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Biomedical subjects

G S Cooper

Publications and source records attributed to G S Cooper.

At least 55 records · Page 3Linked to original sources
PubMed1999

Prospective assessment of the utility of EUS in the evaluation of gallstone pancreatitis.

BACKGROUND: The ability to identify common bile duct stones by noninvasive means in patients with acute biliary pancreatitis is limited. The aim of this study was to prospectively evaluate the ability of endosonography (EUS) to identify cholelithiasis and choledocholithiasis and predict disease severity in patients with nonalcoholic pancreatitis. METHODS: EUS was performed immediately before endoscopic retrograde cholangiopancreatography (ERCP) by separate blinded examiners within 72 hours of admission. Gallbladder findings were compared between EUS and transabdominal ultrasonography (US). Using endoscopic extraction of a bile duct stone as the reference standard for choledocholithiasis, the diagnostic yield of EUS was compared with transabdominal US and ERCP. Features identified during endosonographic imaging of the pancreas were correlated with length of hospitalization. RESULTS: Thirty-six patients were studied. EUS and transabdominal US were concordant in their interpretation of gallbladder findings in 92% of patients. The sensitivity of transabdominal US, EUS, and ERCP for identifying choledocholithiasis was 50%, 91%, and 92% and the accuracy was 83%, 97%, and 89%, respectively. Length of hospital stay was longer in patients with peripancreatic fluid (9.2 vs. 5.7 days, p < 0.1) and shorter in patients with coarse echo texture (2.6 vs. 7.2 days, p < 0.05) demonstrated on EUS. CONCLUSIONS: EUS can reliably identify cholelithiasis and is more sensitive than transabdominal US in detecting choledocholithiasis in patients with biliary pancreatitis. EUS may be used early in the management of patients with acute pancreatitis to select those who would benefit from endoscopic stone extraction. The utility of EUS for predicting pancreatitis severity requires further investigation.

Abdomen↗
PubMed1999

Early endoscopy in upper gastrointestinal hemorrhage: associations with recurrent bleeding, surgery, and length of hospital stay.

BACKGROUND: The impact of upper endoscopy in patients with upper gastrointestinal hemorrhage treated in community practice is unknown. Thus we examined the effectiveness of endoscopy performed within 24 hours of admission (early endoscopy). METHODS: Medical records of 909 consecutive hospitalized patients with upper gastrointestinal hemorrhage who underwent endoscopy at 13 hospitals in a large metropolitan area were reviewed. We evaluated unadjusted and severity-adjusted associations of early endoscopy with recurrent bleeding or surgery to control hemorrhage, length of hospital stay, and associations of endoscopic therapy in patients with bleeding ulcers or varices. RESULTS: Early endoscopy was performed in 64% of patients and compared with delayed endoscopy and was associated with clinically significant reductions in adjusted risk of recurrent bleeding or surgery (odds ratio [OR] 0.70: 95% CI [0.44, 1.13]) and a 31% decrease in adjusted length of stay (95% CI: [24%, 37%]). In patients at high risk for recurrent bleeding, the use of early endoscopic therapy to control hemorrhage was associated with reductions in recurrent bleeding or surgery (OR 0.21: 95% CI [0.10, 0.47]) and length of stay (-31%: 95% CI [-44%, -14%). CONCLUSION: In this study of community-based practice, the routine use of endoscopy, and in selected cases endoscopic therapy, performed early in the clinical course of patients with upper gastrointestinal hemorrhage was associated with reductions in length of stay and, possibly, the risk of recurrent bleeding and surgery.

Adult↗
PubMed1999

FSH levels in relation to hysterectomy and to unilateral oophorectomy.

OBJECTIVE: To examine the association between hysterectomy, unilateral oophorectomy, and ovarian status, measured by FSH concentrations, in women aged 35-49 years. METHODS: From the National Health and Examination Survey III, 1716 women aged 35-49 years were studied. Information on menopausal status, surgical history (hysterectomy, single or bilateral oophorectomy), smoking, and other characteristics was collected in a structured interview, height and weight were measured, and one blood sample was collected. We used logistic regression to analyze FSH concentration in relation to hysterectomy and oophorectomy, controlling for age, ethnicity, body mass index, smoking, education, nulligravidity, and exercise. RESULTS: Hysterectomy with unilateral oophorectomy was associated with an increased prevalence of elevated FSH (above 20 IU/L) (adjusted odds ratio [OR] 2.4, 95% confidence interval [CI] 1.3, 4.6) compared with women who had not had hysterectomies or oophorectomies. Among women with two ovaries, hysterectomy was associated with increased prevalence of elevated FSH (adjusted OR 1.5, 95% CI 1.0, 2.5). As a comparison of the effect size, the observed association between hysterectomy and elevated FSH was smaller than the association between FSH and current smoking (OR 2.0), a factor associated with a 1-2 year decrease in mean age at natural menopause. CONCLUSION: Although the differences in FSH levels were small, there was evidence of elevated FSH in women who have had hysterectomies, even if at least one ovary remained.

