MILITARY MEDICINE, 179, 3;294, 2014
Comorbid Insomnia and Obstructive Sleep Apnea in Military Personnel: Correlation With Polysomnographic Variables LTC Vincent Mysliwiec, MC USA*; Panagiotis Matsangas, PhDf; Tristin Baxter, AAS*; Leigh McGraw, PhD*; MAJ Nici E. Bothwell, MC USA*; Bernard J. Roth, MD* ABSTRACT Objectives; Military personnel undergoing polysomnography are typically diagnosed only with obstructive sleep apnea (OSA). Cotrtorbid insomnia with OSA is a well-established, underappreciated diagnosis. We sought to determine if military personnel with mild OSA met clinical criteria for insomnia and if there was a pattern of polysomnogram (PSG) variables that identified insomnia in these patients. Methods; Retrospective chart review of military personnel with mild OSA; cluster analysis to describe PSG variables. Results; 206 personnel assessed, predominately male (96.6%), mean age 36.5 + 8.14 years, body mass index 30.2 ± 3.66 kg/m"" and apnea hypopnea index of 8.44 ± 2.92 per hour; 167 (81.1%) met criteria for insomnia. Cluster analysis identified a group of patients (N = 52) with PSG variables of increased wakefulness after sleep onset 77.3 minutes (27.7) (p < 0.001) and decreased sleep efficiency 82.6% (5.82) {p < 0.001) consistent with insomnia. Patients in this group were tnore likely to meet criteria for insomnia with an odds ratio 5.27 (1.20, 23.1), {p = 0.009). Conclusions; The majority of military personnel with mild OSA meet criteria for insomnia. Roughly one-third of these patients can be identified by a pattem of PSG variables. Recognizing and treating both comorbid insomnia and OSA could improve clinical outcomes.
INTRODUCTION Comorbid insomnia with obstructive sleep apnea (OSA) is a well-recognized yet underappreciated clinical entity.''^ Depending on the criteria used for insomnia, the reported prevalence of this disorder ranges from 22% to as high as 55% and is more common in females.^"^ Patients with insomnia may receive medical therapy alone when they also have OSA and thus not receive adequate therapy for their sleep disorders."'^ OSA may be underdiagnosed since patients who present with insomnia symptoms often do not receive a polysomnogratn (PSG) as part of their evaluation for insomnia.'° Conversely, there is objective data for the diagnosis of OSA, by virtue of the apnea-hypopnea index (AHI), whereas insomnia remains a clinical diagnosis. Military personnel frequently report sleep disturbances with a prevalence as high as 80%.^'''" Their sleep is short in duration with previous reports of 6 hours or less sleep per night.'^"''' The etiology of their sleep disturbances may result from service-related illnesses of anxiety, depression, posttraumatic stress disorder (PTSD)'^ and mild traumatic brain injury (TBI)"' all of which are associated with insomnia. Recent reports of sleep disorders in military personnel have shown a high rate of OSA.'^'^ Our study of a large cohort of military personnel undergoing PSG reported the most common diagnoses of OSA in 51.2% and insomnia in 30%.'^ This protocol assigned only one major sleep disorder *Department of Pulmonary, Sleep Medicine, Critical Care, Madigan Army Medical Center, 9040A Eitzsimmons Avenue, Tacoma, WA 98431. "["Operations Research Department, Naval Postgraduate School, 1411 Cunningham Road, Monterey, CA 93943. The opinions and assertions in this article are those of the authors and do not necessarily represent those of the Department of the Army, the Department of Defense, or the U.S. Government. doi; 10.7205/MILMED-D-13-00396
294
