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Biomedical subjects

C M Bell

Publications and source records attributed to C M Bell.

At least 19 recordsLinked to original sources
PubMed2006

Brief overview of maternal triglycerides as a risk factor for pre-eclampsia.

BACKGROUND: Features of the metabolic syndrome-maternal obesity, diabetes mellitus and chronic hypertension-are risk factors for pre-eclampsia. OBJECTIVES: To determine the risk of pre-eclampsia in the presence of maternal hypertriglyceridemia, another major element of the metabolic syndrome. SEARCH STRATEGY: Two investigators independently searched PubMed and Embase databases from 1980 to December 2004 for relevant studies. The terms preeclampsia, eclampsia, pregnancy-induced hypertension or toxemia were combined with dyslipidemia, hyperlipidemia, hypertriglyceridemia, lipids, cholesterol, triglycerides (TG) or lipoprotein. SELECTION CRITERIA: We included case-control and cohort studies published in English that included at least 20 women with pre-eclampsia and that sampled serum or plasma TG at any time before, during or after pregnancy. DATA COLLECTION AND ANALYSIS: Mean maternal TG concentrations were compared between cases and controls within each study. The odds ratio of pre-eclampsia was calculated by comparing the risk of pre-eclampsia among women in each higher TG concentration category with that in the lowest reference category. MAIN RESULTS: A total of 19 case-control and 3 prospective cohort studies were included. In 14 studies, the mean TG concentration was significantly higher among pre-eclamptic cases than among unaffected controls; in seven other studies, there was a nonsignificant trend in the same direction. The risk of pre-eclampsia typically doubled with each increasing TG category. In the four studies that adjusted for potential confounders, such as maternal age, parity and body mass index, there was about a four-fold higher risk of pre-eclampsia in the highest relative to the lowest TG category. AUTHOR'S CONCLUSIONS: There exists a consistent positive association between elevated maternal TG and the risk of pre-eclampsia. Given that maternal hypertriglyceridemia is a common feature of the metabolic syndrome, interventional studies are needed to determine whether pre-pregnancy weight reduction and dietary modification can lower the risk of pre-eclampsia.

Biomarkers↗
PubMed2004

Beta-blocker therapy failures in symptomatic probands with genotyped long-QT syndrome.

Beta-blocker therapy is one of the principal therapies for congenital long-QT syndrome (LQTS). However, breakthrough cardiac events occur while being treated with beta-blockers. We sought to determine the frequency of and clinical correlates underlying beta-blocker therapy failures in genotyped, symptomatic LQTS probands. The medical records were analyzed only for genotyped LQTS probands who presented with a LQTS-attributable clinical event and were receiving beta-blocker therapy. The study cohort comprised 28 such patients: 18 KCNQ1/KVLQT1(LQT1), 7 KCNH2/HERG (LQT2), and 3 SCN5A (LQT3). The prescribed beta-blocker was atenolol (12), propranolol (10), metoprolol (4), and nadolol (2). Beta-blocker therapy failure was defined as breakthrough cardiac events including syncope, aborted cardiac arrest (ACA), appropriate implantable cardioverter-defibrillator (ICD) therapy, or sudden death occurring while on beta-blocker therapy. During a median follow-up of 46 months, 7/28 (25%) LQTS probands experienced a total of 15 breakthrough cardiac events. Their initial presentation was ACA (3), bradycardia during infancy (2), and syncope (2). The underlying genotype was KVLQT1 (6) and HERG (1). Two breakthroughs were attributed to noncompliance. Of the 13 breakthroughs occurring while compliant, 10 occurred with atenolol and 3 with propranolol (p = 0.03). In this study cohort, one-fourth of genotyped LQTS probands failed beta-blocker therapy. Treatment with atenolol, young age at diagnosis, initial presentation with ACA, KVLQT1 genotype, and noncompliance may be important factors underlying beta-blocker therapy failures.

Adrenergic beta-Antagonists↗
PubMed2001

Cancer risks in women with 2 breast or ovarian cancers: clues to genetic cancer susceptibility.

Women diagnosed with 2 cancers of the breast and/or ovary are at higher risk of developing subsequent cancers. Using registrations from the Thames Cancer Registry, we quantified the risks at different cancer sites. Increased risks were found for cancers that are part of the BRCA1 and BRCA2 tumour spectrum: oropharyngeal cancer, malignant melanoma of the skin (BRCA2) and colon cancer (BRCA1). We also found significantly increased risks of myeloid leukaemia (probably due to radiotherapy) and of cancer of the corpus uteri (which may be due to hormonal factors).

