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Biomedical subjects

C J McCabe

Publications and source records attributed to C J McCabe.

At least 19 recordsLinked to original sources
PubMed1998

Annual league tables of mortality in neonatal intensive care units: longitudinal study. International Neonatal Network and the Scottish Neonatal Consultants and Nurses Collaborative Study Group.

OBJECTIVE: To assess whether crude league tables of mortality and league tables of risk adjusted mortality accurately reflect the performance of hospitals. DESIGN: Longitudinal study of mortality occurring in hospital. SETTING: 9 neonatal intensive care units in the United Kingdom. SUBJECTS: 2671 very low birth weight or preterm infants admitted to neonatal intensive care units between 1988 and 1994. MAIN OUTCOME MEASURES: Crude hospital mortality and hospital mortality adjusted using the clinical risk index for babies (CRIB) score. RESULTS: Hospitals had wide and overlapping confidence intervals when ranked by mortality in annual league tables; this made it impossible to discriminate between hospitals reliably. In most years there was no significant difference between hospitals, only random variation. The apparent performance of individual hospitals fluctuated substantially from year to year. CONCLUSIONS: Annual league tables are not reliable indicators of performance or best practice; they do not reflect consistent differences between hospitals. Any action prompted by the annual league tables would have been equally likely to have been beneficial, detrimental, or irrelevant. Mortality should be compared between groups of hospitals using specific criteria-such as differences in the volume of patients, staffing policy, training of staff, or aspects of clinical practice-after adjusting for risk. This will produce more reliable estimates with narrower confidence intervals, and more reliable and rapid conclusions.

Cohort Studies↗
PubMed1998

Effect of computed tomography of the appendix on treatment of patients and use of hospital resources.

BACKGROUND: In patients with clinically suspected appendicitis, computed tomography (CT) is diagnostically accurate. However, the effect of routine CT of the appendix on the treatment of such patients and the use of hospital resources is unknown. METHODS: We performed appendiceal CT on 100 consecutive patients in the emergency department who, on the basis of history, physical examination, and laboratory results, were to be hospitalized for observation for suspected appendicitis or for urgent appendectomy. Outcomes were determined at surgery and by pathological examination in 59 patients, and by clinical follow-up two months later in 41 patients. Treatment plans made before CT were compared with the patients' actual treatment. We also determined the costs of surgery that revealed no appendicitis (from data on 61 patients), one day of observation in the hospital (from data on 350 patient-days in patients with suspected appendicitis), and appendiceal CT (from data on all pelvic CT examinations in 1996). RESULTS: Fifty-three patients had appendicitis, and 47 did not. The interpretations of the appendiceal CT scans were 98 percent accurate. The results of CT led to changes in the treatment of 59 patients. These changes resulted in the prevention of unnecessary appendectomy in 13 patients, admission to the hospital for observation in 18 patients, admission to the hospital for observation before necessary appendectomy in 21 patients, and admission to the hospital for observation before the diagnosis of other conditions by CT in 11 patients. The effects of performing appendiceal CT on the use of hospital resources included the prevention of unnecessary appendectomy in 13 patients (for a savings of $47,281) and the prevention of unnecessary hospital admission for 50 patient-days (for a savings of $20,250). After the cost of 100 appendiceal CT studies ($22,800) was subtracted, the overall savings was $447 per patient. CONCLUSIONS: Routine appendiceal CT performed in patients who present with suspected appendicitis improves patient care and reduces the use of hospital resources.

Adolescent↗
PubMed1998

Evaluation of a diabetic foot screening and protection programme.

We set out to evaluate a clinical foot-screening programme in terms of primary outcomes (reductions in the incidence of ulcers and lower limb amputation) and process outcomes (compliance with screening, the number of patients not completing the programme and the use of chiropody services and prescribed footwear and cost). All but 4 of 2001 patients attending a general diabetic out-patient clinic were allocated randomly to index and control groups. The exceptions were patients who presented with active ulcers and were placed in the index group. Primary and secondary screening programmes identified 128 high risk patients in the index group and these were admitted to the foot protection programme. At 2-year follow-up, 11 fewer ulcers were reported from the index group. There were 7 amputations (1 major, 6 minor) in the index group and 23 (12 major and 13 minor) in the control group. The differences were not statistically significant for ulceration or minor amputations but significant for major amputations (p < 0.01). The total cost of the 2-year programme was pounds sterling 100,372 (1991-92 costs), with a mean cost per patient of approximately pounds sterling 100. Taking pounds sterling 12,000 as a conservative estimate of the cost of a major amputation, the foot clinic was cost-effective in terms of amputations averted. The process outcomes were much less satisfactory. Cost-effectiveness could have been improved if it had been possible to improve patient compliance.

