ORIGINAL RESEARCH article

Front. Neurol., 04 November 2025

Sec. Neurocritical and Neurohospitalist Care

Volume 16 - 2025 | https://doi.org/10.3389/fneur.2025.1624631

Continuous positive airway pressure in acute ischemic stroke patients with obstructive sleep apnea: analysis of the National Inpatient Sample database

  • 1. Department of Neurology, Xiaolan People's Hospital of Zhongshan (the Fifth People's Hospital of Zhongshan), Zhongshan, Guangdong, China

  • 2. Department of Pediatric Orthopedic, Center for Orthopedic Surgery, the Third Affiliated Hospital of Southern Medical University, Guangzhou Guangdong, China

  • 3. Division of Orthopaedic Surgery, Department of Orthopaedics, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, China

Abstract

Background:

Obstructive sleep apnea (OSA) is an established independent risk factor for stroke. However, the efficacy of continuous positive airway pressure (CPAP) in patients with acute ischemic stroke and comorbid OSA (AIS-OSA) remains uncertain. This study aimed to assess the impact of CPAP on hospitalization outcomes for AIS-OSA patients using data from the National Inpatient Sample (NIS).

Methods:

A retrospective data analysis was conducted using the NIS to identify patients hospitalized with a diagnosis of AIS-OSA between 2010 and 2019 with complete data. Patients were categorized into two groups based on CPAP treatment during hospitalization. Logistic regression analyses were performed to identify factors associated with CPAP treatment.

Results:

Among 103,004 patients with AIS-OSA, those who received CPAP had statistically significant longer lengths of stay (LOS), higher medical expenses, and increased in-hospital mortality rates. Conversely, this group also exhibited higher proportions of routine discharges, suggesting potentially improved long-term outcomes. Independent predictors for CPAP treatment included advanced age, Black race, congestive heart failure, and obesity. Besides, factors such as pneumonia, acute myocardial infarction, pulmonary embolism, intracranial hemorrhage, thrombolysis, and mechanical thrombectomy may be associated with CPAP treatment, but this association does not imply causation.

Conclusion:

This study identified independent predictors and associated factors for CPAP treatment in hospitalized AIS-OSA patients. Our observation may suggest that surviving patients who received CPAP treatment had more favorable prognoses, however, randomized trials are needed to determine causality.

Introduction

Sleep apnea, a prevalent chronic disease, is recognized as an independent risk factor for stroke, cardiovascular disease, and all-cause mortality (, ). It has been shown to increase the incidence rate of acute ischemic stroke (AIS) and is associated with worse functional outcomes and higher stroke recurrence rates (, ). More than half of stroke survivors exhibit sleep apnea during the acute post-stroke phase, with obstructive sleep apnea (OSA) being the most prevalent subtype (, ). The pathophysiology linking OSA to stroke remains unclear (). Given that stroke and OSA are intertwined conditions with shared risk factors and comorbidities (), OSA poses additional challenges in the acute-phase management of stroke patients. Continuous positive airway pressure (CPAP) is the gold standard for OSA treatment, targeting both anatomical and non-anatomical mechanisms (). Some studies suggest that OSA therapy is feasible and may improve long-term outcomes in stroke patients (), while others indicate that CPAP treatment could also aid in stroke prevention (, ). However, due to limited evidence in the acute phase, there are no clear clinical guidelines for this patient population.

Understanding the epidemiology and outcomes of patients with acute ischemic stroke and comorbid obstructive sleep apnea (AIS-OSA) is crucial for identifying subgroups that may benefit from CPAP and for recognizing unmet needs within this patient population.

This study analyzed the prevalence, comorbidities, complications, and outcomes of hospitalized patients with AIS-OSA using data from the National Inpatient Sample (NIS). Furthermore, the outcomes of AIS-OSA patients who received CPAP during hospitalization were examined.

Materials and methods

Data source

This retrospective study utilized the NIS, a Healthcare Cost and Utilization Project (HCUP) database sponsored by the Agency for Healthcare Research and Quality (AHRQ). The NIS is an all-payer database that approximates a 20% stratified sample of discharges from community hospitals in the United States (, ).

The NIS database was retrieved for data on hospitalizations from 2010 to 2019. The NIS database comprises an identified collection of procedural and diagnostic codes from participating hospitals. As the NIS dataset does not directly involve human subjects (consistent with federal regulations and guidance), it is exempt from institutional review board approval.

