Obstructive sleep apnea has little impact on quality of life in the elderly

1. Introduction 

It is estimated that between 2% and 4% of the general, middle-aged population suffers from obstructive sleep apnea (OSA), the most common form of respiratory sleep disorders [1]. The presence of OSA is associated with increased cardiovascular comorbidity [2], [3], [4], an increased rate of motor vehicles accidents [5], [6], and a greater decline in health related quality of life (HRQoL) [7], [8]. Various studies have shown that the number of sleep-disordered breathing (SDB) instances increases with age [8], [9], [10], [11]. The explanatory causes for this phenomenon are diverse and include a reduced response to hypoxia, greater ventilatory instability, and reduced contractile capacity of the pharyngeal musculature during sleep, increasing collapsibility of the airway – all of which are physiological aspects of aging [12], [13], [14]. For this reason, there is an ongoing debate as to the maximum number of SDB that can be considered normal and, therefore, what definition of OSA should be considered indicative for treatment in elders, either based on OSA impact on HRQoL or its prognosis in terms of morbidity and mortality.

The measurement of HRQoL allows a multidimensional approximation of the impact that the disease produces on the individual who suffers from it. Various authors agree in noting that the presence of OSA degrades HRQoL significantly. Nevertheless, the majority of these studies were done with middle-aged subjects, and thus it is unknown whether this association is stable over time and the exact influence that variables such as comorbidity (frequent in older subjects) have in this association. In recent decades, the population pyramid in developed countries has shifted toward elders due to an increase in life expectancy, which makes studies of the presence of OSA or related excessive daytime sleepiness (EDS) and their effect on HRQoL in this age group increasingly important. The objective of our study was to analyze the impact of the number of SDB and the presence of OSA-related symptoms, especially EDS, on HRQoL in the over-65 population, as compared to younger subjects and an age and gender-adjusted general population.

2. Materials and methods 

3. Results 

Of the 255 patients initially diagnosed with OSA (AHI⩾10), 43 patients were excluded (Fig. 1). The excluded patients had higher CCI scores (2.5 [1–6] vs. 2 [1–6]; p=0.01) and were older (72.2 [5.5] vs. 63.1 [2.7]; p=0.04) than patients included in the study. Finally, 212 subjects were included, of whom 109 were over age 65 (74.6 [6,8], range: 66–83) and 103 were 65 or under (51.7 [6,5], range: 17–65). Table 1 shows the characteristics of the groups. There were no significant differences in AHI, BMI, or ESS between the two groups. Older patients presented significantly higher CCI scores, lower subjective assessment of sleep quality, less subjective hours of sleep, greater use of psychotropic medications, more prevalence of arterial hypertension and greater nocturnal desaturation indices (CT90 and lowest Sa02). The mean recording time of the polysomnographic studies was 6.7 (2.2)h.

View Large Image Download to PowerPoint

Fig. 1. Study protocol flowchart. AHI, apnea–hypopnea index; BMI, body mass index; Sa02, oxygen saturation; CT90%, nocturnal time with an oxygen saturation under 90%; ESS, epworth sleepiness scale; OSA, obstructive sleep apnea; SF-36, short-form-36.

Table 1. Baseline characteristics of study patients

	Variables	Over 65 (n=109)	65 and under (n=103)	p
	Age (years)	74.6 (6.8)	51.7 (6.5)	0.0001
	Chronic snoring (%)	106 (97.2%)	99 (96.1%)	ns
	Witnessed apneas (%)	78 (71.6%)	80 (77.7%)	ns
	Subjective hours of sleep	6.7 (2.3)	6.8 (2.1)	ns
	Subjective sleep quality	2.3 (1.4)	3.1 (1.3)	0.01
	BMI (kg/m2)	31.8 (3.5)	32.2 (5.7)	ns
	Neck circumference (cm)	42.3 (5.4)	43.5 (3.6)	ns
	ESS	11.6 (5.1)	11.9 (4.4)	ns
	ESS>11	51 (46.8%)	49 (47.6%)	ns
	AHT (%)	67 (0.47)	51 (0.5)	0.02
	CCIa	3 (1–6)	1 (1–3)	0.001
	Psychotropic medicationsb	53 (48.6%)	22 (21.4%)	0.001
	AHI (events/h)	32.1 (21.1)	31.5 (17.4)	ns
	AI (events/h)	23.7 (17.6)	23.4 (23.1)	ns
	HI (events/h)	14.4 (13.8)	13.3 (10.2)	ns
	AHI>30 (%)	63 (57.8%)	57 (55.3%)	ns
	CT90% (%)	42.9 (33.9)	19.4 (26.3)	0.0001
	Mean Sa02 (%)	89.4 (3.1)	91.3 (3.7)	0.01
	Lowest Sa02 (%)	73.3 (8.1)	75.3 (9.1)	ns

