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Biomedical subjects

C W Howden

Publications and source records attributed to C W Howden.

At least 37 records · Page 2Linked to original sources
PubMed2001

Prophylactic antibiotic administration reduces sepsis and mortality in acute necrotizing pancreatitis: a meta-analysis.

Severe acute pancreatitis is frequently complicated by local and systemic infections resulting in substantial morbidity, mortality, and health care costs. Antibiotic prophylaxis may prevent some infections. We searched for randomized, controlled trials comparing antibiotic prophylaxis with no prophylaxis in patients with acute necrotizing pancreatitis (ANP). Only trials that used antibiotics that reach minimum inhibitory concentration (MIC) in necrotic pancreatic tissue were included. We calculated relative risk reduction (RRR), absolute risk reduction (ARR), and number needed to treat (NNT) for individual trials and pooled data. Antibiotic prophylaxis significantly reduced sepsis by 21.1% (NNT = 5) and mortality by 12.3% (NNT = 8) compared with no prophylaxis. There was also a nonsignificant trend toward a decrease in local pancreatic infections (ARR = 12%; NNT = 8). Antibiotic prophylaxis decreases sepsis and mortality in patients with ANP. All patients with ANP should be given prophylaxis with an antibiotic with proven efficacy in necrotic pancreatic tissue.

Anti-Bacterial Agents↗
PubMed2001

Differing attitudes toward virtual and conventional colonoscopy for colorectal cancer screening: surveys among primary care physicians and potential patients.

OBJECTIVES: To investigate attitudes among primary care physicians and potential patients concerning "virtual" and conventional colonoscopy for colorectal cancer screening. METHODS: We sent 1000 questionnaires to primary care physicians by electronic or postal mail and administered 400 to potential patients. Questionnaires contained progressively detailed information about the tests and asked for choices based on information presented. RESULTS: One hundred eight-eight primary care physicians and 323 potential patients were included. Results indicated the following: 76.6% of potential patients and 47.3% of physicians initially preferred virtual colonoscopy because of its noninvasive nature; 23.6% of potential patients and 52.9% of physicians valued the ability of conventional colonoscopy to visualize the mucosa directly; and 67.4% of potential patients and 51.6% of physicians preferred virtual colonoscopy because it does not require sedation. Considering all information, most potential patients preferred virtual to conventional colonoscopy (60.2% vs 25.7%), whereas more physicians preferred conventional to virtual colonoscopy (44.9% vs 30.3%). Additionally, 82.3% of potential patients would comply more with recommendations for colorectal cancer screening, and 61.7% of physicians would refer more patients for screening, if virtual colonoscopy was available. CONCLUSIONS: Potential patients preferred virtual to conventional colonoscopy, whereas physicians favored conventional colonoscopy. Physicians placed more importance on the ability of conventional colonoscopy to visualize the mucosa directly, the opportunity for therapy, and cost. Potential patients were more encouraged than physicians by the availability of virtual colonoscopy for improving participation in colorectal cancer screening.

Colonoscopy↗
PubMed2001

An audit of the utility of in-patient fecal occult blood testing.

OBJECTIVES: Recent surveys of physician practice have suggested the existence of excessive, inappropriate use of the fecal occult blood test (FOBT). We studied the implementation of this test in hospitalized patients. METHODS: We performed a retrospective chart review of 1000 randomly selected patients who had been discharged from the Medicine service at four teaching hospitals. Patient demographics, clinical presentation, presence or absence of overt GI bleeding, and use of medications that might affect the FOBT were recorded. Reviewers assessed whether patients who had FOBT would have been candidates for colon resection if asymptomatic colon cancer had been found. RESULTS: Digital rectal examination was documented in 44.8% of patients; the findings were recorded in only 9%. A total of 421 patients had FOBT on admission, usually on stool obtained at digital rectal examination. Of the patients with a positive FOBT, 17% had active GI bleeding. Only 41.1% of patients with a positive FOBT were referred to the gastroenterology service. In 70.5% of patients, FOBT could be considered inappropriate because of factors such as age, active GI bleeding, or use of aspirin or other nonsteroidal anti-inflammatory drugs. CONCLUSIONS: The FOBT, which is validated only for colorectal cancer screening, is often performed inappropriately in patients admitted to the hospital. This test should be restricted in hospital practice. It would be preferable to identify patients who are appropriate candidates for colorectal cancer screening at the time of hospital discharge and to advise them about the appropriate performance of the FOBT at home.

Adolescent↗
PubMed2001

Management of heartburn in a large, randomized, community-based study: comparison of four therapeutic strategies.

