Background & Aims: pH impedance monitoring detects acid and non-acid reflux events, but little is known about which parameters predict outcomes of different management strategies. We evaluated a cohort of medically and surgically managed patients following pH-impedance monitoring to identify factors that predict symptom improvement after therapy. Methods: In a prospective study, we followed 187 subjects undergoing pH impedance testing from January 2005 through August 2010 at Washington University in St. Louis (mean age, 53.8±0.9 years; 70.6% female). Symptom questionnaires assessed dominant symptom intensity (DSI) and global symptom severity (GSS) at baseline and on follow up. Data collected from pH impedance studies included acid exposure time (AET), reflux exposure time (RET, duration of impedance drop 5 cm above lower esophageal sphincter, reported as percentage of time similar to AET), symptom reflux correlation (symptom index and symptom association probability, SAP), and total numbers of reflux events. Univariate and multivariate analyses were performed to determine factors associated with changes in DSI and GSS after therapy. Results: Of study subjects, 49.7% were tested on proton pump inhibitor (PPI) therapy and 68.4% were managed medically. After 39.9±1.3 months follow up, DSI and GSS scores decreased significantly (P<.05). On univariate analysis, abnormal AET predicted decreased DSI and GSS scores (P≤.049 for each comparison); RET and SAP from impedance-detected reflux events (P≤.03) were also predictive. On multivariate analysis, abnormal AET consistently predicted symptomatic outcome; other predictors included impedance-detected SAP, older age, and testing performed off PPI therapy. Abnormal RET, acid symptom index or SAP, and numbers of reflux events did not independently predict decrease in DSI or GSS scores. Conclusion: Performing pH impedance monitoring off PPI therapy best predicts response to anti-reflux therapy. Key parameters with predictive value include increased AET, and correlation between symptoms and reflux events detected by impedance.
Background Mean nocturnal baseline impedance (MNBI), a novel pH-impedance metric, may be a surrogate marker of reflux burden. Aim To assess the predictive value of MNBI on symptomatic outcomes after antireflux therapy. Methods In this prospective observational cohort study, pH-impedance studies performed over a 5-year period were reviewed. Baseline impedance was extracted from 6 channels at three stable nocturnal 10-min time periods, and averaged to yield MNBI. Distal and proximal esophageal MNBI values were calculated by averaging MNBI values at 3, 5, 7, and 9 cm, and 15 and 17 cm, respectively. Symptomatic outcomes were measured as changes in global symptom severity (GSS, rated on 100-mm visual analog scales) on prospective follow-up after medical or surgical antireflux therapy. Univariate and multivariate analyses assessed the predictive value of MNBI on symptomatic outcomes. Results Of 266 patients, 135 (50.8%) were tested off PPI therapy and formed the study cohort (52.1±1.1 yrs, 63.7% F). The 59 with elevated acid exposure time (AET) had lower composite and distal MNBI values than those with physiologic AET (p<0.0001), but similar proximal MNBI (p=0.62). Linear AET negatively correlated with distal MNBI, both individually and collectively (Pearson's r=−0.5, p<0.001), but not proximal MNBI (Pearson's r=0, p=0.72). After prospective follow-up (94 patients followed for 3.1±0.2 yrs), univariate and multivariate regression models showed that distal MNBI, but not proximal MNBI, was independently predictive of linear GSS improvement. Conclusions Distal esophageal MNBI negatively correlates with AET and, when assessed off PPI therapy, is independently predictive of symptomatic improvement following antireflux therapy.
OBJECTIVES Although screening colonoscopy is effective in preventing distal colon cancers, effectiveness in preventing right-sided colon cancers is less clear. Previous studies have reported that retroflexion in the right colon improves adenoma detection. We aimed to determine whether a second withdrawal from the right colon in retroflexion vs. forward view alone leads to the detection of additional adenomas. METHODS Patients undergoing screening or surveillance colonoscopy were invited to participate in a parallel, randomized, controlled trial at two centers. After cecal intubation, the colonoscope was withdrawn to the hepatic flexure, all visualized polyps removed, and endoscopist confidence recorded on a 5-point Likert scale. Patients were randomized to a second exam of the proximal colon in forward (FV) or retroflexion view (RV), and adenoma detection rates (ADRs) compared. Logistic regression analysis was used to evaluate predictors of identifying adenomas on the second withdrawal from the proximal colon. RESULTS A total of 850 patients (mean age 59.1±8.3 years, 59% female) were randomly assigned to FV (N=400) or RV (N=450). Retroflexion was successful in 93.5%. The ADR (46% FV and 47% RV) and numbers of adenomas per patient (0.9±1.4 FV and 1.1±2.1 RV) were similar (P=0.75 for both). At least one additional adenoma was detected on second withdrawal in similar proportions (10.5% FV and 7.5% RV, P=0.13). Predictors of identifying adenomas on the second withdrawal included older age (odds ratio (OR)=1.04, 95% confidence interval (CI)=1.01–1.08), adenomas seen on initial withdrawal (OR=2.8, 95% CI=1.7–4.7), and low endoscopist confidence in quality of first examination of the right colon (OR=4.8, 95% CI=1.9–12.1). There were no adverse events. CONCLUSIONS Retroflexion in the right colon can be safely achieved in the majority of patients undergoing colonoscopy for colorectal cancer screening. Reexamination of the right colon in either retroflexed or forward view yielded similar, incremental ADRs. A second exam of the right colon should be strongly considered in patients who have adenomas discovered in the right colon, particularly when endoscopist confidence in the quality of initial examination is low.
OBJECTIVES pH-impedance testing detects reflux events irrespective of pH, but its value in predicting treatment outcome is unclear. We prospectively evaluated subjects treated medically after pH-impedance testing to determine predictors of symptom improvement. METHODS Subjects referred for pH-impedance testing completed questionnaires in which dominant symptoms and global symptom severity (GSS) were recorded. Acid-reflux parameters (acid-exposure time, AET; symptom association by Ghillebert probability estimate, GPE; symptom index, SI) and impedance reflux parameters (reflux-exposure time, RET; number of reflux events; GPE and SI with impedance data) were extracted. Symptoms and GSS were prospectively reevaluated after medical therapy. Univariate and multivariate analyses determined predictors of GSS improvement following medical management. RESULTS Over 5 years, 128 subjects (mean 53.3 ± 1.3 years, 66.4% female; typical symptoms 57.0%, 53.9% tested on therapy) underwent pH-impedance testing and subsequent medical therapy for reflux symptoms, and completed required questionnaires. On follow-up 3.35 ± 0.14 years later, mean GSS declined by 45.0%, with 42.2% patients reporting ≥50% GSS improvement. On univariate analysis, total AET, AET ≥4.0%, and GPE for all reflux events predicted both linear and ≥50% GSS improvement, but RET and number of reflux events did not. On multivariate analysis, controlling for testing on or off therapy, only AET (P = 0.003) and GPE for all reflux events (P = 0.029) predicted GSS improvement. CONCLUSIONS Acid-based reflux parameters offer greater value over impedance-based nonacid-reflux parameters in predicting symptomatic responses to proton pump inhibitor (PPI) therapy. Our findings support conducting pH-impedance studies off PPI therapy to maximize clinical utility in predicting outcome.
SUMMARY BackgroundThere is uncertainty about how to measure patient-reported outcomes (PROs) in IBS. The Food and Drug Administration (FDA) emphasizes that PROs must be couched in a conceptual framework, yet existing IBS PROs were not based on such a framework.
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