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Biomedical subjects

David Armstrong

Publications and source records attributed to David Armstrong.

At least 19 recordsLinked to original sources

Validation of the Rockall scoring system for outcomes from non-variceal upper gastrointestinal bleeding in a Canadian setting.

AIM: To validate the Rockall scoring system for predicting outcomes of rebleeding, and the need for a surgical procedure and death. METHODS: We used data extracted from the Registry of Upper Gastrointestinal Bleeding and Endoscopy including information of 1869 patients with non-variceal upper gastrointestinal bleeding treated in Canadian hospitals. Risk scores were calculated and used to classify patients based on outcomes. For each outcome, we used chi2 goodness-of-fit tests to assess the degree of calibration, and built receiver operating characteristic curves and calculated the area under the curve (AUC) to evaluate the discriminative ability of the scoring system. RESULTS: For rebleeding, the chi2 goodness-of-fit test indicated an acceptable fit for the model [chi2 (8) = 12.83, P = 0.12]. For surgical procedures [chi2 (8) = 5.3, P = 0.73] and death [chi2 (8) = 3.78, P = 0.88], the tests showed solid correspondence between observed proportions and predicted probabilities. The AUC was 0.59 (95% CI: 0.55-0.62) for the outcome of rebleeding and 0.60 (95% CI: 0.54-0.67) for surgical procedures, representing a poor discriminative ability of the scoring system. For the outcome of death, the AUC was 0.73 (95% CI: 0.69-0.78), indicating an acceptable discriminative ability. CONCLUSION: The Rockall scoring system provides an acceptable tool to predict death, but performs poorly for endpoints of rebleeding and surgical procedures.

Adolescent↗

The relationship between general practice characteristics and quality of care: a national survey of quality indicators used in the UK Quality and Outcomes Framework, 2004-5.

BACKGROUND: The descriptive information now available for primary care in the UK is unique in international terms. Under the 'Quality and Outcomes Framework' (QOF), data for 147 performance indicators are available for each general practice. We aimed to determine the relationship between the quality of primary care, as judged by the total QOF score, social deprivation and practice characteristics. METHODS: We obtained QOF data for each practice in England and linked these with census derived data (deprivation indices and proportion of patients born in a developing country). Characteristics of practices were also obtained. QOF and census data were available for 8480 practices. RESULTS: The median QOF score was 999.7 out of a possible maximum of 1050 points. Three characteristics were independently associated with higher QOF scores: training practices, group practices and practices in less socially deprived areas. In a regression model, these three factors explained 14.6% of the variation in QOF score. Higher list sizes per GP, turnover of registered patients, chronic disease prevalence, proportions of elderly patients or patients born in a developing country did not contribute to lower QOF scores in the final model. CONCLUSION: Socially deprived areas experience a lower quality of primary care, as judged by QOF scores. Social deprivation itself is an independent predictor of lower quality. Training and group practices are independent predictors of higher quality but these types of practices are less well represented in socially deprived areas.

Aged↗

Symptoms of men and women presenting with acute coronary syndromes.

This study evaluated symptom similarities and differences between men and women presenting with acute coronary syndromes (ACSs) and determined whether differences in presentation are intrinsic to patient gender or to other factors. This study was a subgroup analysis of patients from an ACS registry. We compared differences in symptom presentation between men and women and analyzed them using binary logistic regression with all variables and 2 x 2 interactions. Patient gender was forced to remain in the models. Women comprised 35% of the 1,941 patients admitted with confirmed ACS. Men were more likely to present with chest pain, left arm pain, or diaphoresis. Nausea was more common in women. Dyspnea did not differ between groups. After binary logistic regression, gender remained a statistically significant predictor of diaphoresis and nausea, but not of chest or left arm pain. We found that differences in occurrence of chest pain and left arm pain between men and women are explainable by differences in co-morbidities and history; the higher occurrence of diaphoresis in men and of nausea in women is partly related to maleness or femaleness. In conclusion, gender should be considered when evaluating patients with symptoms of ACS.

Acute Disease↗

The development and validation of an endoscopic grading system for Barrett's esophagus: the Prague C & M criteria.