OBJECTIVE: Our objective was to compare four management strategies for heartburn: therapy with an H2-receptor antagonist (ranitidine), therapy with a proton pump inhibitor (lansoprazole), crossover from ranitidine to lansoprazole ("step-up" therapy), and crossover from lansoprazole to ranitidine ("step-down" therapy). METHODS: This was a controlled, double-blind, multicenter trial comprising 593 adults with heartburn, randomized to one of four groups for 20 wk. Subjects received either ranitidine 150 mg b.i.d. for 20 wk, or lansoprazole 30 mg once daily for 20 wk, or ranitidine 150 mg b.i.d. for 8 wk [corrected] followed by lansoprazole 30 mg once daily for 12 wk ("step-up"), or lansoprazole 30 mg once daily for 8 wk followed by ranitidine 150 mg b.i.d. for 12 wk ("step-down"). Outcome measures were based on self-reports in daily diaries of 24-h heartburn severity, measured by maximum daytime and nighttime severity, and percentage of 24-h heartburn-free days measured by absence of both daytime and nighttime heartburn. RESULTS: Median heartburn severity was significantly lower (p < 0.05) for lansoprazole (0.25) than the other groups (0.46 ranitidine, 0.44 "step-up," 0.35 "step-down"). The lansoprazole group had a significantly higher percentage of 24-h heartburn-free days (median 81.4%, p < 0.01) than other groups (66.6, 66.9, and 73.6%, respectively). In the "step-up" and "step-down" groups, heartburn was less severe, and percentages of 24-h heartburn-free days were higher during lansoprazole treatment regardless of treatment sequence. CONCLUSION: Proton pump inhibitor treatment provides more consistent heartburn relief than an H2-receptor antagonist, or "step-up" or "step-down" therapy.

2-Pyridinylmethylsulfinylbenzimidazoles↗
PubMed2001

The utility of urgent colonoscopy in the evaluation of acute lower gastrointestinal tract bleeding: a 2-year experience from a single center.

OBJECTIVE: Urgent colonoscopy is often recommended to evaluate acute rectal bleeding. However, it may not identify a source because of blood in the lumen or inadequate preparation. Our aim was to determine the utility of urgent colonoscopy as the initial test for acute rectal bleeding. METHODS: This was a retrospective chart review of all patients discharged in 1997 and 1998 with an International Classification of Diseases, 9th Revision, code for hematochezia or rectal bleeding. RESULTS: We identified 514 charts but excluded 424 because of inaccurate coding. In the 90 with confirmed acute rectal bleeding, colonoscopy was the initial test in 39; age, sex, and race distributions were similar to those who did not have colonoscopy. A definite source of bleeding was seen at colonoscopy in only three patients, a probable source in 26, and no source in 10. Therapeutic intervention in four patients with a definite or probable source was successful in three. The commonest reasons for not performing urgent colonoscopy were bleeding from presumed hemorrhoids or bleeding that was clinically insignificant. Spontaneous resolution of bleeding and length of hospital stay were not affected by urgent colonoscopy. Five patients had surgery for unrelated reasons. In-hospital mortality was 2% and was unrelated to bleeding. CONCLUSION: Urgent colonoscopy as the initial investigation in acute lower GI tract bleeding probably does not alter the outcome in most cases. Identification of a definite bleeding source leading to successful therapeutic intervention is rare. Spontaneous resolution is frequent, length of hospital stay is similar, and clinical outcome is excellent regardless of whether or not urgent colonoscopy is performed.

Acute Disease↗
PubMed2000

Oral pharmacokinetics of omeprazole and lansoprazole after single and repeated doses as intact capsules or as suspensions in sodium bicarbonate.

BACKGROUND: Omeprazole and lansoprazole can be given in sodium bicarbonate as, respectively, simplified omeprazole suspension and simplified lansoprazole suspension. We previously found the antisecretory effect of omeprazole 20 mg given as simplified omeprazole suspension to be lower than with intact capsules. However, lansoprazole 30 mg as simplified lansoprazole suspension produced an effect similar to that seen with intact capsules. AIM: To evaluate the absorption of both drugs when given orally as capsules or as suspensions in sodium bicarbonate. METHODS: In random order, we gave 5-day courses of omeprazole 20 mg and lansoprazole 30 mg as capsules and as suspensions in sodium bicarbonate to 12 healthy women. Serial blood samples were taken on days 1 and 5 of each course for pharmacokinetic measurements. RESULTS: There was impairment of omeprazole absorption when given as simplified omeprazole suspension. Maximum plasma concentration and area under the concentration/time curve were lower with simplified omeprazole suspension than with omeprazole capsules (P=0.034 and 0.013, respectively, on day 5). No differences were found in lansoprazole absorption when simplified lansoprazole suspension was compared with its standard capsule formulation. Relative bioavailability of omeprazole from simplified omeprazole suspension compared to the capsule was 58.4% on day 5. The corresponding value for lansoprazole was 84.7%. CONCLUSIONS: Simplified omeprazole suspension 20 mg does not supply adequate omeprazole for systemic absorption. Lansoprazole absorption from simplified lansoprazole suspension is maintained.

