13, and the knockouts had normal respiratory chain function in the heart at birth and developed mitochondrial cardiomyopathy postnatally. In this paper, we describe a heart-knockout strain obtained by mating Tfam(loxP) mice to animals expressing cre-recombinase from the alpha-myosin heavy chain (Myhca) promoter. This promoter is active from embryonic day 8, and the knockouts had onset of mitochondrial cardiomyopathy during embryogenesis. The age of onset of cardiac respiratory chain dysfunction can thus be controlled by temporal regulation of cre-recombinase expression. Further characterization demonstrated that approximately 75% of the knockouts died in the neonatal period, whereas, surprisingly, approximately 25% survived for several months before dying from dilated cardiomyopathy with atrioventricular heart conduction blocks. Modifying gene(s) affect the life span of the knockouts, because approximately 95% of the knockout offspring from an intercross of the longer-living knockouts survived the neonatal period. Thus, the tissue-specific knockouts we describe here not only reproduce important pathophysiological features of mitochondrial cardiomyopathy but also provide a powerful system by which to identify modifying genes of potential therapeutic value.

Cardiac hypertrophy with preserved contractile function after selective deletion of GLUT4 from the heart

Glucose enters the heart via GLUT1 and GLUT4 glucose transporters. GLUT4-deficient mice develop striking cardiac hypertrophy and die prematurely. Whether their cardiac changes are caused primarily by GLUT4 deficiency in cardiomyocytes or by metabolic changes resulting from the absence of GLUT4 in skeletal muscle and adipose tissue is unclear. To determine the role of GLUT4 in the heart we used cre-loxP recombination to generate G4H(-/-) mice in which GLUT4 expression is abolished in the heart but is present in skeletal muscle and adipose tissue. Life span and serum concentrations of insulin, glucose, FFAs, lactate, and beta-hydroxybutyrate were normal. Basal cardiac glucose transport and GLUT1 expression were both increased approximately 3-fold in G4H(-/-) mice, but insulin-stimulated glucose uptake was abolished. G4H(-/-) mice develop modest cardiac hypertrophy associated with increased myocyte size and induction of atrial natriuretic and brain natriuretic peptide gene expression in the ventricles. Myocardial fibrosis did not occur. Basal and isoproterenol-stimulated isovolumic contractile performance was preserved. Thus, selective ablation of GLUT4 in the heart initiates a series of events that results in compensated cardiac hypertrophy.

A review of the management of 323 consecutive patients seen in a specific learning difficulties clinic

Visual correlates of specific learning difficulties (SpLD) include: binocular instability, low amplitude of accommodation, and Meares-Irlen Syndrome. Meares-Irlen Syndrome describes asthenopia and perceptual distortions which are alleviated by using individually prescribed coloured filters. Data from 323 consecutive patients seen over a 15 month period in an optometric clinic specialising in SpLD are reviewed. Visual symptoms and headaches were common. 48% of patients were given a conventional optometric intervention (spectacles, orthoptic exercises) and 50% were issued with coloured filters, usually for a trial period. 40% of those who were given orthoptic exercises were later issued with coloured overlays. 32% of those who were issued with coloured overlays were ultimately prescribed Precision Tinted lenses. Approximately half the sample were telephoned more than a year after the last clinical appointment. More than 70% of those who were prescribed Precision Tints were still wearing them daily, and results for this intervention compared favourably with data for non-tinted spectacles. The data suggest that many people with SpLD need optometric care and that the optometrist needs to be skilled in orthoptic techniques and cognisant of recent research on coloured filters.

Out-of-hours work in cardiothoracic surgery: implications of the New Deal and Calman for training

With the introduction of the New Deal and the Calman Report, the duration of higher specialist training will be halved. We have examined the effect of reduced on-call rotas on exposure to relatively uncommon out-of-hours emergencies in cardiothoracic surgery. Operations for post-infarction ventricular septal defect, aortic dissection or transection, oesophageal perforation and pulmonary embolus performed out-of-hours between 1990 and 1995 were identified from hospital records. Over 6 years, the period of higher specialist training in cardiothoracic surgery, a trainee would see seven aortic emergencies on a 1:2 rota, four on a 1:4 rota and two on a 1:6 rota. These figures provide a powerful argument in support of the English Clause which allows trainees to be available for 83 hours a week, equivalent to a 1:4 rota, rather than 56 hours a week, equivalent to a 1:6 rota under the New Deal. This may need supplementation by a mechanism whereby trainees are 'on call for training'.

