Open Journal of Nursing, 2013, 3, 445-452 OJN
http://dx.doi.org/10.4236/ojn.2013.36060 Published Online October 2013 (http://www.scirp.org/journal/ojn/)
Undiagnosed obstructive sleep apnea in hypertensive
outpatients in primary care—Associations with sleep
complaints, depressive symptoms and global perceived
health
Anders Broström1,2, Ola Sunnergren3,4, Kristofer Årestedt5,6, Peter Johansson7,8, Per Nilsen9,
Bengt Fridlund1, Eva Svanborg1,3
1Department of Nursing Science, School of Health Sciences, Jönköping University, Jönköping, Sweden
2Department of Clinical Neurophysiology, Linköping University Hospital, Linköping, Sweden
3Department of Clinical and Experimental Medicine, Division of Clinical Neurophysiology, Faculty of Health Sciences, Linköping
University, Linköping, Sweden
4Department of ENT, Ryhov Hospital, Jönköping, Sweden
5School of Health and Caring Sciences, Faculty of Health, Social Work and Behavioural Sciences, Linnaeus University, Kalmar,
Sweden
6Department of Medicine and Health Sciences, Division of Nursing Sciences, Faculty of Health Sciences, Linköping University,
Linköping, Sweden
7Department of Cardiology, Linköping University Hospital, Linköping, Sweden.
8Department of Medicine and Health Sciences, Division of Cardiovascular Medicine, Faculty of Health Sciences, Linköping Univer-
sity, Linköping, Sweden
9Division of Health Care Analysis, Faculty of Health Sciences, Department of Health and Society, Linköping University, Linköping,
Sweden
Received****************2013
Copyright © 2013 Anders Broström et al. This is an open access article distributed under the Creative Commons Attribution License,
which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
ABSTRACT
Objective: 1) To describe the prevalence of undiag-
nosed obstructive sleep apnea (OSA) and depressive
symptoms in hypertensive men and women below 65
years of age, and 2) to describe the association of OSA
to subjective sleep complaints, depressive symptoms
and global perceived health. Design: Cross-sectional
design focusing on nursing care outcomes of obstruct-
tive sleep apnea. Setting: Four primary care health
centres in Sweden. PATIENTS: 411 consecutive pa-
tients (52% women), mean age 57.9 years (SD 5.9
years), with diagnosed hypertension (BP > 140/90).
Main Outcome Measures: Prevalence of OSA and
depressive symptoms, and association of OSA to sleep
complaints, depressive symptoms and global per-
ceived health. RESULTS: Mild, moderate and severe
OSA was seen among 29%, 16% and 14% of patients,
respectively. Depressive symptoms were seen in 16%
of the total group, with a higher prevalence among
men, compared to women, 21% vs. 12%. No differ-
ences were found regarding blood pressure, estimated
sleep need, sleep sufficiency index, insomnia symp-
toms, daytime sleepiness or depressive symptoms with
respect to different degrees of OSA. Apnea-hypopnea
index was significantly associated to perceived health
after adjustment for gender and comorbidities, but
when depressive symptoms and non-restorative sleep
were added to the model, 33% of the variance in glo-
bal perceived health was explained. Conclusion: OSA
is highly prevalent among patients with hypertension
in primary care and does together with sleep com-
plaints and depressive symptoms have a negative im-
pact on global perceived health. Hypertensive pa-
tients without subjective sleep complaints or depres-
sive symptoms may still have OSA.
Keywords: Depression; Global Perceived Health;
Hypertension; Nursing Care; Obstructive Sleep Apnea;
Sleep Disordered Breathing; Sleep
1. INTRODUCTION
The worldwide prevalence of hypertension (HT) has
been estimated to be as high as 1 billion individuals. Es-
timates suggest that HT is responsible for 62 percent of

A. Broström et al. / Open Journal of Nursing 3 (2013) 445-452 446
cerebrovascular disease, 49 percent of ischemic heart
disease (IHD), and 7.1 million deaths each year [1]. Ob-
structive sleep apnea (OSA) occurs in 24% of men and
9% of women when defined as at least five respiratory
pauses per hour of sleep [2]. OSA is associated to various
types of cardiovascular disease (e.g., stroke, IHD, heart
failure, arrhythmias) and can cause an increased mortal-
ity [3]. A suggested mechanism is the increased cardio-
vascular stress (i.e., sympathetic activation) caused by
the breathing related events (i.e., the apneas/hypopneas
that causes hypoxia) [3]. Another suggested cause is the
high and increasing prevalence of obesity [4]. Swedish
data indicate an increasing obesity problem among HT
patients, and, as a consequence, an increasing occurrence
of OSA [5].