BACKGROUND & AIMS: Barrett's esophagus (BE) is a premalignant condition for esophageal adenocarcinoma, its diagnosis relying initially on recognition of a columnar-lined distal esophagus. We aimed to develop and validate explicit, consensus-driven criteria for the endoscopic diagnosis and grading of BE. METHODS: An international working group agreed on criteria and developed materials for their formal evaluation using video-endoscopic recordings gathered in a standardized manner in 29 patients. The criteria included assessment of the circumferential (C) and maximum (M) extent of the endoscopically visualized BE segment as well as endoscopic landmarks. The recordings were scored according to these criteria by a separate international panel of 29 endoscopists. RESULTS: The Prague C & M Criteria give explicit guidance on the endoscopic recognition of BE and grading of its extent. The overall reliability coefficients (RC) for the assessment of the C & M extent of the endoscopic BE segment above the gastroesophageal junction were 0.95 and 0.94, respectively. The rates of exact agreement (for C & M values) for pairwise comparisons of individual patient values were 53% and 38%, respectively, whereas the values for agreement within a 2-cm interval were 97% and 95%, respectively. The overall RC for endoscopic recognition of BE >/=1 cm was 0.72, whereas for BE <1 cm, it was 0.22. The RCs for recognizing the location of the gastroesophageal junction and the diaphragmatic hiatus were 0.88 and 0.85, respectively. CONCLUSIONS: The Prague C & M Criteria have high overall validity for the endoscopic assessment of visualized BE lengths.

Barrett Esophagus↗

Esomeprazole 40 mg once a day in patients with functional dyspepsia: the randomized, placebo-controlled "ENTER" trial.

OBJECTIVE: The etiologies of functional dyspepsia (FD) are unclear, but in some studies, treatment with a proton pump inhibitor has been beneficial. The objective of this study was to evaluate the efficacy of esomeprazole 40 mg once a day compared to placebo in achieving symptom relief in primary care patients with FD. METHODS: This was a randomized, placebo-controlled trial in adult FD patients, who had at least moderate severity of symptoms, defined as a score of > or =4 on a 7-point Global Overall Symptom (GOS) scale. Patients were excluded if they had predominant symptoms of heartburn or regurgitation; after a normal baseline endoscopy, patients were randomized to esomeprazole 40 mg once daily or placebo for 8 wk. The primary outcome measure was symptom relief (GOS < or =2) at 8 wk. RESULTS: Of the 502 enrolled patients, 224 were randomized. The main reasons for exclusion were abnormal endoscopic findings, especially esophagitis. A significantly greater proportion of patients in the esomeprazole group achieved symptom relief at 4 but not at 8 wk compared to placebo: 4 wk esomeprazole 50.5% versus placebo 32.2%, p= 0.009; 8 wk esomeprazole 55.1% versus placebo 46.1%, p= 0.16. A similar relationship at 4 and 8 wk was seen for symptom resolution (GOS = 1) and improvement (DeltaGOS > or =2). CONCLUSION: For the primary outcome measure of symptom relief at 8 wk, there was no statistically significant difference between esomeprazole 40 mg once a day and placebo. However, at 4 wk, esomeprazole was significantly more effective than placebo for symptom relief. The difference in therapeutic gain between 4 and 8 wk was largely due to a higher placebo response rate at 8 wk.

Administration, Oral↗

An evidence-based, Latin-American consensus on gastro-oesophageal reflux disease.

In recognition of the high prevalence of gastro-oesophageal reflux disease (GORD) and its importance in Latin America, the InterAmerican Association of Gastroenterology and the InterAmerican Society of Digestive Endoscopy organized a Latin-American Consensus on GORD in Cancun, Mexico in September 2004. The main objectives of the consensus meeting were to provide evidence-based guidance with respect to the diagnosis and treatment of GORD, relevant to all countries in the region. The methodology, results and recommendations of the consensus are described in detail.

Adult↗

The role of etiquette and experimentation in explaining how doctors change behaviour: a qualitative study.

Despite increasing interest over the last 30 years in individual variations in clinical practice, various research studies have thrown only limited light on either understanding or changing doctors' behaviour. This qualitative study explored a sample of British general practitioners' accounts of the influences on their prescribing, and identified the locus of the problem in their defence of professional identity through clinical autonomy, a tactic that precluded use of more customary change agents such as line management and economic incentives. The study identified two mechanisms, clinical etiquette and clinical experimentation, however, that enabled change to occur within the constraints imposed by the commitment to clinical autonomy.

Humans↗

Embodiment and ethics: constructing medicine's two bodies.