BMI, body mass index; AHI, apnea–hypopnea index; AI, apnea index; HI, hypopnea index; Sa02, oxygen saturation; CT90%, nocturnal time with an oxygen saturation under 90%; AHT, arterial hypertension; CCI, Charlson comorbidity index.

a Represents median and 25–75th percentiles. b Percentage of patients taking at least one type of psychotropic medication a day, including benzodiazepines and derivatives, neuroleptics, antidepressants, and opiates.

A complete PSG study needed to be performed in 32 patients who presented EDS (ESS>11) but an AHI<10 in the study AS, or who presented clinical indications of a diagnosis other than OSA that would explain their EDS. The intraclass correlation coefficient in these patients between the AHI values obtained from the AS and those obtained from the PSG studies was statistically significant (0.91, p=0.0001). Only two individuals, with AHI of three and seven and ESS of 13 and 12, respectively, were diagnosed with OSA, scoring 14 and 19, respectively, on the AHI determined by PSG.

Taken together, patients in the 65 and under group with OSA (AHI⩾10) presented significantly lower values, with respect to normal reference values, in all subscales of the SF-36 except in the GH subscale, when adjusted for age and gender (Table 2). These differences were larger in the subgroup of individuals with EDS (ESS>11). In the subgroup of patients with AHI between 10 and 30, scores were lower in five of the eight subscales (PF, RP, VT, SF, and RE). There were no significant observed differences in the group with the greatest number of SDB (AHI>30), although there was also a tendency toward a greater decline in HRQoL (Fig. 2a).

Table 2. Scoring of the MOS SF-36 questionnaire, by subscale and age group in comparison with normal reference values adjusted by age and sex

		Over 65 (n=109)			65 and under (n=103)
	MOS SF-36 Subscale	Score	Normative value	p value	Score	Normative value	p value
	Physical function	62.1 (24.2)	73.3 (27)	0.009	68.5 (22.6)	90.3 (17.1)	<0.001
	Role-physical	66.5 (36.3)	77.5 (41.5)	0.01	63.2 (27.8)	87.6 (30.4)	<0.001
	Bodily pain	69.7 (29.4)	75.3 (28.7)	ns	71.1 (25.1)	81.9 (26)	0.02
	General health	58.4 (25.7)	59 (22.1)	ns	63.6 (21.1)	70.9 (19.6)	ns
	Vitality	62.4 (24.9)	66.5 (23.4)	ns	57.8 (23.7)	71.8 (21)	0.007
	Social function	83.6 (27.1)	85 (25.8)	ns	82.2 (21.7)	94.1 (15.6)	0.02
	Role-emotional	84.1 (25.3)	92.1 (25.9)	ns	80.1 (22.9)	94.6 (21.8)	0.01
	Mental health	78.7 (21.6)	74.8 (19.3)	ns	67.8 (25.9)	77.9 (18.7)	0.01

PF, physical function; RP, role-physical; BP, bodily pain; GH, general health; VT, vitality; SF, social function; RE, role-emotional; MH, mental health.

View Large Image Download to PowerPoint

Fig. 2. Scores in the dimensions of the MOS SF-36 questionnaire compared to the general population, adjusted for age and sex (continuous line), by number of sleep-disordered breathing events and the presence of excessive daytime sleepiness in subjects under age 65 (a) and under age 65 (b). ∗p<0.05 with respect to normal reference values; ¶p<0.05 between ESS>11 and AHI=10–30 or AHI>30; PF, physical function; RP, role-physical; BP, bodily pain; GH, general health; VT, vitality; SF, social function; Re, role-emotional; MH, mental health; AHI, apnea–hypopnea index; ESS, epworth sleepiness score.