Adult↗
PubMed1999

Pregnancy recency and risk of ovarian cancer.

OBJECTIVE: A recent analysis suggested that ovarian cancer risk increased with time since last birth, possibly because of some aspect of pregnancy that affects the clearance of cells that have undergone malignant transformation. We analyzed data from four case-control studies pertaining to ovarian cancer risk in relation to age at first pregnancy, age at last pregnancy, and years since last pregnancy: 628 cases and 3432 neighborhood or population controls, ages 18-79, were included. METHODS: We used logistic regression to analyze associations between ovarian cancer risk, controlling for study, age (at diagnosis or corresponding reference age for controls), race, parity, oral contraceptive use, tubal ligation, family history of ovarian or breast cancer, and excluding women with a history of infertility. RESULTS: An early age at first pregnancy was associated with an increased risk of ovarian cancer (odds ratio 1.4, 95% confidence interval (1.1-1.8) for ages < or =19 compared to > or =25). Years since last pregnancy was also associated with increased ovarian cancer risk, with odds ratios of 1.4, 1.4, 1.8, and 2.1 for 10-14, 15-19, 20-24, and > or =25 years compared to 0-9 years (trend test p = 0.004), respectively. CONCLUSION: These observations support the results from the previous study, and raise additional questions about the role of pregnancy in the etiology of ovarian cancer.

Adolescent↗
PubMed1999

Are readmissions to the intensive care unit a useful measure of hospital performance?

BACKGROUND: Although patients readmitted to intensive care units (ICUs) typically have poor outcomes, ICU readmission rates have not been studied as a measure of hospital performance. OBJECTIVES: To determine variation in ICU readmission rates across hospitals and associations of readmission rates with other ICU-based measures of hospital performance. RESEARCH DESIGN: Observational cohort study. SUBJECTS: One hundred three thousand nine hundred eighty four consecutive ICU patients who were admitted to twenty eight hospitals who were then transferred to a hospital ward in those 28 hospitals. MEASURES: Predicted risk of in-hospital death and ICU length of stay (LOS) were determined by a validated method based on age, ICU admission source, diagnosis, comorbidity, and physiologic abnormalities. Severity-adjusted mortality rates, LOS, and readmission rates were determined for each hospital. RESULTS: One or more ICU readmissions occurred in 5.8% patients who were initially classified as postoperative and in 6.4% patients who were initially classified as nonoperative. In-hospital mortality rate was 24.7% in patients who were readmitted as compared with 4.0% in other patients (P < 0.001). After adjusting for predicted risk of death, the odds of death remained 7.5 times higher (OR 7.5, 95% CI, 6.8-8.3). Readmitted patients also had longer (P < 0.001) ICU LOS (5.2 vs. 3.7 days) and hospital LOS (29.3 vs. 11.7 days). Severity-adjusted readmission rates varied across hospitals from 4.2% to 7.6%. Readmission rates were not correlated with severity-adjusted hospital mortality, ICU LOS, or hospital LOS. CONCLUSIONS: ICU patients who were subsequently readmitted have a higher risk of death and longer LOS after adjusting for severity of illness. However, readmission rates were not associated with severity-adjusted mortality or LOS. Those data indicate that ICU readmission may capture other aspects of hospital performance and may be complementary to these measures.

Female↗
PubMed1999

The sensitivity of Medicare claims data for case ascertainment of six common cancers.

