1. Caution About Overinterpretation of Symptom Indexes in Reflux Monitoring for Refractory Gastroesophageal Reflux Disease 
James C. Slaughter, Marion Goutte, Jennifer A. Rymer, Amanke C. Oranu, Jonathan A. Schneider, C. Gaelyn Garrett, David Hagaman, Michael F. Vaezi 
Clinical Gastroenterology and Hepatology 
Volume 9, Issue 10, Pages (October 2011)
DOI: /j.cgh
Copyright © 2011 AGA Institute Terms and Conditions

2. Figure 1
Forty eight–hour pH tracing (middle tracing) and a 1.5-hour window (bottom tracing) demonstrating the construct of a 2 × 2 contingency table (top table). pH tracing time for each of the 2 monitored days was divided into consecutive 2-minute intervals excluding time for meals. A 2-minute period was considered reflux positive (R+) when pH fell below 4 and lasted 5 seconds or more. The cells for the 2 × 2 contingency table were constructed based on the number of intervals when a subject indicated a symptom within 2 minutes of a reflux event (S+R+); the number of intervals a subject indicated a symptom without a corresponding reflux event (S+R−), asymptomatic reflux positive (S−R+), and asymptomatic reflux negative (S−R−) intervals.
Clinical Gastroenterology and Hepatology 2011 9, DOI: ( /j.cgh )
Copyright © 2011 AGA Institute Terms and Conditions

3. Figure 2
The multivariate association between SAP (A) and SI (B), probability of refluxing (R+), probability of reporting symptoms near reflux (S+R+), and the probability of reporting symptoms without a reflux event (S+R−). The color-coded panel to the right of the figures provides the color coding for SAP and SI values, respectively. SAP and SI are both highly dependent on probability of reflux (R+). As reflux rates increase so does likelihood of abnormal SAP (dark blue) and SI (green and blue).
Clinical Gastroenterology and Hepatology 2011 9, DOI: ( /j.cgh )
Copyright © 2011 AGA Institute Terms and Conditions

4. Figure 3
Histogram representing day-to-day variability in the SAP (A) and SI (B) values for a typical subject with reflux probability (R+) of 5%, symptoms near refluxing (S+R+) of 5%, and symptoms not near refluxing (S+R−) of 1%. Keeping all variables constant on 36% of the days monitored SAP would be abnormal (>95%) while the remaining 64% of days SAP would be normal (A). For SI, similar patterns in the variability are observed (only 2% of the days monitored were above 50%), although the distribution of SI is more symmetric than for SAP (B).
Clinical Gastroenterology and Hepatology 2011 9, DOI: ( /j.cgh )
Copyright © 2011 AGA Institute Terms and Conditions