Pharmacologic efficacy in neuropsychiatry: a review of placebo-controlled treatment trials. A report of the ANPA Committee on Research

Psychiatric disorders frequently compound the disability and complicate the management of neurologic conditions. These disorders result in increased morbidity for the person afflicted, stress for the caregiver, and financial burden. This study reviews the randomized double-blind placebo-controlled pharmacologic treatment trials of psychosis, depression, anxiety, and agitation in neurologic conditions from 1966 to 1998. Ten studies involving psychosis, 13 involving depression, and 20 involving anxiety-agitation meeting the committee's criteria were identified. Relatively few randomized double-blind placebo-controlled pharmacologic treatment trials of psychiatric disorders complicating neurologic disease have been conducted. These trials do not strongly support one specific pharmacologic approach to treatment. Further study of newer psychotropic agents, augmentation strategies, and novel use of other agents may help improve the treatment of psychiatric disorders observed in patients with neurologic disease.

Chronic inhalation carcinogenicity study of commercial hexane solvent in F-344 rats and B6C3F1 mice

The carcinogenic and chronic toxicity potential of commercial hexane solvent was evaluated in F-344 rats and B6C3F1 mice (50/sex/concentration/species) exposed by inhalation for 6 h/day, 5 days/week for 2 years. Target hexane vapor concentrations were 0, 900, 3000, and 9000 ppm. There were no significant differences in survivorship between control and hexane-exposed groups, and clinical observations were generally unremarkable. Small, but statistically significant decreases in body weight gain were seen in rats of both sexes in the mid- and high-exposure groups and in high-expsoure female mice. The only noteworthy histopathological finding in rats was epithelial cell hyperplasia in the nasoturbinates and larynx of exposed groups. This response was judged to be indicative of upper respiratory tract tissue irritation. No significant differences in tumor incidence between control and hexane-exposed rats were found. In mice, uterine tissue from the high-exposure females exhibited a significant decrease in the severity of cystic endometrial hyperplasia compared to controls. An increase in the combined incidence of hepatocellular adenomas and carcinomas was observed in high-exposure female mice. The incidence of liver tumors was not increased in the mid- or low-exposure female mice or in male mice exposed to hexane. An increased incidence of pituitary adenomas was observed in female, but not male mice. This finding was not believed to have been treatment-related because the incidence in the control group was unusually low, and the incidence in exposed groups was not dose-related and was within the historical control range. No other neoplastic changes judged to be treatment-related were observed in tissues from male or female mice. In conclusion, chronic exposure to commercial hexane solvent at concentrations up to 9000 ppm was not carcinogenic to F-344 rats or to male B6C3F1 mice, but did result in an increased incidence of liver tumors in female mice.

Neuropsychiatric correlates and treatment of lenticulostriatal diseases: a review of the literature and overview of research opportunities in Huntington's, Wilson's, and Fahr's diseases. A report of the ANPA Committee on Research. American Neuropsychiatric Association

This report reviews clinical neuropsychiatric findings and opportunities for research in Huntington's, Wilson's, and Fahr's diseases. Consistent, systematic methodology is lacking among neuropsychiatric studies in these lenticulostriatal diseases. Systematic cross-sectional and longitudinal assessments are needed to ascertain the prevalence of psychiatric disorders as a function of disease course. Preliminary synthesis of existing data suggests the following heuristic relationships in these diseases: depression with parkinsonian states; personality changes with caudate or putamen disease; psychosis, impulsivity, and sexual disorders with caudate disease; dementia and mania with caudate and pallidal diseases; and compulsions with pallidal disease. Correlation of neuropsychiatric findings with disease stage, clinical signs, and radiologic, metabolic, physiologic, and pathologic markers of disease will add to our understanding of these conditions.