Breast Neoplasms↗
PubMed2001

Mortality among patients admitted to hospitals on weekends as compared with weekdays.

BACKGROUND: The level of staffing in hospitals is often lower on weekends than on weekdays, despite a presumably consistent day-to-day burden of disease. It is uncertain whether in-hospital mortality rates among patients with serious conditions differ according to whether they are admitted on a weekend or on a weekday. METHODS: We analyzed all acute care admissions from emergency departments in Ontario, Canada, between 1988 and 1997 (a total of 3,789,917 admissions). We compared in-hospital mortality among patients admitted on a weekend with that among patients admitted on a weekday for three prespecified diseases: ruptured abdominal aortic aneurysm (5454 admissions), acute epiglottitis (1139), and pulmonary embolism (11,686) and for three control diseases: myocardial infarction (160,220), intracerebral hemorrhage (10,987), and acute hip fracture (59,670), as well as for the 100 conditions that were the most common causes of death (accounting for 1,820,885 admissions). RESULTS: Weekend admissions were associated with significantly higher in-hospital mortality rates than were weekday admissions among patients with ruptured abdominal aortic aneurysms (42 percent vs. 36 percent, P<0.001), acute epiglottitis (1.7 percent vs. 0.3 percent, P=0.04), and pulmonary embolism (13 percent vs. 11 percent, P=0.009). The differences in mortality persisted for all three diagnoses after adjustment for age, sex, and coexisting disorders. There were no significant differences in mortality between weekday and weekend admissions for the three control diagnoses. Weekend admissions were also associated with significantly higher mortality rates for 23 of the 100 leading causes of death and were not associated with significantly lower mortality rates for any of these conditions. CONCLUSIONS: Patients with some serious medical conditions are more likely to die in the hospital if they are admitted on a weekend than if they are admitted on a weekday.

Acute Disease↗
PubMed2001

Incidence of multiple primary cancers in a cohort of women diagnosed with breast cancer in southeast England.

Among women in the Thames Cancer Registry database with a first breast cancer diagnosed between 1961-1995 observed numbers of subsequent cancers were compared with expected numbers and standardized incidence ratios were calculated. The occurrence of breast cancers subsequent to cancers at other sites was also examined. Women diagnosed with breast cancer before age 50 had significantly elevated risks for 9 cancer sites namely, oesophagus, stomach, lung, bone, connective tissue, breast, corpus uteri, ovary and myeloid leukaemia compared with 2 sites (corpus uteri and myeloid leukaemia) in women diagnosed at age 50 and above. Some of these associations are consistent with the effects of known inherited cancer susceptibility genes, shared environmental factors, or therapy.

Age Factors↗
PubMed2000

Systematic overview of cost-utility assessments in oncology.

PURPOSE: Cost-utility analyses (CUAs) present the value of an intervention as the ratio of its incremental cost divided by its incremental survival benefit, with survival weighted by utilities to produce quality-adjusted life years (QALYs). We critically reviewed the CUA literature and its role in informing clinical oncology practice, research priorities, and policy. METHODS: The English-language literature was searched between 1975 and1997 for CUAs. Two readers abstracted from each article descriptions of the clinical situation and patients, the methods used, study perspective, the measures of effectiveness, costs included, discounting, and whether sensitivity analyses were performed. The readers then made subjective quality assessments. We also extracted utility values from the reviewed papers, along with information on how and from whom utilities were measured. RESULTS: Our search yielded 40 studies, which described 263 health states and presented 89 cost-utility ratios. Both the number and quality of studies increased over time. However, many studies are at variance with current standards. Only 20% of studies took a societal perspective, more than a third failed to discount both the costs and QALYs, and utilities were often simply estimates from the investigators or other physicians. CONCLUSION: The cost-utility literature in oncology is not large but is rapidly expanding. There remains much room for improvement in the methodological rigor with which utilities are measured. Considering quality-of-life effects by incorporating utilities into economic studies is particularly important in oncology, where many therapies obtain modest improvements in response or survival at the expense of nontrivial toxicity.

Clinical Trials as Topic↗
PubMed2000

The quality of reporting in published cost-utility analyses, 1976-1997.