Ambulatory Care Facilities↗
PubMed1998

The computed tomography appearance of recurrent and chronic appendicitis.

The objective of this study was to determine computed tomography (CT) appearance of recurrent and chronic appendicitis. In 100 consecutive appendiceal CT examinations of proven appendicitis, 18 patients met criteria for recurrent (multiple discrete episodes) or chronic (continuous symptoms > 3 weeks, pathological findings) appendicitis. CT findings were reviewed. Ten patients had recurrent appendicitis, 3 had chronic appendicitis, 3 had both, and 2 had pathological chronic appendicitis. CT findings in 18 recurrent/chronic cases were identical to 82 acute appendicitis cases, including pericecal stranding (both 100%), dilated (> 6 mm) appendix (88.9% versus 93.9%), apical thickening (66.7% versus 69.5%), adenopathy (66.7% versus 61.0%), appendolith(s) (50% versus 42.7%), arrowhead (27.8% versus 22.0%), abscess (11.1% versus 11.0%), phlegmon (11.1% versus 6.1%), and fluid (5.6% versus 19.5%). CT findings in recurrent and chronic appendicitis are the same as those in acute appendicitis. Appendiceal CT can be beneficial for evaluating patients with suspected recurrent or chronic appendicitis.

Adult↗
PubMed1998

Retinoid X receptor expression in the normal pituitary and clinically 'non-functioning' pituitary tumours.

OBJECTIVE: The glycoprotein hormone common alpha-subunit is frequently expressed in clinically 'non-functioning' tumours (NFTs) of the anterior pituitary, despite normal levels of T3 and gonadal steroids. This observation suggests abnormal negative-feedback regulation of the alpha-subunit by T3 and gonadal steroids in NFTs. We have previously documented reduced expression of thyroid hormone receptor (TR) variants in NFTs compared to normals and proposed that this observation may, in part, explain the defective negative regulation. Due to the important role of retinoid X receptors (RXRs) in transactivating TR-mediated transcriptional regulation, via heterodimer formation, we hypothesize that aberrant RXR isoform expression in NFTs may contribute to the defective negative regulation of the alpha-subunit by T3. DESIGN: Comparison of RXR isoform protein and mRNA expression in NFTs and normal pituitaries. PATIENTS AND TUMOURS: Twenty clinically non-functioning pituitary tumours and 27 normal pituitaries were obtained for analysis. MEASUREMENTS: Immunocytochemistry and semiquantitative RT-PCR was performed on tumours and normal pituitaries to determine the relative levels of expression of RXR isoform proteins and mRNAs, respectively. RESULTS: RXR alpha was expressed in a similar proportion (approximately 50%) of both normal human pituitaries and NFTs, while RXR beta and gamma were each observed in 26% of normals but were undetectable in NFTs. The application of semiquantitative RT-PCR revealed similar levels of mRNAs encoding the RXR alpha and RXR beta isoforms in normals and NFTs but significantly reduced expression of RXR gamma mRNA was observed in NFTs. CONCLUSIONS: We propose that abnormal RXR isoform expression in clinically 'non-functioning' pituitary tumours may contribute to abnormal T3-mediated negative regulation of alpha-subunit production.

DNA-Binding Proteins↗
PubMed1998

Differential regulation of the human thyrotropin alpha-subunit promoter by thyroid hormone receptors alpha1 and beta1.

The differential tissue expression of thyroid hormone receptor (TR) isoforms implies that they fulfil different roles in mediating triiodothyronine (T3) regulation. We have examined the differential roles of TR isoforms in mediating T3-dependent repression of the human thyrotropin (TSH)-alpha subunit gene promoter in vitro, and have assessed TR binding characteristics using gel mobility shift assays. Expression of transfected TR in JEG-3 cells revealed that TRalpha1 and TRbeta1 differentially inhibited TSHalpha subunit expression in the presence of T3, with TRbeta1 twice as potent as TRalpha1. TRalpha2 antagonized T3-dependent repression when coexpressed with TRalpha1 and TRbeta1. Gel mobility shift assays, performed in the presence and absence of JEG-3 nuclear extract, demonstrated that TRbeta1 bound with higher affinity to the wild-type TSHalpha negative thyroid hormone response element (nTRE) than TRalpha1. In vivo, the differential DNA binding of TR variants to nTREs may determine the ability of receptors to mediate T3-dependent repression.

Cell Line↗
PubMed1998

An abnormality of thyroid hormone receptor expression may explain abnormal thyrotropin production in thyrotropin-secreting pituitary tumors.