BACKGROUND: Although Medicare claims data have been used to identify cases of cancer in older Americans, there are few data about their relative sensitivity. OBJECTIVES: To investigate the sensitivity of diagnostic and procedural coding for case ascertainment of breast, colorectal, endometrial, lung, pancreatic, and prostate cancer. SUBJECTS: Three hundred and eighty nine thousand and two hundred and thirty-six patients diagnosed with cancer between 1984 and 1993 resided in one of nine Surveillance Epidemiology and End Results (SEER) areas. MEASURES: The sensitivity of inpatient and Part B diagnostic and cancer-specific procedural codes for case finding were compared with SEER. RESULTS: The sensitivity of inpatient and inpatient plus Part B claims for the corresponding cancer diagnosis was 77.4% and 91.2%, respectively. The sensitivity of inpatient claims alone was highest for colorectal (86.1%) and endometrial (84.1%) cancer and lowest for prostate cancer (63.6%). However, when Part B claims were included, the sensitivity for diagnosis of breast cancer was greater than for other cancers (93.6%). Inpatient claim sensitivity was highest for earlier years of the study, and, because of more complete data and longer follow up, the highest sensitivity of combined inpatient and Part B claims was achieved in the late 1980s or early 1990s. CONCLUSIONS: Medicare claims provide reasonably high sensitivity for the detection of cancer in the elderly, especially if inpatient and Part B claims are combined. Because the study did not measure other dimensions of accuracy, such as specificity and predictive value, the potential costs of including false positive cases need to be assessed.

Aged↗
PubMed1999

The utility of Medicare claims data for measuring cancer stage.

BACKGROUND: The validity of using claims data for measuring tumor stage, one of the most important determinants of choice of therapy and long-term survival, is unknown. OBJECTIVES: To determine the relative accuracy of both inpatient and hospital Outpatient Medicare claims for measuring the stage of disease of six commonly diagnosed cancers. RESEARCH DESIGN: Analysis of a database linking Surveillance, Epidemiology, and End Results (SEER) registry data and Medicare claims in patients aged 65 years with cancer. SUBJECTS: Three hundred twenty thousand, six hundred and thirty seven cases of invasive breast, colorectal, endometrial, lung, pancreatic, and prostate cancers diagnosed between 1984 and 1993. MEASURES: Using SEER files as the "gold standard," concordance with Medicare claims, as well as sensitivity and positive predictive value of coding for each stage was measured. RESULTS: Although Medicare data correctly categorized local, regional, and distant stage tumors in 97%, 33%, and 65%, respectively, the data substantially overestimated the proportion of localized tumors and underestimated the rate of regional stage disease. The highest concordance was observed for breast and colorectal cancer. However, the sensitivity and positive predictive values were never simultaneously 80% within one stage of a specific cancer. The accuracy of coding for stage in Outpatient files was inferior to inpatient data. CONCLUSIONS: With few exceptions, Medicare claims have limited utility as a measure of cancer stage. If tumor registry data are not available, investigators should consider the trade offs in sensitivity and predictive value when considering a study that will use claims data.

Aged↗
PubMed1999

The role of genetic factors in autoimmune disease: implications for environmental research.

Studies in both humans and in animal models of specific disorders suggest that polymorphisms of multiple genes are involved in conferring either a predisposition to or protection from autoimmune diseases. Genes encoding polymorphic proteins that regulate immune responses or the rates and extent of metabolism of certain chemical structures have been the focus of much of the research regarding genetic susceptibility. We examine the type and strength of evidence concerning genetic factors and disease etiology, drawing examples from a number of autoimmune diseases. Twin studies of rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), type I diabetes, and multiple sclerosis (MS) indicate that disease concordance in monozygotic twins is 4 or more times higher than in dizygotic twins. Strong familial associations (odds ratio ranging from 5-10) are seen in studies of MS, type I diabetes, Graves disease, discoid lupus, and SLE. Familial association studies have also reported an increased risk of several systemic autoimmune diseases among relatives of patients with a systemic autoimmune disease. This association may reflect a common etiologic pathway with shared genetic or environmental influences among these diseases. Recent genomewide searches in RA, SLE, and MS provide evidence for multiple susceptibility genes involving major histocompatibility complex (MHC) and non-MHC loci; there is also evidence that many autoimmune diseases share a common set of susceptibility genes. The multifactorial nature of the genetic risk factors and the low penetrance of disease underscore the potential influence of environmental factors and gene-environment interactions on the etiology of autoimmune diseases.

Animals↗
PubMed1999

Occupational exposure to crystalline silica and autoimmune disease.

