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Volume 14 No. 02
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Patient-Reported Outcomes in Older Adults With Obstructive Sleep Apnea Treated With Continuous Positive Airway Pressure Therapy

Jennifer Pallansch, BS1; Yiping Li, MD2; James Bena, MS3; Lu Wang, MS3; Nancy Foldvary-Schaefer, DO, MS4
1Case Western Reserve University School of Medicine, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio; 2Kaiser Permanente Los Angeles Medical Center (LAMC), Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio; 3Department of Quantitative Health Sciences, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio; 4Sleep Disorders Center, Neurological Institute, Cleveland Clinic, Cleveland, Ohio

ABSTRACT

Study Objectives:

Although continuous positive airway pressure (CPAP) therapy is regarded as the gold standard treatment for obstructive sleep apnea (OSA) in adults, outcomes in older patients are limited. This study examines the effect of CPAP therapy in older adults with OSA (older than 60 years) compared to younger adults (age 18 to 60 years) to inform the current standard of practice.

Methods:

We performed a retrospective study with a convenience sample to compare responses to CPAP treatment in older versus younger adults with OSA using validated, patient-reported outcomes (PROs). A total of 532 patients were analyzed at baseline and at 3, 6, and 12 months after CPAP initiation. The effects of CPAP adherence and OSA severity on PRO scores were measured in each age group.

Results:

Patients older than 60 years had higher apnea-hypopnea indices but lower Epworth Sleepiness Scale (ESS), Fatigue Severity Scale (FSS), and Patient Health Questionnaire-9 (PHQ-9) scores and higher Functional Outcomes of Sleep Questionnaire (FOSQ) scores at baseline compared to patients age 18 to 60 years. At 1 year after CPAP initiation, significant and comparable improvements in ESS, FSS, PHQ-9, and FOSQ scores were observed in patients older than 60 years relative to younger patients. When stratifying by OSA severity, change between age groups was significantly different only for PHQ-9 in patients with mild OSA, with greater improvements observed in younger patients.

Conclusions:

This study adds to the limited data on treatment outcomes with CPAP therapy in older adults with OSA. Patients older than 60 years achieve improvement in sleepiness, fatigue, depressive symptoms, and quality of life analogous to that of younger adults.

Citation:

Pallansch J, Li Y, Bena J, Wang L, Foldvary-Schaefer N. Patient-reported outcomes in older adults with obstructive sleep apnea treated with continuous positive airway pressure therapy. J Clin Sleep Med. 2018;14(2):215–222.


BRIEF SUMMARY

Current Knowledge/Study Rationale: Obstructive sleep apnea (OSA) is a chronic disease associated with numerous adverse health and psychosocial outcomes, and the burden of OSA is only increasing with an aging population and a movement away from fee-for-service to performance-based pay. Despite the increasing prevalence of OSA with age, treatment effects in older populations have been inadequately studied.

Study Impact: This study examined the effects of continuous positive airway pressure (CPAP) treatment on sleep-related patient-reported outcomes in older adults to address this disparity and guide current standards of care. Our study demonstrated that elderly patients with OSA have a response to CPAP therapy comparable to that of younger adults and further supports CPAP therapy use in patients older than 60 years.

INTRODUCTION

Obstructive sleep apnea (OSA) is characterized by repeated episodes of complete or partial obstruction of the upper airway during sleep. Current estimates suggest that as many as one in four American adults have OSA, with more conservative estimates of 13% in men and 6% in women.1,2 Most of these cases remain undiagnosed.3 The prevalence of OSA is nearly twofold to threefold higher in the elderly compared with middle-aged populations, largely attributable to age-related increases in pharyngeal collapsibility.4,5 Yet, treatment outcomes in older adults with OSA are poorly elucidated. An estimated 29% of adults will older than 60 years in developed countries by 2030, underscoring the need to better understand age-related outcome characteristics in this growing sector of the population.6 This study aims to address current knowledge gaps by comparing sleep-related patient-reported outcomes (PROs) in older versus younger adults with OSA after initiation of continuous positive airway pressure (CPAP) therapy.

METHODS

This study was approved by the Institutional Review Board of the Cleveland Clinic.

