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Biomedical subjects

I M Harvey

Publications and source records attributed to I M Harvey.

At least 19 recordsLinked to original sources
PubMed2003

Influence of specialization on the management and outcome of patients with pancreatic cancer.

BACKGROUND: Cancer care is increasingly specialized. Relationships between pancreatic cancer care, mortality and patterns of clinical practice among the full spectrum of patients, including those with irresectable tumours, are not well understood. METHODS: A cohort of 782 patients diagnosed prospectively with pancreatic cancer in 29 acute hospitals in England and Wales over 1 year were followed for 2-3 years. The effects of doctors' and hospitals' specialization, indicated by annual patient volumes, on operative mortality rates, survival times, and test and treatment provision were studied. Multiple logistic and Cox regression models were used to control for prognostic factors and treatments, providing adjusted odds and hazard ratios associated with a higher volume of ten patients annually. RESULTS: Patients managed by higher-volume hospitals survived significantly longer (hazard ratio 0.88 (95 per cent confidence interval (c.i.) 0.83 to 0.93); P < 0.001). They were more likely to undergo cytological examination (odds ratio (OR) 1.21 (95 per cent c.i. 1.01 to 1.35)), resection (OR 1.44 (1.17 to 1.79)) and biliary stenting (OR 1.17 (1.02 to 1.34)), and were less likely to have bypass surgery (OR 0.66 (0.55 to 0.78)). Patients of higher-volume doctors were more likely to undergo endoscopic retrograde cholangiopancreatography (OR 1.59 (1.19 to 2.11)), percutaneous transhepatic cholangiography (OR 1.50 (1.12 to 2.00)), laparoscopy (OR 1.81 (1.07 to 3.06)), resection (OR 1.84 (1.29 to 2.61)) and bypass surgery (1.71 (1.25 to 2.33)). CONCLUSION: Specialization appears to improve survival and to promote more thorough investigation.

Clinical Competence↗
PubMed2003

Anti-inflammatory drugs, analgesics and the risk of perforated colonic diverticular disease.

BACKGROUND: Acute perforated colonic diverticular disease has a mortality rate of up to 30 per cent, but little is known about its aetiology. The aim of this study was to test the hypothesis that three classes of drugs, namely non-steroidal anti-inflammatory drugs (NSAIDs), opioid analgesics and corticosteroids, are risk factors for perforated diverticular disease. METHODS: All patients with confirmed perforated colonic diverticular disease were identified over a 5-year period in two hospitals in Norfolk, UK. Two control groups were selected and matched for age, sex and hospital of admission. Data on medication use were obtained from hospital records. Odds ratios for each drug were calculated using conditional logistic regression. RESULTS: Opioid analgesics, NSAIDs and corticosteroids were all positively associated with perforated colonic diverticular disease. The odds ratio for opioid analgesics was 1.8 (95 per cent confidence interval (c.i.) 1.1 to 3.0) in the analysis with ophthalmology controls and 3.1 (95 per cent c.i. 1.8 to 5.5) in that with dermatology controls. Respective odds ratios for NSAIDs were 4.0 (95 per cent c.i. 2.1 to 7.6) and 3.7 (95 per cent c.i. 2.0 to 6.8), and those for corticosteroids were 5.7 (95 per cent c.i. 2.2 to 14.4) and 7.8 (95 per cent c.i. 2.6 to 23.3). CONCLUSION: Opioid analgesics, NSAIDs and corticosteroids are all positively associated with perforated colonic diverticular disease. The consistency of these associations, together with plausible biological mechanisms, suggests that these drugs may have a causative role in this condition.

Adrenal Cortex Hormones↗
PubMed2003

Do calcium channel blockers and antimuscarinics protect against perforated colonic diverticular disease? A case control study.

