Prevalence of probable obstructive sleep apnea risk and severity in a population of dental patients
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- Levendowski, D.J., Morgan, T., Montague, J. et al. Sleep Breath (2008) 12: 303. doi:10.1007/s11325-008-0180-z
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Obstructive sleep apnea is a commonly undiagnosed chronic disease. While dentists represent an important resource for identifying people at risk for primary snoring and sleep apnea, less than 50% of dentists are capable of identifying the common signs and symptoms of sleep disordered breathing. The aim of this study is to assess the prevalence of probable obstructive sleep apnea/sleep disordered breathing and symptoms associated with this condition in a population of dental patients using a validated questionnaire and software that could be administered in a dental office. A retrospective analysis conducted at two dental practices using questionnaire responses obtained from 175 men and 156 women, and sleep study data obtained in the patient’s homes from 75 men and 30 women with a portable recorder. Forty-six percent of the men and 19% of the women reported snoring frequently or always. Of the 67% of the men and 28% of the women identified as having a high pre-test probability (high risk) of having at least mild sleep apnea, over 33% of the men and 6% of the women surveyed were predicted to have moderate or severe sleep apnea. In a subgroup of 105 patients classified at high risk who completed an overnight sleep study, 96% had an apnea hypopnea index (AHI) greater than five events per hour. Seventy percent of those predicted to have moderate or severe OSA by questionnaire had an AHI greater than 20. All patients previously diagnosed with sleep apnea were correctly classified at high risk by ARES questionnaire. There was a high concordance between the predicted OSA risk and the degree of sleep disordered breathing. The high prevalence of undiagnosed sleep apnea in dental patients suggests that dentists could provide a valuable service to their patients by incorporating sleep apnea screening and treatment into their practice. Those who practice sedation dentistry should consider additional precautions when managing patients with risk of sleep apnea.
KeywordsSleep apneaSleep disorder breathingHome monitoringPrevalenceOSA severityOSA risk
Obstructive sleep apnea (OSA) has recently gained recognition as one of the most common, under-diagnosed chronic diseases [1, 2] and is responsible for more mortality and morbidity than any other sleep disorder . It is characterized by frequent loud snoring and recurrent failures to breathe adequately during sleep (termed apneas or hypopneas) as a result of full or partial collapse of the upper airway. OSA causes increased accident risk because of daytime drowsiness and has been associated with hypertension, increased risk of congestive heart failure, coronary artery disease, myocardial infarction, cardiac arrhythmias, diabetes, and stroke [4–9].
In 1993, a large study of a middle-aged workforce estimated that 4% of men and 2% of women met the criteria for sleep apnea syndrome [i.e., Apnea Hypopnea Index (AHI) of five or more events per hour and hypersomnolence], and 24% and 9%, respectively, had sleep disordered breathing (i.e., AHI ≥ 5). More recent reports suggest that the prevalence of OSA is increasing in part due to the rise in obesity, a major risk factor for OSA. In 1993, obesity, based on a body mass index (BMI) ≥30, impacted 15–19% of the population in one quarter of the USA . In 2006, 92% of the US states reported obesity rates in excess of those considered extreme in 1993 (i.e., 15–19%). Almost half of the US states now report at least 25% of their population is obese . The prevalence of OSA has shown a corresponding increase. In St. Louis, MO, USA, where the obesity rate is 28%, 19% of an adult surgical population was estimated to have moderate, severe, or very severe OSA . A telephone survey conducted by the National Sleep Foundation found that 31% of men and 21% of women met the Berlin questionnaire criteria, indicating a high risk of OSA . In another recent study, 53% of the male transportation workers were identified as being at “high risk” of OSA with 22% predicted to have severe OSA using the ARES questionnaire .
The aim in this study was to assess the prevalence of probable OSA in a population of dental patients.
Materials and methods
The ARES analyses provides classifications of OSA risk (i.e., those in need of a sleep study), which includes “high risk” [i.e., predicted apnea/ hypopnea index (AHI) five or more events per hour), “low risk” (i.e., not classified as high-risk but indications such as co-morbid disease, high BMI or neck circumference plus hypersomnolence, etc.), or “no apparent risk” (AHI < 5). The OSA severity categories include minimal (predicted AHI < 5), mild (AHI = 6–20), moderate (AHI = 21–40), and severe (AHI > 40).
The first dental practice had no prior experience treating OSA or fitting mandibular repositioning devices (MRD). Two-hundred and twenty-nine consecutive ARES questionnaire responses were obtained from patients upon arrival for a scheduled dental appointment.
The second dental office had been fitting MRDs for the treatment of OSA for over 15 years. For this practice, questionnaires were mailed to 870 patients between the ages of 45 and 80 years and who were not being treated by the dentist for OSA. Of the 108 returned responses, 102 were complete and could be used for analysis (12.4% response rate).
T tests and chi-squared analysis were used to assess differences in the demographics and prevalence between the two dental practices.