The first 'modern' presentation of medical ethics is generally acknowledged to be Percival's text of 1803. The main theme of this influential pamphlet was the way in which medical practitioners should relate to one another. Two centuries later, clinical practice has very different moral underpinnings: bioethics, which first emerged in the middle of the 20(th) century, is not concerned with how doctors should interact with each other but with the responsibilities of medical practitioners to their patients. The shift from an ethics based on the relationship between practitioners to one based on the relationship with their patients is viewed as a major advance brought about by a more enlightened society engaging with the consequences of new technologies. But rather than addressing the changing picture of medical ethics in its own terms (which over the last few decades has been from the perspective of bioethics) I examine the history of medical ethics in its close relationship to the form and nature of the medical profession. Further, in a parallel thread I describe contemporary developments in public health and explore the similarities and connections between the two.

Codes of Ethics↗

Addition of glutamine to essential amino acids and carbohydrate does not enhance anabolism in young human males following exercise.

We examined the effect of a post-exercise oral carbohydrate (CHO, 1 g.kg(-1).h(-1)) and essential amino acid (EAA, 9.25 g) solution containing glutamine (0.3 g/kg BW; GLN trial) versus an isoenergetic CHO-EAA solution without glutamine (control, CON trial) on muscle glycogen resynthesis and whole-body protein turnover following 90 min of cycling at 65% VO2 peak. Over the course of 3 h of recovery, muscle biopsies were taken to measure glycogen resynthesis and mixed muscle protein synthesis (MPS), by incorporation of [ring-2H5] phenylalanine. Infusion of [1-13C] leucine was used to measure whole-body protein turnover. Exercise resulted in a significant decrease in muscle glycogen (p < 0.05) with similar declines in each trial. Glycogen resynthesis following 3 h of recovery indicated no difference in total accumulation or rate of repletion. Leucine oxidation increased 2.5 fold (p < 0.05) during exercise, returned to resting levels immediately post-exercise,and was again elevated at 3 h post-exercise (p < 0.05). Leucine flux, an index of whole-body protein breakdown rate, was reduced during exercise, but increased to resting levels immediately post-exercise, and was further increased at 3 h post-exercise (p < 0.05), but only during the CON trial. Exercise resulted in a marked suppression of whole-body protein synthesis (50% of rest; p < 0.05), which was restored post-exercise; however, the addition of glutamine did not affect whole-body protein synthesis post-exercise. The rate of MPS was not different between trials. The addition of glutamine to a CHO + EAA beverage had no effect on post-exercise muscle glycogen resynthesis or muscle protein synthesis, but may suppress a rise in whole-body proteolysis during the later stages of recovery.

Adult↗

13C urea breath test for (Helicobacter pylori): determination of the optimal cut-off point in a Canadian community population.

AIM: To determine the test characteristics and the optimal cut-off point for the (13)C urea breath test ((13)C UBT) in a Canadian community laboratory setting. METHODS: Of 2232 patients (mean age +/- SD: 51+/-21 years, 56% female) who completed a (13)C UBT, 1209 were tested to evaluate the primary diagnosis of (Helicobacter pylori) infection and 1023 were tested for confirmation of eradication following treatment. Cluster analysis was performed on the (13)C UBT data to determine the optimal cut-off point and the risk of false-positive and false-negative results. Additionally, 176 patients underwent endoscopic biopsy to allow validation of the sensitivity and specificity of the (13)C UBT against histology and microbiology using the calculated cut-off point. RESULTS: The calculated cut-off points were 3.09 delta/1000 for the whole study population (n=2232), 3.09 delta/1000 for the diagnosis group (n=1209) and 2.88 delta/1000 for the post-treatment group (n=1023). When replacing the calculated cut-off points by a practical cut-off point of 3.0 delta/1000, the risk of false-positive and false-negative results was lower than 2.3%. The (13)C UBT showed 100% sensitivity and 98.5% specificity compared with histology and microbiology (n=176) for the diagnosis of active (H pylori) infection. CONCLUSIONS: The (13)C UBT is an accurate, noninvasive test for the diagnosis of (H pylori) infection and for confirmation of cure after eradication therapy. The present study confirms the validity of a cut-off point of 3.0 delta/1000 for the (13)C UBT when used in a large Canadian community population according to a standard protocol.

Biopsy↗

Practice Audit in Gastroenterology (PAGE) program: a novel approach to continuing professional development.

