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Dive into the research topics where Brian T. Johnston is active.

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Featured researches published by Brian T. Johnston.


Journal of the National Cancer Institute | 2011

Risk of Malignant Progression in Barrett’s Esophagus Patients: Results from a Large Population-Based Study

Shivaram Bhat; Helen G. Coleman; Fouad Yousef; Brian T. Johnston; Damian McManus; Anna Gavin; Liam Murray

BACKGROUND Barretts esophagus (BE) is a premalignant lesion that predisposes to esophageal adenocarcinoma. However, the reported incidence of esophageal adenocarcinoma in patients with BE varies widely. We examined the risk of malignant progression in patients with BE using data from the Northern Ireland Barretts esophagus Register (NIBR), one of the largest population-based registries of BE worldwide, which includes every adult diagnosed with BE in Northern Ireland between 1993 and 2005. SUBJECTS AND METHODS We followed 8522 patients with BE, defined as columnar lined epithelium of the esophagus with or without specialized intestinal metaplasia (SIM), until the end of 2008. Patients with incident adenocarcinomas of the esophagus or gastric cardia or with high-grade dysplasia of the esophagus were identified by matching the NIBR with the Northern Ireland Cancer Registry, and deaths were identified by matching with records from the Registrar Generals Office. Incidence of cancer outcomes or high-grade dysplasia was calculated as events per 100 person-years (% per year) of follow-up, and Cox proportional hazard models were used to determine incidence by age, sex, length of BE segment, presence of SIM, macroscopic BE, or low-grade dysplasia. All P values were from two-sided tests. RESULTS After a mean of 7.0 years of follow-up, 79 patients were diagnosed with esophageal cancer, 16 with cancer of the gastric cardia, and 36 with high-grade dysplasia. In the entire cohort, incidence of esophageal or gastric cardia cancer or high-grade dysplasia combined was 0.22% per year (95% confidence interval [CI] = 0.19% to 0.26%). SIM was found in 46.0% of patients. In patients with SIM, the combined incidence was 0.38% per year (95% CI = 0.31 to 0.46%). The risk of cancer was statistically significantly elevated in patients with vs without SIM at index biopsy (0.38% per year vs 0.07% per year; hazard ratio [HR] = 3.54, 95% CI = 2.09 to 6.00, P < .001), in men compared with women (0.28% per year vs 0.13% per year; HR = 2.11, 95% CI = 1.41 to 3.16, P < .001), and in patients with low-grade dysplasia compared with no dysplasia (1.40% per year vs 0.17% per year; HR = 5.67, 95% CI = 3.77 to 8.53, P < .001). CONCLUSION We found the risk of malignant progression among patients with BE to be lower than previously reported, suggesting that currently recommended surveillance strategies may not be cost-effective.


American Journal of Epidemiology | 2008

The Incidence of Esophageal Cancer and High-Grade Dysplasia in Barrett's Esophagus: A Systematic Review and Meta-Analysis

Fouad Yousef; Christopher Cardwell; Marie Cantwell; Karen Galway; Brian T. Johnston; Liam Murray

Barretts esophagus is a well-recognized precursor of esophageal adenocarcinoma. Surveillance of Barretts esophagus patients is recommended to detect high-grade dysplasia (HGD) or early cancer. Because of wide variation in the published cancer incidence in Barretts esophagus, the authors undertook a systematic review and meta-analysis of cancer and HGD incidence in Barretts esophagus. Ovid Medline (Ovid Technologies, Inc., New York, New York) and EMBASE (Elsevier, Amsterdam, the Netherlands) databases were searched for papers published between 1950 and 2006 that reported the cancer/HGD risk in Barretts esophagus. Where possible, early incident cancers/HGD were excluded, as were patients with HGD at baseline. Forty-seven studies were included in the main analysis, and the pooled estimate for cancer incidence in Barretts esophagus was 6.1/1,000 person-years, 5.3/1,000 person-years when early incident cancers were excluded, and 4.1/1,000 person-years when both early incident cancer and HGD at baseline were excluded. Corresponding figures for combined HGD/cancer incidence were 10.0 person-years, 9.3 person-years, and 9.1/1,000 person-years. Compared with women, men progressed to cancer at twice the rate. Cancer or HGD/cancer incidences were lower when only high-quality studies were analyzed (3.9/1,000 person-years and 7.7/1,000 person-years, respectively). The pooled estimates of cancer and HGD incidence were low, suggesting that the cost-effectiveness of surveillance is questionable unless it can be targeted to those with the highest cancer risk.