Demographic and anthropomorphic characteristics
Site 2—mailed survey
Male (n = 124)
Female (n = 105)
Male (n = 51)
Female (n = 51)
Male (n = 175)
Female (n = 156)
Mean ± SD
52 ± 14.0
55 ± 15.8
55 ± 9.2
56 ± 7.7
53 ± 12.8
55 ± 13.7
42 ± 2.7
35 ± 3.3
42 ± 2.7
34 ± 3.6
42 ± 2.7
35 ± 3.4
Body mass index
28 ± 4.6
26 ± 6.1
27 ± 3.6
23 ± 4.9
28 ± 4.3
25 ± 5.8
7 ± 5.1
6 ± 4.1
7 ± 4.8
6 ± 4.5
7 ± 5.0
6 ± 4.2
High blood pressure
Obstructive sleep apnea
The average BMI across all participants was relatively low with only 19% of those surveyed reporting a BMI in the obese range. An equivalent percentage of men and women reported high blood pressure (29.1% and 25.0%, respectively) when the responses from the two sites were combined. A significantly greater number of women reported high blood pressure when the responses were obtained consecutively vs. the mailed survey (28.6% vs. 17.6%). All 24 of the dental patients previously diagnosed with OSA were correctly classified with as high risk of OSA and 75% were predicted to have moderate or severe OSA.
Distribution of responses typically used to identify OSA
Rarely 0–1/week (%)
Sometimes 1–2/week (%)
Frequent 3–4/week (%)
Almost always 5–7/week (%)
In the past month, snored or told you snored?
Do you wake up choking or gasping?
Told you stop breathing or wake up choking or gasping?
Distribution of predicted OSA severity stratified by OSA Risk for all dental patients
No apparent risk
Possibly, as a result of the age of the surveyed population, only 25% of the men and 60% of the women had no apparent risk of having OSA (Fig. 3), while 34% and 6%, respectively, were predicted to have moderate or severe OSA (Table 3). Of those who completed a sleep study, 96% were confirmed to have at least mild sleep-disordered breathing (i.e., AHI > 5). The term high risk was used to characterize patients who should be considered for a sleep study; however, an asymptomatic patient with an AHI of five does not suggest a perilous condition. Of interest, 70% of the patients classified at high risk by questionnaire (and previously undiagnosed) exhibited sleep-disordered breathing of at least 15 events per hour, a threshold commonly used to refer patients for treatment of OSA.
The prevalence of high risk by the ARES questionnaire in female dental patients was similar to women between 50 and 64 years classified as OSA risk by the Berlin questionnaire in the National Sleep Foundation (NSF) survey (i.e., 29%) . Comparatively, the percentage of male dental patients classified as high-risk OSA (68%) was almost twice the number of men between 50–64 years classified at OSA risk (37%) in the NSF survey. The sensitivity and specificity of the two instruments are similar . The prevalence of OSA risk in these dental populations was similar to that reported in preoperative patients (12). In a population of male transportation workers, those classified as high-risk of OSA by ARES questionnaire was 50%, compared with 68% in male dental patients . The increased prevalence in this study may be explained by differences in the mean age of the transportation workers and dental patients (i.e., 41 and 53 years, respectively), given that the risk of OSA increases with age .
The subgroup of patients who completed sleep studies was selected based on the need to rule out individuals for a clinical study protocol. Thus, one of the limitations of this study was that the sensitivity and specificity of the ARES questionnaire could not be cross-validated against the previous report (i.e. 0.94 and 0.76, respectively). The positive predictive value of the instrument in this community-based population, however, was slightly better than that of the previous observation (i.e., 0.96 vs. 0.91, respectively) .
The proportion of patients classified with severe OSA by questionnaire that had an AHI greater than 40 was less than previously reported . This is likely a result of developing the predictive model using questionnaire responses from a more select group of patients with a greater likelihood of having severe disease (e.g., suspected of having OSA or preoperative patients, etc.) vs. questionnaire responses from a community based population. It should be noted that, in both the model development data set and this community-based population, the same percentage of those with an AHI greater than 20 were predicted to have moderate or severe OSA (i.e., 70%).
In this survey, 46% of men and 19% of women snored at least three times per week, and 37% and 15%, respectively, reported witnessed apneas. Comparatively, 37% of Hong Kong bus drivers (96% male) reported snoring at a similar frequency, while only 8% reported witnessed apneas .
The mean percentage of dental patients with high blood pressure (27%) and heart disease (7%) was similar to those surveyed by the NSF (29% and 10%, respectively) . Nineteen percent of the dental patients in this study were considered obese (BMI > 30), while the reported obesity in California is between 20% and 25%. The prevalence of diabetes in this study (5%) was less than the 11% reported in the NSF survey, possibly as a result of the lower BMIs. The mean BMI and prevalence of obesity in this population may be low in comparison to other regions of the USA as a result of the socioeconomic factors favoring these two dental practices.
One of the goals of this study was to assess whether the prevalence of OSA risk obtained by questionnaire would be impacted by the method used to obtain the responses, as either might be appropriate for surveying a dental population. These data suggest that the prevalence of OSA risk will not be significantly biased whether responses are obtained consecutively in person or from a direct mailing.
The percentage of dental patients found to have a high pretest probability of having undiagnosed OSA was substantially greater than previous prevalence estimates. Given the high concordance between the predicted OSA risk and the degree of sleep disordered breathing, these results suggest that dentists could provide a valuable service to their patients by incorporating sleep apnea screening and treatment into their practice. Those who practice sedation dentistry should consider additional precautions when managing patients with risk of sleep apnea.
This study was funded by the National Institute of Dental and Craniofacial Research (NIDCR-DE016772). Daniel Levendowski, Chris Berka, and Philip Westbrook are employees of and shareholders in Advanced Brain Monitoring.
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