Inclusion and exclusion criteria

All patients aged 18 years or older, admitted to the hospital with a primary diagnosis of AIS and OSA, were included in this study. AIS was identified using the International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) codes 433 and 434, and the International Classification of Diseases, Tenth Revision, Clinical Modification (ICD-10-CM) code I63. OSA was identified using ICD-9-CM codes 327.23, 780.51, 780.53, and 780.57, and ICD-10-CM code G47.33. Cases with a primary diagnosis code other than AIS and OSA were excluded. Patients with other forms of stroke were also excluded. Baseline demographic data, including age, race, sex, number of comorbidities, type of admission (non-elective, elective), hospital bed size, hospital teaching status, hospital location, type of insurance, discharge disposition, length of stay (LOS), in-hospital mortality, and total hospital charges (TOTCHG), were extracted. Clinical variables, representing the known history of Acquired Immune Deficiency Syndrome (AIDS), alcohol abuse, deficiency anemia, rheumatoid diseases, chronic blood loss anemia, congestive heart failure, chronic pulmonary disease, coagulopathy, depression, diabetes (uncomplicated), diabetes (with chronic complications), drug abuse, hypertension, hypothyroidism, liver disease, lymphoma, fluid and electrolyte disorders, metastatic cancer, neurological disorders, obesity, paralysis, peripheral vascular disorders, psychoses, pulmonary circulation disorders, renal failure, solid tumor without metastasis, peptic ulcer disease, valvular disease, and weight loss, were obtained using ICD-9-CM and ICD-10-CM diagnosis codes (Table 1). Patients were categorized into two groups: CPAP and no-CPAP, based on the presence of ICD-9-CM procedure code 93.90 and ICD-10-CM procedure codes 5A09357, 5A09457, and 5A09557. Patients younger than 18 years or those with missing data were excluded from this research (Figure 1).

Table 1

Variables categoriesSpecific variables
Patient demographicsAge (≤64 years and ≥65 years), sex (male and female), race (White, Black, Hispanic, Asian or Pacific Islander, Native American and Other), number of Comorbidity
Hospital characteristicsType of admission (non-elective, elective), bed size of hospital (small, medium, large), teaching status of hospital (nonteaching, teaching), location of hospital (rural, urban), type of insurance (Medicare, Medicaid, private insurance, self-pay, no charge, other), location of the hospital (northeast, Midwest or north central, south, west), disposition (routine, transfer to short-term, hospital, transfer other, HHC, AMA, died in hospital, discharged alive), TOTCHG, LOS
ComorbiditiesAIDS, alcohol abuse, deficiency anemia, rheumatoid diseases, chronic blood loss anemia, congestive heart failure, chronic pulmonary disease, coagulopathy, depression, diabetes (uncomplicated), diabetes (with chronic complications), drug abuse, hypertension, hypothyroidism, liver disease, lymphoma, fluid and electrolyte disorders, metastatic cancer, neurological disorders, obesity, paralysis, peripheral vascular disorders, psychoses, pulmonary circulation disorders, renal failure, solid tumor without metastasis, peptic ulcer disease, valvular disease and weight loss

Variables used in binary logistic regression analysis.

AIDS, acquired immunodeficiency syndrome.

Figure 1

Outcomes

Outcomes assessed in this study included discharge disposition, in-hospital mortality, TOTCHG, LOS, and in-hospital complications. In-hospital complications were categorized as neurological complications (seizure, intracranial hemorrhage, receipt of thrombolysis, receipt of mechanical thrombectomy) and medical complications (sepsis, acute myocardial infarction, deep vein thrombosis, pulmonary embolism, cardiac arrest, acute kidney injury, pneumonia, urinary tract infection).

Statistical analysis

Patients with AIS-OSA were identified using ICD-9 and ICD-10-CM codes. This cohort was subsequently stratified into two groups based on the administration of CPAP therapy during hospitalization. Continuous variables are presented as median and interquartile range (IQR). Categorical variables are presented as frequencies and percentages. Comparisons of demographics, clinical characteristics, and outcomes between the groups were conducted using the Mann–Whitney U test for continuous variables and the chi-square test or Fisher’s exact test, as appropriate, for categorical variables. Regression analyses were performed to identify statistically significant factors associated with CPAP therapy and to evaluate the association between CPAP therapy and the specified outcomes, after adjusting for identified confounding variables. All statistical comparisons were two-tailed, and statistical significance was defined as a p-value less than 0.05 (p < 0.05). Statistical analyses were performed using SPSS software, version 25 (IBM Corp., Armonk, NY).

Results

Incidence of CPAP in AIS-OSA patients

Between 2010 and 2019, a total of 106,061 patients with AIS-OSA were identified in the NIS database. Following the exclusion of patients who did not meet the prespecified inclusion criteria, a final cohort of 103,004 AIS-OSA patients was included in the analysis. Among these, 6,478 patients received CPAP treatment during hospitalization, yielding a CPAP utilization rate of 6.3% (Table 2). The data showed that the utilization rate of CPAP remained relatively consistent throughout the study period from 2010 to 2019 (Figure 2). Among AIS-OSA patients who received CPAP treatment, 75.4% were treated for less than 24 h, 15.6% for 24–96 h, and 9.1% for more than 96 h (Figure 3).

