How to Compute the EraFlux Score

By Dieter Menne (Menne Biomed Consulting, Tübingen) and Werner Schwizer (UniversitätsSpital Zürich)

 

The EraFlux score was developed to quantify the severity of gastro-esophageal reflux (GERD) in the clinical study EraFlux; it is also the basic relapse criterion in the current mulitcenter study ERASTRAT. The symptoms are assessed by the study physician or a study nurse in face-to-face interviews or in telephone interviews.

Click here for a javascript-program to calculate the Eraflux score on-line.

Definition of Symptoms

To define the severity of GERD, four symptoms were used

Grading of Symptoms

Definition of Just-Below-Critical Cases

We used our professional medical expertise to define symptom patterns just below a level we rated critical. Identical sets of conditions were used for retrosternal pain and heartburn, a separate set was defined for dysphagia.

The example in the above table means that one mild episode of 5-9 minutes per day was just below the critical level. The same conditions, with two episodes instead of one episode per day , would be considered critical. No attempt was made to create a set of boundary conditions that were internally consistent. Instead, the boundary conditions were used to create a set of weights for the symptom gradings that minimized the inconsistencies inherent in every mapping of multi-dimensional patterns to a linear score.

Score Weights

The additive weights for each level of symptom grading were derived using an exhaustive search under the following constraints

Eraflux Score

We defined the Eraflux score as the maximum of the symptom scores for retrosternal pain, heartburn, regurgitation and dysphagia. We first considered using a sum criterion, but found that it did not adequately follow the general well-being of the patients.

Just-Below-Critical Symptom Gradings for Retrosternal Pain and Heartburn

Note that some lower levels of symptoms (e.g. once per week for episodes, very mild for intensity are not shown in the figures below, because these were always considered uncritical.

Retrosternal Pain and Heartburn

Just-Below-Critical Symptom Gradings for Dysphagia

Score Weights for Retrosternal Pain and Heartburn

Number of Episodes

none

0

1/week

3

every 3 days

6

every 2 days

9

daily

12

     
Episodes per day

none

0

1/day

2

2/day

4

3/day

6

4/day

8

>4/day

10

   
Duration

none

0

<1 min

1

< 5 min

2

< 10 min

3

<30 min

4

<60 min

5

>60 min

6

 
Intensity

none

0

very mild

3

mild

6

moderate

9

strong

12

very strong

15

   
Sum of Pain or Sum of Heartburn  

 

Score Weights for Regurgitation

Number of Episodes

none

0

1/week

3.4

every 3 days

6.8

every 2 days

10.2

daily

13.6

   
Episodes per day

none

0

1/day

2.2

2/day

4.4

3/day

6.6

4/day

8.8

>4/day

11.0

 
Intensity

none

0

very mild

3.4

mild

6.8

moderate

10.2

strong

13.6

very strong

17

 
Sum of Regurgitation  

Score Weights for Dysphagia

Number of Episodes

none

0

1/week

6.3

every 3 days

12.5

every 2 days

18.8

daily

25.0

   
Intensity

none

0

very mild

6.3

mild

12.5

moderate

18.8

strong

25.0

very strong

31.3

 
Sum of Dysphagia  

 

The EraFlux score is the maximum of the symptom scores for retrosternal pain, heartburn, regurgitation and dysphagia.