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Biomedical subjects

G S Cooper

Publications and source records attributed to G S Cooper.

At least 91 records · Page 5Linked to original sources
PubMed1997

Lack of gender and racial differences in surgery and mortality in hospitalized Medicare beneficiaries with bleeding peptic ulcer.

OBJECTIVE: Determine the relation of race and gender to outcome from bleeding peptic ulcer. DESIGN: Retrospective cohort study. SETTING: All acute care hospitals in the United States. PATIENTS: A 100% sample of hospitalized Medicare beneficiaries older than 64 years (n = 82,868) with a primary discharge diagnosis of peptic ulcer with hemorrhage. MEASUREMENTS AND MAIN RESULTS: Surgical treatment was performed in 6.9% of patients, 30-day mortality was 8.5%, and average length of stay was 9.4 days. Surgery was somewhat more common in men than women (7.3% vs 6.5%, p < .001), and in whites than African Americans (6.9% vs 6.3%, p < .001), but neither race nor gender was associated with surgery in multivariable analysis adjusting for potentially confounding factors. Mortality rates were similar in African Americans and whites (8.5%), and somewhat higher in men than women (10.7% vs 9.3%, p < .001). In multivariable analysis, there was no difference in mortality across gender and racial groups. Although unadjusted and adjusted lengths of stay were longer for African Americans and shorter for men, the differences were modest (i.e., 16% increase and 6% decrease in multivariable analysis, respectively, p < .0001). CONCLUSIONS: In this national sample, there is no significant gender or racial difference in therapy and outcome for patients with hemorrhagic peptic ulcer. The findings raise the possibility that studies that have shown race and gender differences in management of coronary artery disease and cancer may not be generalizable to other common diagnoses.

Black or African American↗
PubMed1997

A prognostic model for patients with end-stage liver disease.

BACKGROUND & AIMS: Survival of patients with end-stage liver disease is variable and difficult to predict. A two-phase prospective cohort study was conducted at five teaching hospitals to develop and evaluate a model for prediction of death. METHODS: Five hundred thirty-eight hospitalized patients with a history of chronic liver disease and two or more signs of decompensation were studied. RESULTS: The cumulative incidence of death was 30% at 30 days and 50% at 6 months. In 295 patients in phase I, time till death was independently associated (P < 0.01) with five factors measured on study day 3: renal insufficiency, cognitive dysfunction, ventilatory insufficiency, age > or = 65 years, and prothrombin time > or = 16 seconds. These risk factors stratified 243 patients in phase II into three groups with cumulative incidences of death at 30 days of 12%, 40%, and 74%, respectively. Integration of the prognostic model with physicians' predictions led to improved estimates of the probability of death. Although performance of liver transplantation after study entry was independently associated with enhanced survival, the intensity of other acute therapies was not. CONCLUSIONS: Five risk factors were associated with the risk of death in patients with end-stage liver disease and provided a quantitative basis to complement physicians' prognostic estimates.

Adult↗
PubMed1997

Racial disparity in the incidence and case-fatality of colorectal cancer: analysis of 329 United States counties.

In the United States, blacks have higher death rates from colon cancer than whites, and the survival disparity may be due in part to differences in screening programs and acute medical care in counties with a high concentration of blacks. We studied 148,947 Medicare beneficiaries with newly diagnosed colorectal cancer in 1989-1991 who resided in the 329 most populous counties in the United States to determine the relationship of race and county racial composition to cancer incidence and survival. Counties were divided into quartiles based on proportion of blacks in the population, and aggregate incidence and 2-year case-fatality rates were compared within and between quartiles. Within each quartile, the adjusted incidence rate for whites was consistently higher than that for blacks (P < 0.0001), and case-fatality rates were consistently lower among whites (P < 0.0001) for all but the quartile with the lowest proportion of blacks. Between quartiles, the incidence rates for both whites (P = 0.0001) and blacks (P = 0.008) decreased progressively, and case fatality rates increased progressively for both whites (P = 0.001) and blacks (P = 0.007) as the proportion of blacks increased. When counties were grouped into three different geographic areas, racial disparity in survival was observed in all regions. The variability between groups of counties in colon cancer incidence and mortality for both white and black patients may suggest differences at the county level in screening and treatment. However, consistent racial disparity within county quartiles may reflect persistent deficiencies in access to and quality of care for black patients.

Aged↗
PubMed1997

A retrospective analysis of the efficacy and safety of metformin in the African-American patient.

