Sleep Apnea Treatment

Epidemiology

The prevalence of the OSAHS ranges from 4-6% in men and in 2-4% of women among the general adult population of middle-aged figure, which increases markedly with age. The diagnosis is difficult to access so it is one of the main problems faced by specialists, it is estimated that only 5-9% of the population with relevant tax treatment has an OSAHS. Clinical research seeks alternatives to the costly polysomnography diagnostic, which is currently the gold standard.

Sleep apnea is, along with insomnia, one of the most common sleep disorders. But unlike insomnia, comparable to epidemiological data, the OSAHS is a rare disease known by the general population. The lack of diagnosis is the major medical problem to be solved. Recent studies show, that only 6% of medical records developed in primary care, include explicit references to possible disorders during sleep. This underdiagnosis implies have fatal consequences, because the pathology is ignored by patients, who, without being diagnosed, do not know how to justify and cope with the symptoms that they face every day.

In 1993 the "New England Journal of Medicine" published the first study of the prevalence of OSAHS of Young et al, that describes a random sample of 602 workers (male and female) aged between 30 and 60. The importance of this study is, that it showed obvious advantages to the elderly ones, because the previous epidemiological surveys on the prevalence of OSAHS were severely limited by a relatively small number of persons and restricted only to male subjects. Through nocturnal polysomnography, the AHI (apnea / hypopnea index) was calculated, according to sex and age variables. The study concludes, that the estimated prevalence of OSAHS, defined as AHI greater than 5 or equal, was 9% in women and 24% men. Extrapolating the data to the general population, they estimated that 2% of women and 4% of middle-aged active men, match the minimum criteria for the diagnosis of sleep apnea syndrome. The results also reflected that male sex and obesity are strongly associated with the presence of OSAHS. Habitual snorers, without gender distinction, tend to have a higher prevalence of sleep apnea-hypopnea index of 15 or more episodes per hour, a respiratory disturbance level, that merits clinical consideration for treatment. The high prevalence shown in the study of Young et al banished any tendency to discriminate medically OSAHS as a public health problem of first magnitude.

Despite th lack of recent samplings on the epidemiology of SBD in Spain, an estimated 2-4% meets the criteria for SAHS. In over 65% years, the percentage rises to 25%. One of the most complete spanish population sampling was published in 2001 in the "American Journal of Respiratory and Critical Care Medicine", which shows similar results of incidence of the desease to other international studies. This study by Duran et al, estimated the prevalence of OSA among a representative sample of the general population mixed between 30 to 70 years old people, considering also the wide spectrum of clinical features, including hypertension associated with breathing disorders. The study was conducted between July 1993 and November 1997 among a random sample population of 2,148 subjects from Victoria, who were between 30-70 years old. The study was structured in two phases. At first, 100% of the subjects with the questionnaire at home and portable polysomnography were assessed. The questionnaire included questions about sleep-disordered breathing (snoring), somnolence, symptoms, medical history, medication use, alcohol consumption, cigarette smoking, demographic and anthropometric data. The clinical examination included measures of neck circumference, peak flow and blood pressure. Subsequent in the portable polysomnography four channels were monitored: heart rate, snoring, oxygen saturation and body position. In a second phase of the study, a subgroup of OSAHS patients diagnosed provisionally as those who underwent night conventional polysomnography in a sleep laboratory, were evaluated. The anylized conclusion was: the presence of habitual snoring was found in 35% and pauses in breathing in 6%. Both features occurred more frequently in men with a tendency to increase with age and were significantly associated with obstructive sleep apnea. Daytime sleepiness was present in 18% of the subjects, that were not associated with OSAHS. An apnea-hypopnea index (AHI)> 10 was found in 19% of men and in 15% of women. The prevalence of OSAHS (AHI> 5) increased with age in both sexes. The AHI was associated with hypertension after adjusting age, sex, body mass index, neck circumference, alcohol consumption and smoking. This study shows the link between OSA and hypertension.

The results of prevalence in Spain range between the different authors. In a study published in 1997 on a sample of 1360 adults in the metropolitan area of Zaragoza, Marin et al.finds evidence of OSA (defined as snoring, excessive daytime sleepiness and nocturnal oximetry more than 10 episodes of desaturation of at least 4%) in 2.2% of men and 0.8% of women. In 1995, Zamarrón et al noted, that on 693 individuals between 20 and 70 years drawn from general population, 6.8% had an index of episodes greater than or equal to 5 accompanied by snoring and excessive daytime sleepiness. Finally, Solans et al in a study in Mataró, found that 10% of men and 3.4% of women in their sample, aged between 30-70 years, have an AHI greater than or equal to 10 and a score of Epworth sleepiness scale greater than 10. All studies conclude in a high prevalence of OSAHS a proven relationship with hypertension, higher incidence in males and a progressive increase with age. But in the case of the OSAHS, it has also be taken into account the dates of underdiagnosis.

Studies detect, that only approximately 5-10% of the population with relevant OSAHS are diagnosed and treated and it is estimated that in Spain there are 2 million people with sever OSAHS, which require emergency treatment, most of them still undiagnosed. In this sense has to be mentioned a very interesting study on cases of undiagnosed OSA made to 502 patients attending the otolaryngology consultation because of sleep disorders. After interrogation and exploration of the UA, the cases with clinical suspicion of OSAHS (14 7%), underwent nocturnal polysomnography. The results suggested, that the subgroup under polysomnographic sleep study obtained an index of apnea / hypopnea index, up to 5, which means 4.78% of the subjects. The authors concluded that "untreated patients have a higher risk of cardiovascular and neurological complications, higher accident rates, reduced quality of life and increased health care consumption. It is therefore necessary to reduce these consequences by early diagnosis and treatment. "