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Truckers Drive Their Own Assessment for Obstructive Sleep Apnea: A Collaborative Approach to Online Self-Assessment for Obstructive Sleep Apnea: Difference between revisions

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== 4. Results ==
== 4. Results ==
{| class="wikitable" style="text-align: left; width: 100%;"
|+ Table 1. Descriptive statistics and variable types
! Question or Variables
! Scale Type
! Mean, Median, or Mode°
|-
| ''Height''
| Continuous
| 70.29 in.
|-
| ''Weight''
| Continuous
| 240.1 lbs.
|-
| ''BMI''
| Continuous
| 33.94 kg/m<sup>2</sup>
|-
| ''Gender''
| Binary
| 91.8% Male
|-
| ''Overall Berlin Score''
| Binary
| 55.9% Positive
|-
| Have you ever nodded off or fallen asleep while driving a vehicle?
| Binary
| 20.5% Yes
|-
| Do you have high blood pressure?
| Binary
| 39.5% Yes
|-
| Do you snore?
| Categorical
| 66.2% Yes
|-
| Does your snoring bother other people?
| Categorical
| 43.4% Yes
|-
| How often do you snore?
| Ordinal&dagger;
| Median: 1-2 times a week
|-
| How often has someone noticed that you quit breathing during your sleep?
| Ordinal
| Median: Never or nearly never
|-
| How often do you feel tired or fatigued after your sleep?
| Ordinal
| Median: 1-2 times a month
|-
| During your waking time, how often do you feel fatigued, or not up to par?
| Ordinal
| Median: 1-2 times a month
|-
| How loud is your snoring?
| Ordinal
| Median: Slightly louder than breathing
|-
| colspan=3 style="font-size: 8pt" | &dagger;In our logistic regression analyses, ordinal variables were treated as univariate continuous variables ranging from 0-4 where 0 was the lowest response and 4 was the highest response.
&deg; The descriptive statistic was chosen based on the scale type of the variable in question. Continuous data, such as GPA or weight, is best described by its mean. Ordinal data, such as great, good, or bad, is best described by its median. Categorical data, such as gender or race, is best described by the mode<sup>[19]</sup>.
|}


Over the nine months of data collection, a total 595 individuals took the survey. Of these, 55.9% scored positive on the overall Berlin survey, and 78.3% were positive on objective (BMI, hypertension) section. We have no way to determine the non-completion rate of the study. We did not collect data on participants' age. The type and treatment of variable in our data set as well as descriptive statistics can be found in Table 1.  
Over the nine months of data collection, a total 595 individuals took the survey. Of these, 55.9% scored positive on the overall Berlin survey, and 78.3% were positive on objective (BMI, hypertension) section. We have no way to determine the non-completion rate of the study. We did not collect data on participants' age. The type and treatment of variable in our data set as well as descriptive statistics can be found in Table 1.  


=== 4.1. Obesity and Hypertension ===
=== 4.1. Obesity and Hypertension ===
<center>[[File:JSCM-Figure1.png]]<br />
'''Figure 1. Histogram of Body Mass Indices of 595 Self-Selected Commercial Drivers'''</center>


More than two-thirds of the respondents were obese; 69.6% had a BMI > 30 kg/m<sup>2</sup>, and 47.6% had a BMI > 33 kg/m<sup>2</sup>. 35.6% of CMVDs surveyed had a BMI > 35 kg/m<sup>2</sup>. Figure 1 presents a frequency histogram of BMIs of the respondents. Obesity correlated with snoring loudness (the louder the snoring, the greater likelihood of obesity) (p<0.05) and with hypertension (p<0.05). More than a third (39.5%) of participants reported hypertension, which correlated with feeling tired/fatigued after sleep (p<0.05)
More than two-thirds of the respondents were obese; 69.6% had a BMI > 30 kg/m<sup>2</sup>, and 47.6% had a BMI > 33 kg/m<sup>2</sup>. 35.6% of CMVDs surveyed had a BMI > 35 kg/m<sup>2</sup>. Figure 1 presents a frequency histogram of BMIs of the respondents. Obesity correlated with snoring loudness (the louder the snoring, the greater likelihood of obesity) (p<0.05) and with hypertension (p<0.05). More than a third (39.5%) of participants reported hypertension, which correlated with feeling tired/fatigued after sleep (p<0.05)


