Obstructive sleep apnea treatment disparities among older adults with neurological disorders

Abstract

Objective

To characterize obstructive sleep apnea treatment patterns among older Americans with neurological conditions.

Setting and Participants

Claims data from a 5% fee-for-service sample of Medicare beneficiaries were analyzed to determine the proportion of older adults with OSA who received and were adherent to continuous positive airway pressure therapy, and examine potential gaps in OSA care among neurological populations. Logistic regression was used to determine whether gender or race/ethnicity modified the associations between neurological morbidities and OSA treatment or adherence.

Results

Data from n=102,618 beneficiaries with OSA were identified. The prevalence of stroke, cognitive disorders or Parkinson’s in this sample were 7%, 3% and 2% respectively. Overall, OSA-diagnosed individuals (73%) obtained treatment, and most treated were adherent to CPAP (72%). Lower proportions of OSA treatment and adherence were observed in neurological conditions, particularly stroke. In logistic regression models, gender and race/ethnicity each modified associations between neurological comorbidity and OSA treatment and adherence. Women as compared to men with a given neurological condition were uniformly less likely to receive CPAP or adhere to treatment (p<0.01 for each condition). Similarly, in comparison to whites with the same neurological condition, OSA treatment was significantly lower among all other races with stroke, and among blacks with cognitive disorders.

Conclusions

Older women and minorities with neurological conditions may be more vulnerable to gaps in OSA care. Targeted strategies to improve treatment disparities and neurological outcomes in older adults could be informed by these data.

INTRODUCTION

Obstructive sleep apnea (OSA) is a common condition that is associated with serious health and socioeconomic consequences. (1) Although continuous positive airway pressure (CPAP) effectively ameliorates OSA symptoms, (2–4) and is likely to lower risk of adverse health, functional, and neurological outcomes,(5–8) up to 50% of individuals with OSA do not consistently use CPAP on a regular or optimal basis.(9–11)

Prior studies, largely comprised of middle-aged individuals, have provided some insight into CPAP adherence patterns and disparities that may drive gaps in treatment.(12, 13) However, little is known about CPAP adherence or treatment disparities among older individuals - a population that may disproportionately experience OSA and many of its consequences. Up to 56% of older Americans may suffer from OSA, even though the majority remain undiagnosed. (1) Older individuals are also more likely to suffer from neurological disorders such as stroke and dementia – conditions that are independently associated with a high prevalence of OSA. (14–16) Indeed, OSA is prevalent in 50–70% of stroke patients and among 50% of those with dementia. (17, 18) Furthermore, untreated OSA may contribute to poor functional outcomes in neurological disorders; (19–22) yet, data on possible treatment and treatment adherence disparities among subgroups of older Americans with OSA, particularly subgroups with concomitant neurological disorders, are lacking. This gap in knowledge is magnified by a dearth of information on gender and racial disparities in OSA care. Women and blacks with neurological disease may separately experience worse neurological outcomes, yet the role that gender and race may play in the relationship between OSA and functional outcomes in older persons is not well understood. To optimize neurological outcomes for older Americans, an improved understanding of the scope and treatment patterns of OSA among older persons is necessary. The overarching aim of this investigation was quantify gaps in OSA treatment patterns among Medicare beneficiaries, including potential disparities in OSA treatment and adherence to CPAP therapy among Medicare beneficiaries with neurological conditions.

PARTICIPANTS AND METHODS

We performed a retrospective cross-sectional study of a representative 5% sample of all Medicare beneficiaries. All study procedures were approved by the University of Michigan Institutional Review Board (IRBMED).

Data were obtained from 2,758,197 older Americans (aged 65 or older), derived from a 5% random sample of Medicare beneficiaries from the Medicare Beneficiary Summary File (2011–2013 files). Of the total 5% sample, we selected individuals with OSA, defined as one or more OSA diagnosis codes in any position in the Medicare carrier file. (N=102,618, Table 1, Figure 1).