to each patient, which was OSA if the AHI was greater than or equal to 5. In a subsequent observational study, we identified a high rate of comorbid insomnia and OSA (38.2%) in a select group of military personnel (110 subjects) who were referred for sleep difficulties.'^ With this study, we sought to determine if comorbid insomnia and OSA was similarly prevalent in our larger cohort of military personnel with a PSG diagnosis of mild OSA. Once OSA, defined by an AHI > 5 on the PSG report, is diagnosed, many clinicians treat this disorder alone. Insomnia is only considered if the response to therapy is inadequate. However, characteristic PSG variables consistent with insomnia could suggest the diagnosis of comorbid insomnia and OSA before a trial of OSA therapy.'" These variables are sleep onset latency (SOL) > 31 minutes, wakefulness after sleep onset (WASO) > 31 minutes, and sleep efficiency (SE) < 85%, although such quantitative criteria are not typically incorporated into PSG diagnostic interpretations. Determining PSG characteristics of patients with comorbid insomnia and OSA may improve recognition of this often underdiagnosed clinical entity. Better recognition may facilitate earlier diagnosis and treatment, likely resulting in improved clinical outcomes. We hypothesized that there is a high incidence of insomnia in military personnel diagnosed with mild OSA. We also sought to identify PSG variables that could help identify patients with comorbid insomnia and OSA as opposed to OSA alone using cluster analysis. METHODS
Study Participants This retrospective study was approved by the Institutional Review Board at Madigan Army Medical Center in Tacoma, Washington. From January 1, 2010 to December 31, 2010,
MILITARY MEDICINE, Vol. 179. March 2014
Comorbid Insomnia and Mild OSA
207 U.S. Army, Air Force, and Navy personnel underwent a PSG and were diagnosed with mild OSA using criteria of AHI > 5 and 31 minutes, WASO > 31 minutes, and SE < 85%. of insomnia, 81.1%. This is higher than most civilian studies These results show that patients with a WASO > 31 minutes on comorbid insomnia and OSA'* '^ but similar to a study by diagnosed with mild OSA are more likely to have a diagnosis Krakow et al where 40 of 44 crime victims with PTSD were of anxiety (OR 2.49 [1.17-5.28]). diagnosed with insomnia and sleep-disordered breathing.^^ It is possible that the higher prevalence in military personnel is attributable to a number of factors to include the persisTABLE M. Insomnia Symptoms in Patients With Comorbid tence of maladaptive sleep practices from combat deployInsomnia and OSA Diagnosis ments, sleep deprivation, and fragmentation, which is known Comorbid to exacerbate sleep disordered breathing"^'^^ and comorbid Insomnia and service-related disorders (anxiety, depression, PTSD, and OSA, A'= 167, mild TBI).'^''^'^^ The interaction between insomnia and % (No.) OSA promotes a greater severity of illness, both in terms of Difficulty Initiating Sleep 71.3(119) sleep disorders as well as increased medical and psychiatric Difficulty Maintaining Sleep 82.6(138) morbidity.^^ In nonmilitary populations, anxiety, stress, and 'Waking Up too Early 0.6(1) Chronically Nonrestorative/Poor Quality Sleep 93.4(156) depression were all elevated in comorbid insomnia and OSA Chronically Nonrestorative/Poor Quality Sleep 4.2 (7) patients as compared to OSA alone.^ This is consistent with in Isolation the clinical characteristics of our cohort, noting that 24.3%
296
MILITARY MEDICINE, Vol. 179, March 2014
Comorbid Insomnia and Mild OSA
TABLE
Polysomnographic Variables and Demographic Characteristics of Mild OSA Patients With and Without Insomnia
PSG Variables, Mean (SD) SOL (Minutes) REM latency (Minutes) TST (Hour) SE (%) NI (% TST) N2 (% TST) N3 (% TST) Stage REM (% TST) WASO (Minutes) Arousal Index (Events/hr) AHI (Events/hr) Desaturation (%) Demographic Characteristics, Mean (SD) Age Male Sex, % BMI ESS Self-Reported-Polysomnogram Sleep Duration (Hour) Self-Reported-Home Sleep Duration (Hour)
Without Insomnia {N = 28)
With Insomnia (N= 167)
5.36 (5.41) 82.0(41.6) 7.72 (0.569) 95.5 (2.65) 9.14(5.00) 48.4 (9.88) 18.3(9.17) 19.9 (6.28) 21.9(12.9) 18.6(7.06) 9.05 (2.77) 86.3 (4.04)
12.1 (15.6) 113(65.3) 7.04 (0.941) 90.1 (8.43) 9.58 (5.00) 46.4 (10.8) 17.3 (7.86) 17.1(5.47) 44.3 (36.6) 20.9 (8.79) 8.40 (2.90) 86.0 (3.95)
34.0 (7.33) 100 30.7 (3.55) 11.3(4.94) 5.26(1.42) 6.80(1.22)
36.9 (8.28) 95.8 30.2 (3.69) 12.8 (5.07) 5.32(1.68) 5.61 (1.34)
p Value"
Cohen's d
8.3 3.62 13.5 15.5 0.262 1.25 0.134 5.25 13.8 1.85 1.38 0.232
