Supplements New Approaches to the Management and Treatment of Insomnia
The Economic Impact of Insomnia in Managed Care: A Clearer Picture Emerges
An important question for managed care organizations is whether insomnia is associated with increased consumption of healthcare resources. Even though a large number of adults complain of insomnia, few actually receive a diagnostic code for the condition. Consequently, it has been challenging to consistently measure both direct medical costs and indirect costs attributable to insomnia. Recent data have provided a clearer picture showing that insomnia is a costly medical condition. This paper summarizes current understanding of the prevalence of insomnia and explores its impact on health-related quality of life, workplace productivity, and healthcare resource utilization.
(Am J Manag Care. 2006;12:S246-S252)
Insomnia: A National Problem in America
Managed care organizations (MCOs) have generally viewed insomnia as a limited clinical problem, one that does not have a significant effect on medical costs. Fortunately, major strides have been made in understanding and measuring the economic impact of insomnia, although unanswered questions certainly remain. The National Institutes of Health (NIH) 2005 State-of-the-Science Conference statement on the treatment of insomnia concludes1:
Insomnia is the most common sleep complaint across all stages of adulthood, and for millions, the problem is chronic. Insomnia can be a symptom of other disorders, like depression, or it can be a primary disorder in itself...[C]hronic insomnia is often associated with a wide range of adverse conditions, including mood disturbances, difficulties with concentration, and memory.
The National Academy of Sciences Institute of Medicine, in its 2006 publication, Sleep Disorders and Sleep Deprivation: An Unmet Public Health Problem, has noted2:
It is estimated that 50 to 70 million Americans chronically suffer from a disorder of sleep and wakefulness, hindering functioning and adversely affecting health and longevity. The cumulative long-term effects of sleep loss and sleep disorders have been associated with a wide range of deleterious health consequences, including increased risk of hypertension, diabetes, obesity, depression, heart attack, and stroke.
The institute's Committee on Sleep Medicine and Research concluded that awareness among the general public and healthcare professionals is low given the magnitude of the burden.2
Although a surprisingly large number of adults complain of insomnia, few are actually given a diagnostic code for the condition. As a result, it has been challenging to consistently measure direct medical costs attributable to insomnia (eg, physician visits) and indirect costs (eg, changes in workplace productivity). Recently, however, a clearer picture is emerging that shows insomnia to be a costly medical condition.
This paper summarizes current understanding of the prevalence of insomnia and explores its impact on health-related quality of life (HRQOL), workplace productivity, and healthcare resource utilization.
Prevalence of Insomnia and Its Impact on HRQOL and Resource Utilization
Several studies have measured the proportion of the adult population affected by insomnia. The typical reported range is 25% to 30%, but the definitions of insomnia used in the assessment can affect the results. Community- or population-based prevalence estimates found in the literature have generally relied on responses to telephone interviews or self-administered questionnaires.
Despite the variance in methodology and sample populations, these estimates have reported broadly similar results. The National Sleep Foundation conducted telephone interviews with 1000 randomly selected US residents and found that about 25% experienced occasional insomnia, whereas for an additional 9%, insomnia was a chronic, nightly occurrence.3 A survey of 588 employees at a telecommunications firm found that 30% reported a sleep problem, providing a snapshot of insomnia in a healthy working population.4 In a survey of 3447 members of 5 MCOs, Hatoum et al stratified insomnia into 2 severity levels based on daytime effects. Level II insomnia, characterized by daytime dysfunction in addition to insomnia, was more prevalent than level I insomnia (difficulty in falling or staying asleep)–32.5% versus 13.5%.5
As mentioned above, operational definitions of insomnia can affect prevalence estimates. In a study of over 12 000 French adults, 3 different criteria were applied and produced markedly divergent results. When insomnia was defined as "a nocturnal sleep problem," prevalence was 73%, whereas the prevalence of subjects with "at least one sleep problem three times per week for a month" was 29%.6 When the French study used criteria similar to those for insomnia cited in the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision (DSM-IV-TR),7 which call for daytime consequences in addition to at least 1 sleep problem 3 times per week, prevalence estimates fell still further, to 19%.6 The 2005 NIH State-of-the-Science Conference statement concluded: "Population- based studies suggest that about 30 percent of the general population has complaints of sleep disruption....The importance of sleep disruption often rests with its impact on the individual's daytime function."1 Based on a literature review, Walsh has suggested that more severe forms of insomnia may be more persistent than milder forms.8