Thorax | 1998

Evaluation and outcome of patients with chronic non-productive cough using a comprehensive diagnostic protocol

Lorcan McGarvey; Liam Heaney; John Lawson; Brian T. Johnston; C.M. Scally; Madeleine Ennis; D.R.T. Shepherd; J. MacMahon

BACKGROUND Asthma, post-nasal drip syndrome (PNDS), and gastro-oesophageal reflux (GOR) account for many cases of chronic non-productive cough (CNPC). Each may simultaneously contribute to cough even when clinically silent, and failure to recognise their contribution may lead to unsuccessful treatment. Methods—Patients (all lifetime non-smokers with normal chest radiographs and spirometric measurements) referred with CNPC persisting for more than three weeks as their sole respiratory symptom underwent histamine challenge, home peak flow measurements, ear, nose and throat (ENT) examination, sinus CT scanning, and 24 hour oesophageal pH monitoring. Treatment was prescribed on the basis of diagnoses informed by investigation results. RESULTS Forty three patients (29 women) of mean age 47.5 years (range 18–77) and mean cough duration 67 months (range 2–240) were evaluated. On the basis of a successful response to treatment, a cause for the cough was identified in 35 patients (82%) as follows: cough variant asthma (CVA) (10 cases), PNDS (9 cases), GOR (8 cases), and dual aetiologies (8 cases). Histamine challenge correctly predicted CVA in 15 of 17 (88%) positive tests. ENT examination and sinus CT scans each had low positive predictive values for PNDS (10 of 16 (63%) and 12 of 18 (67%) positive cases, respectively), suggesting that upper airways disease frequently co-exists but does not always contribute to cough. When negative, histamine challenge and 24 hour oesophageal pH monitoring effectively ruled out CVA and GOR, respectively, as a cause for cough. CONCLUSION This comprehensive approach aids the accurate direction of treatment and, while CVA, PNDS and GOR remain the most important causes of CNPC to consider, a group with no identifiable aetiology remains.


Digestive Diseases and Sciences | 1997

Ineffective Esophageal Motility (IEM) (The Primary Finding in Patients with Nonspecific Esophageal Motility Disorder)

Louis P. Leite; Brian T. Johnston; Jeffrey Barrett; June A. Castell; Donald O. Castell

Nonspecific esophageal motility disorder (NEMD)is a vague category used to include patients with poorlydefined esophageal contraction abnormalities. Thecriteria include “ineffective” contractionwaves, ie, peristaltic waves that are either of lowamplitude or are not transmitted. The aim of this studywas to identify the prevalence of ineffective esophagealmotility (IEM) found during manometry testing and to evaluate esophageal acid exposure andesophageal acid clearance (EAC) in patients with IEMcompared to those with other motility findings. Weanalyzed esophageal manometric tracings from 600consecutive patients undergoing manometry in our laboratoryfollowing a specific protocol from April 1992 throughOctober 1994 to identify the frequency of ineffectivecontractions and the percentages of other motility abnormalities present in patients meetingcriteria for NEMD. Comparison of acid exposure and EACwas made with 150 patients who also had both esophagealmanometry and pH-metry over the same time period. Sixty-one of 600 patients (10%) met thediagnostic criteria for NEMD. Sixty of 61 (98% ) ofthese patients had IEM, defined by at least 30%ineffective contractions out of 10 wet swallows.Thirty-five of these patients also underwent ambulatoryesophageal pH monitoring. Patients with IEM demonstratedsignificant increases in both recumbent medianpercentage of time of pH 4 (4.5%) and median distal EAC (4.2 min/episode) compared to those with normalmotility (0.2%, 1 min/episode), diffuse esophageal spasm(0%, 0.6 min/episode), hypertensive LES (0%, 1.8min/episode), and nutcracker esophagus (0.4% 1.6 min/episode). Recumbent acid exposure inIEM did not differ significantly from that in patientswith systemic scleroderma (SSc) for either variable(5.4%, 4.2 min/episode). We propose that IEM is a more appropriate term and should replace NEMD,giving it a more specific manometric identity. IEMpatients demonstrate a distinctive recumbent refluxpattern, similar to that seen in patients with SSc. This finding indicates that there is anassociation between IEM and recumbent GER. Whether IEMis the cause or the effect of increased esophageal acidexposure remains to be determined.