In the group of patients over age 65 with OSA (AHI⩾10) analyzed together, there was only a significant observed deterioration in domains related to the physical state of the patient (PF and RP), with respect to normal reference values (Table 2). Within this age group, a significant deterioration in the RP, PF, and VT subscales was seen in the subgroup of patients with EDS (ESS>11), while both the subgroup with AHI between 10 and 30 and the subgroup with AHI>30 only showed significant decreases in the RP and PF subscales (Fig. 2b).

There were greater correlations between polygraphic/polysomnographic and clinical parameters in patients 65 and under than in those over 65 (see Table 3). The presence of EDS in the latter group was correlated with lower subjective sleep quality (r: −0.15; p<0.05); greater use of psychotropic medications (r: 0.31, p<0.001) and a higher CCI score (0.23, p<0.05). The latter two factors were comorbidity indicators. Finally, the multivariate analysis for each SF-36 subscale in patients 65 and under showed that the presence of EDS (ESS>11) negatively affected all but the MH subscale, greater age affected three subscales, higher BMI four subscales, and greater AHI two subscales (Table 4). In general, the domains most affected (with the greatest percentage of explained variance) in this subgroup of patients were those that addressed the physical sphere of the patient, while the domains least affected were those corresponding to the emotional, social, or mental sphere. In the over 65 group, the variables with the greatest influence were the CCI and the nocturnal oxygen desaturation parameters (CT90 and lowest Sa02), which negatively affected four and five of the eight questionnaire subscales, respectively, and greater age, which affected three of the eight subscales. The presence of EDS only had a significantly negative association with the VT subscale, while AHI is not associated with any questionnaire subscale in this group (Table 4). Finally, subjective sleep quality affected only two questionnaire subscales (VT and GH). As in the 65 and under group, the domains most affected were those related to physical condition of the patient while the domains least affected were those related to social, mental and emotional aspects, influenced only by regular use of psychotropic medications.

Table 3. Correlation between polygraphic/polysomnographic and clinic parameters in the age groups 65 and under (a) and over 65 (b)

		AHI (events/h)	Lowest Sa02 (%)	CCI	ESS	Psychotropic medications (no. of medication)	BMI (kg/m2)	Subjective sleep quality (0–5)
	(a) 65 and under (n=103)
	AHI (events/h)	–	−0.36⁎	0.09	0.37⁎	0.11	0.31⁎	0.14
	Lowest Sa02 (%)	−0.36⁎	–	−0.13	−0.25⁎⁎	0.12	0.27⁎⁎	0.09
	CCI	0.09	−0.13	–	0.11	0.13	0.19⁎⁎⁎	−0.18⁎⁎
	ESS	0.37⁎	−0.25⁎⁎	0.11	–	0.22⁎⁎⁎	0.21⁎⁎⁎	−0.31⁎
	Psychotropic medications (no. of medication)	0.11	0.12	0.13	0.22⁎⁎⁎	–	0.18⁎⁎⁎	−0.21⁎⁎
	BMI (kg/m2)	0.31⁎	−0.27⁎	0.19⁎⁎⁎	0.21⁎⁎⁎	0.18⁎⁎⁎	–	0.13
	Subjective sleep quality (0–5)	0.14	0.09	−0.18⁎⁎	−0.31⁎	−0.21⁎⁎	0.13	–
	(b) Over 65 years (n=109)
	AHI (events/h)	–	−0.25⁎⁎⁎	0.23⁎⁎⁎	0.12	0.13	0.18	0.10
	Lowest sa02 (%)	−0.19⁎⁎⁎	–	−0.44⁎	−0.14	−0.14	−0.24⁎⁎⁎	0.17⁎⁎⁎
	CCI	0.21⁎⁎⁎	−0.44⁎	–	0.23⁎⁎⁎	0.31⁎⁎	0.17	−0.24⁎⁎
	ESS	0.12	−0.14	0.23⁎⁎⁎	–	0.23⁎⁎	0.11	−0.15⁎⁎
	Psychotropic medications (no. of medication)	0.13	−0.14	0.31⁎⁎	0.34⁎⁎	–	0.26⁎⁎⁎	−0.23⁎⁎
	BMI (kg/m2)	0.18	−0.24⁎⁎⁎	0.17	0.11	0.26⁎⁎⁎	–	−0.17⁎⁎⁎
	Subjective sleep quality (0–5)	0.10	0.17⁎⁎⁎	−0.24⁎⁎	−0.15⁎⁎⁎	−0.23⁎⁎	−0.17⁎⁎⁎	–

AHI, apnea–hypopnea index; Sa02, oxygen saturation; CCI, Charlson comorbidity index; ESS, epworth sleepiness score; BMI, body mass index.

