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.

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.

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.

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.

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.

Writing nursing history in Canada: issues and approaches

Should the history of nursing be presented as part of medical history? Twenty years ago the answer would have been “yes.” Nurses writing about their collective past shared with physician-historians an interest in questions of professionalization, elite institutions (especially hospitals), higher education, dynamic and respected leaders, and interpretive frameworks that often affirmed the profession’s achievements. For these reasons, nursing was often treated as a subset of medicine, an important, although often less important in its own right, adjunct to the reform of the hospital and the rise of scientific medicine.

The role of expectations in patients' reports of post-operative outcomes and improvement following therapy

Outcomes research typically focuses on the technical capabilities associated with treatment that predicts patients' post-therapy outcomes adjusting for health-related factors. Research on the ability of placebo therapy to alter outcomes suggests that a patient's expectations about therapy can also influence outcomes. Few studies have examined the effects of expectations and their implications for assessing outcomes. This study followed 348 patients who had surgery for benign prostatic hyperplasia. Four hypotheses are tested: whether positive expectations about improvement influence: 1) patients' postoperative reports of symptoms; 2) their belief that they have improved; 3) their overall health after treatment; and 4) whether these effects persist during the year following treatment. Using step-wise regression to control for sociodemographic and clinical factors, we found positive expectations did not appear to strongly influence a patient's report of postoperative symptoms or their overall health. However, we found strong support for positive expectations increasing the likelihood of reporting they felt better after surgery, even after controlling for symptom changes. This effect persisted throughout the postoperative year. We conclude that positive expectations result in a more optimistic view of improvement after surgery rather than altering reports of outcomes or health.

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.

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.

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.

Differences in outcome of transurethral resection of the prostate for benign prostatic hypertrophy between three diagnostic categories

As part of a prospective cohort study of 388 men undergoing transurethral resection of the prostate (TURP) for benign prostatic hypertrophy, pre-operative factors and the outcome of surgery during the first post-operative year were compared between patients in whom their surgeon felt the principal reason for operating was chronic retention (37%), acute retention (with no chronic retention) (28%), or symptomatic prostatism (with no history of chronic or acute retention) (35%). Although in many respects the patients in the 3 diagnostic categories were similar, patients with chronic retention were more likely to be younger, of higher social class and to have worse general health. Patients with acute retention were more likely to present with a urinary tract infection and to have electrocardiographic abnormalities, and symptomatic patients presented with more severe urinary symptoms. Minor differences between the categories with regard to post-operative morbidity and mortality were not statistically significant at the 5% level. However, some significant differences did exist. Patients with acute retention were more likely to experience urinary and non-urinary infections and impotence after surgery, while symptomatic patients reported less improvement in their health status as regards pain and social isolation. These results suggest that the method of categorisation is clinically valid and a necessary distinction to make when auditing TURP.

Criterion validation of the Nottingham Health Profile: patient views of surgery for benign prostatic hypertrophy

As part of a prospective cohort study of 388 men undergoing TURP for benign prostatic hypertrophy, the Nottingham Health Profile (NHP) was self-administered before and at 3, 6 and 12 months after surgery. By comparison of pre- and post-operative NHP scores with other patient-reported health measures the criterion validity of the Profile was examined. Before surgery, statistically significant linear trends were observed for increasing NHP score (i.e. having more health problems) with both worsening self-rated general health and increasing severity of prostatic symptoms. One year after surgery, the extent of reduction in NHP score was significantly linearly associated with a perceived favourable outcome of surgery and to a lesser extent with a reduction in prostatic symptoms. In addition, changes in NHP scores during follow-up were associated with perceived changes in operative outcome during the same period, patients with the greatest reduction in NHP score tending to report more successful surgery at 12 months than at the 3 month assessment.

Patient-perceived health status before and up to 12 months after transurethral resection of the prostate for benign prostatic hypertrophy

As part of a prospective cohort study of 388 men undergoing transurethral resection of the prostate (TURP) for benign prostatic hypertrophy, the perceived physical, social and emotional health before and 3, 6 and 12 months after surgery was assessed using the Nottingham Health Profile. Before surgery, 88% of patients reported one or more specific health problems, most commonly concerning sleep (75%). The areas of daily life considered by the patients to be most affected by their health status were employment (by 33% of those currently in work), sex life (31%), social life (29%) and holidays (29%). Comparisons with other patient groups are described. Three months after surgery the proportion of patients reporting at least one health problem had fallen to 66%. Significant improvements occurred in all aspects of health, particularly sleeping problems. The improvements persisted for all aspects during the year following surgery with the exception of physical mobility, which deteriorated. These improvements were reflected in a significant reduction in perceived limitations in the patients' daily lives, with a tendency for the patients to perceive fewer limitations 1 year after surgery than at the 3-month assessment.