Occupational exposure to silica dust has been examined as a possible risk factor with respect to several systemic autoimmune diseases, including scleroderma, rheumatoid arthritis, systemic lupus erythematosus, and some of the small vessel vasculitidies with renal involvement (e.g., Wegener granulomatosis). Crystalline silica, or quartz, is an abundant mineral found in sand, rock, and soil. High-level exposure to respirable silica dust can cause chronic inflammation and fibrosis in the lung and other organs. Studies of specific occupational groups with high-level silica exposure (e.g., miners) have shown increased rates of autoimmune diseases compared to the expected rates in the general population. However, some clinic- and population-based studies have not demonstrated an association between silica exposure and risk of autoimmune diseases. This lack of effect may be due to the limited statistical power of these studies to examine this association or because the lower- or moderate-level exposures that may be more common in the general population were not considered. Experimental studies demonstrate that silica can act as an adjuvant to nonspecifically enhance the immune response. This is one mechanism by which silica might be involved in the development of autoimmune diseases. Given that several different autoimmune diseases may be associated with silica dust exposure, silica dust may act to promote or accelerate disease development, requiring some other factor to break immune tolerance or initiate autoimmunity. The specific manifestation of this effect may depend on underlying differences in genetic susceptibility or other environmental exposures.

Arthritis, Rheumatoid↗
PubMed1999

Linking environmental agents and autoimmune disease: an agenda for future research.

Autoimmune diseases are influenced by multiple factors including genetics, age, gender, reproductive status, hormones, and potential environmental contaminants. A workshop, "Linking Environmental Agents and Autoimmune Diseases," was convened at the National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, 1-3 September 1998, to review current knowledge about links between environmental exposures and autoimmune disease, to identify and prioritize research needs, and to develop an integrated, multidisciplinary research agenda. Participants spent the last half-day of the workshop in small group discussions for the purpose of developing consensus on research needs. Research needs identified were a) develop research tools needed to explore links between environmental agents and autoimmune disease; b) establish a disease registry or surveillance system; c) develop and validate strategies for screening chemicals for the potential to induce or exacerbate autoimmune disease; d) develop an emergency response strategy to gain information from accidental exposures; and e) conduct hypothesis-driven research in occupationally exposed groups and/or in experimental animals. There was consensus that meetings like this workshop and projects that facilitate interactions between specialties should be encouraged. A multidisciplinary approach is needed to address this problem.

Animals↗
PubMed1999

Community-wide assessment of intensive care outcomes using a physiologically based prognostic measure: implications for critical care delivery from Cleveland Health Quality Choice.

STUDY OBJECTIVES: To examine the applicability of a previously developed intensive care prognostic measure to a community-based sample of hospitals, and assess variations in severity-adjusted mortality across a major metropolitan region. DESIGN: Retrospective cohort study. SETTING: Twenty-eight hospitals with 38 ICUs participating in a community-wide initiative to measure performance supported by the business community, hospitals, and physicians. PATIENTS: Included in the study were 116,340 consecutive eligible patients admitted to medical, surgical, neurologic, and mixed medical/surgical ICUs between March 1, 1991, and March 31, 1995. MAIN OUTCOME MEASURES: The risk of hospital mortality was assessed using a previous risk prediction equation that was developed in a national sample, and a reestimated logistic regression model fit to the current sample. The standardized mortality ratio (SMR) (actual/predicted mortality) was used to describe hospital performance. RESULTS: Although discrimination of the previous national risk equation in the current sample was high (receiver operating characteristic [ROC] curve area = 0.90), the equation systematically overestimated the risk of death and was not as well calibrated (Hosmer-Lemeshow statistic, 2407.6, 8 df, p < 0.001). The locally derived equation had similar discrimination (ROC curve area = 0.91), but had improved calibration across all ranges of severity (Hosmer-Lemeshow statistic = 13.5, 8 df, p = 0.10). Hospital SMRs ranged from 0.85 to 1.21, and four hospitals had SMRs that were higher or lower (p < 0.01) than 1.0. Variation in SMRs tended to be greatest during the first year of data collection. SMRs also tended to decline over the 4 years (1.06, 1.02, 0.98, and 0.94 in years 1 to 4, respectively), as did mean hospital length of stay (13.0, 12.4, 11.6, and 11.1 days in years 1 to 4; p < 0.001). However, excluding the increasing (p < 0.001) number of patients discharged to skilled nursing facilities attenuated much of the decline in standardized mortality over time. CONCLUSIONS: A previously validated physiologically based prognostic measure successfully stratified patients in a large community-based sample by their risk of death. However, such methods may require recalibration when applied to new samples and to reflect changes in practice over time. Moreover, although significant variations in hospital standardized mortality were observed, changing hospital discharge practices suggest that in-hospital mortality may no longer be an adequate measure of ICU performance. Community-wide efforts with broad-based support from business, hospitals, and physicians can be sustained over time to assess outcomes associated with ICU care. Such efforts may provide important information about variations in patient outcomes and changes in practice patterns over time. Future efforts should assess the impact of such community-wide initiatives on health-care purchasing and institutional quality improvement programs.