2-Pyridinylmethylsulfinylbenzimidazoles↗
PubMed2000

Vitamin B12 levels during prolonged treatment with proton pump inhibitors.

Reduced serum vitamin B12 (cobalamin) levels have been documented occasionally during long-term treatment with a proton pump inhibitor (PPI) in selected groups of patients. This has largely been confined to patients being treated for Zollinger-Ellison syndrome who have sustained drug-induced achlorhydria, which does not ordinarily occur during treatment with a PPI. An appreciation of normal cobalamin metabolism and the pharmacological action of the PPIs adequately explain the mechanism for this reduction. PPIs do not promote the development of pernicious anemia.

Absorption↗
PubMed2000

Twenty-four-hour intragastric pH: tolerance within 5 days of continuous ranitidine administration.

OBJECTIVE: To investigate further the phenomenon of pharmacological tolerance to H2-receptor antagonists, we undertook a study of the antisecretory effect of ranitidine with continuous daily administration. METHODS: A total of 28 healthy male volunteers were given ranitidine 150 mg q.i.d. for 5 days. Twenty-four-hour intragastric pH monitoring was performed predosing and on days 1 and 5 of ranitidine administration. Serial blood samples were collected on days 1 and 5 of ranitidine administration for pharmacokinetics. RESULTS: Mean 24-h intragastric pH was 2.62 predosing, 4.22 on day 1 of ranitidine administration and 3.28 on day 5 (p = 0.001, ranitidine day 1 vs. day 5). Intragastric pH was >3, 4, and 5 for 69.9%, 54.3%, and 35.9%, respectively, on day 1 of ranitidine administration and was 45.8%, 30.1%, and 20.8% on day 5 (p<0.005 for each comparison). Subjects' Helicobacter pylori status did not affect the antisecretory effect of ranitidine. There was no alteration in ranitidine pharmacokinetics to account for its reduced antisecretory effect. CONCLUSION: This study has demonstrated a statistically significant reduction in the antisecretory effect of ranitidine within 5 days of continuous administration which is not explained by altered ranitidine pharmacokinetics. This is further evidence for the development of a form of pharmacological tolerance to an H2-receptor antagonist within a few days of continuous daily dosing.

Administration, Oral↗
PubMed2000

Colorectal cancer screening and surveillance practices by primary care physicians: results of a national survey.

OBJECTIVE: Screening for colorectal cancer reduces its morbidity and mortality and is cost-effective. Screening is usually the responsibility of primary care physicians who may be unsure about its implementation. We aimed to assess primary care physicians' knowledge and practice regarding colorectal cancer screening, and to compare their responses with those of three national experts and with published guidelines. METHODS: We mailed a postal questionnaire to 2,310 primary care physicians regarding demographics, nature of practice, use of screening tests, and six hypothetical patients who may have been candidates for screening or surveillance. We used published national guidelines and the collective opinions of the three external experts as the so-called "gold standard." RESULTS: Of all respondents, 85.1% offered colorectal cancer screening. Most used suitable tests, starting at an appropriate age; 49.8% continued screening indefinitely irrespective of patients' age and 43.6% performed fecal occult blood testing without appropriate dietary advice to patients. Also, respondents frequently performed this test for inappropriate indications. Only 51.8% would follow a positive fecal occult blood test with colonoscopy. CONCLUSIONS: Colorectal cancer screening practices by primary care physicians vary considerably from those recommended. Many offer screening to individuals in whom it is not appropriate, and continue it into advanced age. Frequent, inappropriate use of fecal occult blood tests will produce many false positives. Primary care physicians often do not appropriately follow a positive test. Further educational efforts are needed in an attempt to improve practice and further reduce the morbidity and mortality from colorectal cancer.

Colorectal Neoplasms↗
PubMed2000

Survey of internal medicine residents' use of the fecal occult blood test and their understanding of colorectal cancer screening and surveillance.