Global perceived health (GPH) is an important out-
come in nursing care, incorporating depression, insomnia
and daytime sleepiness as crucial components [6], of
which all are associated with OSA in patients referred to
sleep clinics, but also with poor health perceptions in the
general population [7]. Simultaneous use of antidepres-
sant and antihypertensive medications may increase the
likelihood of OSA syndrome (OSAS) diagnosis [8]. Im-
proved knowledge about the links between OSA, subjec-
tive sleep complaints, depression and GPH in hyperten-
sive outpatients may help nurses to identify patients, as
well as targets for nursing interventions. The purpose of
this study was 1) to describe the prevalence of different
severity levels of OSA in adults with HT in primary care,
and 2) to explore the contributions of OSA to subjective
insomnia and daytime sleepiness, depressive symptoms
and GPH in patients with undiagnosed OSA.
2. MATERIALS AND METHODS
2.1. Design and Selection Criteria
A cross-sectional design focusing on nursing care out-
comes of OSA breathing was used. After ethical approval
(Dnr M29-07), all 918 eligible patients 18 - 65 years of
age with diagnosed hypertension (140/90) at four pri-
mary care centres in Sweden were screened. Exclusion
criteria were terminal disease, ongoing treatment for
OSAS, severe psychiatric disease, dementia, alcohol/drug
abuse, or difficulties reading and understanding the Swe-
dish language.
2.2. Clinical Variables
A nurse (i.e., specialized on pulmonary medicine) and a
physician (i.e., specialized in ear nose and throat diseases)
collected all data at the hospital. The data comprised
weight, height, blood pressure, subjective sleep (i.e.,
sleep duration, estimated sleep need), medication and
co-morbidities. Diagnosis of diabetes mellitus was based
on a history, current treatment (oral therapy or insulin) or
a fasting blood glucose value ≥7 mmol/l. IHD was de-
fined on the basis of a history of angina pectoris and/or
myocardial infarction and/or coronary angioplasty and/or
coronary bypass surgery. Respiratory disease was prem-
ised on a history of asthma or chronic obstructive pul-
monary disease, or on current treatment (β2 agonists and/
or inhaled corticosteroids).
2.3. Self-Rating Scales
The 11 items of the Berlin Sleep Apnea Questionnaire
(BSAQ) focusing on occurrence of OSA symptoms/
characteristics (i.e., part 1; snoring, witnessed apneas,
part 2; daytime sleepiness, part 3; occurrence of obesity,
and HT) was used to measure the risk of having OSA [9].
If two of the three parts are showing an “occurrence” of
symptoms/characteristics the patient is supposed to have
a high risk of suffering from OSA. The 3 items of the
Minimal insomnia symptoms scale (MISS) were used to
measure difficulties initiating sleep, difficulties main-
taining sleep and difficulties with non-restorative sleep
[10]. The patients grade their difficulties on a scale
ranging from no problems (0), to very great problems (4).
The Epworth sleepiness scale (ESS) was used to measure
daytime sleepiness [11]. The eight items (i.e., different
daily situations in which the subjects are asked to rate the
likeliness of dozing or falling asleep) are rated on a scale
of 0 - 3 and are summarised into a score between 0 - 24
points with a cut-off of >10 indicating excessive daytime
sleepiness. The 14 items Hospital anxiety and depression
scale (HAD) was used to measure depressive symptoms
[12]. The scores from the seven depression items ranges
from 0 - 21, the higher score the more depressive symp-
toms. A cut-off of ≥7 was used to indicate depressive
symptoms. The first question concerning current health
status from the SF-36, was used to measure GPH [13].