Table 2

CharacteristicsCPAPNo CPAPp
Total (n = count)6,47696,528
Total incidence (%)6.3%
Age (median, years)68 (60,76)69 (60, 77)0.016
Age group (%)
18–444.43.50.002
45–6433.233.3
65–7432.632.5
≥7529.830.7
Gender (%)
Male63.562.70.163
Female36.537.3
Race (%)
White71.273.9<0.001
Black15.212.1
Hispanic5.64.5
Asian or Pacific Islander1.71.1
Native American0.40.4
Other5.98.0
Number of comorbidity (%)
00.31.0<0.001
13.16.0
28.413.5
≥388.179.5
LOS (median, d)6 (3–11)4 (2–7)<0.001
TOTCHG (median, $)62003.0 (31820.3–124985.8)37725.5 (21830.0–71796.0)<0.001
Type of insure (%)
Medicare65.766.8<0.001
Medicaid8.06.3
Private insurance21.422.2
Self-pay2.02.3
No charge0.10.2
Other2.82.2
Bed size of hospital (%)
Small12.413.60.001
Medium25.126.2
Large62.560.3
Elective admission (%)12.116.6<0.001
Type of hospital (teaching %)67.562.6<0.001
Location of hospital (urban, %)93.892.0<0.001
Region of hospital (%)
Northeast19.813.2<0.001
Midwest or North Central25.330.1
South38.440.1
West16.616.6
Disposition
Routine43,773 (45.3%)1,985 (30.7%)0.001
Transfer to short-term hospital2,771 (2.9%)227 (3.5%)
Transfer other31,863 (33.0%)2,760 (42.6%)
Home Health Care (HHC)14,284 (14.8%)1,028 (15.9%)
Against medical advice (AMA)474 (0.5%)25 (0.4%)
Died in hospital446 (6.9%)3,325 (3.4%)
Discharged alive38 (0.0%)5 (0.1%)

AIS-OSA patient and hospital characteristics (2010–2019).

LOS, length of stay; TOTCHE, total charge.

Figure 2

Figure 3

Demographics and hospital characteristics

Patients who received CPAP were statistically significantly younger compared to those who did not (median age 68 years vs. 69 years, p = 0.016). The age distribution also differed statistically significantly between the two groups, with the CPAP group exhibiting a higher proportion of patients aged 18–44 years (4.4% vs. 3.5%) and 65–74 years (32.6% vs. 32.5%, p = 0.002) (Table 2). Furthermore, a statistically significant difference was observed in the race distribution: Black (15.2% vs. 12.1%), Hispanic (5.6% vs. 4.5%), and Asian or Pacific Islander (1.7% vs. 1.1%) patients comprised slightly larger proportions in the CPAP group (p < 0.001) (Table 2). AIS-OSA patients treated with CPAP were more likely to have more than three comorbidities (88.1% vs. 79.5%, p < 0.001). Moreover, patients receiving CPAP had a statistically significantly higher likelihood of using Medicaid as their primary insurance (8.0% vs. 6.3%, p < 0.001) (Table 2).

The geographic distribution of patients exhibited marked variability. A greater proportion of AIS-OSA patients receiving CPAP were treated at large hospitals (62.5% vs. 60.3%, p = 0.001), hospitals located in the Northeast region (19.8% vs. 13.2%, p < 0.001), and urban hospitals (93.8% vs. 92.0%, p < 0.001). Most patients in both cohorts were treated at teaching hospitals (67.5% vs. 62.6%, p < 0.001). Notably, AIS-OSA patients receiving CPAP treatment were less likely to have elective admissions (12.1% vs. 16.6%, p < 0.001). The baseline characteristics of the study cohorts are summarized in Table 2.

In-hospital quality measures and disposition

Patients with AIS-OSA who received CPAP exhibited a statistically significant increase in the median LOS (6 days [IQR, 3–11 days] vs. 4 days [IQR, 2–7 days], odds ratio [OR]: 2.68 (95% confidence interval [CI], 2.6–2.8), p < 0.001) compared to patients who did not receive CPAP. Consequently, CPAP treatment was associated with elevated medical expenditures. Specifically, the median hospitalization costs for patients receiving CPAP were substantially higher, with total hospital charges amounting to $62,003 (IQR, $31,820–$124,986) compared to $37,726 (IQR, $21,830–$71,796) for those without CPAP (p < 0.001) (Table 2). Among patients who survived to discharge, those with AIS-OSA who received CPAP had a statistically significantly greater proportion discharged to routine care (45.3% vs. 30.7%, p < 0.001) (Table 2). Furthermore, among all AIS-OSA patients, CPAP treatment during hospitalization was found to statistically significantly increase the odds of in-hospital mortality (6.9% vs. 3.4%, p < 0.001) (Table 2).