PURPOSE: Cost-utility analysis is a type of cost-effectiveness analysis in which health effects are measured in terms of quality-adjusted life-years (QALYs) gained. Such analyses have become popular for examining the health and economic consequences of health and medical interventions, and they have been recommended by leaders in the field. These recommendations emphasize the importance of good reporting practices. This study determined 1) the quality of reporting in published cost-utility analyses through 1997 and 2) whether reporting practices have improved over time. We examined quality of reporting by journal type and number of cost-utility analyses a journal has published. DATA SOURCES: Computerized databases were searched through 1997 for the Medical Subject Headings or text keywords quality-adjusted, QALY, and cost-utility analysis. Published bibliographies of the field were also searched. STUDY SELECTION: Original cost-utility analyses written in English were included. Cost-effectiveness analyses that measured health effects in units other than QALYs and review, editorial, or methodologic articles were excluded. DATA EXTRACTION: Each of the 228 articles found was audited independently by two trained readers who used a standard data collection form to determine the quality of reporting in several categories: disclosure of funding, framing, reporting of costs, reporting of preference weights, reporting of results, and discussion. RESULTS: The number of cost-utility analyses in the medical literature increased greatly between 1976 and 1997. Analyses covered a wide range of diseases and interventions. Most studies listed modeling assumptions (82%), described the comparator intervention (83%), reported sensitivity analysis (89%), and noted study limitations (84%). Only 52% clearly stated the study perspective; 34% did not disclose the funding source. Methods of reporting costs and preference weights varied widely. The quality of published analyses improved slightly over time and was higher in general clinical journals and in journals that published more of these analyses. CONCLUSIONS: The study results reveal an active and evolving field but also underscore the need for more consistency and clarity in reporting. Better peer review and independent, third-party audits may help in this regard. Future investigations should examine the quality of clinical and economic assumptions used in cost-utility analyses, in addition to whether analysts followed recommended protocols for performance and reporting.

Cost-Benefit Analysis↗
PubMed2000

Charges for medical care at different hospitals.

BACKGROUND: The United States has a high proportion of people without health insurance (15%) and a low proportion of people without employment (5%), resulting in millions who lack insurance but have some ability to pay. We tested whether hospitals charge similar prices for well-specified elective services to individuals paying out-of-pocket for medical care. METHODS: We surveyed the 2 largest general hospitals from every large city (population >500 000) in the United States and Canada. At each hospital we evaluated 5 diagnostic, 7 therapeutic, and 3 nonclinical services to determine the total charge to patients who pay directly. RESULTS: Overall, 66 hospitals were included (average, 758 beds; not-for-profit, 97% [n = 64]; teaching, 80% [n = 53]). The range in charges was substantial; for example, a screening mammogram was $40 at one hospital in Los Angeles, Calif, and $346 at one hospital in Quebec City. Charges for a screening mammogram were relatively stable between 1996 and 1997 (r=0.79; 95% confidence interval, 0.68-0.87) and unrelated to the hospital's location or charges for other services. The relative amount of variation in charges was similar for high-priced and low-priced services, similar for diagnostic and therapeutic services, and similar for the United States and Canada. CONCLUSIONS: Charges for the same hospital service vary substantially. Greater visibility might reduce some variation by bringing outliers into closer scrutiny. Patients seeking care and paying out-of-pocket could save financially by comparison shopping.

Canada↗
PubMed2000

Methodological issues in the use of guidelines and audit to improve clinical effectiveness in breast cancer in one United Kingdom health region.

AIMS: To develop a system to improve and monitor clinical performance in the management of breast cancer patients in one United Kingdom health region. DESIGN: An observational study of the changes brought about by the introduction of new structures to influence clinical practice and monitor change. SETTING: North Thames (East) Health region, comprising seven purchasing health authorities and 21 acute hospitals treating breast cancer. SUBJECTS: The multi-disciplinary breast teams in 21 hospitals and an audit sample of 419 (28%) of the breast cancer patients diagnosed in 1992 in the region. INTERVENTIONS: Evidence-based interventions for changing clinical practice: regional guidelines, senior clinicians acting as < >, audit of quality rather than cost of services, ownership of data by clinicians, confidential feed-back to participants and education. OUTCOME MEASURES: Qualitative measures of organizational and behavioural change. Quantitative measures of clinical outcomes compared to guideline targets and to results from previous studies within this population. RESULTS: Organizational changes included the involvement, participation of and feedback to 16 specialist surgeons and their multidisciplinary teams in 21 hospitals. Regional clinical guidelines were developed in 6 months and the dataset piloted within 9 months. The audit cycle was completed within 2 years. The pilot study led to prospective audit at the end of 2 years for all breast cancers in the region and a 15-fold increase in high quality clinical information for these patients. Changes in clinical practice between 1990 and 1992 were observed in the use of chemotherapy (up from 17-23%) and axillary surgery (up from 46-76%). CONCLUSIONS: The approach used facilitated rapid change and found a balance between local involvement (essential for sustainability within a hospital setting) and regional standardization (essential for comparability across hospitals). The principles of the approach are generalized to other cancers and to other parts of the UK and abroad.

