In 2016–2017, there were 215,240,000 total adult ED visits in the US, which is equivalent to about 107.62 million ED visits per year. Of these ED visits, 5,985,955 patients (2.8%) were patients with OSA (about 2,992,978 per year). The other basic patient characteristics are shown in Table 1.
As shown in Table 1, the top two groups in the proportion of ED visits were NH White (61.0%) and NH Black (23.3%). The constituent ratio of patients with OSA was 71.2% and 22.3%, and the constituent ratio of patients without OSA was 69.0% and 23.6%, respectively. The proportion of OSA patients and non-OSA patients with NH White was 3.26% and 96.74%, while the proportion of OSA patients and non-OSA patients with NH Black was 2.74% and 97.26%. However, there was no statistical significance in the Race/ethnicity category (P > 0.05). The top three age groups proportions for patients with OSA were 60–74 (30.5%), 50–59 (23.9%) and ≥ 75 (17.9%), all of above age groups were higher than those without OSA. The proportion of patients with OSA and without OSA in different census regions also varied as follows: Northeast, 21.5%, 15.4%; Midwest, 34.8%, 23.9%; South, 28.4%, 39.2%; West, 15.3%, 21.5% (P < 0.01).
As shown in Table 2, among all of the reasons for ED Visit, the proportion of patients with OSA was higher than that of patients without OSA in the specific cause classification of the reason for ED Visit, for example, Respiratory (16.4% vs.10.1%), Musculoskeletal (16.7% vs.14.9%), Cardiovascular and Lymphatic (3.5% vs.2.1%). In addition, within the list of reasons for ED visit, patients with OSA were 1.38 times (95% CI:1.06–1.78), 1.07 times (95% CI:0.83–1.38), and 1.44 times (95% CI:0.96–2.17) more likely to seek treatment for these specific symptoms rather than for general symptoms, respectively (Table 3).
As suggested by Table 3, there is an association between demographic, socioeconomic, and physiological characteristics of ED patients with OSA. With respect to gender, males were 1.28 times (95% CI:1.10–1.48) more like to have OSA than females. With respect to age, if we take the 18–39 age group as the control, those in the 40–49 age group were 3.36 times (95% CI:2.55–4.44) more likely to have OSA; those in the 50–59 age group, were 4.24 times more likely to have OSA (95% CI:3.26–5.51); those in the 60–74 age group were 4.75 times more likely to have OSA (95% CI:3.65–6.20); and those in the 75 and above age group were 3.25 times more likely to have OSA (95% CI:2.37–4.45). Compared to 2016, ED patients were 1.24 times more likely to have OSA in 2017 (95% CI:1.07–1.44). With respect to pain level, compared to ED patients with no pain, those with mild, moderate and severe pain were 1.28 times likely to have OSA (95% CI:0.91–1.81), 1.31 times (95% CI:1.06–1.62) and 1.60 times (95% CI:1.25–2.05).
In Tables 4 and 5 patients with OSA were stratified by ESI, hospital and ICU admission, and medical resources utilization. As shown in these tables, 26.0% of the patients with OSA were classified as immediate or emergent ESI score in the weighted sample, which was higher than immediate or emergent ESI score classification in the patients without OSA (14.6%). And, the patients with OSA were 1.82 times more often assigned as immediate or emergent vs. semi-urgent or non-urgent ESI scores (CI: 1.40–2.37) compared to patients without OSA. Also in the weighted sample, after the ED visit, 30.3% of the patients with OSA were admitted into hospital and 4.3% were admitted into ICU, which was higher than the rates of admission in the patients without OSA (13.7%, 1.7%, respectively) (P < 0.01).The possibilities of hospital admission or ICU admission differed between the patients with or without OSA, respectively; the patients with OSA were 1.76 times (CI: 1.47–2.11) and 1.56 times (CI: 1.06–2.32) more likely to be admitted, respectively. In addition, the patients with OSA were more likely to die in the ED or hospital (26.6%) and more unlikely left before/after triage (0.9%), compared to the rates of the patients without OSA (10.3%, 3%, respectively) (P < 0.01). With regard to the aspect of death in ED or hospital, the former type patients were 2.08 times (CI: 1.72–2.51) more likely to die in the ED or hospital than the latter. In the aspect of left before/after triage, the former type of patients were 58% (CI: 0.21–0.85) less likely than the latter to leave before/after triage. Additionally, in the field of medical resources utilization, the demands of patients with OSA were higher than those of patients without OSA, for example, rate of blood tests performed was 1.94 times higher (75.0% vs. 54.9%, CI: 1.61–2.33), rate of any imaging performed was 1.63 times higher (73.1% vs. 53.9%, CI: 1.37–1.92), rate of X-rays performed in ED was 1.54 times higher (56.1% vs. 36.7%, CI: 1.31–1.81), and rate of CT performed in ED was 1.08 times higher (27.4% vs. 21.4%, CI: 0.90–1.29).