The participants ranked their health as 1) excellent, 2)
very good, 3) good, 4) fair or 5) poor.
2.4. Recordings of Sleep Disordered Breathing
Full-night respiratory recordings were performed in the
patients’ homes, including monitoring of nasal-airflow,
pulse oximetry, respiratory movements and body position.
Data were recorded with a polygraphic equipment (Em-
bletta, Somnologica, ResMed AB, Trollhättan, Sweden)
and all recordings were scored according to the 2007
recommendations of the American Academy of Sleep
Medicine [14] by the same experienced physician who
was blinded to the results of the other data. The total
number of apneas and hypopneas was divided by the
estimated sleep time, giving the apnea-hypopnea index
(AHI). An oxygen-desaturation index (ODI) was calcu-
lated in the same manner. Patients were defined as hav-
ing mild (i.e., AHI > 5), moderate (i.e., >15) or severe

A. Broström et al. / Open Journal of Nursing 3 (2013) 445-452 447
(i.e., >30) OSA.
2.5. Statistical Analysis
Normally distributed variables were analysed with t-test,
ANOVA or Pearson correlations. Mann-Whitney test,
Kruskal-Wallis test, Chi-square test or Spearman rank
correlations were used on non-normally distributed or
dichotomous variables. To examine if AHI was inde-
pendently associated with perceived health, nested linear
regression analysis was used. Before entering the regres-
sion model, AHI was logarithmic transformed to normal-
ity. Adjustments were made for theoretically selected
covariates (i.e., gender, diabetes, IHD, respiratory dis-
ease, body mass index (BMI) and depressive symptoms)
and subjective sleep complaints (i.e. , non-restorative
sleep) with the highest correlation to perceived health.
The significance level was set to p < 0.05. All statistical
analyses were performed with the PASW statistics 18
(IBM Inc., USA).
3. RESULTS
3.1. Study Population
Of the 918 patients 12% (50 men and 59 women) were
omitted from participation due to exclusion criteria’s and
28% (170 men and 159 women) chose not to participate.
Of the 480 patients who participated in the clinical ex-
amination 411 accepted respiratory recordings. Seven-
teen recordings were lost due to technical problems. Thus,
the final study population consisted of 394 patients.
Population characteristics, co-morbidities and medica-
tions are given in Table 1.
3.2. Prevalence of OSA and Depressive
Symptoms
Fifty-nine percent of the 394 patients had OSA (AHI ≥ 5).
Mild, moderate and severe OSA occurred among 29%,
16% and 14% of the patients, respectively. Average ODI
was twice and five times as high in the groups with mo-
derate and severe OSA (20.0 and 45.6, respectively) com-
pared to those with mild OSA (7.9) (p < 0.001) (Table 1).
Neither systolic, diastolic blood pressure nor medication
differed between the three groups of patients with OSA,
or compared to patients without OSA. BMI was signifi-
cantly associated with AHI (p < 0.001). Obesity (BMI ≥
30) was seen in 30%, 43% and 68% of the patients with
mild, moderate and severe OSA, respectively.
Diabetes was more prevalent among patients with at
least mild OSA (p = 0.04, χ2 3.8). Neither history of IHD
nor respiratory disease was associated with severity of
OSA. Prevalence of depressive symptoms in relation to
severity of OSA is presented in Table 2 . A total of 16%
had a HAD score ≥ 7. A larger proportion of men than
women had depressive symptoms, 21% vs. 12% (p <
0.01).
3.3. Association of OSA to Sleep Complaints,
Depressive Symptoms and GPH
Patients with moderate or severe OSA had longer sleep
duration compared to those with mild or no OSA (p <
0.01). The total HAD score was not associated with the
degree of OSA. Patients without OSA had better GPH
compared to individuals with at least mild OSA (p <
0.01). Depressive symptoms, non-restorative sleep, dif-
ficulties maintaining sleep, difficulties initiating sleep
and BMI were the variables with the strongest correla-
tions to perceived health. AHI and ODI were also sig-
nificantly related to GPH (Table 3).
