Clinical Trial Details
— Status: Completed
Administrative data
| NCT number |
NCT02515357 |
| Other study ID # |
46 |
| Secondary ID |
|
| Status |
Completed |
| Phase |
N/A
|
| First received |
|
| Last updated |
|
| Start date |
September 7, 2015 |
| Est. completion date |
January 10, 2020 |
Study information
| Verified date |
January 2021 |
| Source |
Harokopio University |
| Contact |
n/a |
| Is FDA regulated |
No |
| Health authority |
|
| Study type |
Interventional
|
Clinical Trial Summary
Obstructive sleep apnea (OSA) is a sleep disorder characterized by recurrent episodes of
partial or complete collapse of the upper airway during sleep, leading to pauses of breathing
and arousals. Although previously considered as a local abnormality of the respiratory track,
it is nowadays recognized as a systemic disease and an important cause of morbidity and
mortality, since it is strongly associated with obesity (especially abdominal obesity) and
cardiometabolic diseases, including cardiovascular diseases and diabetes mellitus.
Interestingly, recent hypotheses support that the metabolic syndrome pathology, including
insulin resistance, inflammation and oxidative stress may be involved in OSA pathogenesis.
The modification of lifestyle habits, e.g. in terms of diet and physical activity, is
currently explored as a mean of managing the disease in combination with the first line
treatment, i.e., the application of continuous positive airway pressure (CPAP) during sleep.
The available data support that weight loss, achieved through lifestyle modification,
effectively reduces the severity of OSA and improves the associated cardiometabolic disorders
in overweight or obese patients. However, studies exploring the potential effect of diet's
quality or other lifestyle habits (such as physical activity) on OSA severity, besides weight
loss, are currently lacking. Given that a Mediterranean dietary pattern, as well as other
lifestyle habits adopted by the populations in the Mediterranean region, have been proven
beneficial both for the prevention and the resolution of the metabolic syndrome and its
associated cardiometabolic diseases, the aim of the present randomized, controlled,
single-blind study is to implement an intensive intervention based on the Mediterranean
lifestyle (hypocaloric diet and 7 group lifestyle counselling sessions) and to evaluate its
potential benefits, compared with standard care (hypocaloric diet and written advice for
healthy lifestyle), in a sample of patients with OSA.
Description:
Obstructive sleep apnoea (OSA) is a chronic disease characterized by recurrent complete or
partial interruptions of breathing during sleep due to obstruction of the upper airways,
which leads to disturbances in gas exchange, hypoxia and consequent arousals. Beyond its
adverse impact on sleep duration, sleep quality, as well as the functionality and cognitive
function during the day (typical symptoms include fatigue, sleepiness, decreased reflexes,
impaired memory, etc.). OSA is currently recognized as a major cause of morbidity and
mortality due to its strong association with obesity and cardiometabolic diseases, including
the metabolic syndrome (and its individual components, namely abdominal adiposity, impaired
fasting glucose, dyslipidaemia and hypertension), cardiovascular diseases and diabetes
mellitus. According to epidemiological data, its prevalence ranges from 2% to 7% in the
general population (with a clear lead of obese middle-aged men), however it is estimated that
a large proportion of patients (70-80%) remain undiagnosed making the disease a major public
health challenge for the 21st century. Currently, the first line treatment for the management
of moderate-to-severe OSA or mild OSA accompanied by symptoms (such as daytime sleepiness and
cognitive disorders) and other diseases (such as hypertension and heart disease) is the
application of continuous positive airway pressure (CPAP) during sleep, usually via a renal
mask. CPAP has been proven effective in alleviating the symptoms of the disease (e.g. pauses
of breathing during sleep and daytime sleepiness), however it is also characterized by high
rates of non-compliance and its effectiveness in improving cardiometabolic indices has not
yet been confirmed.