=== 4.2. Sleepy Driving ===
=== 4.2. Sleepy Driving ===
With regard to drowsy driving, 20.5% answered positively to the Berlin Questionnaire query about falling asleep while driving. Correlates of sleepy driving are reported in Table 2. Sleepy driving was not associated with BMI, hypertension (p=0.07) or gender, but strongly correlated with severity and frequency of snoring and with witnessed apneas.  
{| class="wikitable" style="text-align: left; width: 100%;"
|+ Table 2. Correlates of drowsy driving and witnessed apnea
! Question
! colspan=2 | Significance (i.e. p-value)&#42;
|-
| &nbsp;
| '''Drowsy Driving'''
| '''Witnessed Apneas&ordf;'''
|-
| ''Overall Berin Score''
| < 0.0001
| < 0.0001
|-
| Do you snore?
| < 0.01
| < 0.001&deg;
|-
| How loud is your snoring?
| < 0.0001
| < 0.0001
|-
| Does your snoring bother other people?
| < 0.01
| < 0.01
|-
| How often do you snore?
| < 0.0001
| < 0.0001
|-
| How often has someone noticed that you quit breathing during your sleep?
| < 0.0001
| n/a&dagger;
|-
| How often do you feel tired or fatigued after your sleep?
| < 0.0001
| < 0.0001
|-
| During your waking time, how often do you feel fatigued, or not up to par?
| < 0.0001
| < 0.0001
|-
| style="font-size: 8pt" colspan=3| &dagger;This value has been omitted since the test described here would be correlating the variable with itself.
&deg;Respondents who answered "yes" had the stated p-value, respondents who answered "I don't know" were weakly correlated with p=0.10478
 
&#42;The significance value is taken from a univariate logistic regression model with the questions as univariate independent variables and the two responses as the dependent variables.
 
&ordf;This variable was transformed such that "Nearly every day" and "3-4 times/week" were a positive response and every other
response was a negative response.
|}
 
 
With regard to drowsy driving, 20.5% answered positively to the Berlin Questionnaire query about falling asleep while driving. Correlates of sleepy driving are reported in Table 2. Sleepy driving was not associated with BMI, hypertension (p=0.07) or gender, but strongly correlated with severity and frequency of snoring and with witnessed apneas.


=== 4.3. Witnessed Apneas ===
=== 4.3. Witnessed Apneas ===
Twenty-one percent of the commercial motor vehicle drivers endorsed the symptom of witnessed apneas; correlates of this symptom are also presented in Table 2. Witnessed apneas were not correlated with BMI, gender, or hypertension, but correlated with classic OSA symptoms.
Twenty-one percent of the commercial motor vehicle drivers endorsed the symptom of witnessed apneas; correlates of this symptom are also presented in Table 2. Witnessed apneas were not correlated with BMI, gender, or hypertension, but correlated with classic OSA symptoms.


== References ==
== 5. Discussion ==
 
The primary findings of this report are that some commercial drivers willingly assess their OSA risk anonymously online, and a majority of those who do so are obese, have positive Berlin screening questionnaires, and would be required to undergo polysomnography (PSG) if suggested guidelines become regulation. Those who reported classic OSA symptoms (snoring, sleepiness) were more likely to report drowsy driving. Contrary to our hypothesis, however, objective data (BMI, hypertension history) did not predict sleepy driving better than did subjective data (sleepiness, snoring).
 