Phytoremediation of trichloroethylene with hybrid poplars

Axenic tumor cultures of poplar cells, clone H11-11, were grown in the presence of [14C]-trichloroethylene (TCE) (uniformly labeled). The cells were capable of metabolizing TCE to produce trichloroethanol, di- and trichloroacetic acid. Some of the carbon from TCE was found in insoluble, nonextractable cell residue, and small amounts were mineralized to [14C]CO2. Poplar cuttings grown in soil and exposed to TCE produced the same metabolites. In field trials, trees were planted in soil in test cells and exposed to TCE via underground water injection during the growing season. During the growing season, at least 95% of the TCE was removed from the influent water stream in cells containing trees. Mass balance studies conducted in the laboratory indicated that 70 to 90% of the TCE was transpired; however, greenhouse and field study results showed that less than 5% of the total TCE taken up by the plants is transpired. These results show that significant TCE uptake and degradation occur in poplars. Poplars appear to be useful for in situ remediation of TCE-contaminated sites under proper conditions.

Arthritis and hepatitis

Arthritis has a fascinating relationship with hepatitis of diverse origins. Either condition can predominate and the correct diagnosis may be elusive, especially in the early stages. Humoral autoimmune mechanisms appear to serve as a bridge connecting the two target organs, whether the syndromes are caused by viral infections or unspecified etiologies. Maintaining a keen awareness of and being able to recognize the clinical arthritis-hepatitis syndromes are critical, enabling the physician to establish accurate diagnoses, to prescribe the correct therapies, and to predict outcomes.

Platelet derived growth factor and fibroblast growth factor basic levels in the vitreous of patients with vitreoretinal disorders

AIM

To determine the potential role of basic fibroblast growth factor (bFGF) and platelet derived growth factor (PDGF) in the pathogenesis of proliferative vitreoretinopathy (PVR).

METHODS

An enzyme linked immunosorbent assay technique was used to determine the quantities of bFGF and PDGF in 38 vitreous samples taken from patients undergoing trans pars plana vitrectomy (PPV) for a variety of vitreoretinal disorders.

RESULTS

bFGF levels ranged from undetectable to 318.7 pg/ml. The mean concentration was 27.57 pg/ml. PDGF levels ranged from undetectable to 160 pg/ml, the mean concentration being 40.06 pg/ml. Eight of 13 patients with clinical evidence of retinal detachment (RD) and PVR had significantly elevated bFGF concentrations, whereas only one of 11 patients with RD and no PVR had detectable bFGF; seven of eight patients with RD and PVR had elevated PDGF concentrations in the vitreous, whereas all 10 patients with RD and no PVR had no detectable vitreous PDGF. Eight patients with vitreous haemorrhage had raised PDGF concentrations, and the levels were particularly high (> 120 pg/ml) in those two patients with active neovascularisation. Two out of nine patients with vitreous haemorrhage had raised bFGF levels.

CONCLUSIONS

bFGF and PDGF concentrations are elevated in PVR even in the absence of vitreous haemorrhage, and not in patients with RD uncomplicated by PVR. This observation suggests that both cytokines may be involved in the pathogenesis of PVR.

Retinocochleocerebral vasculopathy

We report 10 patients with retinocochleocerebral vasculopathy and review the clinical and diagnostic considerations in previously reported patients with this uncommonly recognized disease. The clinical manifestations include acute and subacute multifocal and diffuse encephalopathic symptoms, hearing loss, and visual loss attributable to microangiopathy affecting the arterioles of the brain, retina, and cochlea. Diagnosis is facilitated by demonstration of retinal arteriolar occlusions without uveitis or keratoconjunctivitis, mid- to low-frequency unilateral or bilateral sensorineural hearing loss, and numerous small foci of increased signal in the white and gray matter on T2 weighted brain magnetic resonance imaging. Because many conditions may produce any combination of strokelike cerebral symptoms, encephalopathy, hearing loss, and visual loss, the differential diagnosis for retinocochleocerebral vasculopathy includes connective tissue disease, demyelinating disease, procoagulant state, infection, neoplasm, and more routine mechanisms of cerebral and retinal ischemia. Brain biopsy specimens demonstrate only minimal nonspecific periarteriolar chronic inflammatory cell infiltration with or without microinfarcts. The demonstration of subclinical arteriolar microangiopathy in muscle biopsy specimens, documented in 3 of our patients may assist in making the diagnosis. The clinical course appears to be monophasic. In addition to corticosteroids, treatment options include immunosuppressant agents (cyclophosphamide or azathioprine) aspirin, calcium channel blockers (nimodipine), intravenous immunoglobulin, and plasmapheresis. The etiology of the disease is unknown, but histopathologic and laboratory evidence suggests that an immune-mediated mechanism may be involved.