Sleep-disordered breathing (SDB) is a continuum of symptoms that range from primary snoring with upper airway resistance to frank obstruction seen in obstructive sleep apnea (OSA). This disease spectrum has been reported to affect 10% to 17% of men and 3% to 9% of women in the general population.1 The specific incidence of OSA has been estimated to be about 2% to 4% of the general adult population.2,3 Sleep-disordered breathing often leads to poor sleep quality, which has been associated with many medical comorbidities, including vascular disease, hypertension, major cardiac events, cardiomyopathies, impaired concentration, reduced psychomotor vigilance and cognition, and daytime somnolence.1,2,4-6 Furthermore, there is evidence that the prevalence of SDB continues to grow among the general population.1 However, the prevalence of SDB in various populations (eg, pediatric vs adult, varying body mass index, country of origin) varies widely due to the multifactorial nature of the risk factors and the difficulty in diagnosing SDB.
Some of the more intuitive medical sequelae of SDB are daytime somnolence and subsequent impaired concentration for those with disrupted sleep patterns. Medical literature has paid specific attention to cohorts of personnel who may be at heightened risk from impaired concentration or inability to focus. These populations include but are not limited to sleep-deprived resident physicians, firefighters, truck drivers, and heavy-machine operators.7,8
Military service members represent a distinct cohort that often is relied on to maintain vigilance even in austere environments. Concentration is paramount in order to perform combat operations or tasks that involve operating heavy machinery, such as nuclear submarines, aircraft, or tanks. Given the myriad of unique operational demands on service members, SDB can have detrimental consequences on an individual’s health and his or her military readiness and training. Ultimately, SDB may degrade a unit’s effectiveness and perhaps the country’s military capability.
Active-duty military service members seem to be more susceptible to clinically relevant sleep conditions. In the military, causes of disruptions in normal sleep patterns are multifactorial. Medical literature focuses on circadian disruptions due to shift work and frequent travel, frequent alternating use of caffeine and sedatives, exposure to combat/trauma, and chronic sleep deprivation.9-11 Studies have been published that focus on service members who have returned from combat deployment.10,12,13 However, these studies do not explore the overall burden of disease, and there are no specific data to suggest the prevalence, annual incidence, or associated costs.
To quantify this disease burden in the military, this study focused on the subset of sleep disorders that impact respiration during sleep and determined the prevalence and annual incidence for the entire active-duty population. Additionally, the authors fill a void in the literature by determining the financial burden of SDB on civilian care expenditures.
Methods
This study was a retrospective review of administrative military health care data spanning fiscal years (FYs) 2009 to 2013 (October 1, 2008 to September 30, 2013). The study protocol was approved by the Naval Medical Center Portsmouth Institutional Review Board, and approval was given to waive informed consent. The Health Analysis Department at the Navy and Marine Corps Public Health Center (NMCPHC) obtained and analyzed data from the Military Health System (MHS) Management Analysis and Reporting Tool (M2). The M2 system is an ad hoc query tool used for viewing population, clinical, and financial MHS data, including care received within military treatment facilities (MTFs) and care purchased through TRICARE at civilian facilities. Both inpatient and outpatient health care records were included.
The population included all active-duty service members and guard/reserve members on active duty within all military services, including air force, army, coast guard, and navy branches, between FY 2009 and FY 2013. The authors identified service members with SDB as those with at least 1 ICD-9 diagnosis code related to SDB: obstructive sleep apnea (327.23); sleep-related hypoventilation/hypoxemia (327.26); and other organic sleep disorder (327.80).
Due to the transient nature of the military population, a monthly average over the 5 years of the study determined the overall number of service members eligible for care (1,717,227 service members).
Data Analysis
Prevalence of diagnosed SDB per FY was calculated as the number of service members who received at least 1 SDB diagnostic code between October 1, 2008 and September 30, 2013, over the average total active-duty population. Incidence per year was calculated as the number of new cases per FY, using 2009 as the baseline. Data were stratified by demographic and enrollment information for diagnosed service members and analyzed using SAS 9.4 (Cary, NC) software.
Direct costs associated with SDB treatment fall into 2 categories for service members: (1) care delivered by civilian providers, calculated based on the amount TRICARE paid for the service, using insurance claim data; and (2) care received at MTFs by military providers. Costs for care at MTFs cannot be calculated, as the total cost amount for a single record is not directly attributed to SDB diagnosis.