Table 1:

OSA diagnosis (ICD-9-CM codes) and treatment/adherence (PAP HCPCS codes) from claims files

OSA Diagnosis	327.23 (OSA)
	327.20 (organic sleep apnea, unspecified)
	780.57 (unspecified sleep apnea)
	780.53 (hypersomnia with sleep apnea, unspecified)
INITIAL “Treatment”	E0601 (CPAP, auto CPAP)
	E0470 (ResMed S9VPAP Adapt)
	E0470 (Bilevel, auto bilevel)
	E0471 (Bilevel with backup rate)
	E0562 (heated humidifier
	A7034 (nasal mask)
	A7035 (headgear)
	A7033 (nasal pillows)
	A7032 (nasal cushion)
	A7031 (full cushion)
	A7028 (oral cushion)
	A7027 (comb oral/nasal mask)
	A7036 (chin strap)
	A7037 (Tubing)
	A4604 (heated tubing)
	A7039 (washable filters)
	A7038 (disposable filters)
	A7046 (humid chamber)
Subsequent “Adherence”	A7035 (headgear)
	A7034 (nasal mask)
	A7033 (nasal pillows)
	A7032 (nasal cushion)
	A7031 (full cushion)
	A7028 (oral cushion)
	A7027 (comb oral/nasal mask)
	A7036 (chin strap)
	A7037 (Tubing)
	A4604 (heated tubing)
	A7039 (washable filters)
	A7038 (disposable filters)
	A7046 (humid chamber)

Figure 1:

Obstructive sleep apnea, treatment and adherence to treatment in Medicare beneficiaries

Treatment to OSA and Treatment Adherence

Beneficiaries were labelled as “treated” with CPAP based on the presence of one or more CPAP HCPCS codes, indicating an initial prescription for CPAP equipment, in the Medicare Durable Medical Equipment file. These HCPCS codes are exclusively used for CPAP equipment.

Beneficiaries were considered “adherent” to CPAP treatment, if 2 or more HCPCS claims for CPAP supplies, separated by 1 month or more (for example, filters, cushions, masks, or tubing), were present (Table 1).

Comorbidities and Demographic Characteristics

Neurological comorbidities of interest among beneficiaries with OSA, i.e. stroke, cognitive disorders (the combination of mild cognitive impairment and Alzheimer’s disease), and Parkinson’s disease, were identified using one inpatient code or two outpatient ICD-9 codes. Additional comorbidities and demographic data were extracted from Medicare files for multivariate analyses included hypertension, type 2 diabetes, cardiovascular disease, and depression (Table 2). Demographic information, i.e. age, gender, race/ethnicity, and state and county of residence, were also obtained from Medicare files. We combined state and county of residence to create a unique regions that were used to account for geographical clustering.

Table 2:

ICD-9-CM codes for comorbidities of interest among Medicare beneficiaries

Comorbidity of interest	Variable name	ICD-9 code
Stroke/cerebrovascular disease	stroke	431, 433.x1, 434.x1, 436
Parkinson’s	Park	332
Mild cognitive impairment	MCI	331.83
Alzheimer’s dementia	AD	331.0
Hypertension	HTN	401.x, 402–405.x
Acute myocardial infarction	AMI	410, 410.9
Cardiac arrhythmias	ARR	426.0, 426.13, 426.7, 426.9, 426.10, 426.12 427.0–427.4, 427.6–427.9, 785.0, 996.01 996.04, V45.0, V53.3
Congestive heart failure	CHF	398.91, 402.01, 402.11, 402.91, 404.01, 404.03, 404.11, 404.13, 404.91, 404.93 425.4–425.9, 428.x
Diabetes mellitus, with or without complication	DM	648.0, 249.0, 250.0–250.3, 250.4–250.7, 250.8, 250.9
Depression	DEP	296.2, 296.3, 296.5, 300.4, 309.x, 311
Multiple sclerosis	MS	340

Statistical Analysis

Descriptive statistics were used to characterize the frequencies and proportions of Medicare beneficiaries who were: 1) prescribed CPAP treatment following an OSA diagnosis; and 2) adherent with CPAP. We then estimated the frequencies and proportions of demographic and health characteristics within the same beneficiary subgroups, with a focus on three common comorbid neurological conditions associated with OSA: stroke, mild cognitive impairment or Alzheimer’s disease, and Parkinson’s disease.

