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Biomedical subjects

D F Ransohoff

Publications and source records attributed to D F Ransohoff.

At least 37 records · Page 2Linked to original sources
PubMed1994

Fecal occult blood screening for colorectal cancer. Is mortality reduced by chance selection for screening colonoscopy?

Annual fecal occult blood test (FOBT) screening using rehydrated Hemoccult slides has been reported in the Minnesota Colon Cancer Control Study to reduce colorectal cancer mortality by about 33%. However, some of the benefit of FOBT screening may come from "chance" selection of persons for colonoscopic examination because of the high positivity rate of FOBT (about 10%) that may occur for reasons other than a bleeding cancer or polyp. To determine how much this mechanism could account for the benefit of FOBT screening, we used a simple mathematical model to simulate the course of a cohort of screened persons, incorporating published data including those from the Minnesota study. The results suggest that one third to one half of the mortality reduction observed from FOBT screening in the Minnesota study may be attributable to chance selection for colonoscopy. We conclude that annual FOBT screening with rehydration is a haphazard method for selecting persons for colonoscopy.

Colonoscopy↗
PubMed1993

Treatment of gallstones.

PURPOSE: To critically review the risks and benefits of therapy for asymptomatic and symptomatic persons with gallstones who are considering therapy to prevent future episodes of biliary pain or complications including acute cholecystitis, pancreatitis, or gallbladder cancer. DATA SOURCES: Review of English-language literature regarding the natural history of persons with gallstones and the operative mortality rates for open cholecystectomy and laparoscopic cholecystectomy. Mathematical simulation modeling was used to derive estimates of lifetime risks for gallstone-related mortality and for life expectancy, for prophylactic cholecystectomy and expectant management, for men and women of different ages. RESULTS: For persons with asymptomatic gallstones, natural history is so benign that treatment is generally not recommended. For persons with symptomatic gallstones, (that is, that have caused an episode of biliary pain), the rate for subsequent pain is high so that many persons probably choose cholecystectomy to avoid pain; however, about 30% of persons who have had pain do not have further episodes of pain. The expected loss of life for persons with symptomatic stones managed expectantly is roughly several months, on average, and may not be considered high enough in itself to warrant therapy. Although laparoscopic cholecystectomy has become popular with patients and physicians, its safety is yet unknown compared with open cholecystectomy. CONCLUSION: Prophylactic cholecystectomy should be recommended for most persons with symptomatic gallstones unless the person wants to try a period of watchful waiting to see if pain recurs. Nonsurgical therapy may be suitable for persons with high operative risk. For persons with asymptomatic gallstones, watchful waiting is the best course.

Cholecystectomy↗
PubMed1993

Gastroenterology.

Explore the source record for details and available documents.

Cholecystectomy, Laparoscopic↗
PubMed1993

Exposure rates to patients' blood for surgical personnel.

BACKGROUND: Surgical personnel are at risk of contracting blood-borne diseases through exposure to patients' blood. Exposure rates for each surgical subspecialty have not been previously reported. The purpose of this study was to determine the rates of exposure to patients' blood for operating room personnel. METHODS: The study was conducted at Yale-New Haven Hospital, a level I trauma center and tertiary care hospital. During a 3-month period, exposed personnel were interviewed by a study nurse immediately after a cutaneous exposure to blood or after a sharp injury. RESULTS: During 2292 surgical procedures, 70 sharp injuries and 168 cutaneous exposures to blood were reported. The combined exposure rate (skin contact and sharp injury) was 10.4 per 100 procedures (95% confidence interval, 9.1 to 11.6) and ranged from 21.2 for general surgery to 3.3 for pediatric surgery (goodness-of-fit chi-squared, p < 0.001). The combined exposure rates were also significantly different among types of surgery and ranged from 18 for laparotomies to 4.3 for craniotomies (chi-squared, p < 0.001). The overall sharp injury rate was 3.1 per 100 procedures (95% confidence interval, 2.3 to 3.8) and ranged from 4.3 for general surgery to 1.3 for vascular surgery. CONCLUSIONS: The rate of exposure to blood for operating room personnel, which differ from prior studies, was 10.4 per 100 procedures and was highest for general surgical procedures. The differences in rates among studies might be attributable to different surgical technique, dissimilar case-mix, or different research methods relating to definition or ascertainment of exposure.

Blood↗
PubMed1991

Mechanisms of glove tears and sharp injuries among surgical personnel.