A retrospective analysis was conducted to determine the effects of metformin on glycosylated hemoglobin (HbA1c), body weight, and adverse events in an African-American population. Thirty-six patients who were receiving combination therapy with metformin and either a sulfonylurea or insulin were identified from a hospital pharmacy database. Nineteen patients met the criteria for efficacy analysis. The combination of metformin with either a sulfonylurea or insulin resulted in a decrease of the average HbA1c from a baseline of 10.07% to 7.92% (delta = 2.15%). The effect of combination therapy on weight was variable; however, twice as many patients lost weight compared with those who gained weight. Metformin appeared to be well-tolerated, with gastrointestinal symptoms being the most commonly reported adverse events.

Adult↗
PubMed1996

Are vitamin D receptor polymorphisms associated with bone mineral density? A meta-analysis.

Vitamin D receptor (VDR) polymorphisms have been strongly associated with bone mineral density (BMD) in some studies but not in others. We used a meta-analytic approach to assess quantitatively the association between VDR and BMD and to examine the influence of specific study characteristics (e.g., skeletal site, mean age of subjects, menopausal status) on the reported results. Sixteen papers published in peer-reviewed journals through July 1996 were included. We calculated the mean difference, percent difference, and effect size (mean difference divided by standard deviation), comparing BMD between homozygous genotypes. At the hip, BMD in the BB genotype was lower than in the bb genotype (mean difference, -0.02 g/cm2; percent difference, -2.4% and effect size -0.18; p = 0.032). At the spine, the mean difference was -0.03 g/cm2; percent difference, -2.5%; and effect size, -0.19; p = 0.062. At the distal radius, the VDR effect was estimated as the mean difference, -0.01 g/cm2; percent difference, -1.7%; and effect size, -0.16; p = 0.078. The spine measurements exhibited the greatest between- and within-study variability. The difference in hip BMD between genotypes was larger (i.e., a more negative number) among the younger women and seemed to decrease with increasing age. However, statistical evidence for this trend was weak (p = 0.06). Data from the spine and the radius showed no evidence of a comparable interaction of the VDR effect with age. When we omitted data from the first report of an association between VDR polymorphisms and BMD, our analyses gave similar results, although the overall effect estimates were smaller. In the combined data from 29 study groups, the BB genotype frequency was 17.2, 4.9, and 2.3% in studies of whites, blacks, and Asians, respectively. VDR polymorphisms represent one genetic factor affecting BMD, but further research into the mechanisms, clinical significance, and its relation between other genetic and environmental factors is needed.

Adult↗
PubMed1996

Prospective assessment of colonoscopic intubation skills in trainees.

INTRODUCTION: The American Society for Gastrointestinal Endoscopy recommends a minimum of 100 supervised colonoscopies prior to assessment of technical competence. To establish a measurable standard for competence and to assess this recommendation, performance of colonoscopies at a university hospital was studied. METHODS: Colonoscopic preparation, surgical history, medication usage, technical maneuvers, extent of colon intubated, success rate, and cecal intubation time were prospectively monitored for first-year trainees, second-year trainees, and attendings. RESULTS: Excluding patients with poor preparations or colonic resections, 496 colonoscopies were studied. First-year trainees (n = 5) required attending assistance in 73 of 79 (92%) procedures. Second-year trainees (n = 7), who had performed a mean of 123 colonoscopies prior to the study, required attending assistance in 37 of 102 (36.3%) procedures. Attendings (n = 7) successfully intubated the cecum in 297 of 315 (94.3%) colonoscopies in a median time of 10.5 minutes. Second-year trainees were less successful than attendings in cecal intubation (success rate = 84%, p < 0.05), and required more time (median = 14.5 minutes, p < 0.01). More technical maneuvers were performed, and a lesser extent of colon was intubated, during trainee colonoscopies. CONCLUSIONS: We propose a 90% success rate and a median cecal intubation time of less than 15 minutes as reasonable standards for measuring technical competence. Trainees do not achieve this standard after the performance of 100 supervised colonoscopies.

Cecum↗
PubMed1996

Care of patients with upper gastrointestinal hemorrhage in academic medical centers: a community-based comparison.