Study Population

A Sleep Disorders Center convenience sample was identified through queries of the Cleveland Clinic Neurological Institute's Knowledge Program (KP) and the Sleep Disorders Center's Nihon Kohden polysomnography (PSG) database from 2007 to 2011. The KP is an electronic patient-reported data collection system of disease-specific assessments completed at each outpatient clinic encounter. Inclusion criteria were: (1) age 18 years or older; (2) in-laboratory PSG demonstrating OSA (apnea-hypopnea index [AHI] ≥ 5 events/h) and no other primary sleep disorder identified; (3) in-laboratory positive airway pressure titration (split night or dedicated titration); (4) sleep-related PROs at baseline and at 3 and 6 months following CPAP initiation.

Demographic and Polysomnographic Data

The electronic medical record and PSG database were reviewed for demographic data, medical comorbidities, diagnostic PSG variables, and optimal CPAP settings. Apnea was defined by American Academy of Sleep Medicine criteria with hypopnea defined as a ≥ 50% drop from baseline in the nasal pressure signal excursion associated with a ≥ 3% desaturation or an arousal.7

CPAP Adherence

Adherence to therapy was defined as ≥ 4 hours of average nightly CPAP use on ≥ 70% of days. Self-reported adherence was collected at clinic visits following CPAP initiation. Objective adherence was obtained at 90 days after CPAP initiation when available.

Patient-Reported Outcomes

The following PROs were obtained at baseline and at 3, 6, and 12 months (when available) following the initiation of CPAP therapy.

Epworth Sleepiness Scale (ESS)

Measures sleep propensity with scores ranging from 0 to 24, ≥ 11 indicative of excessive daytime sleepiness.8

Fatigue Severity Scale (FSS)

Measures fatigue with scores ranging from 9 to 63, ≥ 36 indicative of abnormal fatigue levels.9

Patient Health Questionnaire-9 (PHQ-9)

Measures depressive symptoms based on 9 Diagnostic and Statistical Manual of Mental Disorders, 4th Edition criteria of depression with scores ranging from 0 to 27, ≥ 10 indicative of depressive symptoms of at least moderate severity.10

Functional Outcomes of Sleep Questionnaire (FOSQ)

Measures daily functioning in populations with sleep disorders including activity level, vigilance, intimacy and sexual relationships, general productivity, and social outcomes, with lower scores indicating more functional impairment.11

Statistical Analysis

Data management and analysis were performed with SAS software (version 9.4; Cary, North Carolina, United States). Patients were stratified by age (older than 60 years versus 18 to 60 years) and by OSA severity. Analysis based on age (in years) by decade (18–40, 41–50, 51–60, older than 60) was performed initially. Because of the similarity to the two-group analysis on trends of PROs over time and because of small sample sizes after stratification by OSA severity, major findings were described using the two age groups, older than 60 and 18 to 60 years, comparison.

Comparison of baseline characteristics between the two age groups was performed by two-sample t test or Wilcoxon rank-sum test in continuous variables and by χ2 test or Fisher exact test in categorical variables. To account for repeated measures over time on the same patient, mixed-effect models assuming unstructured correlation structure were used to evaluate the trend of PROs change from baseline to 12 months and to assess the difference of change between younger and older groups interacting with OSA severity levels or CPAP adherence status. OSA was defined as mild (AHI 5 to < 15 events/h), moderate (AHI 15 to < 30 events/h), and severe (AHI ≥ 30 events/h). A value of P < .05 was considered statistically significant with noted exceptions where a Bonferroni adjusted significance level was employed. Continuous variables are presented as mean (standard deviation) or median (25th, 75th percentiles), and categorical variables are presented as frequencies.

RESULTS

Sample Characteristics

A total of 532 adults with OSA, including 139 patients older than 60 years (26%), with 1,211 unique visits were included. Mean ages for younger and older groups were 47.1 ± 9.5 and 68.6 ± 6.3, respectively. Sample characteristics are shown in Table 1, and diagnostic PSG data are shown in Table 2. Younger patients had a higher prevalence of obesity whereas older patients had a higher median baseline AHI (39.0 versus 27.9 events/h, P < .001) and more comorbidities. Older patients also had significantly lower total sleep time, sleep efficiency, arousal index, and stage R sleep and stage N3 sleep percentages and had higher stage N1 sleep and stage N2 sleep percentages than younger patients.

