Influence of anxiety and depression on the predictive value of the Reflux Symptom Index

Although the Reflux Symptom Index (RSI) is a validated laryngopharyngeal reflux (LPR) outcomes tool, its predictive value for LPR is controversial. Because psychiatric problems may lead to exaggerated patient-perceived symptoms and RSI values,the aim of this study was to determine whether the positive predictive value of the RSI for pH probe-documented LPR is influenced by anxiety and depression.

We reviewed the charts of all patients who underwent pH probe testing for LPR between January 2006 and July 2008 at our institution. The RSI, Reflux Finding Score (RFS), medical history, and pH probe findings were recorded. Patients with anxiety or depression were included in the psychiatric disorder (+PSY) group, and those without anxiety or depression comprised the non-psychiatric disorder (-PSY) group. Predictive values of the RSI for pH probe-documented LPR were determined for each group.

We included 51 patients: 30 patients (59%) in the -PSY group and 21 patients (41%) in the +PSY group. The mean RSI of the +PSY group was higher than that of the -PSY group (p < 0.05), but the +PSY patients actually had a lower incidence of abnormal probe studies (p < 0.02). The positive predictive value of an elevated RSI for an abnormal pH probe study was poor in the +PSY patients (p = 0.495), but strong in the -PSY group (p = 0.004).

The presence of anxiety and depression impairs the predictive value of the RSI for LPR. This finding potentially explains some of the controversy over the diagnostic utility of the RSI.