OBJECTIVES: The value of gastroesophageal reflux disease (GERD) indicators (acid exposure time (AET), symptom association probability (SAP), and symptom index (SI)) in predicting therapeutic success in noncardiac chest pain (NCCP) has not been systematically evaluated in outcome studies.METHODS: We retrospectively identified 98 subjects with NCCP (age 51.81.2 years, 75 women, mean duration of symptoms 7.30.4 years) who underwent pH monitoring off antireflux therapy. Distal esophageal AET (abnormal if 4.0%), SAP (measured as Ghillibert probability estimate, abnormal if P0.05), and SI (abnormal if 50%) were calculated; symptom severity and change after therapy were assessed on a 10-point Likert scale. Subjects were interviewed 2.80.9 years after the pH study to determine the degree of symptom change (high-degree response (HDR), with definite, sustained symptom improvement) after antireflux therapy. Regression analysis was used to determine the independent predictors of HDR.RESULTS: GERD indicators were present in 61 subjects (62.2%); 52 subjects (53.1%) had abnormal AET, 26 (26.5%) had positive SAP, and 25 (25.5%) had positive SI. With therapy, mean symptom scores improved from 6.30.3 at the time of the pH study to 2.90.3 at the time of interview (P0.001). A total of 58 subjects (59.2%) achieved HDR, and another 29.6% had moderate symptom improvement. On univariate analysis, HDR was associated with positive SAP (P0.003) and elevated AET (P0.015) but not with demographics, SI, or esophageal motor pattern. In regression analysis containing demographics, GERD indicators, psychiatric comorbidity, and esophageal motor pattern, positive SAP was retained as a significant predictor of HDR (P0.003); elevated AET trended toward significance (P0.055). Frequency of HDR was highest when subjects had all three GERD parameters abnormal (93.3% HDR) or both elevated AET and positive SAP (88.2% HDR, P0.001 compared with only one or no GERD parameter abnormal).CONCLUSIONS: Positive statistical tests of symptom association predict the therapeutic success of GERD management in NCCP. When used hierarchically, response to antireflux therapy is best predicted when GERD parameters are all abnormal and poorest when parameters are normal. These results support the importance of GERD, the relevance of symptom association testing during ambulatory pH monitoring, and the value of intensive antireflux therapy in NCCP.