Gut | 1996

Natural history of reflux oesophagitis: a 10 year follow up of its effect on patient symptomatology and quality of life.

Neil I. McDougall; Brian T. Johnston; F. Kee; J. S. A. Collins; R. J. Mcfarland; A. H. G. Love

BACKGROUND--Although oesophagitis is the most common diagnosis made at upper gastrointestinal endoscopy, data on the longterm outcome of affected patients are sparse. AIMS--This study assessed the level of reflux symptoms, quality of life, drug consumption, and complications in patients at least 10 years after diagnosis of oesophagitis at one centre. PATIENTS--One hundred and fifty two patients with typical reflux symptoms and a first time diagnosis by endoscopy of grade I-III oesophagitis between 1981 and 1984, were followed up using a postal questionnaire and telephone interview. RESULTS--Eighteen of 152 patients had died, 33 failed to respond, and 101 replied (mean follow up 11 years, range 121-160 months). Over 70% of patients still had heartburn at least daily (32%) or weekly (19%) or required daily acid suppression treatment (20%). Two patients (2%) had developed oesophageal strictures and one had Barretts oesophagus. Two of eight quality of life scores (physical function and social function) measured by the Short Form-36 were significantly lower than Northern Ireland population scores. CONCLUSION--Nearly three quarters of patients previously diagnosed as having oesophagitis still had significant morbidity related to gastro-oesophageal reflux disease more than 10 years after diagnosis. Some quality of life scores were significantly lower than those of the general population.


Thorax | 2003

Predictors of therapy resistant asthma: outcome of a systematic evaluation protocol

Liam Heaney; E. Conway; Christopher B. Kelly; Brian T. Johnston; C. English; Michael Stevenson; J. Gamble

Background: It has been suggested that asthmatic subjects with persisting symptoms despite adequate maintenance therapy should be systematically evaluated to identify factors contributing to poor control. The aims of this study were to examine the prevalence of these factors in a cohort of sequentially referred poorly controlled asthmatics, and to determine if any factor or combination of factors predicted true therapy resistant asthma (TRA). Methods: Patients were evaluated using a systematic evaluation protocol including induced sputum analysis, psychiatric assessment, ear, nose and throat examination, pulmonary function testing, high resolution CT scan of the thorax, and 24 hour dual probe ambulatory oesophageal pH monitoring; any identified provoking factor was treated. Asthma was managed according to BTS guidelines. Results: Of 73 subjects who completed the assessment, 39 responded to intervention and 34 had TRA. Subjects with TRA had a greater period of instability, a higher dose of inhaled steroids at referral, more rescue steroid use, and a lower best percentage forced expiratory volume in 1 second (FEV1%). Oesophageal reflux, upper airway disease, and psychiatric morbidity were common (57%, 95%, 49%, respectively) but were not more prevalent in either group. Using multivariate logistic regression analysis, inhaled steroid dose >2000 μg BDP, previous assessment by a respiratory specialist, and initial FEV1% of <70% at referral predicted a final diagnosis of TRA. Conclusions: In poorly controlled asthmatics there is a high prevalence of co-morbidity, identified by detailed systematic assessment, but no difference in prevalence between those who respond to intervention and those with TRA. Targeted treatment of identified co-morbidities has minimal impact on asthma related quality of life in those with therapy resistant disease.