Comorbid Insomnia and Obstructive Sleep Apnea in Military Personnel: Correlation With Polysomnographic Variables LTC Vincent Mysliwiec, MC USA*; Panagiotis Matsangas, PhDf; Tristin Baxter, AAS*; Leigh McGraw, PhD*; MAJ Nici E. Bothwell, MC USA*; Bernard J. Roth, MD* ABSTRACT Objectives; Military personnel undergoing polysomnography are typically diagnosed only with obstructive sleep apnea (OSA). Cotrtorbid insomnia with OSA is a well-established, underappreciated diagnosis. We sought to determine if military personnel with mild OSA met clinical criteria for insomnia and if there was a pattern of polysomnogram (PSG) variables that identified insomnia in these patients. Methods; Retrospective chart review of military personnel with mild OSA; cluster analysis to describe PSG variables. Results; 206 personnel assessed, predominately male (96.6%), mean age 36.5 + 8.14 years, body mass index 30.2 ± 3.66 kg/m"" and apnea hypopnea index of 8.44 ± 2.92 per hour; 167 (81.1%) met criteria for insomnia. Cluster analysis identified a group of patients (N = 52) with PSG variables of increased wakefulness after sleep onset 77.3 minutes (27.7) (p < 0.001) and decreased sleep efficiency 82.6% (5.82) {p < 0.001) consistent with insomnia. Patients in this group were tnore likely to meet criteria for insomnia with an odds ratio 5.27 (1.20, 23.1), {p = 0.009). Conclusions; The majority of military personnel with mild OSA meet criteria for insomnia. Roughly one-third of these patients can be identified by a pattem of PSG variables. Recognizing and treating both comorbid insomnia and OSA could improve clinical outcomes.
INTRODUCTION Comorbid insomnia with obstructive sleep apnea (OSA) is a well-recognized yet underappreciated clinical entity.''^ Depending on the criteria used for insomnia, the reported prevalence of this disorder ranges from 22% to as high as 55% and is more common in females.^"^ Patients with insomnia may receive medical therapy alone when they also have OSA and thus not receive adequate therapy for their sleep disorders."'^ OSA may be underdiagnosed since patients who present with insomnia symptoms often do not receive a polysomnogratn (PSG) as part of their evaluation for insomnia.'° Conversely, there is objective data for the diagnosis of OSA, by virtue of the apnea-hypopnea index (AHI), whereas insomnia remains a clinical diagnosis. Military personnel frequently report sleep disturbances with a prevalence as high as 80%.^'''" Their sleep is short in duration with previous reports of 6 hours or less sleep per night.'^"''' The etiology of their sleep disturbances may result from service-related illnesses of anxiety, depression, posttraumatic stress disorder (PTSD)'^ and mild traumatic brain injury (TBI)"' all of which are associated with insomnia. Recent reports of sleep disorders in military personnel have shown a high rate of OSA.'^'^ Our study of a large cohort of military personnel undergoing PSG reported the most common diagnoses of OSA in 51.2% and insomnia in 30%.'^ This protocol assigned only one major sleep disorder *Department of Pulmonary, Sleep Medicine, Critical Care, Madigan Army Medical Center, 9040A Eitzsimmons Avenue, Tacoma, WA 98431. "["Operations Research Department, Naval Postgraduate School, 1411 Cunningham Road, Monterey, CA 93943. The opinions and assertions in this article are those of the authors and do not necessarily represent those of the Department of the Army, the Department of Defense, or the U.S. Government. doi; 10.7205/MILMED-D-13-00396
294