BACKGROUND & AIMS: A common perception among purchasers is that academic medical centers are inefficient and overutilize technology; however, little empirical information exists. The aim of this study was to compare treatment and outcomes of patients with upper gastrointestinal hemorrhage admitted to major teaching hospitals and other hospitals in a large metropolitan area. METHODS: Data on 3801 consecutive eligible patients admitted to five major teaching hospitals and 25 other hospitals from 1991 to 1993 were obtained by review of medical records. Admission severity of illness was measured using validated multivariable models. RESULTS: Rates of upper endoscopy were somewhat lower among the 1004 patients discharged from fellowship hospitals, compared with the other 2797 patients (82.9% vs. 85.6%; P < 0.05), and the use of other procedures was similar. Although patients admitted to fellowship hospitals tended to have a higher severity of illness, both unadjusted (6.3 +/- 9.0 vs. 7.1 +/- 7.5 days; P < 0.01) and risk-adjusted length of stay were somewhat shorter. Mortality rates were similar between hospitals, and patients admitted to fellowship hospitals were somewhat less likely to be transfused. CONCLUSIONS: In patients with upper gastrointestinal hemorrhage, teaching hospitals do not appear to provide inefficient care or overutilize expensive treatments when compared with community facilities. These findings are noteworthy at a time when viability of academic centers and fellowship training is threatened.

Academic Medical Centers↗
PubMed1996

Association of physical and behavioral characteristics with menstrual cycle patterns in women age 29-31 years.

We examined the association between menstrual cycle characteristics (cycle length, variability, and bleeding length) and physical and behavioral attributes in 766 women age 29-31 years. Menstrual cycle data were prospectively recorded as part of the Menstruation and Reproductive History Study of college women in Minnesota, begun by Alan Treloar in 1934. Data on lifetime height, weight, physical activity, alcohol and caffeine consumption, and smoking history were collected in 1990 using a self-administered questionnaire. Cycle variability, as measured by the standard deviation of the cycle length, was increased, and menstrual cycles > or = 42 days in length were more common among women in the lowest quartile of Quetelet index [odds ratio (OR) for long cycle = 1.6;95% confidence interval (CI) = 0.82-3.0] and among the most physically active (OR = 1.7;95% CI = 0.93-3.1). Long menstrual cycles were less common (OR = 0.40;95% CI = 0.22-0.73) among women who drank alcohol than among nondrinkers. Variable or long menstrual cycles may reflect anovulation and relatively low levels of estrogen exposure. We would expect, based on our data, reduced estrogen exposure among lean women, physically active women, and those who do not consume alcohol. These findings suggest an explanation for the reported associations between these factors and breast cancer risk.

Adult↗
PubMed1996

Surgery for colorectal cancer: Race-related differences in rates and survival among Medicare beneficiaries.

This study examined surgery for colorectal cancer among Medicare beneficiaries 65 years of age or older with an initial diagnosis in 1987 (n = 81 579). Black patients were less likely than White to undergo surgical resection (68% vs 78%), even after age, comorbidity, and location and extent of tumor were controlled for. Among those who underwent resection, Black patients were more likely to die (a 2-year mortality rate of 40.0% vs 33.5% in White patients); this disparity also remained after confounders had been controlled. The disparities were similar in teaching and nonteaching hospitals and in private and public hospitals. These data may indicate racially based differences among Medicare beneficiaries in access to and quality of care for colorectal cancer.

Black or African American↗
PubMed1996

A predictive model to identify Clostridium difficile toxin in hospitalized patients with diarrhea.

OBJECTIVES: Although Clostridium difficile is a common pathogen in hospitalized patients with diarrhea, no study has attempted to develop a predictive model to estimate the likelihood of C. difficile positivity. METHODS: We conducted a cross-sectional study at a single hospital of 271 patients with diarrhea for whom stool was tested for C. difficile toxin. The sample was randomly divided into a subset to derive the model (n = 180) and another to validate it (n =91), and independent predictors of toxin positivity were identified using logistical regression analysis. RESULTS: C. difficile toxin was present in 81 patients and absent in 190. In the derivation set, a positive toxin was independently predicted (p < 0.0005) by readmission within 2 wk of prior hospitalization, by a white blood cell count > or = 10,000/mm3, and by presence of fecal leukocytes. In the validation set, C. difficile toxin was present in 24, 29, and 77% of patients with 0, 1, and > or = 2 risk factors, respectively. CONCLUSION: If validated prospectively and/or other centers, the model could identify patients who should be considered for empirical management while awaiting results of toxin assays.

Aged↗
PubMed1996

Menstrual and reproductive history of mothers of galactosemic children.