Sample characteristics.

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Table 1

Sample characteristics.

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Baseline PSG variables by age group.

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Table 2

Baseline PSG variables by age group.

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Patient-Reported Outcomes

Baseline scores and changes in PROs over time by age group are shown in Figure 1. Baseline ESS, PHQ-9, and FSS scores were significantly lower (P = .005, P < .001, P < .001 respectively) and FOSQ scores were higher (P < .001) in the older group, indicating less severe symptoms. In both groups, all scores at 3, 6, and 12 months following CPAP initiation were significantly different from baseline (P < .001). These scores were decreased on ESS, PHQ-9, and FSS and increased on FOSQ. There was no difference among the three follow-up periods in either group for any PRO. Subanalysis by decade followed the same general trends. The younger than 40 years, 40 to 50 years, and 50 to 60 years age groups had significantly higher baseline PHQ-9, FSS, and FOSQ scores when compared to the group older than 60 (all P < .001). For baseline ESS scores, only the group age 40 to 50 years differed significantly from the group older than 60 years (P = .014). The four age groups demonstrated equally robust change in PROs at the 3- and 6-month assessments.

Changes from baseline in PROs between age groups.

Sample sizes of younger and older group are: baseline 393, 139; 3-month 332, 121; 6-month 71, 48; and 12-month 75, 32, respectively.

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Figure 1

Changes from baseline in PROs between age groups.

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Subanalysis by AHI

Baseline and change in PROs were compared between groups stratified by AHI. For ESS (Table 3), baseline scores were significantly different between age groups only for those with severe OSA. ESS scores were significantly reduced for all AHI levels in both age groups between baseline and 3 months apart from patients older than 60 years with mild OSA. The magnitude of ESS change between age groups was not different at any AHI level. For other PROs, older patients generally had lower baseline FSS and PHQ-9 scores and higher FOSQ scores regardless of OSA severity (Table 4). Younger patients in each AHI group achieved significant change in the first 3 months. In older patients, only those with severe OSA demonstrated significant changes in all PRO scores in the first 3 months. Older patients with moderate OSA showed significant change from baseline in ESS and PHQ-9 scores only, whereas changes were not significant for older patients with mild OSA. The magnitude of change between age groups was significantly different only for PHQ-9 scores in those with mild OSA.

Change in ESS score by age and AHI.

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Table 3

Change in ESS score by age and AHI.

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Change in PHQ-9, FSS, and FOSQ scores by age and OSA severity.

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Table 4

Change in PHQ-9, FSS, and FOSQ scores by age and OSA severity.

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CPAP Adherence

Of the entire sample, 72.7% subjectively reported adherence with CPAP in the first 90 days of treatment, including 70.2% of younger patients and 79.9% of older patients. Scores for PROs by adherence status are shown in Figure 2. In younger patients, changes in PROs from baseline to 3 and 6 months were significant in both adherent and nonadherent groups. In older patients, significant change from baseline was found for all PROs only in the adherent group. Comparing change between adherent and nonadherent younger patients, the difference was significant only for ESS at 3 months, with adherent patients showing greater improvement (P = .020). In older patients, no significant difference was found between adherent and nonadherent groups on PRO change from baseline at any time point. The interaction of age group and adherence status was not significant at any time point for any PRO, indicating a consistent pattern over time between groups. Objective adherence data were available for 170 patients overall, including 68 patients older than 60 years (40%). Of these, 137 (81%) were adherent based on objective compliance data. The raw agreement rate between objective and subjective adherence was 90% (91% in older patients, 88% in younger patients).

Changes from baseline in PROs by age and subjective CPAP adherence.

Sample sizes of younger nonadherent patients are: baseline 117, 3-month 100, 6-month 13, 12-month 22. Sample sizes of younger adherent patients are: baseline 276, 3-month 232, 6-month 58, 12-month 53. Sample sizes of older nonadherent patients are: baseline 28, 3-month 25, 6-month 8, 12-month 6. Sample sizes of older adherent patients are: baseline 111, 3-month 96, 6-month 40, 12-month 26.