OBJECTIVE: Primary care physicians have imperfect understanding of current colorectal cancer screening guidelines and recommendations. Furthermore, compliance with colorectal cancer screening by internal medicine residents has been demonstrated to be poor. We sought to identify whether current trainees in internal medicine had adequate understanding of colorectal cancer screening and surveillance and test utilization. METHODS: We applied a structured questionnaire about colorectal cancer screening and the use of fecal occult blood tests to 168 internal medicine residents at four accredited programs in the U.S. They were also asked for recommendations about six hypothetical patients who may have been candidates for screening or surveillance. RESULTS: Seventy-one percent identified 50 yr as the currently recommended age to commence screening in an average-risk individual; 64.3% would begin screening with fecal occult blood testing and flexible sigmoidoscopy and 4.8% with colonoscopy. Most perform fecal occult blood testing on stool obtained at digital rectal exam and without prior dietary restrictions. Many use fecal occult blood testing for indications other than colorectal cancer screening. Only 29% recommended colonoscopy to evaluate a positive fecal occult blood test. Most residents plan to be screened for colorectal neoplasia at the appropriate age; significantly more opted for colonoscopy than recommended it for their patients. CONCLUSIONS: Internal medicine residents have many misperceptions regarding colorectal cancer screening and the utility of the fecal occult blood test. Educational efforts should be directed at internal medicine residents, many of whom plan careers in primary care, where most colorectal cancer screening is currently performed.

Adult↗
PubMed2000

A survey of internal medicine residents' knowledge about Helicobacter pylori infection.

OBJECTIVE: Despite recently published national guidelines, many physicians have only limited knowledge about Helicobacter pylori infection. We conducted this study to assess internal medicine residents' knowledge about H. pylori. METHODS: Two hundred and nineteen residents in seven accredited internal medicine training programs completed a self-administered questionnaire on personal demographics and practices related to testing for-and treating-H. pylori infection. RESULTS: Noon conferences (82%), ward teaching (66%), journals (70%), and sponsored symposia (27%) were their major sources of H. pylori-related information. Forty-eight percent had used office-based tests for the infection. Testing for (and treatment of) Helicobacter pylori infection was recommended by 97% (97%) for newly diagnosed duodenal ulcer, but by only 61% (63%) for a past history of duodenal ulcer. Many recommended testing in unproven conditions and might not have offered treatment to an infected patient. A proton pump inhibitor-based triple-drug regimen was the treatment of first choice of 55%; 20% recommended proton pump inhibitor-based dual regimens. Sixty-six percent and 80%, respectively, underestimated the rates of resistance to clarithromycin and metronidazole. In the absence of gastrointestinal symptoms, 22% would have ordered Helicobacter pylori testing but only 33% of these would undergo treatment if positive. CONCLUSIONS: Internal medicine residents usually test for Helicobacter pylori infection in appropriate conditions, but may not always treat the infection when the result is positive. Most use efficacious treatment regimens although many have inaccurate knowledge of resistance rates, which may adversely influence prescribing. Education should focus on practical issues surrounding Helicobacter pylori testing and treatment such as those contained in the American College of Gastroenterology's 1998 practice guidelines.

Adult↗
PubMed2000

Meta-analysis of randomized, controlled trials of antibiotic prophylaxis before percutaneous endoscopic gastrostomy.

OBJECTIVES: We sought to review the published literature on the value of antibiotic prophylaxis for the prevention of wound infection that occurs after percutaneous endoscopic gastrostomy. We also sought by meta-analysis to estimate the efficacy of antibiotic prophylaxis in preventing wound infection. METHODS: We performed a fully recursive literature search for randomized, controlled trials of antibiotic prophylaxis against wound infection occurring after percutaneous endoscopic gastrostomy. Relative and absolute risk reductions and the numbers needed to treat were derived for individual trials and pooled data. RESULTS: We identified seven trials, two of which did not find a statistically significant benefit of antibiotic prophylaxis. After pooling, antibiotic prophylaxis was found to reduce the relative and absolute risk of wound infection by 73% and 17.5%, respectively. The number needed to treat to prevent one wound infection was 5.7 (95% confidence interval = 4.4-8.0). CONCLUSION: A single intravenous dose of a broad-spectrum antibiotic, given approximately 30 min before percutaneous endoscopic gastrostomy is effective in reducing the incidence of peristomal wound infections.

Antibiotic Prophylaxis↗
PubMed2000

Changes in colorectal cancer over a 15-year period in a single United States city.