BACKGROUND: Practice audit is an important component of continuing professional development that may more readily be undertaken if it were less complex. This qualitative study assessed the use of personal digital assistants to facilitate data collection and review. METHODS: Personal digital assistants programmed with standard questionnaires related to upper gastrointestinal endoscopies (Practice Audit in Gastroenterology-Endoscopy ['PAGE-Endo']) and colonoscopies (PAGE-Colonoscopy ['PAGE-Colo']) were provided to Canadian gastroenterologists, surgeons and internists. Over a three-week audit period, participants recorded indications, and the expected (E) and reported (R) findings for each procedure. Thereafter, participants recorded compliance with reporting, the ease of use and value of the PAGE program, and their willingness to perform another audit. RESULTS: Over 15 to 18 months, 173 participants completed PAGE-Endo (6168 procedures) and 111 completed PAGE-Colo (4776 procedures). Most respondents noted that PAGE was easy to use (99%), beneficial (88% to 95%), and that they were willing undertake another audit (92% to 95%). In PAGE-Endo, alarm features were prevalent (55%), but major reported findings were less common than expected: esophagitis (E 29.9%, R 14.8%), esophageal stricture (E 8.3%, R 3.6%), gastric ulcer (E 17.0%, R 4.7%), gastric cancer (E 4.3%, R 1.0%) and duodenal ulcer (E 11.5%, R 5.7%). In PAGE-Colo, more colonoscopies were performed for symptom investigation (55%) than for screening (25%) or surveillance (20%). There were marked interprovincial variations with respect to sedation, biopsies and technical aspects of colonoscopy. CONCLUSION: Secure, real-time data entry with review of aggregate and individual data in the PAGE program provided an acceptable, straightforward methodology for accredited practice audit activities. PAGE has considerable potential for continuing professional development in gastroenterology and other specialties.

Canada↗

13C urea breath test for (Helicobacter pylori): evaluation of 10-minute breath collection.

AIM: To determine whether a shortened (13)C urea breath test ((13)C UBT) (breath collection time of 10 min) is as reliable as the standard assay (30 min). METHODS: Two hundred ninety-seven patients (mean +/- SD: 53+/-16 years, 57% female) completed a (13)C UBT. Breath samples were obtained at baseline and at 5 min intervals up to 30 min. Sixty-seven patients also underwent endoscopic biopsy. Cluster analysis was performed on the (13)C UBT data to determine the optimal cut-off point at each time interval. Sensitivity and specificity of the (13)C UBT at all intervals compared with histology and culture and against the standard 30 min interval were determined. RESULTS: The calculated optimal cut-off points for each time interval (T), expressed as delta over baseline (delta/1000), were 3.29 delta/1000 at T(5), 3.15 delta/1000 at T(10), 3.42 delta/1000 at T(15), 3.17 delta/1000 at T(20), 2.99 delta/1000 at T(25) and 2.82 delta/1000 at T(30). Except at T(5), the risk of false-positive and false-negative test results at each time interval was lower than 2.3% using these cut-off points. When replacing the cut-off points with 3.0 delta/1000, the risk of error was still lower than 2.3%. The test at T(10) showed 98.6% sensitivity and 98.6% specificity compared with T(30). T(10) and T(30) showed 100% sensitivity and 96% specificity compared with histology and culture. CONCLUSIONS: The (13)C UBT is an accurate, noninvasive test, even when the breath sample interval is reduced to 10 min. The present study confirms the validity of a cut-off point of 3.0 delta/1000 for the 10 min and 30 min (13)C UBT.

Biopsy↗

A randomized controlled trial of laparoscopic nissen fundoplication versus proton pump inhibitors for treatment of patients with chronic gastroesophageal reflux disease: One-year follow-up.

A randomized controlled trial conducted in patients with gastroesophageal reflux disease compared optimized medical therapy using proton pump inhibitor (n = 52) with laparoscopic Nissen fundoplication (n = 52). Patients were monitored for 1 year. The primary end point was frequency of gastroesophageal reflux dis-ease symptoms. Surgical patients had improved symptoms, pH control, and overall quality of life health index after surgery at 1 year compared with the medical group. The overall gastroesophageal reflux disease symptom score at 1 year was unchanged in the medical patients, but improved in the surgical patients. Fourteen patients in the medical arm experienced symptom relapse requiring titration of the proton pump inhibitor dose, but 6 had satisfactory symptom remission. No surgical patients required additional treatment for symptom control. Patients controlled on long-term proton pump inhibitor therapy for chronic gastroesophageal reflux disease are excellent surgical candidates and should experience improved symptom control after surgery at 1 year.

Adult↗