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Figure 2

Changes from baseline in PROs by age and subjective CPAP adherence.

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DISCUSSION

We explored the effects of CPAP therapy in older adults with OSA on sleep-related PROs in an effort to address knowledge gaps in treatment outcomes in this growing population. Our major findings include: (1) improvements in ESS, FSS, PHQ-9, and FOSQ scores were comparably robust in older adults (older than 60 years) and younger adults (18 to 60 years) over 12 months; (2) older patients showed the same course of improvement as younger ones, with significant change occurring in the first 3 months followed by more modest improvements at 6 and 12 months after CPAP initiation; (3) older patients reported less daytime sleep propensity, fatigue, depressive symptoms, and impairment in quality of life and had a lower prevalence of obesity compared to younger adults at baseline despite increased disease severity and a greater number of comorbidities; (4) after stratifying by AHI, the magnitude of change was generally comparable between age groups; and (5) after stratifying by adherence status, the magnitude of improvement for all PROs at all time points was comparable between age groups.

Our primary finding that comparable improvements in the ESS, FSS, PHQ-9, and FOSQ scores occurred in older and younger adults with OSA treated with CPAP therapy extends similar observations in the literature. A 2007 review of clinical trials including or limited to older patients found reductions in sleep propensity as measured by the ESS, improvements in neurobehavioral outcomes and sleep quality, and reductions in cardiovascular events with CPAP compared with placebo, although changes in the FOSQ and other quality of life measures were conflicting.12 Similarly, among 39 community-dwelling elderly patients with mild to moderate Alzheimer disease with OSA, therapeutic CPAP produced significantly greater reductions in ESS scores compared to sham (8.9 to 6.6 versus 7.7 to 6.5) after 6 weeks of therapy, illustrating benefit even in cognitively impaired individuals.13

Consistent with prior observations, we additionally found that older adults with OSA report less daytime sleep propensity and had a lower prevalence of obesity despite having a higher AHI and increased number of comorbidities compared with younger adults.12,14,15 This finding was also observed in a sample of community-dwelling adults participating in the Sleep Heart Health Study, where those individuals older than 65 years had lower mean ESS scores than younger subjects at baseline (7.5 versus 8.0, P = .012).16 Because of these initial differences, elderly patients in our study demonstrated normal baselines in some PROs and still showed improvement in scores with CPAP therapy. The significance of this is unknown but thought to be meaningful improvement given the linear nature of metrics such as the ESS.8 Differences in baseline PROs between older and younger adults with OSA as observed in this study and the literature raises important concerns regarding the standardization of metrics in OSA care paths, as these PROs are primarily validated in middle-aged populations and established cutoff points cannot be reliably applied in the elderly.

In our stratification by AHI, we found parallel trends across all PROs with several exceptions. The magnitude of ESS change was similar between age groups at all levels of OSA severity and similar to the effect size observed in prior research examining OSA cohorts treated with CPAP.17 Although older patients with mild and moderate OSA showed no significant improvement in some PROs over time, the magnitude of change between age groups was significantly different only for PHQ-9 scores in those with mild OSA. This indicates elderly patients with mild OSA may not see subjective improvement in depression symptoms with CPAP therapy but still show change in other PROs comparable to younger adults with the same level of OSA severity. Given this trend, our small sample size of elderly adults with mild OSA, and the improvement in two PROs, this may support the use of CPAP therapy in elderly patients with mild OSA but requires further investigation.

In addition, the lack of relationship between AHI and ESS is supported by our study. Although the same magnitude of change was noted between age groups, our study did not confirm a positive association between ESS and AHI in either age group. This was noted among 2,849 older community-dwelling men from the Osteoporotic Fractures in Men Study, where no association was found between AHI and ESS, Pittsburgh Sleep Quality Index, or FOSQ scores after adjusting for sleep duration, suggesting that the severity of OSA may not be related to the subjective benefits observed after CPAP therapy in either age group.18

