0587 Under-Diagnosis of Sleep Apnea at the US / Mexico Border – Data from the Nogales Cardiometabolic Health and Sleep Study

Abstract Introduction Sleep apnea is both underdiagnosed and undertreated in the US. Few studies have examined the gaps in border communities where access to specialized sleep care may be limited. This study quantifies the rates of underdiagnosis and identified other risk factors in a cohort at the US-Mexico Border. Methods Data were collected from 992 working-age adults (age 25-60) living at the US-Mexico Border. Apnea-Hypopnea Index (AHI) was determined from Embletta home sleep tests scored by certified polysomnographic technicians using the 3% hypopnea rule. Results were classified as None (0.0-4.9), Minimal (5.0-9.9), Mild (10.0-14.9), Moderate (15.0-29.9), and Severe (30+). Actual diagnosis of sleep apnea was assessed in a detailed medical history interview. Cross-tabs and Receiver-Operator Curves (ROCs) were computed, with post-hoc McNemar’s test to evaluate systematic under-diagnosis at each diagnostic cutoff. Logistic regression analysis examined sociodemographic correlates. Future analyses will incorporate symptom reports to ascertain diagnoses for AHI 15. Results Prevalence of sleep apnea categories in the sample was None=61.51%, Minimal=21.35% Mild=7.36%, Moderate=5.57%, and Severe=4.21%. Based on an AHI cutoff of 5.0, 22 of 406 cases were diagnosed, representing 94.6% under-diagnosis, 5.4% sensitivity but 98.5% specificity, and ROC of 0.52. McNemar’s test was significant (X2 = 357.82, p 0.0001), indicating under-diagnosis. Based on an AHI cutoff of 10, 12/161 cases were diagnosed, representing 92.5% under-diagnosis, 7.5% sensitivity but 97.7% specificity, and ROC of 0.53. McNemar’s test was significant (X2 = 102.76, p 0.0001). Based on an AHI cutoff of 15, 7/93 cases were diagnosed, representing 92.5% under-diagnosis, 7.5% sensitivity but 97.3% specificity, and ROC of 0.52. McNemar’s test was significant (X2 = 36.41, p 0.0001). Being underdiagnosed according to the AHI=5 criterion was associated with higher Mexican acculturation (OR=2.31/pt) and negatively related to higher BMI (OR=0.92/pt). Conclusion Sleep apnea is highly under-diagnosed in this US-Mexico border sample, with 90-95% of cases currently under-diagnosed, thus exceeding national estimates of under-diagnosis. The study highlights the urgent need to increase case-finding efforts and awareness, especially among Mexican acculturation and less severe BMI. Support (if any) R01MD011600, R01MH135978