The symptom-association probability: An improved method for symptom analysis of 24-hour esophageal pH data

doi:10.1016/0016-5085(94)90815-X

Gastroenterology

Volume 107, Issue 6, December 1994, Pages 1741-1745

https://doi.org/10.1016/0016-5085(94)90815-X Get rights and content

Abstract

Background/Aims: All methods currently used to quantify the temporal relationships between symptoms and episodes of gastroesophageal reflux, as assessed by 24-hour pH monitoring, have major shortcomings. The aim of this study was to develop and validate a simple, all-comprising statistical method to calculate the probability that gastroesophageal reflux episodes and symptoms are associated. Methods: The 24-hour pH signal was divided into consecutive 2-minute periods. These periods and the 2-minute periods preceding the onset of symptoms were evaluated for the occurrence of reflux. Fisher's Exact Test was then applied to calculate the probability (P value) that reflux and symptom episodes were unrelated. Finally, the symptom-association probability (SAP) was calculated as (1.0 − P) × 100%. The SAP values found in 184 24-hour esophageal pH tests were compared with the symptom index and the symptom sensitivity index. Results: Discordance between the SAP and the symptom index was found in 21 patients (11%) and discordance between the SAP and the symptom-sensitivity index in 28 (15%). False-positive and false-negative symptom index values occurred preferentially in patients with small and large numbers of symptom episodes during the test, respectively (P < 0.05). Conclusions: The SAP is a single, simple, quantitative measure of the strength of the association between symptoms and reflux episodes that is devoid of the disadvantages inherent to previously used methods.

References (15)

G Vantrappen et al.
The irritable oesophagus—a frequent cause of angina-like pain
Lancet
(1987)
EG Hewson et al.
Twenty-four-hour esophageal pH monitoring: the most useful test for evaluating noncardiac chest pain
Am J Med
(1991)
GJ Wiener et al.
The symptom index: a clinically important parameter of ambulatory 24-hour esophageal pH monitoring
Am J Gastroenterol
(1988)
R Breumelhof et al.
The symptom sensitivity index: a valuable additional parameter in 24-hour esophageal pH recording
Am J Gastroenterol
(1991)
G Ghillebert et al.
Ambulatory 24-hour intraoesophageal pH and pressure recordings v provocation tests in the diagnosis of chest pain of oesophageal origin
Gut
(1990)
D Armstrong et al.
Diagnostic assessment of gastroesophageal reflux disease: what is possible vs. What is practical?
Hepatogastroenterology
(1992)
BT Johnston et al.
The binomial symptom index: correlating esophageal symptoms with acid reflux (abstr)
Gastroenterology
(1992)

There are more references available in the full text version of this article.

Cited by (506)