Logistic regression was used to determine whether gender or race/ethnicity modified the associations between neurological morbidities and OSA treatment or adherence. Specifically, we fitted regression models with each neurological comorbidity (stroke, MCI or Parkinson’s disease) as the independent variable, and OSA treatment or treatment adherence as two separate outcomes. In each of these models we included one interaction term – gender or race/ethnicity – with the neurological comorbidity, to examine their joint effects on OSA treatment and treatment adherence. To account for clustering of Medicare beneficiaries by state and county, we estimated the odds ratio and 95% confidence intervals with regression procedures for correlated data. In multivariate analyses we controlled for potential confounders, including age, hypertension, type 2 diabetes, cardiovascular disease, and depression. We further controlled for geographical differences in OSA treatment and treatment adherence. The interaction between gender or race/ethnicity and neurological morbidity was tested with type 3 Wald’s test. Finally, we conducted a comparison of treatment and treatment adherence among racial/ethnic groups with or without neurological comorbidities. SAS 9.4 (Cary, NC) was used for descriptive and regression analyses.

Data Availability Statement

Medicare data was released to the investigators under a data use agreement that precludes reuse or data sharing.

RESULTS

Within a sample of 2,758,197 older Americans, a total of 102,618 (3.7%) carried an OSA diagnosis and were included in this analyses. The majority of these beneficiaries (73%) received CPAP treatment, and of the treated beneficiaries, 72% met criteria to suggest adherence with their prescribed CPAP (Figure 1). This sample of Medicare beneficiaries with OSA diagnoses included mostly men, 74 years old or younger, and white. Common comorbidities in this group included hypertension, type 2 diabetes, cardiovascular disease (including arrhythmia, congestive heart failure, or acute myocardial infarction) and depression (Table 3). Stroke was prevalent in 7% of this sample, while cognitive disorders or Parkinson’s affected 3% and 2% of older adults with OSA, respectively. In Medicare beneficiaries with an OSA diagnosis, both CPAP treatment and adherence generally decreased with age (Table 4). Treatment and adherence were more frequent in men than women, and in non-Hispanic whites than other races or ethnicities. Lower CPAP treatment and adherence generally were observed in Medicare beneficiaries with neurological comorbidities, and particularly stroke, as compared to beneficiaries with two other chronic conditions for comparison, namely cardiometabolic comorbidities or depression (Table 4).

Table 3 :

Demographic Characteristics and comorbidities among Medicare Beneficiaries with Obstructive Sleep Apnea, 2011–2013

Demographic and Health Characteristics	Total Sample
Sample Size N (%)	102,618 (100)
Gender
Men	58,293 (57)
Women	44,325 (43)
Age
65–69	36.010 (35)
70–74	29,540 (29)
75–79	19,543 (19)
80–84	11,376 (11)
85–89	4,830 (5)
90+	1,319 (1)
Race/Ethnicity
Non-Hispanic White	91,040 (89)
Non-Hispanic Black	7,319 (7)
Hispanic	1,267 (1)
Asian	923 (1)
Other	2,069 (2)
Stroke	7,454 (7)
Parkinson’s Disease	2,311 (2)
Cognitive Disorders	3,265 (3)
Multiple Sclerosis	291 (0.3)
Hypertension	86,815 (85)
Diabetes Mellitus	46,607 (45)
Cardiovascular Disease	56,338 (55)
Depression	19,434 (19)

Proportions are rounded to the nearest integer; cognitive disorders include Alzheimer’s disease and mild cognitive impairment; cardiovascular disease incudes cardiac arrhythmias, acute myocardial infarction and congestive heart failure; Other ethnicity-Pacific Islander and Native American; P value from chi square test for equal proportions

