The study

The aim of the study was to create and validate a model with four high-resolution manometry variables in order to predict pathologic gastro-esophageal reflux disease (GERD), defined as acid exposure time (AET) >6% according to Lyon consensus1.
High-resolution manometry was performed following the Chicago Classification 4.02. The variables included were: ineffective esophageal motility (IEM), EGJ-contractile integral (EGJ-CI), EGJ type and response to straight leg raise (SLR) maneuver. These variables have been previously validated as factors favoring GERD3-6

Definitions and figures


70% weak swallows
or ≥50% failed swallows


Contractile integral measured with the DCI software tool over the EGJ during the reference period for three respiratory cycles at the isobaric contour of gastric pressure + 2 mmHg.

SLR maneuver

With the patient in the supine position, one or two legs are raised at an angle of 45° for at least 5 seconds until intra-abdominal pressure is raised. An increase of 11 mmHg of intra-esophageal peak pressure 5 cm above the LES during SLR was considered abnormal.

Negative SLR
slr 2
Positive SLR
slr 4

EGJ type

Type 1:
Superimposed LES and CD
Type 2:
LES-CD separation <3 cm
Type 3:
LES-CD separation ≥3 cm

Study population

The study population has been prospectively enrolled with the following inclusion and exclusion criteria:

Inclusion criteria

  • Age between 18 and 75 years
  • GERD symptoms for at least 6 months
  • HRM and pH-study (both catheter based and wireless) performed within two weeks between each other

Exclusion criteria

  • Body mass index (BMI) >35 kg/m2
  • Prior esophageal surgery
  • Eosinophilic esophagitis
  • Scleroderma
  • Achalasia spectrum disorders
  • Pregnancy

Statistical analysis

A first cohort of patient of 295 patients was prospectively enrolled between July 2021 and March 2022 in order to create the multivariable logistic model to estimate the odd ratio (OR) and 95% confidence intervals (CI) for each variable in the model. A nomogram based on the model was therefore developed.

A second cohort of 233 patients was enrolled between December 2022 and February 2023 to provide external validation. Model accuracy was measured using calibration and discrimination. In the validation model, the corrected Harrel c-index was 0.90, the model-fitting optimism adjusted calibration slope was 0.93 and the integrated calibration index was 0.07, indicating good calibration.

The full study has been published on the UEG Journal and can be found here.


(1) Gyawali CP, Kahrilas PJ, Savarino E, et al. Modern diagnosis of GERD: the Lyon Consensus. 2018 Jul;67(7):1351-1362. PMID: 29437910.

(2) Yadlapati R, Kahrilas PJ, Fox MR, et al. Esophageal motility disorders on high- resolution manometry: Chicago classification version 4.0©. Neurogastroenterol Motil. 2021;33:e14058.

(3) Gyawali CP, Zerbib F, Bhatia S, et al. Chicago Classification update (V4.0): Technical review on diagnostic criteria for ineffective esophageal motility and absent contractility. Neurogastroenterol Motil. 2021 Aug;33(8):e14134. doi: 10.1111/nmo.14134. Epub 2021 Mar 26. PMID: 33768698.

(4) Kahrilas PJ, Mittal RK, Bor S, et al. Chicago Classification update (v4.0): Technical review of high-resolution manometry metrics for EGJ barrier function. Neurogastroenterol Motil. 2021 Oct;33(10):e14113. doi: 10.1111/nmo.14113. Epub 2021 Mar 2. PMID: 33655610; PMCID: PMC8410874.

(5) Nicodème F, Pipa-Muniz M, Khanna K, et al. Quantifying esophagogastric junction contractility with a novel HRM topographic metric, the EGJ-Contractile Integral: normative values and preliminary evaluation in PPI non-responders. Neurogastroenterol Motil. 2014 Mar;26(3):353-60. doi: 10.1111/nmo.12267. Epub 2013 Dec 3. PMID: 24460814; PMCID: PMC4605557.

(6) Siboni S, Kristo I, Rogers BD, et al. Improving the Diagnostic Yield of High-Resolution Esophageal Manometry for GERD: The “Straight Leg-Raise” International Study. Clin Gastroenterol Hepatol. 2022 Oct 19:S1542-3565(22)00970-3. doi: 10.1016/j.cgh.2022.10.008. Epub ahead of print. PMID: 36270615.