Table 4 shows that patients with depressive symptoms
had more difficulties maintaining sleep (p = 0.004), non-
restorative sleep (p = 0.008) and GPH (0.001), but no
differences were seen regarding sleep duration, sleep
need, difficulties initiating sleep or daytime sleepiness.
AHI was significantly associated with GPH after adjust-
ment for gender and co-morbidities (block 3, Table 5).
After adding BMI to the model in block 4 AHI and dia-
betes became non-significant. Depressive symptoms and
non-restorative sleep explained almost 22% of the vari-
ance in GPH.
4. DISCUSSION
An important result of relevance for nursing care was
that a large proportion of hypertensive outpatients had
objective evidence of OSA, but there was no association
to blood pressure. Depressive symptoms were common,
but not clearly related to OSA. Gender, respiratory dis-
ease, BMI, depressive symptoms and non-restorative
sleep explained 33% of the variance in GPH. The preva-
lence of OSA in this study (59%) is larger than that
found in other large community-based general popula-
tion studies, which is somewhat surprising given that the
average BMI in this Swedish study was lower than that
in previous North American studies. For example, the
Sleep Heart Health Study [15] and the Wisconsin Sleep
Cohort Study [16] documented OSA prevalence rates
between 22% - 46%. We included only patients with HT,
which may be an explanation for the difference. Our
finding is in line with Worshop et al. [17], which found
that 38% of 68 hypertensive patients had OSA, regard-
less of hypertensive treatment, compared to 4% among
normotensive controls. A previous study [18] of men
with therapy-resistant HT found that 56% had OSA,
compared with 19% in successfully treated hyperten-
sive’s matched for age and gender.
Two other previous studies [19,20] observed different
rates, but different designs and other scoring criteria’s

A. Broström et al. / Open Journal of Nursing 3 (2013) 445-452 448
Table 1. Characteristics, medication and comorbidities across the groups for obstructive sleep apnea (n = 394).
AHI
Characteristics
<5
No
Obstructive Sleep
Apnea
n = 160, 41%
≥5
Mild
Obstructive Sleep
Apnea
n = 113, 29%
≥15
Moderate
Obstructive Sleep
Apnea
n = 64, 16%
≥30
Severe
Obstructive Sleep
Apnea
n = 57, 14%
p
Gender:
Men n (%) 61 (38) 56 (50) 29 (45) 39 (68)
Women n (%) 99 (62) 57 (50) 35 (55) 18 (32) 0.001
Age:
mean (sd) 57.3 (6.8) 57.8 (7.6) 58.6 (5.5) 58.2 (6.1) NS
Sleep disordered breathing
AHI, m (sd) 2.1 (1.48) 8.8 (2.8) 21.8 (4.4) 49.3 (19.2) 0.001
ODI, m (sd) 2.0 (1.5) 7.9 (3.1) 20.0 (4.9) 45.6 (20.5) 0.001
SaO2-M, m (sd) 94.4 (7.5) 94.0 (3.9) 93.4 (1.7) 92.6 (1.7) 0.001
SaO2-N, m (sd) 88.7 (7.4) 84.2 (8.6) 78.8 (11.3) 75.0 (11.6) 0.001
Total desat, m (sd) 13.8 (12.2) 52.4 (24.0) 128.5 (48.9) 270.3 (158.8) 0.001
Time below 90%, m (sd) 0.5 (4.7) 1.4 (4.8) 6.7 (12.7) 14.6 (13.2) 0.001
Blood pressure:
SBP, mean (sd) 138.8 (17.4) 142.5 (15.7) 140.0 (17.6) 140.0 (19.2) NS
DBP, mean (sd) 86.5 (9.6) 87.9 (10.2) 86.0 (10.7) 89.1 (13.5) NS
BMI:
mean (SD) 27.0 (4.3) 29.0 (4.8) 30.1 (5.6) 31.4 (4.6) 0.001
Medication:
CA-blockers, n (%) 27 (17) 22 (20) 14 (22) 16 (28) NS
B-blockers, n (%) 72 (45) 49 (43) 32 (51) 29 (51) NS
ACEI/ARB, n (%) 90 (56) 66 (58) 34 (53) 33 (58) NS
Digoxin, n (%) 0 (0) 0 (0) 1 (0) 0 (0) NS
Diuretics, n (%) 50 (31) 36 (32) 24 (38) 18 (32) NS