To our knowledge, this report is the first to result from an anonymous screening tool for obstructive sleep apnea in commercial drivers. Nearly 600 individuals took the anonymous screen within a few months. In return, they received fairly specific information about whether or not they would be likely to be referred for polysomnography at their next Commercial Driver Medical Examination, should recommendations currently being considered by the FMCSA become policy. Although this project was initially conceived as a service to commercial drivers, it enabled us to gain some insight into demographics and symptoms in this group. As we hypothesized, those who reported symptoms of sleep apnea (snoring, witnessed apneas) were more likely to report drowsy driving. We were surprised to discover that symptoms such as sleepiness and snoring were correlated with drowsy driving more robustly than did objective data in this anonymous, online survey. Previous reports<sup>[14, 15]</sup> have indicated that objective findings (e.g, BMI, blood pressure) were more predictive of sleep apnea in commercial drivers than subjective symptoms. Indeed, in a prospective study of 440 commercial drivers, Parks et al found that every driver who was subsequently found to have OSA by polysomnography had denied related symptoms on his Commercial Driver Medical Examination<sup>[14]</sup>, and Talmage et al actually found that the Epworth Sleepiness Scale correlated inversely with Apnea plus Hypopnea Index (AHI) as determined by polysomnography in trucker who were undergoing required DOT physicals<sup>[15]</sup>. Possibly, drivers understand that reporting symptoms of sleep apnea on their DOT evaluations will result in potentially lengthy and expensive disruptions in work, and thus avoid reporting them on their commercial driver’s license certifying exam. However, they can and did report these symptoms on this anonymous web-based screening tool. This result suggests that commercials drivers are sincerely interested in knowing whether they might have sleep apnea.
 
The prevalence of obesity in this sample is strikingly high, with about 70% of respondents having a BMI over 30. This compares with the national average of 26.7% in 2009<sup>[16]</sup>. There are several different recommendations about use of BMI in screening commercial drivers for obstructive sleep apnea. The 2006 Triagency Task Force of the American College of Chest Physicians, National Sleep Foundation and American College of Occupational and Environmental Medicine<sup>[2]</sup> recommended sleep apnea evaluation for drivers who had BMI’s over 35 kg/m<sup>2</sup>. That cut point would apply to more than a third (35.6%) of this sample. The Medical Expert Panel convened by the FMCSA produced conflicting guidance; at one point, it included drivers with BMI’s greater than 33 kg/m<sup>2</sup> among those who should be disqualified immediately or denied certification, but in another section, it noted, “Individuals with a BMI > 33 kg/m2 may be conditionally certified for one month pending the findings of a sleep study." The panel noted that this period should be less than one week. However, given the current infrastructure for sleep studies in the United States, obtaining a sleep study within one week is unlikely to be feasible in many cases. Consequently, the panel recommended that a transition period of two years be allowed during which time efforts should be made to improve the infrastructure so that the period between requesting a sleep study and obtaining that study can be reduced to one week for certification purposes” <sup>[10]</sup>. However interpreted, this recommendation would apply to nearly half of this sample. In its deliberations, the Medical Review Board of the FMCSA recommended that drivers with a BMI over 30 be required to undergo testing for sleep apnea prior to certification<sup>[16]</sup>, which would affect nearly two-thirds of the individuals who took used our survey.
 
Strengths of this study include the large number of participants, the specific and select method for recruitment of commercial drivers, and the robust association of classic sleep apnea symptoms with drowsy driving. Weaknesses include the fact that data were collected anonymously (we have no way of knowing who the respondents were), and the self-reported and subjective nature of our screening tool. However, the Berlin Questionnaire was recommended by the FMCSA’s Medical Expert Panel as an appropriate screening tool<sup>[10]</sup>, and was among the most specific of screening tools for OSA in an web-based model<sup>[17]</sup>. Perhaps the biggest weakness is that this self-selected group of respondents included mostly individuals who already suspected that they had sleep apnea. While acknowledging that this is true, we still believe that these survey results present some useful findings.
 