Risk factors associated with CPAP in AIS-OSA patients

Logistic regression analysis was employed to identify risk factors associated with CPAP treatment, revealing the following statistically significant predictors: advanced age (≥65 years, OR: 1.13, 95% CI: 1.1–1.2), Black race (OR: 1.13, 95% CI: 1.1–1.2), more than three comorbidities (OR: 1.73, 95% CI: 1.1–2.7) (Table 3), deficiency anemia (OR: 1.27, 95% CI: 1.2–1.4), congestive heart failure (OR: 1.34, 95% CI: 1.3–1.4), chronic pulmonary disease (OR: 1.43, 95% CI: 1.4–1.5), coagulopathy (OR: 1.32, 95% CI: 1.2–1.5), fluid and electrolyte disorders (OR: 1.62, 95% CI: 1.5–1.7), other neurological disorders (OR: 1.36, 95% CI: 1.3–1.5), obesity (OR: 1.60, 95% CI: 1.5–1.7), paralysis (OR: 1.11, 95% CI: 1.0–1.2), psychoses (OR: 1.14, 95% CI: 1.0–1.3), pulmonary circulation disorders (OR: 1.25, 95% CI: 1.1–1.4), and weight loss (OR: 1.20, 95% CI: 1.1–1.4) (Table 4). Protective factors identified included treatment at a hospital in the Midwest or North Central region (OR: 0.52, 95% CI: 0.5–0.6), a history of AIDS (OR: 0.21, 95% CI: 0.0–0.9), rheumatoid arthritis (OR: 0.82, 95% CI: 0.7–1.0), and hypertension (OR: 0.90, 95% CI: 0.8–1.0) (Table 4).

Table 3

VariableMultivariate Logistic Regression
OR95% CIp
Age ≥65 years old1.1251.049–1.2060.001
Female0.8500.804–0.900<0.001
Race
WhiteRef
Black1.1331.049–1.2240.002
Hispanic1.1791.051–1.3220.005
Asian or Pacific Islander1.5991.303–1.962<0.001
Native American0.9610.643–1.4370.847
Other0.8400.753–0.9380.002
Number of comorbidity
0Ref
11.5881.014–2.4850.043
21.6871.090–2.6090.019
≥31.7271.116–2.6710.014
Type of insurance
MedicareRef
Medicaid1.1521.031–1.2880.012
Private insurance1.0821.003–1.1670.041
Self-pay0.9420.779–1.1380.534
No charge0.8120.412–1.6010.548
Other1.3211.125–1.5520.001
Bed size of hospital
SmallRef
Medium1.0310.944–1.1270.494
Large1.1791.089–1.277<0.001
Elective admission0.8120.750–0.878<0.001
Teaching hospital1.1771.108–1.250<0.001
Urban hospital1.0980.981–1.2300.104
Region of hospital
NortheastRef
Midwest or North Central0.5190.480–0.561<0.001
South0.6050.563–0.651<0.001
West0.6170.565–0.674<0.001
Disposition
RoutineRef
Transfer to short-term hospital1.8171.576–2.094<0.001
Transfer other1.9061.796–2.023<0.001
Home Health Care (HHC)1.5851.467–1.713<0.001
Against medical advice (AMA)1.1600.774–1.7390.472
Died in hospital2.9442.641–3.281<0.001
Discharged alive2.8951.138–7.3620.026

CPAP-associated risk factors in AIS-OSA patients.

AIDS, acquired immunodeficiency syndrome; OR, odds ratio; CI, confidence interval.

Table 4

ComorbiditiesUnivariate analysisMultivariate logistic regression
No CPAPCPAPpOR95% CIp
Acquired immune deficiency syndrome115 (0.1%)2 (0.0%)0.0410.210.05–0.870.031
Alcohol abuse2,943 (3.0%)240 (3.7%)0.0031.100.96–1.270.175
Deficiency anemia12,059 (12.5%)1,087 (16.8%)<0.0011.271.18–1.36<0.001
Rheumatoid arthritis/collagen vascular diseases2,945 (3.1%)159 (2.5%)0.0070.820.70–0.970.017
Chronic blood loss anemia666 (0.7%)52 (0.8%)0.2900.980.73–1.300.863
Congestive heart failure21,673 (22.5%)2,096 (32.4%)<0.0011.341.27–1.43<0.001
Chronic pulmonary disease30,350 (31.4%)2,644 (40.8%)<0.0011.431.35–1.51<0.001
Coagulopathy5,300 (5.5%)557 (8.6%)<0.0011.321.20–1.45<0.001
Depression16,517 (17.1%)1,078 (16.6%)0.3360.990.92–1.060.683
Diabetes, uncomplicated32,699 (33.9%)2,199 (34.0%)0.8941.010.95–1.070.798
Diabetes with chronic complications19,288 (20.0%)1,525 (23.5%)<0.0011.000.94–1.080.924
Drug abuse1,874 (1.9%)167 (2.6%)<0.0011.120.95–1.330.177
Hypertension83,047 (86.0%)5,507 (85.0%)0.0250.900.83–0.970.004
Hypothyroidism15,631 (16.2%)981 (15.1%)0.0270.930.87–1.000.058
Liver disease2,418 (2.5%)207 (3.2%)0.0011.030.88–1.190.737
Lymphoma576 (0.6%)44 (0.7%)0.4051.040.76–1.430.792
Fluid and electrolyte disorders22,249 (23.0%)2,355 (36.4%)<0.0011.621.53–1.72<0.001
Metastatic cancer1,085 (1.1%)85 (1.3%)0.1661.010.81–1.280.908
Other neurological disorders10,906 (11.3%)1,115 (17.2%)<0.0011.361.27–1.46<0.001
Obesity37,679 (39.0%)3,319 (51.3%)<0.0011.601.51–1.69<0.001
Paralysis18,460 (19.1%)1,459 (22.5%)<0.0011.111.04–1.180.001
Peripheral vascular disorders16,835 (17.4%)1,112 (17.2%)0.5800.970.91–1.040.436
Psychoses3,719 (3.9%)299 (4.6%)0.0021.141.01–1.290.042
Pulmonary circulation disorders5,779 (6.0%)598 (9.2%)<0.0011.251.14–1.37<0.001
Renal failure23,161 (24.0%)1,886 (29.1%)<0.0011.061.00–1.130.062
Solid tumor without metastasis2,128 (2.2%)164 (2.5%)0.0831.050.89–1.240.567
Peptic ulcer disease excluding bleeding201 (0.2%)17 (0.3%)0.3581.050.64–1.740.846
Valvular disease10,714 (11.1%)773 (11.9%)0.0380.940.87–1.020.161
Weight loss2,962 (3.1%)323 (5.0%)<0.0011.201.06–1.360.003