Thyrotropin (TSH)-secreting pituitary adenomas cause hyperthyroxinemia in the presence of "inappropriately" elevated concentrations of TSH. TSH production under these circumstances escapes the normal negative feedback effect of thyroid hormone. We propose that this defective negative feedback is mediated by an abnormality of thyroid hormone receptor (TR) expression. Two TSH-secreting pituitary adenomas were analyzed by immunocytochemistry for TR isoform protein expression and by semiquantitative reverse transcriptase polymerase chain reaction (RT-PCR) for TR isoform mRNA expression. The results obtained from these tumors were compared with the findings from six normal human pituitaries. Neither tumor examined expressed detectable levels of nuclear TRalpha or TRbeta proteins, in contrast to the normal pituitaries studied, which expressed all TR isoforms. Application of RT-PCR, however, revealed mRNAs encoding each TR isoform in all tumorous and normal tissues examined. Semiquantitative RT-PCR revealed similar levels of expression of TRalpha and TRbeta isoform mRNAs in tumors and normal tissue, in contrast to the observed difference in TR proteins. Absent TRalpha and TRbeta protein expression, in association with normal mRNA levels, implies a post-transcriptional defect in TR mRNA processing in TSH-secreting adenomas. Reduced TR expression in these tumors may explain defective negative feedback of thyroid hormone on TSH production, and may also contribute to uncontrolled tumor growth.

Adenoma↗
PubMed1998

Economic burden of environmental tobacco smoke on Hong Kong families: scale and impact.

STUDY OBJECTIVE: To examine the financial cost of doctor consultations for cough, phlegm, and wheeze in children living in a home where family members smoke compared with those not exposed to environmental tobacco smoke. To model these costs to provide the Territory of Hong Kong with estimates of potentially avoidable health care resource use. DESIGN: Cross sectional questionnaire survey. SUBJECTS AND SETTING: All children (10,615) in classes primary 3 to 6 (aged 8-13 years) attending 27 schools in two districts of Hong Kong in 1992 and their parents. MEASUREMENTS AND MAIN RESULTS: Doctor consultations during the previous three months for symptoms of either cough, phlegm or wheeze were higher in younger children, ranging from 22.9% in 8 year olds to 8.4% in those aged 12 or over. For those children living in homes with one, or more than one, smoker category (there were four categories of smokers: father, mother, siblings, others), the adjusted odds ratios (95% confidence intervals) for a doctor consultation for any of these symptoms were 1.15 (1.01, 1.31) and 1.38 (1.14, 1.67) respectively. Using US$15 as the minimum cost incurred per consultation, the expected direct cost per annum per child of doctor consultations was 14% higher for children living in a one smoker category home and 25% for two or more compared with exposure to no smokers in the home. Using these values on a territory wide basis, the annual avoidable direct cost associated with exposure to tobacco smoke in children from birth to 12 years of age ranged from US$338,042 to US$991,591. CONCLUSIONS: Exposure to environmental tobacco smoke not only provides a respiratory health risk for children but also an avoidable excess cost to the family's financial resources and health service providers.

Child↗
PubMed1997

Health economics in rheumatology.

Economic evaluations of health-care technologies are playing an increasingly central role in determining which therapies are available to clinicians in the treatment of a whole range of conditions. In rheumatology, a large body of work has already been done on the cost effectiveness of alternative non-steroidal anti-inflammatory drugs (NSAIDs), and much of the current work on disease modifying therapies incorporates economic evaluations. This chapter describes the main techniques of economic evaluation and reviews the strengths and weaknesses of each. Two published economic evaluations are discussed in order to highlight what economic evaluations can offer to the care of people with rheumatoid arthritis, as well as the current limitations of economic evaluation. The objective of this chapter is to equip readers with a critical understanding of economic evaluation that can be used in considering the increasing volume of health economic data that they encounter in their clinical work.

Cost-Benefit Analysis↗
PubMed1997

Helical CT technique for the diagnosis of appendicitis: prospective evaluation of a focused appendix CT examination.

PURPOSE: To evaluate a focused, helical computed tomographic (CT) technique for imaging the appendix in patients suspected of having appendicitis. MATERIALS AND METHODS: One hundred patients prospectively underwent appendix CT examination, with use of oral and colon contrast media and contiguous, thin-collimation, helical CT imaging of the right lower quadrant. Results were correlated with the results of surgery and pathologic examination from 61 patients or from clinical follow-up in 39 patients. RESULTS: CT scans were positive for appendicitis in 59 patients: true-positive in 56 patients on the basis of surgery and pathologic examination, and false-positive in two patients on the basis of clinical follow-up; in the case of the other positive scan, the clinical outcome was indeterminate. CT scans were negative for appendicitis in 41 patients: true-negative in five patients on the basis of surgery and pathologic examination, and true-negative in 36 patients on the basis of clinical follow-up. CT had a sensitivity of 100%, a specificity of 95%, a positive predictive value of 97%, a negative predictive value of 100%, and an accuracy of 98%. The normal appendix was always identified. CT helped establish alternative diagnoses in 33 of the 41 patients (80%) in whom the results of CT were negative for appendicitis. CONCLUSION: Appendix CT examination can help diagnose or exclude appendicitis and establish an alternative diagnosis.