A significant weakness of this study the fact that the respondents to the survey were self-selected, and thus were almost certainly at higher risk for OSA than the general commercial driver population. These results may not be generalizable to the over commercial driver population, although they may be generalizable to the overweight/obese group of drivers. In addition, because of the need for simplicity and brevity, we did not collect demographic data from survey participants. Further, because of our IRB requirements for anonymity, it is impossible to verify if the individuals who completed the survey were actually commercial vehicle drivers, or to be absolutely certain that each respondent only completed the survey once.
 
In an interesting study of clinicians who likely have hands-on experience with screening for OSA in commercial drivers, Durand and Kales<sup>[18]</sup> surveyed American College of Occupational and Environmental Medicine (ACOEM) members regarding recent consensus guidelines for 0 screening commercial drivers for OSA.2 Fewer than half of these clinicians used consensus guidelines or another specific protocol to screen for OSA, citing as explanations that they were unaware of guidelines (36%), that such guidelines were too complicated (12%), that it would affect client retention (10%) or cause inconvenience to drivers (10%). Thus, many commercial driver medical examiners may avoid rigorous screening for OSA because it is complicated or may adversely affect drivers or their practice. In addition, drivers themselves who are suspected of having OSA by their medical examiner and who are referred for screening frequently fail to follow-up with sleep testing or with the examiner who recommended it<sup>[14]</sup>. So, despite the fact the untreated sleep apnea increases crash risk and has a high prevalence in commercial drivers, many medical examiners are not screening for it, and drivers are denying symptoms on their certifying examinations. As noted by the FMCSA’s Medical Expert Panel, cost, complexity, and delay probably contribute an inability to diagnose and expediently treat commercial drivers. Sleep health professionals need expedient, non-punitive tools to keep commercial motor vehicle drivers healthy and driving.
 
== 6. Acknowledgements ==
 
Both authors had full access to the data and participated in writing this report. We gratefully acknowledge the help of Robert Stanton and Gary Hull, and Truckers for a Cause Chapter of Alert Well and Keeping Energetic of the American Sleep Apnea Association (TFAC-AWAKE), who initiated this project and hosted the survey on the TFAC-AWAKE website.
 
== 7. References ==
: <sup>[1]</sup> Tregear S, PhD; James Reston J, Schoelles K, Phillips B, Obstructive Sleep Apnea and Risk of Motor Vehicle Crash: Systematic Review and Meta-analysis, JCSM 2009; 5 (15) : 573-581.  
: <sup>[1]</sup> Tregear S, PhD; James Reston J, Schoelles K, Phillips B, Obstructive Sleep Apnea and Risk of Motor Vehicle Crash: Systematic Review and Meta-analysis, JCSM 2009; 5 (15) : 573-581.  
: <sup>[2]</sup> Hartenbaum N, Collop N, Rosen IM, Phillips B, et al. Sleep apnea and commercial motor vehicle operators: Statement from the joint task force of the American College of Chest Physicians, the American College of Occupational and Environmental Medicine, and the National Sleep Foundation. Chest. 2006;130 (3):902-5.  
: <sup>[2]</sup> Hartenbaum N, Collop N, Rosen IM, Phillips B, et al. Sleep apnea and commercial motor vehicle operators: Statement from the joint task force of the American College of Chest Physicians, the American College of Occupational and Environmental Medicine, and the National Sleep Foundation. Chest. 2006;130 (3):902-5.  
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Med. 2009;51(10):1220-6.  
Med. 2009;51(10):1220-6.  
: <sup>[19]</sup> Stevens, S.S. On the Theory of Scales of Measurement, Science 1946;103 :677-80.
: <sup>[19]</sup> Stevens, S.S. On the Theory of Scales of Measurement, Science 1946;103 :677-80.
[[Category:Journal Papers]]
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