OBJECTIVE: The aim of this study was to identify colorectal cancer trends in different patient groups in one region. METHODS: We reviewed the records of all patients with colorectal cancer who were seen at two hospitals in Columbia, SC, between 1981 and 1995. Patients were divided into three 5-yr cohorts (cohort 1, 1981-1985; cohort 2, 1986-1990; and cohort 3, 1991-1995). We recorded demographic data, histological type, tumor stage, grade, and survival. RESULTS: A total of 1395 patients were diagnosed, of whom 1252 had adenocarcinoma. Mean age of diagnosis was 64.5 yr in black and 66 in white patients (p = 0.036). Adenocarcinoma proximal to the splenic flexure was found in 62% of women and 49% of men (p < 0.001), and in 51% of black and 44% of white patients (p = 0.08). Proximal cancers accounted for 61%, 48%, and 32% of cohorts 1, 2, and 3, respectively. The proportions of patients with advanced stage (III and IV) adenocarcinoma in the three cohorts were 54%, 47%, and 40%, respectively (p = 0.001). Median survival for adenocarcinoma was 23.7, 23.5, and 23.1 months in cohorts 1, 2, and 3 (p = 0.9). CONCLUSIONS: The prevalence and demographics of colorectal cancer have been fairly stable at this center. There has been a significant decrease in proximal cancers. Although adenocarcinoma is being diagnosed at an earlier stage, this has not affected survival. Colonoscopy may be the most appropriate screening method in women and in black patients, in whom proximal cancers are more often found.

Adenocarcinoma↗
PubMed2000

Survey of the opinions, knowledge, and practices of gastroenterologists regarding colorectal cancer screening and use of the fecal occult blood test.

OBJECTIVES: Primary care physicians and internal medicine residents have poor understanding of colorectal cancer screening and the use of fecal occult blood tests. If acceptance and implementation of colorectal cancer screening is to improve, gastroenterologists may have to take a more leading role in the education of their primary care colleagues, physicians in training, and the general public. However, before this can be recommended, it is necessary to determine how closely gastroenterologists follow currently recommended guidelines and how they use fecal occult blood tests. METHODS: We mailed a two-page, structured questionnaire about colorectal cancer screening and use of fecal occult blood tests to 8000 randomly selected gastroenterologists in the United States. RESULTS: We received responses from 24% of the gastroenterologists. Almost all used fecal occult blood tests in the office setting, 86% on stool obtained at rectal examination. The test was frequently used for reasons other than colorectal cancer screening, and often without adequate patient instruction on dietary and medication restrictions. Of the respondents, 98% commenced screening at age < or = 50 yr, whereas 37% either continued screening into advanced age or never stopped. Annual fecal occult blood testing with flexible sigmoidoscopy every 5 yr was the screening strategy recommended by 71% of the respondents, whereas 25% recommended colonoscopy every 10 yr. However, 77% of the gastroenterologists chose colonoscopy for personal colorectal cancer screening. CONCLUSIONS: Gastroenterologists usually give appropriate advice on colorectal cancer screening but often misuse fecal occult blood tests. This may produce excessively high false-positive screening rates, leading to unnecessary diagnostic testing without apparent benefit.

Attitude of Health Personnel↗
PubMed1999

Use of proton-pump inhibitors in complicated ulcer disease and upper gastrointestinal tract bleeding.

The use of proton-pump inhibitors in the management of complicated peptic ulcer disease and upper gastrointestinal bleeding is described. Treatment of peptic ulcers in patients who are Helicobacter pylori positive should include antimicrobial therapy to eradicate the infection; based on considerations of primary antimicrobial resistance and safety, one recommended regimen is the combination of a proton-pump inhibitor (lansoprazole 30 mg or omeprazole 20 mg), clarithromycin 500 mg, and amoxicillin 1 g, each twice daily for 14 days. The proportion of H. pylori-negative ulcers has increased in the United States, now accounting for 39% of patients with ulcers who report no intake of nonsteroidal anti-inflammatory drugs (NSAIDs). Compared with H. pylori-positive ulcers, H. pylori-negative ulcers are more aggressive, characterized by high recurrence rates and increased risk of bleeding and perforation. Long-term therapy with a proton-pump inhibitor may be useful in these patients. Acid suppressants may also have a role in the initial treatment of patients who have a bleeding ulcer, including those associated with NSAID use. For patients who require continuous NSAID therapy, proton-pump inhibitors have been shown to heal a significantly higher percentage of peptic ulcers in eight weeks than histamine H2-receptor antagonists, and maintenance therapy with either lansoprazole or omeprazole reduces ulcer recurrence. Preliminary data suggest a role for proton-pump inhibitors in the prevention of stress ulcers among critically ill patients. Proton-pump inhibitors play an important role in the treatment of both H. pylori-negative and H. pylori-positive peptic ulcers, as well as in upper gastrointestinal tract bleeding. Further study is needed regarding their role in preventing stress ulcers in critically ill patients.

2-Pyridinylmethylsulfinylbenzimidazoles↗