BACKGROUND: The aetiology of perforated colonic diverticular disease (PCDD) remains largely unknown. Perforation may result from a combination of high intracolonic pressures, secondary to excessive colonic segmentation, and impairment of the mucosal barrier. Calcium channel blockers and antimuscarinic drugs, which reduce colonic contractility and tone, could potentially protect against perforation. The aim of this study was to test this hypothesis using a case control design. METHODS: All cases of acute PCDD were identified over a five year period in two hospitals in Norfolk, UK. Each case was matched for age, sex, and date of admission to two controls groups: (1) patients undergoing cataract surgery and (2) patients with basal cell carcinoma. Data on drug use prior to hospital admission were obtained from medical and nursing records and compared between cases and controls. RESULTS: A total of 120 cases of PCDD were identified and matched to 240 controls in each group. A statistically significant protective association was seen between calcium channel blocker use and PCDD using both control groups. The odds ratios were 0.41 (95% confidence interval (CI) 0.18-0.93) using the ophthalmology control group and 0.36 (95% CI 0.16-0.82) using the dermatology control group. CONCLUSIONS: This study has shown for the first time that a protective association exists between calcium channel blockers and PCDD. The validity of this association is supported by the consistent finding in both control groups and the plausible biological mechanisms. Further studies are required to confirm this association but calcium channel blockers may represent a potential preventive therapy in PCDD.

Adult↗
PubMed2002

Cohort study in South and West England of the influence of specialization on the management and outcome of patients with oesophageal and gastric cancers.

BACKGROUND: To evaluate specialization in National Health Service (NHS) cancer care, volume-outcome relationships were examined. METHODS: This was a cohort study of 1512 patients with oesophageal or gastric cancer in 23 acute NHS hospitals. Outcomes were survival time and operative (30 day) mortality. Multiple regression analysis was performed, adjusted for diagnoses, prognoses and treatments. RESULTS: For oesophageal cancer, the operative mortality rate decreased by 40 per cent (odds ratio 0.60 (95 per cent confidence interval (c.i.) 0.36 to 0.99 per cent); P = 0.047) for each increase of ten patients in doctors' annual surgical caseloads, and the risk of death decreased by 8 per cent (hazard ratio 0.92 (95 per cent c.i. 0.85 to 0.99); P = 0.021) for each increase of ten patients in doctors' annual caseloads. For gastric cancer, the operative mortality rate decreased by 41 per cent (odds ratio 0.59 (95 per cent c.i. 0.32 to 1.07)) for each increase of ten patients in doctors' annual surgical caseloads, and the risk of death decreased by 7 per cent (hazard ratio 0.93 (95 per cent c.i. 0.89 to 0.98); P = 0.009) for each increase of ten patients in hospitals' annual caseloads. Patients of higher-volume doctors were more likely to receive most investigations and treatments, independently of presenting features. CONCLUSION: The study supports concentration of services for oesophageal and gastric cancers. Specialization of doctors and their teams is at least as important as specialization of hospitals.

Cancer Care Facilities↗
PubMed2002

Relationship between the birth cohort pattern of Helicobacter pylori infection and the epidemiology of duodenal ulcer.

BACKGROUND: Helicobacter-pylori-related duodenal ulcer (DU) is an important cause of dyspepsia. AIM: To determine the relationship between the pattern of H. pylori infection and the epidemiology of duodenal ulcer in a single population. DESIGN: Prospective two-part study of (i) patients with DU referred for endoscopy because of dyspepsia, and (ii) the incidence of H. pylori infection in the general population of the same area. METHODS: Details of 533 DU patients were recorded, and related to the pattern of H. pylori infection among 10 537 adults in the same community, determined by the (13)C-urea breath test. RESULTS: In patients with DU, birth year was more important than age in determining the rate of presentation for endoscopy (the 'birth cohort' effect). H. pylori infection showed a similar birth cohort effect, and the prevalence decreased steadily in those born in successive years, from 28.8% in the 1930s to 3.5% in the 1970s. The proportion of dyspeptic patients who had duodenal ulcers also fell progressively, from 22.2% in 1979 to 5.7% in 1998. H. pylori prevalence and duodenal ulcer incidence were closely correlated at all ages. DISCUSSION: Duodenal ulcer prevalence (as judged by the rate of referral of duodenal ulcer patients for endoscopy) is determined principally by the distribution of H. pylori infection in the local population. The birth cohort effect seen in adult duodenal ulcer patients reflects the acquisition of H. pylori in childhood. In Bristol, H. pylori prevalence and duodenal ulcer incidence are both declining to very low levels.