Relationship between CPAP treatment and disease comorbidities.

OR, odds ratio; CI, confidence interval.

Risk adjusted for patient characteristics and hospital characteristics, including age, sex, race, number of comorbidity, type of admission, bed size of hospital, teaching status of hospital, location of hospital, type of insurance, location of the hospital.

Factors associated with CPAP in AIS-OSA patients

Among patients with AIS-OSA, CPAP treatment during hospitalization was associated with increased odds of developing sepsis (OR: 2.32; 95% CI: 2.1–2.6), pneumonia (OR: 2.53; 95% CI: 2.4–2.7), acute myocardial infarction (OR: 1.74; 95% CI: 1.5–1.9), deep vein thrombosis (OR: 1.81; 95% CI: 1.6–2.1), pulmonary embolism (OR: 1.58; 95% CI: 1.3–1.9), cardiac arrest (OR: 1.60; 95% CI: 1.3–2.0), acute kidney injury (OR: 1.94; 95% CI: 1.8–2.1), urinary tract infection (OR: 1.42; 95% CI: 1.3–1.5), intracranial hemorrhage (OR: 1.57; 95% CI: 1.4–1.8), receipt of thrombolysis (OR: 1.29; 95% CI: 1.1–1.5), and receipt of mechanical thrombectomy (OR: 1.41; 95% CI: 1.2–1.7) (Table 5).

Table 5

ComplicationsUnivariate analysisMultivariate logistic regression
No CPAPCPAPpOR95% CIp
Medical complications
Sepsis3,789 (3.9%)561 (8.7%)<0.0012.322.12–2.55<0.001
AMI4,676 (4.8%)527 (8.1%)<0.0011.741.58–1.91<0.001
Deep vein thrombosis1,618 (1.7%)194 (3.0%)<0.0011.811.56–2.11<0.001
pulmonary embolism977 (1.0%)103 (1.6%)<0.0011.581.29–1.94<0.001
Cardiac arrest986 (1.0%)105 (1.6%)<0.0011.601.30–1.96<0.001
AKI15,087 (15.6%)1,713 (26.5%)<0.0011.941.83–2.06<0.001
Pneumonia7,000 (7.3%)1,069 (16.5%)<0.0012.532.36–2.71<0.001
UTI8,661 (9.0%)795 (12.3%)<0.0011.421.31–1.53<0.001
Neurological complications
Seizure4,011 (4.2%)299 (4.6%)0.0721.120.99–1.260.073
Intracranial hemorrhage3,068 (3.2%)319 (4.9%)<0.0011.571.40–1.77<0.001
Thrombolysis2,557 (2.6%)219 (3.4%)<0.0011.291.12–1.48<0.001
MT1,637 (1.7%)154 (2.4%)<0.0011.411.20–1.67<0.001
Die in hospital3,325 (3.4%)446 (6.9%)<0.0012.071.87–2.30<0.001
LOS6 (3–11)4 (2–7)<0.0012.682.55–2.82<0.001
TOTCHG62,003 (31,820–124, 986)37,726 (21,830–1,796)<0.0012.412.29–2.54<0.001

Relationship between CPAP treatment and complications.

OR, odds ratio; CI, confidence interval; AKI, acute kidney injury; UTI, urinary tract infection; MT, mechanical thrombectomy; AMI, acute myocardial infarction.