Gut | 2003

Mortality in Barrett’s oesophagus: results from a population based study

Lesley A. Anderson; Liam Murray; S.J. Murphy; Deirdre Fitzpatrick; Brian T. Johnston; R.G.P. Watson; Peter McCarron; Anna Gavin

Background: Patients with Barrett’s oesophagus have an increased risk of oesophageal adenocarcinoma but this cancer only accounts for a small proportion of deaths in these patients. Other causes of death are reportedly raised in this group. We examined cause specific mortality among individuals in a population based Barrett’s oesophagus register. Methods: We constructed a register of all patients diagnosed with columnar mucosa (including specialised intestinal metaplasia) of the oesophagus within Northern Ireland between 1993 and 1999. Deaths occurring within this cohort until 31 December 2000 were identified and mortality rates were compared with the general population. Results: Overall mortality was not raised in Barrett’s patients. During 7413 person years of follow up in 2373 patients there were 253 deaths (standardised mortality ratio (SMR) 96 (95% confidence interval (CI) 84–107)). Mortality from oesophageal cancer was raised in patients with specialised intestinal metaplasia (SMR 774 (95% CI 317–1231)) but only 4.7% of patients died from this cancer. Mortality from stroke (SMR 65 (95% CI 37–93)) was significantly lower than the general population while mortality from non-cancerous digestive system diseases was significantly higher (SMR 211 (95% CI 111–311)). Mortality rates from all other causes were similar to those of the general population. Conclusions: This study demonstrates that the overall mortality rate in patients with Barrett’s oesophagus is closely similar to that of the general population. Oesophageal cancer mortality was raised but is an uncommon cause of death in these patients who also appear to have a reduced risk of death from stroke.


Gut | 2008

Relationship between Helicobacter pylori infection and gastric atrophy and the stages of the oesophageal inflammation, metaplasia, adenocarcinoma sequence: results from the FINBAR case–control study

Lesley A. Anderson; Seamus J. Murphy; Brian T. Johnston; R.G.P. Watson; Heather R. Ferguson; K B Bamford; A Ghazy; Peter McCarron; Ja McGuigan; John V. Reynolds; Harry Comber; Liam Murray

Objective: A number of studies have shown an inverse association between infection with Helicobacter pylori and oesophageal adenocarcinoma (OAC). The mechanism of the apparent protection against OAC by H pylori infection and, in particular, the role of gastric atrophy is disputed. The relationship between all stages of the oesophageal inflammation, metaplasia, adenocarcinoma sequence and H pylori infection and gastric atrophy was explored. Methods: A case–control study involving 260 population controls, 227 OAC, 224 Barrett’s oesophagus (BO) and 230 reflux oesophagitis (RO) patients recruited within Ireland was carried out. H pylori and CagA (cytotoxin-associated gene product A) infection was diagnosed serologically by western blot, and pepsinogen I and II levels were measured by enzyme immunoassay. Gastric atrophy was defined as a pepsinogen I/II ratio of <3. Results: H pylori seropositivity was inversely associated with OAC, BO and RO; adjusted ORs (95% CIs), 0.49 (0.31 to 0.76), 0.35 (0.22 to 0.56) and 0.42 (0.27 to 0.65), respectively. Gastric atrophy was uncommon (5.3% of all subjects), but was inversely associated with non-junctional OAC, BO and RO; adjusted ORs (95% CIs), 0.34 (0.10 to 1.24), 0.23 (0.05 to 0.96) and 0.27 (0.08 to 0.88), respectively. Inverse associations between H pylori and the disease states remained in gastric atrophy-negative patients. Conclusion: H pylori infection and gastric atrophy are associated with a reduced risk of OAC, BO and RO. While use of the pepsinogen I/II ratio as a marker for gastric atrophy has limitations, these data suggest that although gastric atrophy is involved it may not fully explain the inverse associations observed with H pylori infection.


Gastroenterology | 2011

Population-Based Study Reveals New Risk-Stratification Biomarker Panel for Barrett's Esophagus

Jason M. Dunn; Pierre Lao-Sirieix; Helen G. Mulholland; Dahmane Oukrif; Elaine Walker; Sibu Varghese; Brian T. Johnston; Ken Arthur; Damian McManus; Marco Novelli; Laurence Lovat; Liam Murray; Rebecca C. Fitzgerald