Adult↗
PubMed2002

Epidemiology of perforated colonic diverticular disease.

Perforated colonic diverticular disease results in considerable mortality and morbidity. This review appraises existing evidence on the epidemiology and mechanisms of perforation, highlights areas of further study, and suggests an epidemiological approach towards preventing the condition. Computerised searches were used to identify published articles relating to the epidemiology, pathophysiology, and clinical features of perforated colonic diverticular disease. Several drug and dietary exposures have potential biological mechanisms for causing perforation. Of these only non-steroidal anti-inflammatory drugs have been consistently identified as risk factors in aetiological studies. The causes of perforated colonic diverticular disease remain largely unknown. Further aetiological studies, looking specifically at perforation, are required to investigate whether cause-effect relationships exist for both drug and dietary exposures. The identification of risk factors for perforation would allow primary public health prevention, secondary risk factor modification, and early prophylactic surgery to be aimed at people at high risk.

Alcohol Drinking↗
PubMed2000

A systematic review of comparisons of effect sizes derived from randomised and non-randomised studies.

BACKGROUND: There is controversy about the value of evidence about the effectiveness of healthcare interventions from non-randomised study designs. Advocates for quasi-experimental and observational (QEO) studies argue that evidence from randomised controlled trials (RCTs) is often difficult or impossible to obtain, or is inadequate to answer the question of interest. Advocates for RCTs point out that QEO studies are more susceptible to bias and refer to published comparisons that suggest QEO estimates tend to find a greater benefit than RCT estimates. However, comparisons from the literature are often cited selectively, may be unsystematic and may have failed to distinguish between different explanations for any discrepancies observed. OBJECTIVES: The aim was to investigate the association between methodological quality and the magnitude of estimates of effectiveness by comparing systematically estimates of effectiveness derived from RCTs and QEO studies. Quantifying any such association should help healthcare decision-makers to judge the strength of evidence from non-randomised studies. Two strategies were used to minimise the influence of differences in external validity between RCTs and QEO studies: a comparison of the RCT and QEO study estimates of effectiveness of any intervention, where both estimates were reported in a single paper a comparison of the RCT and QEO study estimates of effectiveness for specified interventions, where the estimates were reported in different papers. The authors also sought to identify study designs that have been proposed to address one or more of the problems often found with conventional RCTs. METHODS DATA SOURCES: Relevant literature was identified from: The Cochrane Library, MEDLINE, EMBASE, DARE, and the Science Citation Index. References of relevant papers already identified experts. Electronic searches were very difficult to design and yielded few papers for the first strategy and when identifying study designs. CHOICE OF INTERVENTIONS TO REVIEW FOR STRATEGIES 1 AND 2: For strategy 1, any intervention was eligible. For strategy 2, interventions for which the population, intervention and outcome investigated were anticipated to be homogeneous across studies were selected for review: Mammographic screening (MSBC) of women to reduce mortality from breast cancer. Folic acid supplementation (FAS) to prevent neural tube defects in women trying to conceive. DATA EXTRACTION AND QUALITY ASSESSMENT: Data were extracted by the first author and checked by the second author. Disagreements were negotiated with reference to the paper concerned. For strategy 1, study quality was scored using a checklist to assess whether the RCT and QEO study estimates were derived from the same populations, whether the assessment of outcomes was 'blinded', and the extent to which the QEO study estimate took account of possible confounding. For strategy 2, a more detailed instrument was used to assess study quality on four dimensions: the quality of reporting, the generalisability of the results, and the extent to which estimates of effectiveness may have been subject to bias or confounding. All quality assessments were carried out by three people. DATA SYNTHESIS AND ANALYSIS: For strategy 1, pairs of comparisons between RCT and QEO study estimates were classified as high or low quality. Seven indices of the size of discrepancies between estimates of effect size and outcome frequency were calculated, where possible, for each comparison. Distributions of the size and direction of discrepancies were compared for high- and low-quality comparisons. FOR STRATEGY 2, THREE ANALYSES WERE CARRIED OUT: Attributes of the instrument were described by k statistics, percentage agreement, and Cronbach's a values. Regression analyses were used to investigate -variations in study quality. (ABSTRACT TRUNCATED)