OBJECTIVE: --The development of strategies to prevent exposure to blood for operating room personnel has been hampered by a lack of knowledge about the specific mechanisms of exposure. The purpose of this study was to classify the mechanisms of glove tears and sharp injuries in the operating room. DESIGN: --During a 3-month period, a nurse interviewed operating room personnel immediately after a glove tear or sharp injury had occurred. SETTING: --Yale-New Haven (Conn) Hospital is a tertiary care teaching hospital. RESULTS: --There were 249 glove tears and 70 sharp injuries. Visible skin contact with the patient's blood occurred in 156 glove tears (63%). The mechanism causing the tear could be identified in only 81 (33%). For 230 glove tears (92%), personnel were wearing single gloves. Of 70 sharp injuries, 47 (67%) were caused by needles and usually occurred during suturing. The following three mechanisms accounted for 40 sharp injuries (57%): (1) hands injured while stationary and holding an instrument, 11 (16%)-a position of risk not previously identified; (2) hands injured while retracting tissue, 12 (17%); and (3) injuries caused by sharp instruments not being used, 17 (24%). Instrument passage caused only four sharp injuries (6%). CONCLUSIONS: --The majority of glove tears have an unknown mechanism, and alteration in the manufacture or number of gloves worn may be helpful in reducing cutaneous blood exposures. The identification of specific mechanisms of sharp injuries should lead to effective strategies to prevent exposure to the human immunodeficiency virus and other blood-borne pathogens in the operating room.

Accidents, Occupational↗
PubMed1991

Colonoscopic surveillance after polypectomy: considerations of cost effectiveness.

OBJECTIVE: To assess the cost effectiveness of the current recommendation that persons who have had an adenomatous colon polyp removed have periodic colonoscopic surveillance at fixed and regular intervals. DESIGN: Cost-effectiveness analysis using data from the medical literature in a simulation model to estimate the costs of and the risk for perforation associated with periodic colonoscopic surveillance for a 50-year-old man followed for 30 years. MAIN RESULTS: A program of colonoscopy every 3 years would incur cumulatively a 1.4% risk for colon perforation, a 0.11% risk for perforation-related death, and direct physician costs of $2071 for colonoscopy (discounted at 5%). If a 50-year-old man's cumulative remaining risk for death from cancer is 2.5% after the removal of a single small adenoma and if effectiveness of colonoscopic surveillance every 3 years is 100%, then one death from cancer could be prevented by doing 283 colonoscopies, incurring 0.6 perforations, 0.04 perforation-related deaths, and direct physician costs of $82,000. If surveillance were 50% effective and the cumulative remaining risk for death from cancer were 1.25%--a plausible scenario--1131 colonoscopies would be required to prevent one death from cancer, incurring 2.3 perforations, 0.17 perforation-related deaths, and physician costs of $331,000. CONCLUSIONS: The cost effectiveness of colonoscopic surveillance is very sensitive to estimates of the cumulative remaining risk for death from cancer after polypectomy as well as to surveillance efficacy. For persons whose remaining risk for death from cancer may be low, such as persons with a single small adenoma, recommendations for colonoscopic surveillance at fixed and regular intervals may be excessively costly.

Aged↗
PubMed1991

Is Helicobacter pylori a cause of duodenal ulcer? A methodologic critique of current evidence.

INTRODUCTION: Helicobacter pylori (HP) in the gastric antrum has been strongly associated with both duodenal ulcer (DU) and chronic active gastritis (CAG). The relationship between HP and DU has been interpreted as causal by many observers. An alternate hypothesis is that HP coincidently colonizes CAG, which is independently associated with DU by some yet-unknown mechanism. PURPOSE: To assess the extent to which a causal relationship between HP and DU has been demonstrated, we performed a methodologic critique of published clinical studies. We carried out a literature search to identify clinical studies that included at least 25 subjects. Of the eight studies we identified, six used a cross-sectional design and two used a prospective cohort design. We applied methodologic criteria to assess causation: strength of association, biologic gradient, temporality, and experiment. METHODS: A strong association between HP and DU was demonstrated in all eight studies. Biologic gradient and temporality were not assessed in any study. In the two experimental studies of therapy, loss of antral HP was associated with a decreased rate of DU relapse; however, we did not interpret this as sufficient to support causality because the effect may have been due to a direct mucosal action rather than eradication of HP. CONCLUSION: We conclude that published evidence does not establish HP as a cause of DU. One approach to address causality would be an observational cohort study of ulcer relapse to assess the temporal relationships between HP, CAG, and DU.