Another major finding in our study was the role of age on CPAP adherence, which is controversial in the literature and remains unclear.12 More than 70% of younger and approximately 80% of older patients in our study self-reported adherence with CPAP. The magnitude of change between older and younger groups by adherence status was not significantly different at any time point for any outcome, although change from baseline in older patients was significant only for adherent subjects. Objective adherence data were not available for all cases, but agreement between subjective and objective adherence data was strong for both age groups. Because previous studies have also demonstrated some improvement with CPAP usage at less than conventional cutoff points for adherence, this could play a role in the lack of significant differences observed with adherent and nonadherent patients in this study.19

A final point of consideration is the paucity of literature exploring the performance characteristics of sleep-related PROs in elderly patients despite recommendations to use subjective scales to assess quality of life in patients with OSA. ESS was found to have good internal consistency in more than 3,000 women aged 70 years or older participating in the Study of Osteoporotic Fractures.20 However, in a cross-sectional observational study of independently living nondemented older subjects with daytime sleepiness complaints, almost 60% of subjects and relatives were unable to answer at least one item, suggesting that the ESS may underestimate sleep propensity in older individuals.21 Among the other PROs utilized in this study, there are no comparable studies exploring age effects on FSS scores. However, the FOSQ has been demonstrated to identify functional differences in older patients, and the PHQ-9 has been established as a comparable, if not more effective, tool than ICD-9-CM codes and the 15-item Geriatric Depression Scale for identifying depression in the elderly.2225 Although these studies largely support the use of these PROs in the elderly, further investigation is needed in the future.

This study had several limitations. We chose to report our findings using an age cutoff point of 60 years or older instead of the more traditional 65 years to define the older group because a cutoff point of 65 years would have resulted in significant sample size discrepancies between groups, eroding statistical power. Nonetheless, analyses using 65 years as the cutoff point also showed no significant difference between the two groups on ESS change from baseline to 3 months at any AHI level. Further limitations include small, nonuniform samples that may have affected our results, particularly when analyzing by OSA severity and adherence status. In addition, only patients with serial follow-up visits treated by providers in the main campus sleep disorders center were included, which raises concern for selection bias because patients without follow-up may be more likely to be nonadherent. Therefore, the generalizability of our results to the broader OSA population is unclear and our results may have overestimated PRO improvement. Furthermore, we cannot exclude the presence of comorbid sleep disorders not diagnosed by PSG because this information was not collected. Finally, and most importantly, because objective CPAP adherence data were available for only 32% of our sample, the primary analysis at the 3-month follow-up was based on subjective adherence, which may have contributed to the lack of differences in PROs between adherence groups. However, the agreement between objective and subjective adherence was 90% (91% in older patients, 88% in younger patients) and, therefore, we believe our findings are notable despite this limitation.

As the population continues to age, the diagnosis and treatment of OSA will present an increasing medical and financial burden.6,26 Clinical practice guidelines and care coordination aimed to enhance adherence will become more critical with the shift from fee-for-service to performance-based pay.27 The American Academy of Sleep Medicine recommends adherence monitoring using subjective scales including the ESS and quality of life instruments, yet limited data exist in older patients.28 Because OSA is associated with adverse health and psychosocial outcomes including cardiovascular, metabolic, and neurologic disorders that universally increase with age, further work exploring the initial presentation and response to CPAP therapy in elderly patients is needed.4,12,29,30 Our study adds to the literature on sleep-related PROs in older adults with OSA and supports screening and treatment of OSA given the favorable outcomes observed in this population.

DISCLOSURE STATEMENT

All authors have seen and approved this manuscript. The authors report no conflicts of interest. Financial support for this project was obtained from departmental funding.

ABBREVIATIONS

AHI

apnea-hypopnea index

CPAP

continuous positive airway pressure

ESS

Epworth Sleepiness Scale

FOSQ

Functional Outcomes of Sleep Questionnaire

FSS

Fatigue Severity Scale

KP

knowledge program

OSA

obstructive sleep apnea

PHQ-9

Patient Health Questionnaire-9

PRO

patient-reported outcome

PSG

polysomnography

ACKNOWLEDGMENTS

The authors thank the Knowledge Program Data Registry of the Cleveland Clinic, Cleveland, OH and Cleveland Clinic Homecare Services for providing the data used in these analyses.

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