Psychological Status as an Effect Modifier of the Association Between Allergy Symptoms and Allergy Testing

Objective: Patient-reported outcome measures, while valuable, may not correlate with diagnostic test results. To better understand this potential discrepancy, our objective was to determine whether psychological health is an effect modifier of the association between patient-reported allergy outcome scores and allergy test results. Study Design: Prospective outcomes study. Setting: Tertiary care hospital and community-based clinic. Methods: This study included 600 patients at least 18 years of age who presented for symptoms related to allergic rhinitis and completed the related sinonasal outcome test (SNOT), which includes validated nasal, allergy, and psychological domains. Stratified analyses of odds ratios and Spearman correlation coefficients were utilized to assess for effect modification by psychological status. Results: Worse patient-reported allergic rhinitis symptoms were significantly associated with positive allergy test results (odds ratio [OR] 1.69, 95% confidence interval [CI] 1.22-2.34, P =.002) in patients with better psychological health. In contrast, there was no association in patients with worse psychological health (OR 1.06, 95% CI 0.36-3.10, P =.92). These findings were corroborated by assessments of correlation: allergy domain scores were positively correlated with allergy testing scores (Spearman rho 0.18, 95% CI 0.10-0.25, P <.001) in patients with better psychological health, while there was no correlation in patients with worse psychological health (−0.02, 95% CI −0.16-0.12, P =.77). Conclusions: Psychological status was an effect modifier of the association between allergy domain and allergy testing data. When assessing the relationship between subjective measures, such as sinonasal validated instruments, and objective measures, such as allergy test results, accounting for effect modifiers such as psychological state can provide clinical and research-related insights.