Number of hypertensive drugs, m (sd) 1.49 (0.75) 1.53 (0.82) 1.76 (0.87) 1.74 (0.78) NS
Hypnotics, n (%) 10 (6) 4 (3) 4 (6) 0 (0) NS
Anti-depressant, n (%) 10 (6) 15 (13) 7 (11) 6 (11) NS
Comorbidities:
Diabetes, n (%) 20 (13) 22 (20) 11 (17) 14 (24) NS
IHD, n (%) 20 (13) 14 (13) 11 (17) 13 (23) NS
HC, n (%) 40 (26) 33 (30) 20 (31) 21 (37) NS
RD, n (%) 10 (6) 6 (5) 4 (6) 4 (7) NS
TIA/Stroke, n (%) 3 (2) 2 (2) 0 (0) 3 (5) NS
The AASM criteria were used when patients were categorized into OSA groups based on apnea-hypopnea index <5, ≥5, ≥15 or ≥30. Significant p-values are
bolded. Key: ACEI—Angiotensin converting inhibitor; ARB—Angiotensin receptor blockers; AHI—Apnea-hypopnea index; B-blockers—Beta blockers;
BMI—Body mass index; DBP—Diastolic blood pressure; HC = Hypercholesterolemia, IHD—Ischaemic heart disease; ODI— Oxygen desaturation index;
RD—Respiratory disease; SaO2-M—Mean saturation, SaO2-N—Nadir saturation, SBP—Systolic blood pressure; SD— standard deviation; TIA/stroke—Trans
ischaemic attack/stroke.
were used. Sjöström et al. [19] found in a stratified sam-
ple of hypertensive men that 37% had AHI > 10. In a
community-based case-control study, Hedner et al. [20]
found a prevalence of 82% (AHI > 10) in middle-aged
patients with both HT and diabetes. They also noted a
higher prevalence of severe OSA (AHI > 30), 47% of
men and 24% of women. Comparing our data with those
from Hedner’s sample is difficult, since the metabolic
syndrome is one of the best predictors for OSA [21].
hese high prevalence figues imply that screening of T
r

A. Broström et al. / Open Journal of Nursing 3 (2013) 445-452 449
Table 2. Self-rated sleep, daytime sleepiness, depressive symptoms and perceived health across the severity groups for obstructive
sleep apnea (n = 394).
AHI
Characteristics
<5
No
Obstructive Sleep
Apnea
n = 160, 41%
≥5
Mild
Obstructive Sleep
Apnea
n = 113, 29%
≥15
Moderate
Obstructive Sleep
Apnea
n = 64, 16%
≥30
Severe
Obstructive Sleep
Apnea
n = 57, 14%
p
Self-rated sleep:
Sleep duration, hours, m (sd) 6.7 (1.0) 6.5 (1.2) 7.0 (1.1) 7.0 (1.2) NS
Estimated sleep need, hours, m (sd) 7.6 (0.7) 7.8 (0.9) 7.9 (1.1) 7.9 (0.8) NS
Sleep sufficiency index, %, m (sd) 0.88 (0.13) 0.85 (0.14) 0.89 (0.15) 0.89 (0.16) NS
Self-rated symptoms of obstructive sleep apnea:
High risk on BSAQ, n (%) 92 (59) 95 (84) 58 (92) 49 (89) 0.001
Low risk on BSAQ, n (%) 63 (41) 18 (16) 5 (8) 6 (11) 0.001
Snoring, n (%) 102 (66) 97 (87) 60 (94) 53 (95) 0.001
Witnessed apneas, n (%) 13 (8) 20 (18) 18 (29) 26 (47) 0.001
Insomnia symptoms:
Difficulties initiating sleep, n (%) 17 (11) 15 (13) 4 (6) 3 (6) NS
Difficulties maintaining sleep, n (%) 31 (20) 28 (26) 15 (24) 7 (13) NS
Difficulties with non-restorative sleep, n (%) 24 (15) 26 (23) 13 (21) 9 (16) NS
Daytime sleepiness:
Total ESS score, m (sd) 7.8 (4.4) 7.8 (4.0) 8.0 (4.7) 8.7 (4.3) NS
ESS > 10, n (%) 53 (34) 32 (28) 21 (33) 24 (42) NS
Depressive symptoms:
HAD total score, m (sd) 3.7 (2.5) 4.2 (2.5) 3.9 (2.6) 4.3 (2.7) NS
Yes (HAD ≥ 7), n (%) 19 (12) 22 (19) 9 (14) 12 (21) NS
Perceived health:
m (sd) 2.98 (0.85) 3.24 (0.86) 3.21 (0.68) 3.3 (0.91) 0.04
The AASM criteria were used when patients were categorized into OSA groups based on apnea-hypopnea index <5, ≥5, ≥15 or ≥30. Significant p-values are
bolded. Key: BSAQ—Berlin Sleep Apnea Questionnaire, ESS—Epworth sleepiness scale, HAD—Hospital Anxiety and depression Scale.