Given the strong relationship of OSA with obesity and its concomitant metabolic disorders, as
well as the aforementioned restrictions of the use of CPAP as the sole treatment for the
disease, lifestyle changes have currently emerged as a promising treatment for OSA. Indeed,
several interventional studies have investigated the effect of lifestyle changes on the
treatment of OSA, focusing primarily on weight loss - achieved through a hypocaloric diet,
either solely or in combination with exercise and lifestyle counselling - and the available
data support its effectiveness in reducing the severity of the disease and improving its
associated cardiometabolic disorders in overweight patients. However, studies exploring the
potential effect of diet's quality or other lifestyle habits (such as physical activity) on
OSA severity and associated disorders, besides weight loss, are currently lacking. Given that
a Mediterranean dietary pattern, as well as other lifestyle habits adopted by the populations
in the Mediterranean region, have been proven beneficial both for the prevention and the
resolution of the metabolic syndrome and its associated cardiometabolic diseases, the aim of
the present study is to implement an intervention based on the Mediterranean lifestyle and to
evaluate its potential beneficial effect on biochemical and clinical characteristics of a
sample of patients with OSA, compared with standard care. In addition, the superiority of a
lifestyle intervention based on the Mediterranean lifestyle to a dietary intervention based
only on the Mediterranean diet will be explored, in order to evaluate possible beyond-diet
benefits of the health-promoting lifestyle of the Mediterranean that also included reguiar
physical activity, adequate rest during the day, conviviality, etc.
This study will be a randomized, controlled, single-blind clinical trial. The study sample
will consist of adult (18-65 year old), overweight or obese (Body Mass Index > 25 kg/m2)
patients with moderate or severe OSA (Apnea Hypopnea Index > 15 events/hour) confirmed
through polysomnography at the Center of Sleep Disorders of the 1st Department of Critical
Care and Pulmonary Services of "Evaggelismos" General Hospital of Athens. At baseline,
patients will be informed in detail about the study and will give their written consent.
Then, subjects will be randomly assigned to one of 3 groups: (a) the control group, receiving
CPAP therapy and written general advice for a healthy lifestyle, (b) the Mediterranean diet
group (MDG), participating in a 6-month comprehensive weight-loss dietary intervention based
on the Mediterranean dietary pattern, and (c) the Mediterranean lifestyle group (MLG),
receiving the same intensive dietary intervention as the MDG in addition to other healthy
behaviours incorporated in the traditional lifestyle of the Mediterranean.
Patients allocated in the two intensive intervention arms will attend a comprehensive
intervention, comprising seven 60-min group counselling sessions (up to 5 patients per group)
carried out in the laboratory of Clinical Nutrition & Dietetics of Harokopio University of
Athens under the supervision of experienced clinical dietitians, conducted every two weeks
for the first 2 months and every month for the following 4 months until the end of the
6-month intervention. For both the MDG and the MLG, the intervention will aim at a 5-10%
weight loss during the 6-month period and an increase in the level of adherence to the
plant-based Mediterranean diet. Specifically, all food groups of the Mediterranean diet will
be targeted according to the pattern proposed in the Mediterranean diet pyramid (e.g.
increase in the consumption of fruits, vegetables, whole grains and legumes, decrease in the
consumption of red meat and sweets, preference in olive oil as the main source of dietary
fat, prudent alcohol consumption, etc.), while beneficial culinary practices, as well as
seasonality and locality of food products consumed, will also be addressed. Patients
allocated in the MLG will additionally receive counselling on other lifestyle habits, with
emphasis on adopting a physically active lifestyle and achieving adequate rest during the day
(both night sleep and siesta nap), as parts of the healthy Mediterranean lifestyle. Dietary
or lifestyle counselling will be based on the goal setting theory, while motivational and
behavioural strategies will also be used.
The assessment of patients' clinical, laboratory and lifestyle characteristics will be
performed at baseline, at the end of the 6-month intervention and 1 year after the study
entry at the Center of Sleep Disorders of the 1st Department of Critical Care and Pulmonary
Services of "Evaggelismos" General Hospital of Athens. The evaluation will include: 1) brief
medical history assessment, 2) assessment of the severity of the disease through
polysomnography, 3) evaluation of insomnia through the Athens Insomnia Scale, 4) assessment
of daytime sleepiness through the Epworth Sleepiness Scale, 5) evaluation of the quality of
life through the SF-36 questionnaire, 6) dietary assessment through a semiquantitative food
frequency questionnaire (data from the food frequency questionnaire will be used to evaluate
participants' food group and individual food and beverage consumption, as well as their
adherence to the Mediterranean diet through the Mediterranean Diet Score) and 24-hour dietary
recalls (data from the 24-h dietary recalls will be analysed in terms of energy, macro- and
micronutrient intake using the Nutritionist Pro, version 2.2 software, as well as of meal
frequency and patterns), 7) physical activity assessment through the International Physical
Activity Questionnaire, 8) anthropometric measurements (height, weight, waist and hip
circumference), 9) blood pressure measurement and 10) fasting blood sample and urine sample
collection for laboratory measurements (lipid profile, markers of glucose metabolism, markers
of liver function, inflammatory markers, markers of oxidative stress, etc.) using automated
analysers and/or commercial ELISA kits.