Discussion

A large international case–control study demonstrated a statistically significant association between sleep impairments and the risk of acute stroke (, ). OSA is a well-established risk factor for AIS (). A meta-analysis revealed that OSA is present in up to 70% of stroke and transient ischemic attack patients (). Despite its high prevalence, only a small proportion of stroke patients undergo OSA testing and receive treatment (). According to a cross-sectional study using NIS data, the documented incidence of OSA in acute cerebral infarction patients was 3.1% (). In our retrospective analysis, we identified 103,004 hospitalized AIS-OSA patients between 2010 and 2019, of whom 6,476 (6.3%) received CPAP treatment (Figure 2). Among AIS-OSA patients who received CPAP treatment, most of patients (75.4%) were treated for less than 24 h (Figure 3). However, these aggregate treatment durations do not reflect patients’ adherence to CPAP and are therefore uninformative for assessing therapeutic efficacy (). As administrative codes do not capture why CPAP was withheld, its absence in the non-CPAP group could reflect patient intolerance, refusal, contraindications, or unavailability of equipment during hospitalization, but these reasons cannot be ascertained from the NIS.

While a correlation exists between OSA and stroke, it remains unclear whether varying demographic characteristics or clinical factors influence outcomes in patients with AIS-OSA (). CPAP is the gold standard for OSA treatment, though its efficacy in AIS-OSA patients remains uncertain (, ). Understanding the risk factors affecting CPAP treatment in AIS-OSA patients is crucial for effective disease management.

In this study, patients with AIS-OSA who received CPAP exhibited higher in-hospital mortality, longer LOS, greater TOTCHG, and a different distribution of discharge dispositions (Table 2). These findings were consistent with reports from other national hospital discharge databases (). We also found that AIS-OSA patients treated with CPAP had more than three comorbidities (Table 2). These comorbidities (e.g., sepsis, heart failure, pneumonia) were pre-existing conditions present before the initiation of CPAP treatment, reflecting a greater baseline burden of illness. Compared to non-CPAP-treated patients, those receiving CPAP had higher in-hospital mortality, longer LOS, and greater TOTCHG. However, among surviving CPAP-treated patients, a statistically significantly higher proportion were discharged routinely (Table 2), suggesting that CPAP may be associated with better prognoses and improved neurological recovery at discharge in this subgroup. This paradox also may reflect selection and survivorship biases: patients able to tolerate or be offered CPAP may have been less neurologically impaired at baseline (we lacked NIHSS or GCS data), whereas the most severe cases, who could not tolerate or were never selected for CPAP, died earlier and were thus excluded from the denominator of survivors eligible for discharge. OSA can induce hypercapnia, which paradoxically reduces blood flow to ischemic brain regions while increasing perfusion to unaffected cerebral vessels (). In AIS patients, inadequate perfusion of the ischemic penumbra leads to neurological damage and functional decline (, ). CPAP treatment may help prolong the survival time of the ischemic penumbra, promote neuronal functional recovery, and reduce the risk of neurological deterioration. Furthermore, CPAP improves sleep quality and oxygen saturation by providing pressure support to maintain upper airway patency during sleep (). It also exerts multifaceted effects on stroke pathophysiology, including modulation of neuronal apoptosis, mitochondrial bioenergetics, oxidative stress, angiogenesis, glucose metabolism, and blood–brain barrier regulation (, ).

Our investigation revealed older age (≥ 65 years) and male sex as independent risk factors for CPAP treatment (Figures 4A,B). While OSA can manifest across all ages, its prevalence increases with age, tending to plateau after approximately 65 years (). A significant predominance of OSA in men has been observed (), with hormonal influences on breathing control and upper airway muscle activation during sleep, as well as sex-specific fat distribution, appearing to contribute to this disparity (, ). The analysis indicated a higher incidence of CPAP treatment among Black, Hispanic, and Asian or Pacific Islander individuals (Figures 4C,D). The African American race is associated with untreated OSA and serves as an independent predictor for stroke and elevated all-cause mortality, even after adjusting for cardiovascular risk factors, compared to White individuals (). The prevalence of diagnosed OSA is notably elevated among racial/ethnic minorities, and rates of undiagnosed OSA are particularly high within these groups (). Factors such as a higher likelihood of residing in economically deprived neighborhoods, statistically significantly greater rates of obesity, and increased prevalence of hypertension () contribute to the severity of OSA and influence CPAP usage, consistent with other studies. Glaucylara et al. () reported increased levels of cardiovascular risk factors associated with OSA, including elevated neutrophil counts, an inflammatory marker, which was strongly associated with men, younger individuals, and African American individuals. One study suggested that OSA patients exhibiting phenotypes associated with age, gender, BMI, and sleep apnea severity demonstrate slightly higher CPAP usage ().

Figure 4

Our study revealed a higher likelihood of receiving CPAP treatment in northeastern hospitals (Figures 4E,F), a finding consistent with previous literature. Levi Dunietz et al. reported statistically significant state-level and regional disparities in both CPAP treatment and adherence among Medicare beneficiaries with OSA suggest gaps in delivery of OSA care for Americans (). These gaps may stem from demographic differences, including racial variation, as well as from socioeconomic status, urbanicity, and access to accredited sleep centers (). Patients receiving CPAP were more likely to be Medicaid beneficiaries (Figures 4G,H), possibly due to the higher healthcare costs associated with CPAP-treated patients (, ) and their increased likelihood of belonging to racial/ethnic minority groups residing in economically deprived regions (, ). CPAP treatment was also more prevalent in large hospitals compared to small ones (Figures 4I,J), potentially attributable to the complexity of care and the higher patient volume in larger institutions (46).