Breast Neoplasms↗
PubMed2000

Understanding variations in survival for colorectal cancer in Europe: a EUROCARE high resolution study.

BACKGROUND: Marked differences in population based survival across Europe were found for colorectal cancers diagnosed in 1985-1989. AIMS: To understand the reasons for these differences in survival in a new analysis of colorectal cancers diagnosed between 1988 and 1991. SUBJECTS: A total of 2720 patients with adenocarcinoma of the large bowel from 11 European cancer registries (CRs). METHODS: We obtained information on stage at diagnosis, diagnostic determinants, and surgical treatment (not routinely collected by CRs) and analysed the data in relation to three year observed survival, calculating relative risks (RRs) of death and adjusting for age, sex, site, stage, and determinants of stage. RESULTS: Three year observed survival rates ranged from 25% (Cracow) to 59% (Modena), and were low in the Thames area (UK) (38%). Survival rates between registries for "resected" patients varied less than those for all patients. When age, sex, and site were considered, RRs ranged from 0.7 (95% confidence intervals (CI) 0.6-0.9) (Modena) to 2.3 (95% CI 1.9-2.9) (Cracow). After further adjustment by stage, between registry RR variation was between 0.8 (95% CI 0.6-0.9) and 1.8 (95% CI 1.5-2.2). Inter-registry RR differences were slightly reduced when the determinants of stage (number of nodes examined and liver imaging) were included in the model. The reduction was marked for the UK registries. CONCLUSIONS: The wide differences across Europe in colorectal cancer survival depend to a large extent on differences in stage at diagnosis. There are wide variations in diagnostic and surgical practices. There was a twofold range in the risk of death from colorectal cancer even after adjustment for surgery and disease stage.

Adenocarcinoma↗
PubMed1998

Shopping around for hospital services: a comparison of the United States and Canada.

CONTEXT: Historical comparisons indicate that US hospitals are more expensive than Canadian hospitals, but health care system reform might have changed the relative costs and timeliness of health care in the 2 countries. OBJECTIVE: To estimate the price and convenience of selected hospital services in the United States and Canada for patients in 1997 had they paid out-of-pocket. DESIGN: Cross-sectional telephone survey conducted May 1996 to April 1997. PARTICIPANTS: The 2 largest acute care general hospitals from every city in the United States and Canada with a population greater than 500000. MEASURES: Each hospital was telephoned and asked their price and waiting time for 7 services: magnetic resonance imaging of the head without gadolinium; a screening mammogram; a 12-lead electrocardiogram; a prothrombin time measurement; a session of hemodialysis; a screening colonoscopy; and a total knee replacement. Waiting times were measured in days until earliest appointment and charges were converted to American currency. RESULTS: Overall, 48 US and 18 Canadian hospitals were surveyed. Median waiting times were significantly shorter in American hospitals for 4 services, particularly a magnetic resonance imaging of the head (3 days vs 150 days; P<.001). Median charges were significantly higher in American hospitals for 6 services, particularly for a total knee replacement ($26805 vs $10651; P<.001). Individual services showed no association between shorter waiting times and higher prices within each country, with the exception of a total knee replacement in the United States. CONCLUSION: US hospitals still provide higher prices and faster care than Canadian hospitals for patients who pay out-of-pocket.

Canada↗
PubMed1997

Stationary interphases with extended alkyl chains: a comparative study on chain order by solid-state NMR spectroscopy.

Stationary interphases with long n-alkyl chains (n = 18, 22, 30, 34) have been examined by solid-state NMR spectroscopy. The determination of the silane functionality and the degree of cross-linking of silane ligands on the silica surface was performed by 29Si CP/MAS NMR spectroscopy. High-speed 1H MAS and 13C CP/MAS NMR spectroscopy were utilized to assess alkyl chain order and mobility of the different bonded phases. For this purpose, 1H NMR line widths and 13C chemical shifts have been evaluated. It is shown that stationary phase order and rigidity increase with alkyl chain length. In addition, the temperature-dependent trans/gauche conformational change occurs at higher temperatures for a polymeric C34 phase compared with a C30 sorbent. This behaviour is discussed in the context of previously reported chromatographic (HPLC) shape selectivity differences.