Breast Neoplasms↗
PubMed1997

Profiling outpatient workload: practice variations between consultant firms and hospitals in south west England.

OBJECTIVES: To describe the variation in outpatient new to old ratios between consultants and between providers for seven high volume specialties (four surgical, three medical). DESIGN: This was a descriptive study at consultant and provider unit level based upon patient administration system data from the South and West Regional Health Authority for the financial year 1992-93. Additional components of variance analysis was used to distinguish individual consultant effects from host institution effects. SETTING: The former South Western Regional Health Authority area from Gloucestershire to Cornwall. SUBJECTS: Altogether 345 consultant firms in seven specialties grouped into 13 provider unit groups. MAIN MEASURES: New to old ratio, omitting elective inpatients followed up as outpatients. RESULTS: Variation between consultants is greater in surgical than in medical specialties, while absolute levels of new to old ratios tend to be higher in surgical specialties than in medical. Variation between provider unit groups is also greater in surgical specialties. Analysis of variance shows that more total variance is attributable to provider unit group in gynaecology than in other specialties. CONCLUSIONS: Within individual specialties there is evidence of substantial variation that is not attributable to underlying differences in morbidity patterns. There is evidence of marked variation in terms of both individual consultants and institutions, a finding that provides the springboard for further analytical work. Published routine outpatient activity statistics should distinguish between new referrals, inpatient follow up, and clinic rebookings.

Analysis of Variance↗
PubMed1994

Cigarette smoking is not a risk factor in atopic dermatitis.

BACKGROUND: In recent years several diseases have been shown to have a relationship with smoking. Psoriasis is largely a disease of smokers, whereas acne appears to be associated with not smoking. METHODS: One hundred and fifty patients with atopic dermatitis were sent a postal questionnaire on smoking habits and the results were compared with those from matched controls in the local community. RESULTS: One hundred and twenty-seven patients (85%) completed the questionnaire. There was no apparent difference in the prevalence of current smokers amongst atopic dermatitis patients compared with controls (odds ratio = 1.1, 95% confidence limits 0.65-1.86, P = 0.8). CONCLUSIONS: There was no significant difference between the smoking prevalence of patients with atopic dermatitis and matched controls.

Dermatitis, Atopic↗
PubMed1994

Feasibility, reliability and women's views of a risk scoring system for cervical neoplasia in primary care.

BACKGROUND: A risk assessment scale for cervical neoplasia has been developed which gives a risk score based on four factors: level of education, current smoking status, number of years of oral contraceptive use and number of sexual partners ever. AIM: A pilot study was undertaken to determine the feasibility and acceptability of a self-report data form, used to assess risk of cervical neoplasia, and the test-retest reliability of women's responses to the questions. METHOD: A sample of women attending one general practice were asked to complete a self-report data form which included some highly personal questions, and a questionnaire assessing their level of difficulty and discomfort completing the form. Women were sent a second self-report data form four weeks later in order to assess test-retest reliability. RESULTS: There was a high level of cooperation with the study (94% initial participation rate), little evidence of discomfort with the questions posed, and high test-retest reliability. CONCLUSION: The results of this pilot study have positive implications for a large prospective study evaluating the predictive power of the risk scale in relation to the result of the cervical smear test.

Adolescent↗
PubMed1994

Prospective evaluation of a risk scoring system for cervical neoplasia in primary care.