In this study, acquired immune deficiency syndrome, deficiency anemia, congestive heart failure, chronic pulmonary disease, coagulopathy, fluid and electrolyte disorders, other neurological disorders, paralysis, psychoses, pulmonary circulation disorders, obesity, alcohol abuse, drug abuse, and weight loss were associated with CPAP treatment; however, these associations do not imply causation (Figure 5). Given the interconnected nature of stroke and sleep apnea, with numerous shared risk factors and comorbidities, it remains uncertain at an individual level whether sleep apnea is a potential cause or a consequence of stroke (, ). Obesity, pulmonary circulation disorders, hypertension, diabetes, and other comorbidities are consistently reported in patients with stroke diagnosed with obstructive sleep apnea (, ). All these factors influence the severity of the disease and, consequently, CPAP treatment. In cases of severe OSA, treatment is essential, and CPAP is the recommended first-line therapy ().

Figure 5

Patient-related factors associated with CPAP treatment in our study included sepsis, pneumonia, acute myocardial infarction, deep vein thrombosis, pulmonary embolism, cardiac arrest, acute kidney injury, urinary tract infection, intracranial hemorrhage, thrombolysis, and mechanical thrombectomy (Figure 6). Prior research has indicated that prolonged mechanical ventilation is associated with a high incidence of thrombosis in critically ill patients despite prophylaxis (48). While a prospective randomized clinical trial (49) found that CPAP reduced early pulmonary infection rates and endotracheal intubation rates, our study demonstrated that CPAP treatment was associated with an increased incidence of lung infection. This discrepancy may be attributable to the possibility that CPAP-treated patients in our cross-sectional study presented with more complications, more severe underlying conditions, and a higher predisposition to developing lung infections. Our findings suggest that AIS patients receiving CPAP treatment were more likely to undergo mechanical thrombectomy or thrombolysis and experience acute myocardial infarction or cardiac arrest, potentially due to OSA’s capacity to induce pathological cardiac and cerebrovascular effects (50), and the potential for ischemic stroke lesions in critical areas regulating airway patency or breathing effort to exacerbate sleep apnea ().

Figure 6

The relationship observed between CPAP treatment and complications is associative rather than causal. Establishing a definitive causal link between CPAP and negative outcomes is inherently challenging due to the methodological limitations of observational and database studies. Patients receiving CPAP treatment frequently present with a higher burden of comorbidities or postoperative complications, which may represent the true underlying causes of adverse outcomes, rather than the CPAP treatment itself. While efforts are made to adjust for these confounding factors, a direct causal relationship cannot be definitively established. Notably, a meta-analysis of randomized trials indicated that early CPAP treatment demonstrated no effect, whereas CPAP treatment initiated beyond 7 days showed beneficial effects (). Given that conventional CPAP treatment may not invariably be beneficial and could potentially have adverse effects in specific patient populations, it is exceedingly important to consider a personalized approach to OSA treatment in AIS patients.

Further research is warranted to delineate the clinical characteristics of patients who would and would not derive benefit from CPAP treatment. Moreover, large-scale prospective trials are necessary to rigorously evaluate the risks and benefits of routine versus more selective CPAP application among patients with OSA in the setting of hospitalized AIS in general. Should these findings be corroborated in randomized prospective studies, a more selective treatment paradigm will be essential to improving mortality rates, reducing length of hospital stay, decreasing complications, and lowering associated healthcare expenditures.

While our findings offer valuable insights, several limitations inherent in our analysis warrant consideration. Firstly, our identification of OSA-AIS patients between 2010 and 2019 relied on ICD-9-CM/ICD-10-CM codes. This approach lacked comprehensive data regarding disease severity, as well as scores from the National Institutes of Health Stroke Scale (NIHSS), Glasgow Coma Scale (GCS), and Modified Rankin Scale (MRS). Without these metrics we were unable to adjust for baseline neurological impairment, which is a strong predictor of mortality and functional outcome. To partially address this limitation, we included the comorbidity “other neurological disorders” as a proxy indicator of pre-existing neurological disease burden; nevertheless, this surrogate cannot fully capture acute stroke severity, and residual confounding may remain. Furthermore, because the database contains no information on the timing of CPAP initiation (early versus late), actual adherence during hospitalization, or any pre-admission CPAP treatment, we cannot separate the true effect of CPAP from these unmeasured factors (, 51), any observed associations may therefore reflect timing, adherence, or prior exposure rather than the treatment itself. Secondly, our analysis is further constrained by the absence of device-specific information in the NIS. Knowing whether patients received fixed-level or auto-titrating CPAP (the actual pressure settings) is essential for interpreting any outcome differences (52). Moreover, the beneficial effects of CPAP are highly dependent on adequate adherence: prior work has shown that nightly use of ≥4 h was considered adherent (53). Because the NIS does not record mask-on time or device-download data, we cannot determine whether the observed associations were diluted by sub-therapeutic or intermittent in-hospital use. Thirdly, the inherent challenges associated with incomplete or inaccurate database records and the absence of randomization, characteristic of our study’s retrospective design, introduce a higher risk of unidentifiable confounding factors that could influence the observed results. Fourthly, our study data were derived from the NIS, a United States in-hospital database, which may introduce selection bias due to the exclusion of data from outpatient, nursing home, and global settings. While our larger sample size helps to mitigate the impact of these errors, these limitations should be acknowledged. Despite these constraints, the consistency of our results with previous studies lends further credence to our findings.

