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Biomedical subjects

K McPherson

Publications and source records attributed to K McPherson.

At least 19 recordsLinked to original sources
PubMed1995

The National Prostatectomy Audit: the clinical management of patients during hospital admission.

OBJECTIVE: To determine everyday practice in the hospital management of men undergoing prostatectomy and the extent of its variation. PATIENTS AND METHODS: A total of 5361 patients, who represented 89% of all those undergoing prostatic procedures in four health regions (Mersey, Wessex, Northern and South West Thames) and one test site (within Trent) were recruited by 103 (97%) surgeons. Clinical information was collected on a pre-coded data collection form which was completed during the hospital stay by the principal operator. Patient identification occurred at the time of surgery. RESULTS: Important findings included: (i) both older men and those of higher social class were more likely to undergo prostatectomy with fewer symptoms; (ii) men who waited longer for surgery had worse symptoms by the time of their operation; (iii) there were unexplained differences in routine pre- and post-operative investigation and treatment. Half the men had their flow rate or residual urine measured as part of their pre-operative assessment. About half the men received prophylactic antibiotics; (iv) when large groups were analysed, a consistent proportion of men throughout the study (12%) were undergoing the operation for a second time. The clinical course of men having a repeat operation differed in many ways from those having a first time procedure; (v) the larger proportion of men (62%) had surgery for strong indications as opposed to symptoms alone; (vi) although most operations were performed by consultants, emergency admissions, though symptomatically more severe and sicker, were more likely to be operated on by trainee surgeons; (vii) significant variation in mean pre-operative symptom severity and bother scores were seen between surgeons. CONCLUSION: The clinical management of prostatectomy has been defined in a large and representative UK sample. In some circumstances consistent variations have been identified. It is not yet clear whether these variations influence outcome. These data can be used by surgeons wishing to compare their own patient management with that described here.

Age Factors↗
PubMed1994

Risk of death from cancer and ischaemic heart disease in meat and non-meat eaters.

OBJECTIVE: To investigate the health consequences of a vegetarian diet by examining the 12 year mortality of non-meat eaters and meat eating controls. DESIGN: Prospective observational study in which members of the non-meat eating cohort were asked to nominate friends or relatives as controls. SETTING: United Kingdom. SUBJECTS: 6115 non-meat eaters identified through the Vegetarian Society of the United Kingdom and the news media (mean (SD) age 38.7 (16.8) years) and 5015 controls who were meat eaters (39.3 (15.4) years). MAIN OUTCOME MEASURES: Standardised mortality ratios for cancer, ischaemic heart disease, and total mortality in the two cohorts and death rate ratio in the non-meat eaters compared with meat eaters after adjustment for potentially confounding variables. RESULTS: Standardised mortality ratios (taking the value among the general population as 100) for ischaemic heart disease were 51 (95% confidence interval 38 to 66) for meat eaters and 28 (20 to 38) for non-meat eaters (P < 0.01). Values for all cancers were 80 (64 to 98) and 50 (39 to 62) for meat eaters and non-meat eaters respectively. After adjustment for the effects of smoking, body mass index, and socioeconomic status death rate ratios in non-meat eaters compared with meat eaters were 0.72 (0.47 to 1.10) for ischaemic heart disease and 0.61 (0.44 to 0.84) for all cancers. CONCLUSIONS: The reduced mortality from cancer among those not eating meat is not explained by lifestyle related risk factors, which have a low prevalence among vegetarians. No firm conclusion can be made about deaths from ischaemic heart disease. These data do not justify advice to exclude meat from the diet since there are several attributes of a vegetarian diet apart from not eating meat which might reduce the risk.

Adult↗
PubMed1994

Intensive Care Society's Acute Physiology and Chronic Health Evaluation (APACHE II) study in Britain and Ireland: a prospective, multicenter, cohort study comparing two methods for predicting outcome for adult intensive care patients.

OBJECTIVE: To compare the ability of two methods--Acute Physiology and Chronic Health Evaluation (APACHE II) and Mortality Prediction Model (MPM)--to predict hospital outcome for a large group of intensive care patients from Britain and Ireland. DESIGN: Prospective, multicenter, cohort study. SETTING: Twenty-six general intensive care units in Britain and Ireland. PATIENTS: A total of 8,724 patients admitted to the study. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Probabilities of hospital death for patients were estimated by applying APACHE II and MPM. Predicted risks of hospital death were compared with observed outcomes using four methods of assessing the overall goodness of fit. APACHE II performed better than MPM; the calibration curve for APACHE II lay closer to the line of perfect predictive ability. Lemeshow-Hosmer chi-square statistics were 81 and 57 for APACHE II, and 2515 and 1737 for MPM. The overall correct classification rate for APACHE II was 79%, and this classification rate was 74% for MPM, applying a decision criterion of 50%. The area under the receiver operating characteristic curve was 0.83 with APACHE II and 0.74 with MPM. Even after modifications to the MPM for the assessment of coma, the performance of APACHE II was superior. CONCLUSIONS: APACHE II demonstrated a higher degree of overall goodness of fit, which was superior to MPM for groups of intensive care patients from Britain and Ireland.