The Irritable Infant in the Neonatal Intensive Care Unit: Risk Factors and Biomarkers of Gastroesophageal Reflux Disease
2024, Journal of Pediatrics
To determine risk factors for arching/irritability in high-risk infants and examine the significance of comorbidity and gastroesophageal reflux (GER) characteristics.
Retrospective analysis of 24-hour pH-impedance studies of symptomatic infants in a neonatal intensive care unit (ICU) (n = 516, 30.1 ± 4.5 weeks of gestation, evaluated at 41.7 ± 3.2 weeks postmenstrual age) was conducted. Comparisons were made between infants with >72 vs ≤72 arching/irritability events per day. We characterized risk factors for arching/irritability along with clinical, pH-impedance, and outcome correlates.
Of 39 973 arching/irritability events and 42 155 GER events, the averages per day were 77.6 ± 41.0 and 81.7 ± 48.2, respectively. Acid reflux and impedance bolus characteristics were not significantly different between infants with >72 and ≤72 arching/irritability events (P ≥ .05). The odds ratios (ORs) and 95% confidence intervals (CIs) adjusted for postmenstrual age and weight at evaluation were significant for risk factors of preterm birth (2.3 [1.2–4.4]), moderate or severe neuropathology (2.0 [1.1–3.6]), and presence of oral feeding at testing (1.57 [1.07–2.30]).
Acid GER disease is unlikely the primary cause of arching/irritability and empiric treatment should not be used when arching/irritability is present. Prematurity and neurologic impairment may be more likely the cause of the arching/irritability. Arching/irritability may not be a concern in orally fed infants.
The Utility of Symptom Association Probability (SAP) in Predicting Outcome After Laparoscopic Fundoplication in Patients with Abnormal Esophageal Acid Exposure
2023, Journal of Gastrointestinal Surgery
Abnormal DeMeester score on pH monitoring is a well-established predictor of favorable outcome after antireflux surgery (ARS). Esophageal pH monitoring also facilitates analysis of the temporal association between symptoms and reflux episodes. This association can be expressed with several symptom–reflux association indices with symptom association probability (SAP) being the most reliable. SAP is often used as an adjunct to DeMeester score during preoperative assessment of patients seeking ARS. However, data on the utility of SAP in predicting ARS outcome is limited. The aim of this study was to determine the utility of SAP as an adjunct to DeMeester score in predicting outcomes after fundoplication.
Records of patients who underwent primary fundoplication from 2015 to 2021 were reviewed. Patients with a preoperative DeMeester score >14.7 on Bravo pH monitoring were included. A SAP >95% was considered SAP-positive. Favorable outcome was defined as freedom from proton pump inhibitors (PPIs) and patient satisfaction at 1 year postoperatively. Outcomes were compared based on the presence and number of SAP-positive symptoms, individual typical and atypical SAP-positive symptoms, and within demographic, clinical, and reflux severity subgroups.
The final study population consisted of 597 patients (71.4% female) with a median (IQR) age of 59.0 (49–67). At a mean (SD) follow-up of 10.5 (8) months, 82.0% patients achieved favorable outcome (satisfaction and freedom from PPI), freedom from PPI was 91.7%, and satisfaction was 87.4%. SAP was positive in 430 (72.0%) patients, of which 221 (37.0%) had one SAP-positive symptom, 164 (27.5%) had two SAP-positive symptoms, and 45 (7.5%) had all three SAP-positive symptoms. There was no association between having at least one SAP-positive symptom and favorable outcome (p=0.767). There was no difference in favorable outcome between patients with one, two, or all SAP-positive symptoms (0.785). Outcomes were comparable for SAP-positive typical (p=0.873) and atypical symptoms (p=1.000) and all individual symptoms (p>0.05). Outcomes were also comparable within all subgroups (p>0.05).
Symptom association probability with an abnormal DeMeester score did not enhance the prediction of antireflux surgery outcome. These findings suggest that SAP should not be used in surgical decision-making in patients with objective evidence of reflux.
Prospective validation of reflux monitoring by impedance-pH in predicting PPI response in typical GERD
2023, Digestive and Liver Disease
The Lyon Consensus proposed a hierarchical approach to GERD diagnosis based on conventional and new impedance-pH metrics, namely acid exposure time (AET), number of reflux episodes, post-reflux swallow-induced peristaltic wave (PSPW) index, and mean nocturnal baseline impedance (MNBI).
To define the value of conventional and new impedance-pH parameters as predictors of response to label-dose PPI in typical GERD.
Consecutive adult patients with typical esophageal symptoms were prospectively studied with impedance-pH monitoring and treated with 8-week label-dose PPI. At the end of the PPI course, symptoms response was assessed.
Among 255 patients who entered the study, 168 (65.9%) reported symptom remission. At ROC analysis, both MNBI and PSPW index were significantly associated to PPI responsiveness with AUC of 0.783 and 0.801, respectively. Cut-off values of 1747Ω for MNBI and 50% for PSPW index were identified as discriminators between response and non-response to label-dose PPI. At multivariate analysis, MNBI, PSPW index, and AET >6% were efficient predictors of PPI responses (OR 3, 5.4 and 2.3, respectively). Number of reflux episodes did not predict PPI response.
The novel MII-pH variables together with pathological are highly predictive of response of the typical GERD syndrome to label-dose PPI.
Symptom Scores and pH-Impedance: Secondary Analysis of a Randomized Controlled Trial in Infants Treated for Gastroesophageal Reflux
2022, Gastro Hep Advances
To evaluate and compare gastroesophageal reflux (GER) symptom scores with pH-impedance and test the effects of acid-suppressive medications with or without feeding modifications on pH-impedance in high-risk infants.
Infant Gastroesophageal Reflux Questionnaire Revised (I-GERQ-R) and 24-hour pH-impedance data were analyzed from 94 infants evaluated in a tertiary care setting for GER disease. Longitudinal data from 40 infants that received randomized GER therapy (proton pump inhibitor [PPI] with or without feeding modifications) for 4 weeks followed by 1-week washout were analyzed. Relationships between I-GERQ-R and pH-impedance metrics (acid reflux index, acid and bolus GER events, distal baseline impedance, and symptoms) were examined and effects of treatments compared.
(A) Correlations between I-GERQ-R and pH-impedance metrics were weak. (B) I-GERQ-R sensitivity, specificity, and positive predictive values were suboptimal when correlated with pH-impedance metrics. I-GERQ-R negative predictive value (NPV) was high for acid symptom–association probability (NPV = 84%) and distal baseline impedence (NPV = 86%) thresholds. (C) PPI with feeding modifications (vs PPI alone) did not alter pH-impedance metrics or symptom scores (P > .05); however, bolus clearance metrics worsened for both treatment groups (P < .05).
In high-risk infants (1) I-GERQ-R may be a helpful clinical screening tool to exclude acid-GER disease diagnosis and minimize unnecessary acid-suppressive treatment, but further testing is needed for diagnosis. (2) Acid-suppressive therapy with feeding modifications has no effect on symptom scores or pH-impedance metrics. Clearance of refluxate worsened despite PPI therapy, which may signal development of pharyngoesophageal dysmotility and persistence of symptoms. (3) Placebo-controlled trials are needed in high-risk infants with objective pH-impedance criteria to determine efficacy, safety, and underlying mechanisms. Clinicaltrials.gov ID: NCT02486263.
Post-reflux swallow-induced peristaltic wave index: a new parameter for the identification of non-acid gastroesophageal reflux-related chronic cough
2024, Therapeutic Advances in Respiratory Disease
Multichannel intraesophageal impedance with pH metry in Saudi children
2024, Saudi Journal of Gastroenterology

View all citing articles on Scopus

: Supported in part (to B.L.A.M.W.) by Astra Pharmaceuticals, Rijswijk, The Netherlands.

View full text

The symptom-association probability: An improved method for symptom analysis of 24-hour esophageal pH data

Abstract

Lancet

Am J Med

The symptom index: a clinically important parameter of ambulatory 24-hour esophageal pH monitoring

Am J Gastroenterol

The symptom sensitivity index: a valuable additional parameter in 24-hour esophageal pH recording

Am J Gastroenterol

Ambulatory 24-hour intraoesophageal pH and pressure recordings v provocation tests in the diagnosis of chest pain of oesophageal origin

Gut

Diagnostic assessment of gastroesophageal reflux disease: what is possible vs. What is practical?

Hepatogastroenterology

The binomial symptom index: correlating esophageal symptoms with acid reflux (abstr)

Gastroenterology