OBJECTIVE: To test the hypothesis that female carriers of the galactosemia gene (mothers of galactosemic children) experience impaired fecundability and earlier age at natural menopause. DESIGN: Retrospective cohort study comparing experiences of mothers of galactosemic children with mothers of children with phenylketonuria (PKU). Data collection consisted of a structured telephone interview with sections on menstrual, reproductive, and medical histories. PARTICIPANTS: One hundred three galactosemia carriers and 116 PKU carriers (mean age 35.0 and 38.4 years, respectively), recruited from 38 metabolic disease clinics throughout the United States. MAIN OUTCOME MEASURES: Time-to-pregnancy (a measure of fecundability), menstrual cycle patterns, and natural menopause. RESULTS: No difference was seen between carriers of the galactosemia and the PKU gene in history of > or = 12 months of unprotected intercourse without a pregnancy, physician-diagnosed infertility, or amenorrhea lasting > 6 weeks. The fecundability ratio, adjusting for age and smoking before most recent pregnancy, was 1.17 (95% confidence interval [CI] 0.85 to 1.61). By age 45, 11% of galactosemia carriers who had not had a hysterectomy reported a natural menopause compared with 4% of PKU carriers (risk difference 7.2%, 95% CI -12.7% to 27.1%). CONCLUSION: Fecundability and other measures of fertility did not differ between mothers of galactosemic children and mothers of children with PKU. Suggestions of an earlier age at natural menopause can not be addressed definitively in this cohort because of the small number of participants who were currently age 45 years or older but may warrant additional assessment as the cohort ages.

Adult↗
PubMed1996

Risk of adult acute leukemia in relation to prior immune-related conditions.

We explored the association between immune-related conditions and adult acute leukemia in a study of 624 patients with acute myeloid leukemia (AML), 124 patients with acute lymphoblastic leukemia (ALL), 63 patients with other acute leukemias, and 637 healthy population controls. Common childhood viral diseases were weakly associated with AML and ALL, particularly with early exposure (< or = 5 years of age). Odds ratios (ORs) were elevated for chicken pox and measles at any age, but only the associations with measles were statistically significant [OR = 1.89; 95% confidence interval (CI), 1.40-2.56 for AML and OR = 1.81; 95% CI, 1.07-3.06 for ALL]. There was no association between other infectious diseases, allergies, asthma, or eczema and risk for AML or ALL, although there was a significant association between psoriasis and ALL (OR = 3.23; 95% CI, 1.25-8.30). These results offer little support for either a protective effect of enhanced immune surveillance or a harmful effect from antigenic stimulation in relation to risk for acute leukemia in adults. However, the associations between cancer risk and childhood infectious diseases are intriguing and may warrant additional research.

Acute Disease↗
PubMed1996

Clinical variables associated with colorectal cancer on colonoscopy: a prediction model.

OBJECTIVES: We prospectively evaluated the ability of various indications for colonoscopy to predict colorectal cancer. METHODS: Indications and findings were prospectively recorded for 1223 consecutive colonoscopies performed during an 18-month period at a University Hospital. Colonoscopies performed on 981 patients for indications which included colorectal cancer in the differential diagnosis were included in the study. A group of 653 patients was randomly selected to derive a model predictive of colorectal cancer at colonoscopy; the remaining 328 patients were used to validate the model. RESULTS: Colorectal cancer was found in 44/981 patients (4.5%). Univariate analysis of the derivation set showed that age > 55, occult bleed, anemia, iron deficiency, weight loss, and abnormal CT scan were associated with finding colorectal cancer at colonoscopy in the derivation set, p < 0.05. History of polyps was negatively associated with finding colorectal cancer. Stepwise selection was used to develop a predictive model by using three independent variables-age > 55, iron deficiency, and weight loss. Assigning a score of 1 to each variable, cancer was present in 0% [95% confidence intervals (CI), 0-0.6%], 5.3% (95% CI, 2.3-8.3%), and 17.9% (95% CI, 4.8-31%) of patients in the validation sample with a score of 0, 1, and > or = 2, respectively (p < 0.001 by chi2 for trend). The model was predictive of finding colorectal cancer at colonoscopy, independent of the location or stage of the cancer. CONCLUSIONS: Age, iron deficiency, and weight loss are important independent predictors of colorectal cancer in patients referred for colonoscopy.

Aged↗
PubMed1995

A national population-based study of incidence of colorectal cancer and age. Implications for screening in older Americans.