Cohort Studies↗
PubMed1990

Treatment adherence and risk of death after a myocardial infarction.

The relation of treatment adherence to mortality after a myocardial infarction was investigated among 2175 participants in the Beta Blocker Heart Attack Trial, which had data for measures of treatment adherence, clinical severity, and the psychological and social features that may influence post-infarction mortality. Overall, patients who did not adhere well to treatment regimen (ie, who took less than or equal to 75% of prescribed medication) were 2.6 times more likely than good adherers to die within a year of follow-up (95% confidence interval, 1.2, 5.6). Poor adherers had an increased risk of death whether they were on propranolol (OR = 3.1) or placebo (OR = 2.5). Furthermore, this increased risk of death for poor adherers was not accounted for by measures of the severity of myocardial infarction, sociodemographic features (eg, race, marital status, education), smoking, or psychological characteristics (high life-stress or social isolation).

Adult↗
PubMed1990

Small adenomas detected during fecal occult blood test screening for colorectal cancer. The impact of serendipity.

Yearly fecal occult blood testing (FOBT) has been recommended for men and women over age 50 years as part of a screening regimen intended to reduce colorectal cancer mortality. The primary targets of screening are early, surgically curable colon cancers and large adenomatous colon polyps; however, screening may sometimes reveal only small adenomas (ie, less than 1 cm in diameter). To assess the rates and mechanisms of FOBT detection of small adenomas, we performed quantitative analyses utilizing estimates of adenoma bleeding rates and FOBT sensitivity and specificity. The analysis suggests that the mechanisms of detection of small adenomas is often chance or serendipity. This occurs when an FOBT result is "falsely" positive because of diet or non-neoplastic gastrointestinal bleeding and leads to colonoscopic discovery of a nonbleeding small adenoma. Nevertheless, small adenomas remain undetected in most persons who have them, even if repeated yearly FOBT screening is done. The identification of persons with small adenomas should not be assumed to be an important beneficial outcome of FOBT screening, because the clinical significance of small adenomas is not clear, the mechanism of detection is serendipity, and only a minority of persons with small adenomas are identified. The current recommendations to perform periodic surveillance colonoscopy following removal of small adenomas detected during FOBT screening should be reexamined.

Adenocarcinoma↗
PubMed1990

Management of patients with symptomatic gallstones: a quantitative analysis.

Should persons with symptomatic gallstones (i.e., those that have caused biliary pain) be treated immediately? Or may they be managed expectantly until pain recurs or a biliary complication (i.e., acute cholecystitis or pancreatitis) occurs? To assess the mortality risk of different strategies, we performed a quantitative analysis. For the expectant management strategy that requires surgery only if a biliary complication occurs, the cumulative lifetime probability of gallstone disease death in a 30-year-old man is about 2%, and most deaths occur after age 65. In comparison, elective cholecystectomy has only a 0.1% rate of gallstone disease death, but all deaths occur at age 30. The average amount of life expectancy gained by immediate cholecystectomy compared with expectant management is 52 days, which is reduced to 23 days using 5% discounting. This gain could be increased only slightly by a 100% effective and risk-free therapy such as perfected lithotripsy or medical dissolution. Results are similar for women. The results suggest that, for persons with symptomatic gallstones, the life expectancy gain of immediate cholecystectomy is relatively small and that the potential incremental gain of nonsurgical therapy is also small. For patients and physicians who believe that life expectancy is of primary consideration, the decision about therapy may be made primarily on non-mortality considerations. Some patients and physicians may decide that the risk of symptomatic gallstones is low enough that a policy of expectant management may be acceptable.

Adult↗
PubMed1988

Aortic stenosis, idiopathic gastrointestinal bleeding, and angiodysplasia: is there an association? A methodologic critique of the literature.

To assess the reported association between colonic angiodysplasia and aortic stenosis, we performed a quantitative and methodologic analysis of the literature. In four controlled studies that support an association between aortic stenosis and idiopathic gastrointestinal bleeding there are major methodologic deficiencies including the following: nonblinded data collection, noncomparable diagnostic examination, nonblinded ascertainment of exposure, and noncomparable demographic susceptibility. None of the studies directly assesses angiodysplasia. Additional case reports about aortic valve replacement used to treat bleeding from angiodysplasia are limited in number and in duration of follow-up. We conclude that the existing literature does not demonstrate an association between aortic stenosis and angiodysplasia. Further controlled evaluation of this topic would be useful.

Aortic Valve Stenosis↗