Table 3. Correlations between demographics, sleep apnea variables, sleep complaints, depressive symptoms and perceived health in
patients with hypertension (n = 394).
Variables Perceived health
p
Gender 0.03 NS
Apnea hypopnea index 0.16 0.02
Oxygen desaturation index 0.17 0.001
SaO2-M − 0.10 NS
SaO2-N − 0.12 0.02
Total desaturations 0.13 0.009
Time below 90% 0.08 NS
Systolic blood pressure 0.04 NS
Diastolic blood pressure − 0.05 NS
Body mass index 0.27 0.001
Diabetes 0.14 0.005
Ischemic heart disease 0.15 0.005
Respiratory disease 0.16 0.002
Total night sleep hours − 0.04 NS
Estimated sleep need 0.21 0.001
Sleep sufficiency index − 0.20 0.001
Difficulties initiating sleep 0.23 0.001
Difficulties maintaining sleep 0.25 0.001
Non-restorative sleep 0.42 0.001
ESS score 0.12 0.02
HAD score 0.38 0.0001
Key: ESS—Epworth sleepiness scale, HAD—Hospital anxiety and depression scale, SaO2-M—Mean saturation, SaO2-N—Nadir saturation.

A. Broström et al. / Open Journal of Nursing 3 (2013) 445-452 450
Table 4. Self-rated sleep, insomnia symptoms, daytime sleepiness and perceived health in patients with hypertension (n = 394) with
respect to degree of depressive symptoms.
Characteristics
No
Depressive symptoms
HAD < 7
n = 332, 84%
Depressive symptoms
HAD ≥ 7
n = 62, 16%
p
Gender:
Men, n (%) 146 (44) 39 (63)
Women, n (%) 186 (56) 23 (37) 0.008
Age, mean (SD)
Self-rated sleep:
Total night sleep, hours, m (sd) 6.75 (1.06) 6.64 (1.3) NS
Estimated sleep need, hours, m (sd) 7.73 (0.86) 7.82 (0.80) NS
Sleep sufficiency index, %, m (sd) 0.88 (0.13) 0.85 (0.17) NS
Insomnia symptoms:
Difficulties initiating sleep, n (%) 27 (8) 12 (19) NS
Difficulties maintaining sleep, n (%) 60 (18) 21 (34) 0.004
Difficulties with non-restorative sleep, n (%) 53 (16) 19 (31) 0.008
Daytime sleepiness:
Total score, m (sd) 7.9 (4.2) 8.4 (4.7) NS
ESS > 10, n (%) 107 (82) 23 (18) NS
Perceived health:
m (sd) 3.0 (0.84) 3.7 (0.74) 0.001
Key: AHI—Apnea-hypopnea index; ESS—Epworth sleeiness scale, DS—Depressive symptoms.