Table 4:

Demographic Characteristics and comorbidities among Medicare Beneficiaries with Diagnosis of Obstructive Sleep Apnea (n=102,618) by Treatment and Treatment Adherence

Demographic and Health Characteristics	Treated among Diagnosed a	Untreated among Diagnosed	Adhered among Treated b	Non-adherent among Treated
Sample Size N (%)	74,737 (73)	27,881 (27)	53,610 (72)	21,127 (28)
Gender
Men	44,369 (76)	13,924 (24)	32,341 (73)	12,028 (27)
Women	30,368 (69)	13,957 (31)	21,269 (70)	9,099 (30)
Age
65–69	26,336 (73)	9,674 (27)	18,449 (70)	7,887 (30)
70–74	21,977 (74)	7,563 (26)	16,197 (74)	5,780 (26)
75–79	14,347 (73)	5,196 (27)	10,479 (73)	3,868 (27)
80–84	8,097 (71)	3,279 (29)	5,780 (71)	2,317 (29)
85–89	3,225 (67)	1,605 (33)	2,198 (68)	1,027 (32)
90+	755 (57)	564 (43)	507 (67)	248 (33)
Race/Ethnicity
Non-Hispanic White	67,031 (74)	24,009 (26)	48,855 (73)	18,176 (27)
Non-Hispanic Black	5,019 (69)	2,300 (31)	3,113 (62)	1,906 (38)
Hispanic	749 (59)	518 (41)	375 (50)	374 (50)
Asian	514 (56)	409 (44)	318 (62)	196 (38)
Other c	1,424 (69)	645 (31)	949 (67)	475 (33)
Stroke	5,086 (68)	2,368 (32)	3,493 (69)	1,593 (31)
Parkinson’s Disease	1,533 (66)	778 (34)	1,016 (66)	517 (34)
Cognitive Disorders d	2,164 (66)	1,101 (34)	1,444 (67)	720 (33)
Hypertension	63,708 (73)	23,107 (27)	46,257 (73)	17,451 (27)
Diabetes Mellitus	34,799 (75)	11,808 (25)	25,052 (72)	9,747 (28)
Cardiovascular Diseases	33,361 (72)	12,919 (28)	24,089 (72)	9,272 (28)
Depression	13,676 (70)	5,758 (30)	9,689 (71)	3,987 (29)

^aTotal diagnosed sample size=102,618

^bTotal treated sample size=74,737

^cOther ethnicity-Pacific Islander and Native American

^dCognitive disorders include mild cognitive impairment and Alzheimer’s disease

Multivariate analyses demonstrated significant interactions between gender and neurological disorders with respect to both OSA treatment and treatment adherence, such that women with an OSA diagnosis and a neurological disorder were uniformly and often substantially less likely than men with the same neurological disorder to obtain and adhere to OSA treatment (Table 5a, 5b). Specifically, women with stroke had lower odds for OSA treatment in comparison to women without stroke (OR=0.84, 95% CI 0.77, 0.91). While men with stroke also had lower odds for OSA treatment in comparison to men without stroke, the magnitude of the effect was attenuated (OR=0.95, 95% CI 0.94, 0.97). Similarly, the odds ratio of Adherence to OSA treatment was much lower in women and men with Parkinson’s disease in comparison to women and men without this condition, (OR=0.59, 95% CI 0.49, 0.72) and (OR=0.84, 95% CI 0.73, 0.97), respectively. Alternatively, these same results can be interpreted to indicate that among women as opposed to men, presence (vs absence) of a given neurologic condition had a larger negative impact (statistically) on CPAP treatment and adherence.