Prevalence surveys have illuminated aspects of the association of insomnia with demographic patterns and comorbidities, as well as the influence of insomnia on patients' behaviors and HRQOL. In the survey of telecommunications workers, insomnia was reported by a significantly higher proportion of women than men (34% vs 26%), and by a higher proportion of separated, widowed, or divorced respondents than single or married respondents. Statistically significant associations with insomnia were also demonstrated among respondents receiving medical treatment for gastrointestinal problems, frequent headaches, muscle pain, or neck or back pain; and among those with a possible mental health condition (based on responses to a 5-item version of the Mental Health Index).4 Among managed care enrollees, severe insomnia (ie, insomnia accompanied by daytime dysfunction) was more prevalent among women and nonwhite individuals, and was reported more frequently by patients with multiple comorbidities (assessed by proxy, using prescription records).5
Some studies have documented a reduction in HRQOL among patients with insomnia. Zammit et al9 compared 261 individuals with insomnia with 101 people without any sleep complaint using the 36-item shortform health survey of the Medical Outcomes Study (SF-36).10 These researchers found that the insomnia group had lower mean scores on all subscales of the SF-36 than the control group (P <.0001 or lower for each comparison), indicating impairments across multiple quality of life (QOL) domains. The patients with insomnia also had significantly higher mean item scores on the Zung depression scale and the Zung anxiety scale.9 In a French study, Leger et al compared good sleepers to patients with either severe insomnia (2 sleep complaints =3 times per week, with impaired daytime functioning) or mild insomnia (occasional sleep difficulties) also using the SF-36. Across all 8 SF-36 domains, patients with severe insomnia had significantly lower scores than both those with mild insomnia and good sleepers, whereas patients with mild insomnia had significantly lower scores than good sleepers.11
As noted earlier in this paper, insomnia is a prevalent disorder that may be unrecognized or overshadowed by costly comorbid conditions, such as depression, cancer, irritable bowel syndrome, cardiovascular disease, and other conditions.12 The most consistent clinical correlate with severe or chronic insomnia is depression.8 However, although severe insomnia is generally a symptom of depression, the reverse can also be true. In addition, insomnia can be an independent complaint to some extent in patients with depression.8 One study showed that 44% of patients with depression who were considered to be complete responders to fluoxetine, based on Hamilton Depression (HAM-D)13 scale scores, still experienced substantial sleep disturbances.14 Other comorbidities that have demonstrated significant associations with insomnia include various forms of cardiovascular disease, chronic obstructive pulmonary disease, peptic ulcer disease, osteoarthritis, and rheumatoid arthritis.15
The association of comorbidities with increased insomnia risk has been supported by studies demonstrating higher rates of insomnia among selected populations compared with the community at large. A survey of patients in primary care clinics found that 69% reported insomnia (50% occasional, 19% chronic).16 In a study of patients being treated for alcoholism, 61% were scored as having symptomatic insomnia based on responses to the Sleep Disorders Questionnaire. Patients with insomnia were twice as likely to relapse to alcohol use during a post-treatment follow-up period (mean follow-up, 5 months; relapse rates: patients with insomnia, 60%; patients without insomnia, 30%); this difference remained statistically significant after adjustment for other variables. In contrast, relapse was not predicted by a history of self-medication for insomnia using alcohol.17
A consistent finding in population- and community-based assessments of insomnia is a high rate of self-medication among those reporting sleep problems. In the National Sleep Foundation survey, 4 of 10 subjects with insomnia reported self-medication using over-the-counter (OTC) sleep aids or alcohol.3 Significantly greater use of prescription and OTC sleep medications, as well as daytime use of caffeine for wakefulness, was found among telecommunications workers reporting sleep problems than among those without sleep problems.4 Both the MCO survey and the employee survey discussed earlier in this paper found that twice as many subjects with insomnia reported using OTC sleep aids than prescription sleep medications.4,5
In summary, the prevalence of insomnia in the community is high, with several major studies suggesting that a substantial part of the population experience some form of insomnia. These studies also document that insomnia exerts a profound negative effect on HRQOL, productivity, and everyday functioning. Further research is needed to delineate the relationship between insomnia and comorbidities. As noted by Martin et al, it is not always clear whether insomnia is a cause, effect, or correlate of the identified association.18
Assessing the Costs of Insomnia
A particularly important question for MCOs is whether insomnia is associated with increased consumption of healthcare resources. Various studies have shown that the impact is substantial. As early as 1997, Simon and VonKorff concluded: "Insomnia among primary care patients is associated with greater functional impairment, lost productivity, and excess health care utilization." 19 The 2005 NIH State-of-the-Science Conference statement noted that estimates place the direct and indirect annual costs of chronic insomnia at tens of billions of dollars, but cautioned that such estimates are based on many assumptions and vary extensively. In estimating the economic consequences of insomnia, it is difficult to separate the effects of insomnia from the effects of comorbid conditions?."1 Recent data have begun to clarify the true economic costs attributable to insomnia.