OSA in patients with HT in primary care should be per-
formed. OSA-related apneas and desaturations are im-
portant both for self-rated sleepiness (i.e., due to in-
creased number of awakenings and a disturbed sleep
structure) and for cardiovascular disease (i.e., by sympa-
thetic activation and increased levels of catecholamine’s,
causing inflammation, arterial stiffness and atherosclero-
sis) [22]. Continuous positive airway pressure, often ini-
tiated and managed by nurses, can reduce cardiovascular
morbidity and mortality [23,24], particularly in adherent
patients with severe OSAS.
Blood pressure reductions have been found especially
in sleepy patients [25-27] with frequent desaturations,
but also when hypertension is severe, untreated or re-
fractory [22]. Surprisingly, we found no association be-
tween OSA severity and blood pressure, GPH, or self-
rated sleepiness in contrast to previous studies where a
dose-response relationship was found between night-time
blood pressure and increasing AHI [16,22]. However,
this may be due to the fact that our patients were already
regularly followed and controlled, mostly successfully, at
nurse-led outpatient clinics for hypertension. Further-
more, we found that more than 50% of those with severe
OSA (i.e., AHI ≥ 30) scored <10 on the ESS, thus indi-
cating a lack of excessive daytime sleepiness. We used
validated questionnaires [9-13], but did not evaluate pa-
tients who had sought medical attention for OSA, which
might explain the lower amount of sleeping difficulties,
daytime sleepiness and depressive symptoms found com-
pared to samples from sleep clinics [23-28]. This finding
sheds light on the difficulties that nurses may have in
identifying patients with OSA in primary care [29].
More studies set in primary care are needed to explore
symptom profiles and clinical characteristics of patients
with OSA. Research thus far has predominantly been
performed in other settings [15,16,21]. Knowledge from
primary care studies can facilitate nurses to identify pa-
tients with a high cost-benefit for referral to sleep clinics.
Questionnaires, such as the BSAQ [9,30] and simple two
channel recording devices [31] may be suitable for
nurses working at hypertensive clinics in primary care to
identify patients. However, they are not comparable to
validated diagnostic tools, such as polygraphy or poly-
somnography, and need to be more thoroughly evaluated
regarding sensitivity and specificity. Limitations of this
study include the cross-sectional design and the
relatively low participation rate. Stratifying men and
women with different levels of OSA will strengthen the

A. Broström et al. / Open Journal of Nursing 3 (2013) 445-452 451
Table 5. Linear regression model for perceived health in pa-
tients with hypertension (n = 394).
Variable Beta R2 R
2 changep
Block 1
AHI log10 0.133
0.015 0.018 0.013
Block 2
AHI log10 0.158 0.004
Gender (Male 1, female 2) 0.104 NS
0.028 0.010 0.008
Block 3
AHI log10 0.142 0.010
Gender 0.124 0.024
Ischemic heart disease 0.063 NS
Diabetes 0.117 0.028
Respiratory disease 0.160 0.002
0.073 0.045 0.001
Block 4
AHI log10 0.064 NS
Gender 0.118 0.027
Ischemic heart disease 0.073 NS
Diabetes 0.069 NS
Respiratory disease 0.141 0.007
Body Mass Index 0.231 0.001
0.116 0.043 0.001
Block 5
AHI log10 0.065 NS
Gender 0.112 0.017
Ischemic heart disease 0.085 0.060
Diabetes 0.074 NS
Respiratory disease 0.104 0.021
Body Mass Index 0.160 0.001
HAD score 0.270 0.001
Non-restorative sleep 0.311 0.001
0.331 0.215 0.001
Key: ESS—Epworth sleepiness scale, HAD—Hospital anxiety and depres-
sion scale, SaO2-M—Mean saturation, SaO2-N—Nadir saturation.
treatment evidence for nursing care interventions. Still,
these results suggest that snoring patients with hyperten-
sion, elevated BMI and/or diabetes should be investi-
gated for OSA. Treating OSA may positively influence
hypertension, sleep quality, depression, and GPH, al-
though further nursing research is needed to confirm
such a benefit.
5. ACKNOWLEDGEMENTS
The Swedish Heart Lung Foundation, Grant 20090547.
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