Carbon Isotopes↗
PubMed1997

Safety of topical 5-aminosalicylic acid in pregnancy.

OBJECTIVE: To assess the safety and efficacy of topical 5-aminosalicylic acid preparations for therapy of distal colitis during pregnancy. METHODS: Nineteen pregnancies in sixteen consecutive patients with proven distal colitis were identified prospectively at a tertiary care center. All patients were given trials of weaning off medication and all failed. All subjects were on maintenance topical 5-aminosalicylic acid therapy at the time of conception. They were followed throughout their pregnancy and thereafter. Their children were also closely examined and followed by a pediatrician. RESULTS: The mean age at delivery was 25.8 yr, and the mean duration of illness was 4.6 yr. After taking topical therapy, there were no relapses during the pregnancy. There were 19 successful full-term pregnancies with no fetal abnormalities. The mothers and children were followed for more than 6 months. CONCLUSION: In this series, topical 5-aminosalicylic acid appears safe, effective, and well tolerated in the management of pregnant patients with distal colitis.

Abnormalities, Drug-Induced↗
PubMed1994

Management of breast cancer in southeast England.

OBJECTIVE: To examine the extent to which management of invasive breast cancer reflected consensus guidelines in the Thames regions in 1990. DESIGN: Population based study of case notes. SETTING: Thames Cancer Registry. SUBJECTS: All women with breast cancer diagnosed in early 1990 (417 cases) resident in the four Thames regions. Hospital records were traced for 346 cases, of which 12 were ineligible because of misclassification in initial registration and were excluded from the analysis. 334 cases were analysed. MAIN OUTCOME MEASURES: Investigations and treatment in the six months after diagnosis, stage of disease. RESULTS: Of the 334 women identified, 86 were aged under 50. Three years after diagnosis, 74 were dead, seven (8%) aged under 50 and 67 (27%) aged 50 or over. Axillary surgery was used to stage cancer in only 155 cases (46%), although this is recommended in the guidelines. Only 79 (24%) case notes had any information recorded on stage. Stage could be determined reliably for only half of the sample. Treatment varied widely within the same age group and stage of disease. In particular, chemotherapy was not routinely given to patients under 50 with stage II disease. Only 17 records showed evidence that the patient was participating in a clinical trial. CONCLUSIONS: There was a lack of consensus on the management of breast cancer among clinicians in 1990. More patients should be included in clinical trials.

Adult↗
PubMed1990

An open controlled assessment of osteopathic manipulation in nonspecific low-back pain.

An open controlled pilot trial on nonspecific low-back pain sufferers demonstrated responsiveness to osteopathic manipulation of some patients presenting with pain durations of 14 to 28 days. No response was demonstrated in those with shorter episodes at presentation. The advantage to manipulated patients was maximal between 1 and 2 weeks after commencing treatment, but was not discernable after 4 weeks. The demonstration of a similar responsive stratum by other investigators, with both teams totally unaware of each other's work during data collection, suggests a high degree of reliability for this finding.

Activities of Daily Living↗
PubMed1990

Attaining specificity in the measurement of ethanol in breath.

In most cases, new breath alcohol measuring devices satisfy the requirements for accuracy and precision. All instruments however, have responded to some substances other than ethanol. In this area of instruments specificity for ethanol there is scope for further development. Substances other than ethanol may be distinguished as interfering substances by the use of two methods of ethanol detection. One example of this is dual-wavelength infra-red detection. Alternatively, infra-red detection could be coupled to a fuel-cell or Taguchi cell detector. Comparison of the two readings obtained should allow most substances other than ethanol to be distinguished as interfering substances. Two instruments using two modes of ethanol detection are the Intoximeter 3000 (3.4 um infra-red plus Taguchi cell) and the BAC DataMaster (dual wavelength infra-red). These have proved unsuitable because of incomplete specificity for ethanol, largely because acetone appears to be considered the only potential interfering substance. In the selection of two modes of ethanol detection, each system must be chosen such that a comparison of the response from each mode would indicate a wide range of possible interfering substances, not just acetone. A performance specification has been developed, against which future commercial instruments will be evaluated.

Breath Tests↗