Alcohol intake and the U-shaped curve: do non-drinkers have a higher prevalence of cardiovascular-related disease?

The data from the Oxford Vegetarian Study consists of the observation of around 11,000 individuals followed since the early 1980s. There are around 6000 subjects who do not eat meat and 5000 roughly matched individuals who do. An assiduous questionnaire survey was conducted at recruitment which inquired about health status, diet, drinking and other habits. We have tested the hypothesis that the U-shaped curve relating quantity of alcohol consumed and health is an artefact of selection of some individuals with high consumption and high risk migrating to the no-consumption group but retaining a high risk. The Oxford Vegetarian Study consists of a high proportion of lifelong teetotallers and ex-drinkers, and hence is particularly suitable for testing this hypothesis. We have examined the standardized rates of cardiovascular risk factors among the different dietary and drinking groups separately for men and women, as the bulk of the observed relationship of alcohol with health is mediated through cardiovascular mechanisms. We were unable to find a difference in the prevalence of risk factors between ex-drinkers and teetotallers, but we did find differences associated with dietary practices, particularly among females. These data cast some doubt on the hypothesis that selection may explain the apparent protective effect of moderate drinking when compared with groups currently not drinking (for whatever reason) and heavy drinking.

Comparison of NHS and private patients undergoing elective transurethral resection of the prostate for benign prostatic hypertrophy

OBJECTIVES

To compare the operative thresholds and clinical management of men undergoing elective transurethral resection of the prostate for benign prostatic hypertrophy in the NHS and privately.

DESIGN

Cohort study of patients recruited by 25 surgeons during 1988.

SETTING

Hospitals in Oxford and North West Thames regions.

PATIENTS

Of 400 consecutive patients, 129 were excluded because of open surgery (nine), lack of surgeons' information (three), and emergency admission (117) and three failed to give information, leaving 268 patients, 214 NHS patients and 54 private patients.

MAIN MEASURES

Sociodemographic factors, prevalence and severity of symptoms, comorbidity, general health (Nottingham health profile) obtained from patient questionnaire preoperatively and reasons for operating, and operative management obtained from surgeons perioperatively.

RESULTS

NHS and private patients were similar in severity of symptoms and prevalence of urinary tract abnormalities. They differed in four respects: NHS patients' general health was poorer as a consequence of more comorbid conditions (49, 23% v 7, 13% in severe category); the condition had a greater detrimental effect on their lives (36, 17% v 2, 4% severely affected; p < 0.01); private patients received more personalised care more quickly and were investigated more before surgery, (29, 54% v 60, 20% receiving ultrasonography of the urinary tract); and NHS patients stayed in hospital longer (57, 27% v 3, 6% more than seven days; p < 0.001).

CONCLUSIONS

Private patients' need for surgery, judged by symptom severity, was as great as that of NHS patients, and there was no evidence of different operative thresholds in the two sectors, but, judged by impact on lifestyle, NHS patients' need was greater.

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.

Mortality, morbidity and complications following transurethral resection of the prostate for benign prostatic hypertrophy

A total of 388 men undergoing transurethral resection of the prostate for benign prostatic hypertrophy during 1988 entered a prospective cohort study designed to examine the outcome of surgery during postoperative year 1. Self-administered questionnaires were completed preoperatively, and at 3, 6 and 12 months postoperatively. The surgeons completed 1 questionnaire shortly after surgery and another questionnaire 3, 6 or 12 months later. The mortality rate during the 12 months of followup was 2.8% (11 deaths). The surgeons reported perioperative complications in 14% of the patients and immediate postoperative complications, excluding urinary tract infections, in 17%. During the first 3 months postoperatively 38% of the patients reported incontinence and 25% had a urinary tract infection. Between 6 and 12 months postoperatively only 12% of the patients were troubled by either condition. The postoperative prevalence of impotence (24%) did not alter during followup and was similar to that reported preoperatively (22%). Of the patients 74% reported feeling better and 78% experienced a decrease in the overall level of symptoms postoperatively. The improvement in symptom levels was greatest in those with the most severe preoperative symptoms, and obstructive symptoms were alleviated slightly more than irritative symptoms.