Endometriosis, Anxiety, Allergic Rhinoconjunctivitis and Asthma: A population-based study

OBJECTIVES: To evaluate the association between endometriosis, anxiety, allergic rhinoconjunctivitis and asthma in hospitalized women, and to determine the role of age. DESIGN: Cross-sectional study using inpatient hospital discharge data from 2007 to 2014. Participants/Materials: The study included 12,814,970 hospitalized women aged 18-49 years from the Healthcare Cost and Utilization Project (HCUP) National Inpatient Sample (NIS) in the United States. Diagnoses of asthma, allergic rhinoconjunctivitis, endometriosis, and anxiety were identified using ICD-9 codes. SETTING: U.S. community hospitals in the HCUP NIS database between 2007 and 2014. METHODS: Of the 12,814,970 patients hospitalized between 2007 and 2014, 1,042,015 (8.1%) had asthma, 50,867 (0.4%) had allergic rhinoconjunctivitis, 831,239 (6.5%) had anxiety without endometriosis, 85,990 (0.7%) had endometriosis without anxiety, and 8,880 (0.1%) had both anxiety and endometriosis. Multivariable logistic regression models were used to estimate adjusted odds ratios (ORs) and 95% confidence intervals (CIs) for the associations between endometriosis, anxiety, and asthma, adjusting for age, race, insurance type, smoking, obesity, hypertension, diabetes, thyroid disease, dyslipidemia, atherosclerosis, and depression. Analyses were stratified by age groups (18-34 and 18-49 years). RESULTS: Among hospitalized women aged 18-49 and 18-34 years, the coexistence of anxiety and endometriosis was associated with the highest odds of asthma and allergic rhinoconjunctivitis. For asthma, adjusted odds ratios (ORs) were 2.07 (95% CI: 1.94-2.20) among patients aged 18-49 years and 2.57 (2.35-2.81) in patients aged 18-34 years. The ORs for allergic rhinoconjunctivitis were 2.78 (2.30-3.36) and 3.45 (2.55-4.66), respectively. Anxiety or endometriosis alone was also significantly associated with both conditions. LIMITATIONS: The study used administrative data lacking information on disease severity, outpatient diagnoses, and treatment details. As a cross-sectional study, it cannot establish causality or temporal relationships. CONCLUSIONS: Endometriosis and anxiety were independently associated with asthma and allergic rhinoconjunctivitis, with stronger associations in women under 35 years. The combination of both conditions was associated with the highest likelihood of asthma and allergic rhinoconjunctivitis, suggesting a potential synergistic effect. Given the nature of the study, future research is needed to explore the shared inflammatory mechanisms. Our findings support clinical awareness of related inflammatory and psychological comorbidities when managing asthma, allergic rhinoconjunctivitis, or endometriosis.