Table 5a:

Treatment of Obstructive Sleep Apnea among 11,800 Medicare Beneficiaries with Diagnosis of Neurological Comorbidity by Gender

Neurological	Adjusted Odds Ratio a
Morbidity	(95% CI)		p value b
	Men	Women
Stroke	0.95 (0.94, 0.97)	0.84 (0.77, 0.91)	<0.0001
Cognitive Disorders	0.95 (0.92, 0.98)	0.80 (0.70, 0.90)	<0.0001
Parkinson’s Disease	0.92 (0.89, 0.95)	0.74 (0.63, 0.86)	<0.0001

Table 5b:

Adherence to Treatment of Obstructive Sleep Apnea among 11,800 Medicare Beneficiaries with Diagnosis of Neurological Comorbidity by Gender

Neurological	Adjusted Odds Ratio a
Morbidity	(95% CI)		p value b
	Men	Women
Stroke	0.87 (0.80, 0.95)	0.84 (0.76, 0.92)	<0.0001
Cognitive Disorders	0.88 (0.78, 1.01)	0.72 (0.63, 0.84)	<0.0001
Parkinson’s Disease	0.84 (0.73, 0.97)	0.59 (0.49, 0.72)	<0.0001

^aAdjusted for race, age, hypertension, diabetes, cardiovascular disease, depression and state of residence

^bP-value is obtained from a model that includes an interaction term of gender and the corresponding neurological disorder

Reference category includes Medicare beneficiaries of the same gender without the specified neurological morbidity. For example, the odds of OSA treatment is 0.74 for women with Parkinson’s disease relative to women without Parkinson’s disease.

Race and ethnicity also significantly modified associations between neurological morbidity and OSA treatment and CPAP adherence. Relative to whites with the same neurological condition, treatment for OSA was less likely among all other races with stroke, and among blacks with cognitive disorders. (Table 6a). Furthermore, the presence of stroke significantly lowered the odds of OSA treatment within each category of race/ethnicity. In other words, whites, blacks or Hispanics affected by stroke were less likely to be treated for OSA, as compared with stroke-free older adults in their same racial/ethnic group. For example, whites with stroke were less likely to be treated for OSA than white without stroke (OR=0.84, 95% CI 0.79, 0.90). However, among all race/ethnicity groups, Hispanics with stroke had the lowest odds to obtain OSA treatment in comparison to stroke-free Hispanics, (OR=0.54, 95% CI 0.35, 0.82).

Table 6a:

Treatment of Obstructive Sleep Apnea among 11,800 Medicare Beneficiaries with Diagnosis of Neurological Comorbidity by Race/Ethnicity

		Adjusted Odds Ratio a
		(95% CI)			p value b
Neurological Disorders	White Non-Hispanic	Black Non-Hispanic	Hispanic	Asian/Other c
Stroke	0.84 (0.79, 0.90)	0.74 (0.64, 0.85)	0.54 (0.35, 0.82)	0.83 (0.61, 1.12)	<0.0001
Cognitive Disorders	0.84 (0.76, 0.92)	0.57 (0.44, 0.75)	0.99 (0.60, 1.62)	0.87 (0.57, 1.34)	<0.0001
Parkinson’s Disease	0.73 (0.66, 0.81)	1.03 (0.61, 1.71)	0.85 (0.37, 1.94)	0.71 (0.42, 1.21)	<0.0001

Adherence to OSA treatment was less likely among blacks and Hispanics with stroke as compared to whites with stroke, but similar across all races among beneficiaries with cognitive disorders or Parkinson’s disease. (Table 6b).

Table 6b:

Adherence to Treatment of Obstructive Sleep Apnea among 11,800 Medicare Beneficiaries with Diagnosis of Neurological Comorbidity by Race/Ethnicity

		Adjusted Odds Ratio a
		(95% CI)			p value b
Neurological Disorders	White Non-Hispanic	Black Non-Hispanic	Hispanic	Asian/Other c
Stroke	0.84 (0.78, 0.90)	0.83 (0.67, 1.02)	1.15 (0.71, 1.89)	1.35 (0.89, 2.03)	<0.0001
Cognitive Disorders	0.78 (0.70, 0.86)	1.00 (0.66, 1.45)	1.47 (0.84, 2.57)	0.94 (0.51, 1.61)	<0.0001
Parkinson’s Disease	0.75 (0.67, 0.84)	0.87 (0.49, 1.52)	1.06 (0.40, 2.76)	0.62 (0.32, 1.19)	<0.0001