Adult↗
PubMed1994

Transurethral resection of the prostate for benign prostatic hypertrophy: factors associated with a successful outcome at 1 year.

OBJECTIVE: To investigate which patient and health service factors are predictive of outcome following transurethral resection for benign prostatic hypertrophy. PATIENTS AND METHODS: A total of 388 men were assessed before and 3, 6 and 12 months following surgery. Twenty-one patient characteristics and 12 health service factors were considered. Successful outcome was assessed in terms of avoidance of adverse effects of the operation (survival, lack of early complications and later problems) and improvement in symptoms, health status (assessed in three ways) and quality of life. An overall assessment based on all eight outcome measures was also used. Relationships between possible predictors and outcome were explored whilst controlling for three potential confounders: age, diagnostic category and co-morbidity. A linear logistic model was employed. RESULTS: Patients who had severe pre-operative symptoms but who otherwise enjoyed good health gained the most benefit from surgery. Generally speaking, outcome was not associated with any of the 12 health service factors studied. CONCLUSION: The results support the policy of watchful waiting for mild or moderately symptomatic patients as even if surgery becomes necessary because of a deterioration in the condition, the benefit resulting will be greater. However, any benefits of waiting for surgery would have to be balanced against any increase in urinary tract pathology or co-morbidity that men may suffer whilst waiting, as these will increase the likelihood of an adverse outcome of surgery. The question of whether to wait or not will only finally be resolved by means of a randomized controlled trial comparing transurethral resection of the prostate with watchful waiting.

Adult↗
PubMed1994

The Cochrane Lecture. The best and the enemy of the good: randomised controlled trials, uncertainty, and assessing the role of patient choice in medical decision making.

This lecture aimed to create a bridge to span the conceptual and ideological gap between randomised controlled trials and systematic observational comparisons and to reduce unwanted and unproductive polarisation. The argument, simply put, is that since randomisation alone eliminates the selection effect of therapeutic decision making, anything short of randomisation to attribute cause to consequent outcome is a waste of time. If observational comparison does have any significant part in evaluating medical outcomes, there is a grave danger of "the best", to paraphrase Voltaire, becoming "the enemy of the good". The first section aims to emphasise the advantages of randomised controlled trials. Then the nature of an essential precondition--medical uncertainty--is discussed in terms of its extent and effect. Next, the role of patient choice in medical decision making is considered, both when outcomes can safely be attributed to treatment choice and when they cannot. There may be many important situations in which choice itself affects outcome and this could mean that random comparisons give biased estimates of true therapeutic effects. In the penultimate section, the implications of this possibility both for randomised controlled trials and for outcome research is pursued and lastly there are some simple recommendations for reliable outcome research.

Consumer Behavior↗
PubMed1994

Tobacco consumption and chemical analysis of cigarettes in Bahrain.

A 10.0% random sample of smokers in Bahrain was identified from a previous national morbidity survey which was completed in February 1983. Tobacco consumption and the average yields of tar, nicotine, and carbon monoxide (CO) of seven brands of cigarettes were examined. The 1982 adult tobacco consumption (2.3 kg) in Bahrain was generally lower than in developed countries. Similarly, cigarette per person consumption (734) was less than 69 other countries out of 130 that had data available. Tar, nicotine, and CO analysis of the five leading brands and two others which were previously popular in Bahrain showed that the average yields were mostly comparable with the same brands in the UK.

Adolescent↗
PubMed1993

Intensive Care Society's APACHE II study in Britain and Ireland--I: Variations in case mix of adult admissions to general intensive care units and impact on outcome.

OBJECTIVES: To describe the extent of variation in the case mix of adult admissions to general intensive care units in Britain and Ireland and investigate the impact of such variation on outcome. DESIGN: Prospective, cohort study of consecutive admissions to intensive care units. SETTING: 26 general intensive care units in Britain and Ireland. SUBJECTS: 9099 admissions to the intensive care units studied. MAIN OUTCOME MEASURE: Death or survival at discharge before and after adjustment of case mix (age, history of chronic conditions, surgical status, diagnosis, and severity of illness) according to the APACHE II method. RESULTS: Important differences in case mix were found, with large variations between the units. Hospital mortality was significantly associated with most of the case mix factors investigated. CONCLUSIONS: Comparing crude death rates in hospital between intensive care units may be misleading indicators of performance. The collection of data on case mix needs to be standardised and differences in case mix adjusted for when comparing outcome between different intensive care units.