APACHE↗
PubMed1999

Menstrual and reproductive risk factors for ischemic heart disease.

The role of hormones in ischemic heart disease is of considerable interest, but limited data are available pertaining to risk factors associated with endogenous hormones. We examined the association between menstrual and reproductive factors and ischemic heart disease in a cohort of 867 white, college-educated women who prospectively recorded menstrual cycle data for at least 5 years from their early 20s through their menopause. Ischemic heart disease history was obtained from a self-administered (N = 714) or proxy-administered (N = 153) questionnaire completed at a mean age of 73 years. The analysis included 44,899 person-years of follow-up and 45 cases of myocardial infarction, angioplasty, heart bypass surgery, or ischemic heart disease-related mortality. Ischemic heart disease risk decreased with increasing age at menarche (age-adjusted RR 0.76 per year, 95% CI = 0.60-0.95). Considering menstrual cycle characteristics ages 28-32, there was little overall association with length, variability, or bleeding duration. Ischemic heart disease risk increased with later age at first birth (age-adjusted RR 2.90 for ages 33-43 compared with 25-29) and later age at last birth (age-adjusted RR 3.79 for ages > or =40 compared with 35-39), but there was little association with high parity.

Age Distribution↗
PubMed1999

Procedure-specific outcomes assessment for endoscopic ultrasonography.

Endosonography (EUS) is a relative newcomer to the field of gastrointestinal endoscopy. Nevertheless, two prospective studies with similar results have shown that EUS leads to a change in management in roughly two-thirds of patients in whom it is performed, with many of these changes being to less invasive or less expensive management. Preliminary investigations on the use of catheter probes for performing EUS have shown similar effects. Specific investigations on the effect of EUS on the outcomes of patients with submucosal tumors, esophageal cancers, pancreatic cancers, and rectal cancers need to be performed. Selective studies have demonstrated EUS to be cost-effective for the management of submucosal tumors and ampullary tumors. The complication rate of EUS appears to be comparable to that of upper endoscopy. There is little or no information regarding training in EUS, practice variation, or affect of EUS on quality of life.

Cost-Benefit Analysis↗
PubMed1999

Active and passive smoking and the occurrence of natural menopause.

We examined smoking in relation to natural menopause in 543 women who prospectively recorded menstrual data from their 20s. Mean age at natural menopause was 0.8 years younger (95% CL = -1.5, -0.0) in 98 women who smoked at menopause compared with 362 never-smokers (RR 1.3, 95% CI = 1.0-1.7). We did not observe a decrease in age at natural menopause in former smokers, a dose-response among current smokers, or a lower age at menopause with passive smoke exposure at home. These results suggest that the effect of smoking on ovarian senescence is limited to active smoking during the menopausal transition.

Adult↗
PubMed1999

p27 cell-cycle inhibitor is inversely correlated with lymph node metastases in right-sided colon cancer.

p27, a cyclin-dependent kinase inhibitor, suppresses proliferation of normal and neoplastic cells. Expression of p27 is correlated with survival in colon cancer. To some degree, right-sided colon cancers differ biologically and clinically from left-sided colon cancers. We analyzed 41 patients with right-sided colon cancers, including 18 cases with regional lymph node metastases and 23 cases with negative lymph nodes. Immunostaining for p27 was performed on histologic sections of primary cancers and scored. Correlation of p27 protein expression with histologic parameters was performed by t-test and multivariate analysis. Decreased p27 protein expression was associated with large tumor size. As percentages of positively stained tumor cells decreased from 70 to 29%, the mean tumor size increased from 1.9 to 7.3 cm. p27 protein expression significantly decreased in primary cancers with angiolymphatic invasion or with positive lymph nodes in comparison with those without angiolymphatic invasion (26 +/- 6 vs. 44 +/- 5%, P < 0.03) or with negative lymph nodes (23 +/- 4 vs. 47 +/- 6%, P < 0.003). p27 expression was not statistically different in terms of depth of tumor invasion (T1/T2 vs. T3/T4), tumor type or tumor differentiation. Multivariate analysis revealed that low p27 expression in primary cancers was correlated with lymph node metastases (P = 0.01). However, it did not correlate with any other histologic parameters. In summary, decreased p27 expression was associated with an increased likelihood of lymph node metastases in colon cancers, independent of depth of tumor invasion. This implies that p27 is a potentially important predictor for tumor metastasis and patient's prognosis in right-sided colon cancers.

Adenocarcinoma↗