BACKGROUND & AIMS The risk of progression of Barretts esophagus (BE) to esophageal adenocarcinoma (EAC) is low and difficult to calculate. Accurate tools to determine risk are needed to optimize surveillance and intervention. We assessed the ability of candidate biomarkers to predict which cases of BE will progress to EAC or high-grade dysplasia and identified those that can be measured in formalin-fixed tissues. METHODS We analyzed data from a nested case-control study performed using the population-based Northern Ireland BE Register (1993-2005). Cases who progressed to EAC (n = 89) or high-grade dysplasia ≥ 6 months after diagnosis with BE were matched to controls (nonprogressors, n = 291), for age, sex, and year of BE diagnosis. Established biomarkers (abnormal DNA content, p53, and cyclin A expression) and new biomarkers (levels of sialyl Lewis(a), Lewis(x), and Aspergillus oryzae lectin [AOL] and binding of wheat germ agglutinin) were assessed in paraffin-embedded tissue samples from patients with a first diagnosis of BE. Conditional logistic regression analysis was applied to assess odds of progression for patients with dysplastic and nondysplastic BE, based on biomarker status. RESULTS Low-grade dysplasia and all biomarkers tested, other than Lewis(x), were associated with risk of EAC or high-grade dysplasia. In backward selection, a panel comprising low-grade dysplasia, abnormal DNA ploidy, and AOL most accurately identified progressors and nonprogressors. The adjusted odds ratio for progression of patients with BE with low-grade dysplasia was 3.74 (95% confidence interval, 2.43-5.79) for each additional biomarker and the risk increased by 2.99 for each additional factor (95% confidence interval, 1.72-5.20) in patients without dysplasia. CONCLUSIONS Low-grade dysplasia, abnormal DNA ploidy, and AOL can be used to identify patients with BE most likely to develop EAC or high-grade dysplasia.


Cancer Research | 2006

Nonsteroidal anti-inflammatory drugs and the esophageal inflammation-metaplasia-adenocarcinoma sequence.

Lesley A. Anderson; Brian T. Johnston; R.G. Peter Watson; Seamus J. Murphy; Heather R. Ferguson; Harry Comber; Jim McGuigan; John V. Reynolds; Liam Murray

Observational studies suggest that nonsteroidal anti-inflammatory drugs (NSAIDs) reduce the risk of esophageal adenocarcinoma, but it is not known at what stage they may act in the esophageal inflammation-metaplasia-adenocarcinoma sequence. In an all-Ireland case-control study, we investigated the relationship between the use of NSAIDs and risk of reflux esophagitis, Barretts esophagus, and esophageal adenocarcinoma. Patients with esophageal adenocarcinoma, long-segment Barretts esophagus and population controls were recruited from throughout Ireland. Esophagitis patients were recruited from Northern Ireland only. Data were collected on known and potential risk factors for esophageal adenocarcinoma and on the use of NSAIDs, including aspirin, at least 1 year before interview. Associations between use of NSAIDs and the stages of the esophageal inflammation-metaplasia-adenocarcinoma sequence were estimated by multiple logistic regression. In total, 230 reflux esophagitis, 224 Barretts esophagus, and 227 esophageal adenocarcinoma and 260 population controls were recruited. Use of aspirin and NSAIDs was associated with a reduced risk of Barretts esophagus [odds ratio [OR; 95% confidence interval (95% CI)], 0.53 (0.31-0.90) and 0.40 (0.19-0.81), respectively] and esophageal adenocarcinoma [OR (95% CI), 0.57 (0.36-0.93) and 0.58 (0.31-1.08), respectively]. Barretts esophagus and esophageal adenocarcinoma patients were less likely than controls to have used NSAIDs. Selection or recall bias may explain these results and the results of previous observational studies indicating a protective effect of NSAIDs against esophageal adenocarcinoma. If NSAIDs have a true protective effect on the esophageal inflammation-metaplasia-adenocarcinoma sequence, they may act early in the sequence.

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Liam Murray

Queen's University Belfast

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Helen G. Coleman

Queen's University Belfast

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Damian McManus

Belfast Health and Social Care Trust

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Anna Gavin

Queen's University Belfast

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Joy Ardill

Queen's University Belfast

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Shivaram Bhat

Queen's University Belfast

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J. S. A. Collins

Queen's University Belfast

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Marie Cantwell

Queen's University Belfast

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