⁎ p<0.001. ⁎⁎ p<0.01. ⁎⁎⁎ p<0.05.

Table 4. Multiple regression analysis of the MOS-SF 36 subscales

		65 and under (n=103)			Over 65 (n=109)
	Dependent variable	Independent variable	Accumulative r2 coefficient	p value	Independent variable	Accumulative r2 coefficient	p value
	Physical function	ESS>11	0.17	0.001	CCI	0.22	<0.001
		Age	0.20	0.005	Age	0.27	0.005
		BMI	0.22	0.03	CT90	0.30	0.02
	Role-physical	ESS>11	0.15	0.002	Age	0.22	<0.001
		IAH	0.19	0.03	CCI	0.28	0.01
		Age	0.21	0.04	Lowest Sa02	0.31	0.03
	Bodily pain	ESS>11	0.19	0.001	CCI	0.15	0.006
		BMI	0.21	0.03	Age	0.21	0.009
	General health	BMI	0.11	0.01	CCI	0.18	0.001
		Age	0.14	0.03	Subjective sleep quality	0.23	0.01
		ESS>11	0.17	0.04	Lowest Sa02	0.26	0.02
	Vitality	ESS>11	0.14	0.003	CCI	0.17	0.007
		BMI	0.18	0.02	Subjective sleep quality	0.21	0.02
		Subjective sleep quality	0.22	0.03	ESS>11	0.24	0.04
		AHI	0.24	0.04
	Social function	ESS>11	0.14	0.008	–	–
	Role-emotional	ESS>11	0.16	0.003	Psychotropic medications	0.12	0.008
	Mental health	–	–	–	Psychotropic medications	0.13	0.007
					Lowest Sa02	0.17	0.03

4. Discussion 

Our results show that the impact of the presence of OSA or EDS on HRQoL was greater in younger patients than those over 65. In the older patients, the presence of comorbidities and the level of nocturnal oxygen desaturation were the variables more closely related to HRQoL.

Like almost all physiological functions, sleep deteriorates over time. Elders have more destructured sleep and decreased pharyngeal muscle tone [12], [13], [14], so it is not unexpected that both the number of SDB and the prevalence of OSA syndrome increase with age [8], [9], [10], [11]. Duran et al. [22] observed, in 428 individuals aged 71 to 100, that 80% presented an AHI>5, more than 60% had AHI>10 and up to 20% also presented EDS [25], figures at odds with the accepted prevalence of OSA in 2–4% of the general middle-aged population [1]. The impact of OSA in elder patients remains controversial. Some authors have even proposed the existence of two different types of OSA, depending on age, one which appears at early ages and has a more florid symptomatology and one that appears in old age and which has a more uncertain impact – probably affecting the neurocognitive sphere of the patient to a greater extent [23].

One of the key aspects of the global effect of any disease on the individual is its impact on HRQoL. According to our results in younger patients, some factors related to the presence of OSA such as obesity, AHI, and, especially, the existence of EDS, have an important impact on HRQoL. This impact is more marked in dimensions related to the physical sphere of the individual (PF, RP, VT), and less in those that deal with social, emotional or mental aspects, as seen in other studies [24], [25], [26], [27]. Nevertheless, in elders, factors related to OSA have little impact on HRQoL (only EDS has a negative effect on VT), which is more associated with measures of chronic comorbidity such as the CCI, alterations in oxygen saturation or the regular use of psychotropic medications. These differential impacts on HRQoL in the two age groups were observed irrespective of the fact that the polygraphic/polysomnographic (AHI) and clinical profiles of patients included in the study did not change with age, a phenomenon already observed by other authors [12].