BACKGROUND: Against a background of concern over the costs of the cervical screening programme in the United Kingdom, increased precision in targeting groups at high risk of having an abnormal cervical smear offers a means of increasing efficiency. Previous papers have described the development of a risk scoring system and its feasibility and reliability in primary care. AIM: A study was carried out to assess the validity of the scoring system by testing its predictive ability on a prospective data set. METHOD: Consecutive attenders for cervical smear tests at seven practices and three clinics were recruited for the study. The women completed a questionnaire from which their risk scores could be calculated. The scores were compared with cytology and histology results. Various performance statistics were obtained. RESULTS: In terms of cervical intraepithelial neoplasia (CIN) 2 or 3, there was an 11 fold increased risk among the low risk group (scores of four or five) compared with the very low risk group (scores of three or less). The system enabled the identification of 75% (95% confidence interval 62% to 84%) of cases of CIN 2 or 3 among the 21% of the 3629 women with known histology who had a score of four or five. CONCLUSION: Given the ease with which risk status can be ascertained (a risk score could not be calculated for only 23 of 3661 women) and the magnitude of difference in risk, the risk scoring system appears to have potential for assisting the targeting of screening resources. Studies of risk perception and behaviour, and ultimately a randomized controlled trial, are required to assess the effectiveness and cost effectiveness of risk targeting.

Adolescent↗
PubMed1992

Smoking habits in psoriasis: a case control study.

We have examined smoking habits in 108 patients with psoriasis, including some with palmoplantar distribution, and compared the results with matched controls from the community. There was a significant association between psoriasis, current smoking status (OR = 2.7, 95% CI 1.44-5.42, P less than 0.01) and smoking habits prior to the onset of disease (OR = 3.75, 95% CI 1.68-9.47, P less than 0.001). There was also a marked dose-response relationship; the relative risk of psoriasis in those currently smoking more than 20 cigarettes/day was significantly elevated (OR = 5.3, 95% CI 2.1-13.0, P less than 0.001). Separate analysis of patients without palmoplantar distribution of psoriasis showed a significant association with smoking prior to onset of psoriasis (OR = 3.6, 95% CI 1.5-9.8, P less than 0.001). Smoking may play a role in the aetiology of this common skin disorder.

Adolescent↗
PubMed1992

Risk targeting in cervical screening: a new look at an old problem.

In the face of continuing debate about the level of effectiveness of the United Kingdom cervical cytology screening programme in preventing cervical cancer, more precise targeting of high risk groups might offer a means of enhancing its efficiency. Broad risk targeting is already practised by screening only sexually active women aged 20 to 65 years. This paper describes a risk scoring system constructed from the available literature and designed to be used by primary care health professionals and patients. The system involves four independent risk factors: educational level, current smoking habit, years of oral contraceptive use and number of sexual partners. Since the objective is simply to identify women at relatively high risk, inclusion of a factor neither requires nor implies causality. The next steps are to study the feasibility of putting the scale to practical use and to investigate its predictive value in a prospective evaluation.

Age Factors↗
PubMed1989

Reflex and dilatation: a clinical epidemiological evaluation.

The recent controversy surrounding the use of the reflex anal dilatation (RAD) sign in cases of suspected sexual abuse is a general illustration of the difficulties clinicians face in determining which symptoms, signs or laboratory tests to use in their daily practice. The evidence required fully to evaluate RAD is incomplete. The specificity in particular is uncertain. Sufficient evidence is, however, available to permit a quantitative examination of the test's performance under various circumstances. Our analysis suggests that, at the prevalence of anal abuse reported in one large series of children referred to paediatricians with suspected sexual abuse (13%), only if the specificity of the test is 99% or greater, may the positive predictive value of RAD be as high as 90%. At the likely prevalence of anal abuse in the general child population (less than 0.5%), however, an even higher specificity of 99.99% would be necessary to achieve a similar positive predictive value.

Anal Canal↗