BACKGROUND: Population-based screening programs with flexible sigmoidoscopy have been advocated as a means to reduce the death rate from colorectal cancer. Because other studies have suggested a greater prevalence of lesions inaccessible to sigmoidoscopy in older patients, the expected yield of this procedure may differ in these subgroups. METHODS: A 100% sample of Medicare beneficiaries 65 years or older with a first known diagnosis of colorectal cancer in 1987 was studied. Tumor site was divided into rectum, distal colon (distal to splenic flexure) and proximal colon. The analysis was also stratified by sex, race, and presence or absence metastatic disease, and incidence rates at each site by 5-year age group were calculated. RESULTS: Among the 75,266 patients studied, the incidence of colorectal cancer increased from 1.59 patients/1000 in patients age 65-69 years to 3.87 patients/1000 in patients age 85 years and older. Although the incidence rates at all three sites increased, the increment was greatest for proximal tumors. The incidence trends with age also persisted in an analysis of only metastatic lesions. Moreover, incidence rates were consistently higher in men than in women and higher in whites than in blacks at all sites, though the age-related increase in incidence was consistent among all four groups. CONCLUSIONS: The proportion of tumors beyond the reach of sigmoidoscopy increased with age, as did the actual incidence of accessible lesions. These patterns were also consistent in subgroup analyses. As the age-related increase in incidence was observed for metastatic tumors at all sites in the colon, age-related differences in screening and diagnostic evaluation alone do not adequately explain the findings. These data underscore the need for further studies of the relative benefits of cancer screening and pathogenic factors in tumor development in different subgroups of the older population.

Age Factors↗
PubMed1995

Follicle-stimulating hormone concentrations in relation to active and passive smoking.

OBJECTIVE: To determine the association between various forms of tobacco exposure and ovarian status, as measured by FSH concentrations, in women 38-49 years old. METHODS: Two hundred ninety women between 38-49 years old, who had not had hysterectomy or oophorectomy, completed a self-administered questionnaire that included information on tobacco exposure and had serum FSH levels measured on days 2-4 of the menstrual cycle. Linear regression was used to assess the relation between FSH and tobacco exposure. RESULTS: Controlling for age and other factors, FSH concentrations were 66% higher among current smokers (geometric mean FSH 14.0 mIU/mL) and 39% higher among nonsmokers with passive smoke exposure (11.7 mIU/mL), compared to nonsmoking women without passive smoke exposure (8.4 mIU/mL). The estimated increase in FSH for each year of age was greater for current smokers than for nonsmokers (16 versus 6%, respectively). Ex-smokers did not have higher FSH concentrations, and there was no association between prenatal exposure to tobacco smoke and FSH. CONCLUSION: Both active and passive smoking are associated with elevated FSH concentrations in women 38-49 years old. The effect, limited to women with current exposure, is consistent with a shorter duration of the menopausal transition period.

Adult↗
PubMed1995

Measurement of lactose consumption reliability and comparison of two methods.

The objective of this study was to assess the reliability of lactose consumption measured with a food-frequency questionnaire and to compare food-frequency data to prospectively recorded data. A self-administered food-frequency questionnaire (FF1) was completed by 295 women ages 38 to 49. Two months later, 75 received the same food-frequency questionnaire (FF2), and 75 received a 1-week diet diary listing 23 commonly eaten lactose-containing foods. Estimated mean intake of lactose was 16.1 g/d with FF1. Intake was slightly (but not significantly) higher at follow-up: Mean difference (95% confidence interval) was 1.4 (-0.8, 3.7) g/d for FF2 versus FF1, and 0.5 g (1.3, 2.3) g/d for the diet diary versus FF1. A moderate level of correlation was found: r = 0.57 between FF1 and FF2, and r = 0.65 between FF1 and the diet diary. Smaller subsets of items (n = 15 and n = 7) could be used to estimate lactose, with 89% and 82% agreement within tertiles, respectively. Since relatively few foods contain substantial amounts of lactose, a limited food-frequency or structured diary may be useful in research studies on the association between lactose consumption and ovarian cancer or other diseases.

Adult↗
PubMed1995

The use of questionnaire data to classify peri- and premenopausal status.

We assessed how well questionnaire data could classify peri- vs premenopausal status in 280 women, ages 38-49 years. Sixty-seven per cent of those who reported use of hormone replacement therapy begun when menstrual periods were irregular, or who had hot flashes at least once a day, or whose last menstrual period was at least 60 days in length, were perimenopausal by hormonal assay (early follicular phase serum follicle-stimulating hormone > or = 15 international units per liter), with a sensitivity of 0.56 [95% confidence interval (CI) = 0.41-0.72] and a specificity of 0.95 (95% CI = 0.93-0.98). In the classification of premenopausal status, the criterion of no menstrual cycle length changes in the past 5 years yielded the highest sensitivity (0.61; 95% CI = 0.54-0.67) and specificity (0.81; 95% CI = 0.68-0.93). With these few items, researchers can improve the classification of peri- and premenopausal status when longitudinal or hormonal assessments cannot be obtained.

Adult↗