^aAdjusted for age, gender, hypertension, diabetes, cardiovascular disease, depression and state of residence

^bP-value is obtained from a model that includes an interaction term of race and the corresponding neurological disorder

^cOther includes Pacific Islander or Native American

Reference category includes Medicare Beneficiaries of the same race without the specified neurological morbidity. For example, the odds of OSA treatment are 0.54 for Hispanics with stroke compared with stroke-free Hispanics

DISCUSSION

Data from this nationally representative sample of Medicare beneficiaries suggest that although nearly ¾ of individuals with OSA receive treatment and show evidence of at least some adherence with use of CPAP equipment, the presence of a comorbid neurological condition is associated with notably lower frequencies of CPAP treatment and adherence. These results were unlikely to represent a more general impact of comorbid illness, as they persisted after adjustment for some of the most common non-neurologic medical comorbidities. Moreover, gender and race significantly modified associations between neurological morbidities and both CPAP treatment and adherence. Women with stroke, cognitive disorders, and Parkinson’s disease are less likely than the men with those same diagnoses to obtain or adhere to OSA treatment. Furthermore, as compared to white beneficiaries with stroke, all other races with stroke are less likely to be treated for OSA. Blacks with cognitive disorders also appear less likely to be treated for OSA than whites with cognitive disorders. These observations provide new insight into what appear to be substantial national OSA treatment and adherence disparities among older Americans with neurological conditions – in association with gender and race -- and shed light on subgroups who may be more vulnerable to gaps in OSA care.

Although the prevalence of OSA is estimated to be higher in older adults as compared to middle-aged adults,(1, 23) population-based investigations to characterize patterns in OSA treatment among older individuals remain scarce. Even less is known about patterns in OSA care for older Americans with neurological disorders- patients who may stand to lose most from lack of treatment. Contributing to the uncertainty, available estimates regarding the proportion of older adults in general who are adherent to CPAP therapy vary widely.(1, 24, 25) Collectively, these gaps in knowledge indicate an unmet need to determine which patients are most vulnerable to gaps and barriers in OSA treatment, in order to enhance the delivery of high-quality sleep care in older patients, particularly those with pre-existing neurological conditions. Interventions to improve CPAP use have potential for success,(9) but must be informed by factors that influence decisions to pursue and adhere to treatment within older persons.

Although additional population-based studies that focus on OSA treatment trends in older adults and neurological populations are needed, prior interventional and observational studies have previously implicated female gender and race as possible risk factors for CPAP non-adherence, and support our findings of female gender and race as important effect modifiers. In a national cohort study (mean age 58.6 years),(26) Palm et al found that although age itself was associated with a higher odds of treatment adherence (similar to our study), female gender and coexisting hypertension were risk factors for lower adherence and discontinuation of CPAP. In terms of race, a randomized controlled trial that compared the effect of CPAP versus sham CPAP therapy on neurocognitive function in persons with OSA (mean age 65) found white participants to have better treatment adherence when compared to non-whites.(25) In a recent meta-analysis, 16 of 22 studies that directly compared CPAP adherence between whites and blacks showed worse CPAP adherence in blacks compared to whites.(27) In the same meta-analysis, only four existing studies were identified that directly compared CPAP adherence in US Hispanics to whites. Although all four showed equivalent CPAP adherence,(12, 13, 28, 29) one of the largest studies consisted of veterans (a population who may not face the same barriers to healthcare access), and none of the studies included population-based estimates. Further, none of these prior analyses focused on older populations, or patients with neurological conditions.