Age Factors↗
PubMed1993

Intensive Care Society's APACHE II study in Britain and Ireland--II: Outcome comparisons of intensive care units after adjustment for case mix by the American APACHE II method.

OBJECTIVES: To compare outcome between intensive care units in Britain and Ireland both before and after adjustment for case mix with the American APACHE II method and to validate the American APACHE II method in Britain and Ireland. DESIGN: Prospective, cohort study of consecutive admissions to intensive care units. SETTING: 26 general intensive care units in Britain and Ireland. SUBJECTS: 8796 admissions to the study intensive care units. MAIN OUTCOME MEASURE: Death or survival at discharge from intensive care unit and hospital. RESULTS: At discharge from both intensive care unit and hospital there was a greater than twofold variation in crude mortality between the 26 units. After adjustment for case mix, variations in mortality were still apparent. For four intensive care units the observed numbers of deaths were significantly different from the number predicted by the American APACHE II equation. The overall goodness of fit, or predictive ability, of the APACHE II equation for the British and Irish data was good, being only slightly inferior to that obtained when the equation was tested on the data from which it had been derived. When patients were grouped by various factors such as age and diagnosis, the equation did not adjust across the subgroups in a uniform manner. CONCLUSIONS: The American APACHE II equation did not fit the British and Irish data. Use of the American equation could be of advantage or disadvantage to individual intensive care units, depending on the mix of patients treated.

Cohort Studies↗
PubMed1993

Measuring the impact of menopausal symptoms on quality of life.

OBJECTIVE: To examine the impact of menopausal symptoms on the overall quality of life of women. DESIGN: Data collection with a questionnaire administered by an interviewer, incorporating two different quality of life measurement techniques (time trade off and rating scale). SETTING: Specialist menopause clinic and two general practices in Oxford. SUBJECTS: 63 women aged 45-60 years recruited opportunistically during a clinic or appointment with a general practitioner; no exclusion criteria. RESULTS: Subjects gave very low quality of life ratings for health states with menopausal symptoms. The time trade off method of measuring preferences for these health states (on a scale from 0 to 1, where preference for full health is given as 1) yielded utility values of 0.64 for severe menopausal symptoms and 0.85 for mild symptoms. The rating scale measurement technique yielded even lower values: utilities of 0.30 and 0.65 were obtained for severe and mild symptoms respectively. Kappa scores indicated that the two methods produced results that were poorly related but not contradictory. Comparison of quality of life ratings before and after treatment with hormone replacement therapy showed significant improvements: with the rating scale measurement technique mean increases in utility values after the relief of severe and mild menopausal symptoms were 0.56 and 0.18 respectively. CONCLUSIONS: Quality of life may be severely compromised in women with menopausal symptoms, and perceived improvements in quality of life in users of hormone replacement therapy seem to be substantial. This emphasises the need to include quality of life measurements when assessing outcomes of hormone replacement therapy. Several limitations may exist with widely applied measurement techniques, calling for the development of appropriate and well validated instruments for measuring quality of life associated with reduced health states.

Data Collection↗
PubMed1993

Diagnostic dilatation and curettage: is it used appropriately?

OBJECTIVE: To determine patterns of use of dilatation and curettage in Britain as compared with those in the United States; to examine variations in utilisation rates within one regional health authority. DESIGN: Analysis of routinely collected hospital inpatient statistics. SETTING: Statistics for England, Scotland, and the United States; local statistics for Oxford region. SUBJECTS: All inpatient episodes in which dilatation and curettage was performed but excluding those related to pregnancy. RESULTS: Dilatation and curettage rates remained stable in Britain between 1977 and 1990, whereas in the United States they declined dramatically. In 1989-90 the rate was 71.1 per 10,000 women in England as compared with only 10.8 per 10,000 in America. In 1989, 6936 women underwent diagnostic dilatation and curettage in the Oxford region, making it the most common elective operation. A total of 2726 (39%) of these women were under 40. There was a more than twofold variation in usage of the procedure among district health authorities within the region and even greater variation in rates in women under 40. The proportion of patients treated as day cases in the district general hospitals ranged from 22% to 82%. CONCLUSIONS: Dilatation and curettage may frequently be used inappropriately. The considerable variations in usage of dilatation and curettage internationally and nationally indicate differences in clinical perception of its appropriateness. This makes it suitable for audit. In developing guidelines it will be important to agree on the most appropriate patients and the relative merits of alternative methods of endometrial sampling. Probably this could result in considerable cost savings at no risk and possibly some benefit to patients.

Adolescent↗