Conclusion

Our findings indicate that hospitalized AIS-OSA patients treated with CPAP experienced increased in-hospital mortality, LOS, and TOTCHG. However, among the surviving CPAP-treated patients, a statistically significantly higher proportion experienced routine discharge. This observation may suggest that surviving patients who received CPAP treatment had more favorable prognoses. We also identified independent predictors and associated factors for CPAP treatment in hospitalized AIS-OSA patients. Randomized controlled trials specifically focusing on AIS-OSA patients within various high-risk groups are necessary to refine the current consensus regarding the initiation of CPAP in the acute setting.

Statements

Data availability statement

The datasets presented in this study can be found in online repositories. The names of the repository/repositories and accession number(s) can be found at: https://www.hcup-us.ahrq.

Ethics statement

Ethical approval was not required for the studies involving humans. The studies were conducted in accordance with the local legislation and institutional requirements. Written informed consent for participation was not required from the participants or the participants’ legal guardians/next of kin in accordance with the national legislation and institutional requirements. Written informed consent was not obtained from the individual(s) for the publication of any potentially identifiable images or data included in this article because as the NIS dataset does not directly involve human subjects (consistent with federal regulations and guidance), it is exempt from institutional review board approval.

Author contributions

YZ: Writing – review & editing, Writing – original draft. CZ: Writing – review & editing. MQ: Writing – review & editing. HW: Writing – review & editing. JH: Writing – review & editing. XL: Writing – review & editing. HX: Writing – review & editing. QW: Writing – original draft, Writing – review & editing.

Funding

The author(s) declare that no financial support was received for the research and/or publication of this article.

Acknowledgments

We acknowledge the Healthcare Cost and Utilization Project (HCUP) and the participating U.S. Hospitals for creating and maintaining the Nationwide Inpatient Sample. We are grateful to our departmental biostatistics team for methodological guidance and to our colleagues for helpful discussions during the preparation of this manuscript.

Conflict of interest

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Generative AI statement

The authors declare that no Gen AI was used in the creation of this manuscript.

Any alternative text (alt text) provided alongside figures in this article has been generated by Frontiers with the support of artificial intelligence and reasonable efforts have been made to ensure accuracy, including review by the authors wherever possible. If you identify any issues, please contact us.

Publisher’s note

All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.

Abbreviations

AIS, acute ischemic stroke; OSA, obstructive sleep apnea; CPAP, continuous positive airway pressure; AIS-OSA, acute ischemic stroke and comorbid obstructive sleep apnea; NIS, Nationwide Inpatient Sample; HCUP, Healthcare Cost and Utilization Project; AHRQ, Agency for Healthcare Research and Quality; CD-9-CM, International Classification of Diseases, Ninth Revision, Clinical Modification; ICD-10-CM, International Classification of Diseases, Tenth Revision, Clinical Modification; LOS, length of stay; TOTCHG, total hospital charges; AIDS, acquired immune deficiency syndrome; IQR, interquartile range; NIHSS, National Institutes of Health Stroke Scale; GCS, Glasgow Coma Scale; MRS, Modified Rankin Scale.

References

Summary

Keywords

obstructive sleep apnea, acute ischemic stroke, continuous positive airway pressure, outcomes, Nationwide Inpatient Sample, routine discharge

Citation

Zeng Y, Zheng C, Qi M, Wang H, He J, Li X, Xie H and Wang Q (2025) Continuous positive airway pressure in acute ischemic stroke patients with obstructive sleep apnea: analysis of the National Inpatient Sample database. Front. Neurol. 16:1624631. doi: 10.3389/fneur.2025.1624631

Received

03 June 2025

Accepted

20 October 2025

Published

04 November 2025

Volume

16 - 2025

Edited by

Gilbert Seda, Scripps Mercy Hospital, United States

Reviewed by

Ahmet Cemal Pazarlı, Gaziosmanpaşa University, Türkiye

Fanwen Meng, National Healthcare Group Health Services and Outcomes Research, Singapore

Updates

Copyright

*Correspondence: Qin Wang,

Disclaimer

All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher.

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