Acute Disease↗
PubMed1997

Thyroid hormone and estrogen receptor expression in normal pituitary and nonfunctioning tumors of the anterior pituitary.

Nonfunctioning tumors (NFTs) of the anterior pituitary often express elevated levels of the glycoprotein hormone alpha-subunit, which, under normal physiological conditions, is under negative feedback control by thyroid and gonadal steroid hormones. We postulate that inappropriately elevated levels of expression of alpha-subunit in the face of normal levels of these target organ hormones may reflect an abnormality of thyroid hormone receptors (TRs) and/or gonadal steroid receptors in NFTs. Using immunocytochemistry and Western blotting we have examined TR and estrogen receptor (ER) protein expression in normal human anterior pituitary glands and NFTs. Pretranslational expression of these receptors was examined using semiquantitative reverse transcriptase-PCR. Expression of all TR variant and ER proteins was reduced in pituitary tumors compared with that in normal pituitaries. The expression of messenger ribonucleic acids encoding the TR beta1 and TR beta2 isoforms and ER was also significantly reduced in tumors compared with normal tissues, although there was no difference between tumors and normals in the level of expression of TR alpha1 and alpha2 messenger ribonucleic acids. We suggest that reduced expression of TRs and ER may account for inappropriate expression of the glycoprotein hormone alpha-subunit gene in some NFTs and may contribute to uncontrolled tumor growth.

Female↗
PubMed1997

A focused appendiceal CT technique to reduce the cost of caring for patients with clinically suspected appendicitis.

OBJECTIVE: This investigation analyzed the potential impact on hospitalwide variable costs and total costs of introducing a focused helical CT technique for diagnosing appendicitis. MATERIALS AND METHODS: This investigation had three components. First, we retrospectively reviewed the records of 651 patients who had admitting diagnoses of appendicitis. Second, we determined variable costs and total costs for the components of these patients' care. Third, we projected change in costs if the focused appendiceal CT technique had been used to guide patient management. RESULTS: Using focused appendiceal CT in 100 patients would have decreased the number of nontherapeutic appendectomies by 13. The average length of stay for observation would have also decreased by 1 day because the diagnosis of an abnormal appendix or an alternative diagnosis would have been made more quickly. Savings in variable costs and total costs would have been $23,030 and $45,556 per 100 patients, respectively. CONCLUSION: Routine use of focused appendiceal CT would lower the costs of caring for patients with clinically suspected appendicitis.

Adolescent↗
PubMed1997

Helical CT combined with contrast material administered only through the colon for imaging of suspected appendicitis.

OBJECTIVE: Helical CT combined with contrast material administered by mouth and through the colon has been shown to be accurate for appendiceal imaging. This investigation was performed to determine if helical CT combined with contrast material administered only through the colon has comparable accuracy. SUBJECTS AND METHODS: One hundred patients prospectively underwent appendiceal CT imaging with thin-collimation, helical scanning limited to the lower abdomen and upper pelvis after contrast material was administered only through the colon. CT results were correlated with surgical and pathologic findings at appendectomy (56 patients), other surgery (three patients), or clinical follow-up at least 2 months after the CT scan (41 patients). RESULTS: Fifty-three CT scans were interpreted as positive for appendicitis, including 52 true-positives (with surgical-pathologic correlation) and on false-positive (with clinical follow-up). Forty-seven CT scans were interpreted as negative for appendicitis, including 40 true-negatives with clinical follow-up, three true-negatives with appendectomy and pathologic correlation, three true-negatives with other surgery and pathologic correlation, and one false-negative with appendectomy and pathologic correlation. CT had a 98% sensitivity, 98% specificity, 98% positive predictive value, 98% negative predictive value, and 98% accuracy for diagnosing or excluding appendicitis. In 47 normal appendix cases at CT, the appendix was seen in 44 cases (94%), and an alternative diagnosis was identified in 29 cases (62%). CONCLUSION: For diagnosing appendicitis, helical CT combined with contrast material administered only through the colon proved to be as accurate (98%) as helical CT combined with contrast material administered by mouth and through the colon. Helical CT with contrast material administered only through the colon also could be performed immediately and without any of the potential patient risks or discomforts of contrast material administered i.v. or by mouth.

Adult↗