The gender and racial differences in treatment and adherence noted in this study and others, highlight potential inequities in healthcare delivery at the population level, with direct clinical relevance for older women and minorities with neurological conditions. While OSA is a commonly recognized risk factor for the development of several neurological diseases, (30–32) a growing body of literature also demonstrates the impact of OSA in patients with pre-existing neurological disease. Obstructive sleep apnea contributes to poor functional outcomes among patients with stroke, cognitive disorders, and PD, including depressed mood, impaired functional capacity and cognition, prolonged rehabilitation, increased mortality, and increased risk of stroke recurrence in patients with a first stroke. (19–21) Furthermore, prior work has demonstrated a link between OSA and cognitive dysfunction in individuals with dementia. This is particularly relevant for women and minorities who may disproportionately experience adverse neurological outcomes. Prior data suggests that women with stroke may experience more stroke events, as well as poorer recovery rates, functionality and quality of life. (33) Similarly, the impact of dementia appears to be higher for women compared with men, and while the prevalence of dementia in men remains stable after age 85, dementia rates in women continue to increase with age.(34) Racial disparities also exist in stroke rates, severity, and survival, with higher burden among blacks.(35) Blacks and Hispanics may also be atat higher risk for being diagnosed with cognitive impairment or AD, yet less likely to receive a timely diagnosis and treatment for Alzheimer’s disease, despite greater disease severity.(36–41) Fortunately, recent data suggest that CPAP may improve performance in specific cognitive domains or delay cognitive decline among patients with cognitive impairment, (22, 42, 43) improve stroke outcomes, (44) and reduce stroke risk in treatment adherent patients.(45) Successful treatment with CPAP has also been shown to improve patient-reported outcomes in older individuals.(46) Such observations underscore the need for targeted interventions to enhance OSA treatment, which potentially can be facilitated through understanding which neurological subpopulations are most vulnerable to treatment gaps and barriers to care.

Despite its scope, this study does have limitations. As data were derived from Medicare claims files, the actual prevalence of OSA and OSA under-treatment could have been underestimated. For example, although the American Academy of Sleep Medicine and many accredited sleep laboratories consider an apnea-hypopnea index (AHI) of 5 or more to qualify a patient for CPAP treatment, Medicare rules require a minimum AHI of 15 for CPAP coverage, unless a secondary diagnosis is also present (including excessive daytime sleepiness, mood disorders, and hypertension). Consequently, patients with milder forms of OSA (AHI<15) who did not have secondary diagnosis claims could plausibly be denied CPAP coverage or escape OSA diagnosis in claim files. Along these lines, data regarding symptomatic OSA consequences such as sleepiness or fatigue, and other factors such as presence of social support – which could influence decision to pursue and maintain CPAP treatment -- are not uniformly available from claims data. Such data, if available for future analyses, could provide potential explanations for the relatively high prevalence of CPAP treatment and adherence seen across the entire sample relative to other published studies,(1) as well as discrepant findings seen among women and minorities. Diagnoses of stroke and Parkinson’s disease in Medicare claims files carry a moderate sensitivity, 59% and 66% respectively, but higher sensitivity for dementia (85%). However, these disorders have a high specificity in claims data, 89% for dementia diagnosis and 99% for stroke or Parkinson’s disease. (47–49) Finally, we cannot rule out the possibility that beneficiaries whom we labeled as “untreated” or “non-adherent” could have obtained CPAP equipment through other payers, in which case CPAP treatment would not be captured in Medicare claims files. However, we believe chances of such misclassification were minimized by restricting our analysis to fee-for-service beneficiaries as they are unlikely to fulfil their prescription with other insurers.

CONCLUSIONS

In short, this population-based study of Medicare beneficiaries with OSA suggests that older persons with neurological disorders, and in particular, women and non-whites with neurological disorders, are less likely to receive CPAP or remain adherent to CPAP therapy. Although further investigation is needed to understand mechanisms by which gender and race could affect decision making regarding OSA treatment, this study expands upon what is known about influential factors that impact sleep apnea treatment in chronic neurological conditions. Given the suspected neurological consequences of untreated OSA, and likely therapeutic benefit of CPAP, targeted strategies to improve treatment disparities and thereby neurological outcomes may be warranted.

ABBREVIATIONS

AHI

apnea hypopnea index

CPAP

continuous positive airway pressure

OSA

obstructive sleep apnea