Several studies indicate that elderly patients consider the presence of EDS to be attributed to age, the use of certain medications or reduced physical activity, but not a pathological condition. Therefore, they consider a certain amount of EDS to be normal for their age [13], [28]. Nevertheless, younger people, who are much more active and have less comorbidities, tend to consider the presence of EDS to be a pathology, given that it interferes with their daily lives. Nevertheless, when direct questions are asked about situations in which they tend to fall asleep (for example, using the ESS), it is revealed that the presence of EDS reported by the patient is the same as or higher than in younger subjects [29]. This phenomenon would explain our results in that the initial level of subjective EDS, as reported by the patients themselves, was similar in both age groups but its impact on HRQoL was much lower in elders than in younger patients.

In elders, on the other hand, the presence of OSA or the number of SDB is not independently associated with a decline in HRQoL. This may be explained by the increasing number of SDB that appear with age and that probably do not present as a pathological condition until they exceed a given limit, as has been suggested by some authors [30]. In this sense, the correlation seen between polygraphic/polysomnographic parameters (AHI and nocturnal oxygen desaturation) and the presence of EDS in elder patients is lower than that observed in younger patients. This may be because, in young patients, OSA alone probably explains the majority of EDS. In elders, however, EDS is probably conditioned by many other factors [27].

Very few studies have analyzed the effect of OSA or an excess SDB on HRQoL in elders. Baldwin et al. [8] in a large group (mean age 63.2 years), observed that the presence of EDS quantified as an ESS>11 had a negative impact on all dimensions of the SF-36. These results are similar to those seen in our study in patients 65 and under (mean age 51.7 years) but very different from those observed in the over 65 group (mean age 74.6 years). We believe that the difference in mean age between the Baldwin et al. study and our over 65 group (more than 11 years) may explain the differences in the results.

Therefore, the results presented in this study indicate that the impact on HRQoL of the presence of OSA, with or without EDS, depends on patient age. This would support the hypothesis, already suggested by other authors [23], of the existence of two different types of age-dependent OSA, or at least two levels of impact, independent of cardiovascular involvement, which was not analyzed in the present study.

Some limitations presented by our study should be discussed. The sleep laboratory used in the study serves a population with an elevated mean age. The result is, although consecutive patients were included in the study, approximately 50% of patients were over 65 years of age. In addition, some diseases not included in the CCI, such as depression or anxiety, were not directly quantified and are known to have important impacts on both patients with OSA [31] and elders [32]. This situation was evaluated indirectly by quantifying the number of regular psychotropic medications taken. Furthermore, our study only included males due to the small number of women available in our database, creating results that are not applicable to both genders; there are well-known and significant differences in HRQoL between genders at the same age, as reported in the literature [17], [18], [19]. Finally, the AS system does not allow quantification of hours of sleep or the diagnosis of other sleep-related pathologies, which is especially important in elderly patients, and which could increase the possibility of false negatives in individuals unable to sleep on the night of the study or in individuals with a high pretest probability of having OSA. In the present study, we attempted to minimize this possibility in two ways. First, we only considered valid those studies in which the patient claimed to have slept for at least 4h, and for which there were at least 4h of recorded data. Patients that did not meet these requirements after two sleep studies with the AS were excluded from our study. Second, the performance of an additional, complete PSG study was requested in those patients with EDS (ESS>11), but with an AHI<10 or with suspected, alternative diagnoses of OSA that would explain their EDS. Even with these criteria, the agreement between AHI values measured by the AS and the PSG studies was statistically significant (r=0.92, p<0.0001) in this group (i=32). The AS failed to confirm the OSA diagnosis in only two of the patients identified for a complete PSG study.

Despite the existence of few studies that analyze the impact of OSA in elders and the effect of CPAP in these patients, there is agreement that this treatment should be considered at all ages due to its effectiveness and tolerance [33]. We believe that the results of our study do not contradict this idea, despite concluding that the impact of OSA on HRQoL in elderly patients is limited. Other factors, such as the cardiovascular or neurocognitive impact of OSA in the elderly, or the positive effect of CPAP in these situations, have already been suggested by some authors, and were not analyzed in this study [21], [33], [34]. On the other hand, we have observed a significant impact of the presence of EDS on some physical dimensions (vitality) of elders who may benefit from CPAP treatment to the same extent as seen in younger patients [35], [36].

We conclude that, in our study, the presence of OSA is not associated with a decrease in HRQoL in elders, while the presence of EDS only has a slight effect on HRQoL. This finding is contrary to findings in younger subjects. Based on these results, we believe that studies to clarify the role of CPAP treatment on HRQoL in elderly patients with OSA are needed.