to each patient, which was OSA if the AHI was greater than or equal to 5. In a subsequent observational study, we identified a high rate of comorbid insomnia and OSA (38.2%) in a select group of military personnel (110 subjects) who were referred for sleep difficulties.'^ With this study, we sought to determine if comorbid insomnia and OSA was similarly prevalent in our larger cohort of military personnel with a PSG diagnosis of mild OSA. Once OSA, defined by an AHI > 5 on the PSG report, is diagnosed, many clinicians treat this disorder alone. Insomnia is only considered if the response to therapy is inadequate. However, characteristic PSG variables consistent with insomnia could suggest the diagnosis of comorbid insomnia and OSA before a trial of OSA therapy.'" These variables are sleep onset latency (SOL) > 31 minutes, wakefulness after sleep onset (WASO) > 31 minutes, and sleep efficiency (SE) < 85%, although such quantitative criteria are not typically incorporated into PSG diagnostic interpretations. Determining PSG characteristics of patients with comorbid insomnia and OSA may improve recognition of this often underdiagnosed clinical entity. Better recognition may facilitate earlier diagnosis and treatment, likely resulting in improved clinical outcomes. We hypothesized that there is a high incidence of insomnia in military personnel diagnosed with mild OSA. We also sought to identify PSG variables that could help identify patients with comorbid insomnia and OSA as opposed to OSA alone using cluster analysis. METHODS
Study Participants This retrospective study was approved by the Institutional Review Board at Madigan Army Medical Center in Tacoma, Washington. From January 1, 2010 to December 31, 2010,
MILITARY MEDICINE, Vol. 179. March 2014
Comorbid Insomnia and Mild OSA
207 U.S. Army, Air Force, and Navy personnel underwent a PSG and were diagnosed with mild OSA using criteria of AHI > 5 and 31 minutes, WASO > 31 minutes, and SE < 85%. of insomnia, 81.1%. This is higher than most civilian studies These results show that patients with a WASO > 31 minutes on comorbid insomnia and OSA'* '^ but similar to a study by diagnosed with mild OSA are more likely to have a diagnosis Krakow et al where 40 of 44 crime victims with PTSD were of anxiety (OR 2.49 [1.17-5.28]). diagnosed with insomnia and sleep-disordered breathing.^^ It is possible that the higher prevalence in military personnel is attributable to a number of factors to include the persisTABLE M. Insomnia Symptoms in Patients With Comorbid tence of maladaptive sleep practices from combat deployInsomnia and OSA Diagnosis ments, sleep deprivation, and fragmentation, which is known Comorbid to exacerbate sleep disordered breathing"^'^^ and comorbid Insomnia and service-related disorders (anxiety, depression, PTSD, and OSA, A'= 167, mild TBI).'^''^'^^ The interaction between insomnia and % (No.) OSA promotes a greater severity of illness, both in terms of Difficulty Initiating Sleep 71.3(119) sleep disorders as well as increased medical and psychiatric Difficulty Maintaining Sleep 82.6(138) morbidity.^^ In nonmilitary populations, anxiety, stress, and 'Waking Up too Early 0.6(1) Chronically Nonrestorative/Poor Quality Sleep 93.4(156) depression were all elevated in comorbid insomnia and OSA Chronically Nonrestorative/Poor Quality Sleep 4.2 (7) patients as compared to OSA alone.^ This is consistent with in Isolation the clinical characteristics of our cohort, noting that 24.3%
296
MILITARY MEDICINE, Vol. 179, March 2014
Comorbid Insomnia and Mild OSA
TABLE
Polysomnographic Variables and Demographic Characteristics of Mild OSA Patients With and Without Insomnia
PSG Variables, Mean (SD) SOL (Minutes) REM latency (Minutes) TST (Hour) SE (%) NI (% TST) N2 (% TST) N3 (% TST) Stage REM (% TST) WASO (Minutes) Arousal Index (Events/hr) AHI (Events/hr) Desaturation (%) Demographic Characteristics, Mean (SD) Age Male Sex, % BMI ESS Self-Reported-Polysomnogram Sleep Duration (Hour) Self-Reported-Home Sleep Duration (Hour)
Without Insomnia {N = 28)
With Insomnia (N= 167)
5.36 (5.41) 82.0(41.6) 7.72 (0.569) 95.5 (2.65) 9.14(5.00) 48.4 (9.88) 18.3(9.17) 19.9 (6.28) 21.9(12.9) 18.6(7.06) 9.05 (2.77) 86.3 (4.04)
12.1 (15.6) 113(65.3) 7.04 (0.941) 90.1 (8.43) 9.58 (5.00) 46.4 (10.8) 17.3 (7.86) 17.1(5.47) 44.3 (36.6) 20.9 (8.79) 8.40 (2.90) 86.0 (3.95)
34.0 (7.33) 100 30.7 (3.55) 11.3(4.94) 5.26(1.42) 6.80(1.22)
36.9 (8.28) 95.8 30.2 (3.69) 12.8 (5.07) 5.32(1.68) 5.61 (1.34)
p Value"
Cohen's d
8.3 3.62 13.5 15.5 0.262 1.25 0.134 5.25 13.8 1.85 1.38 0.232
