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The Real Burden of Restless Legs Syndrome: Clinical and Economic Outcomes
Rachel E. Salas, MD; and Anthony B. Kwan

The Real Burden of Restless Legs Syndrome: Clinical and Economic Outcomes

Rachel E. Salas, MD; and Anthony B. Kwan
Restless legs syndrome (RLS) is a highly prevalent and substantially underdiagnosed sensorimotor disorder. Only relatively recently have the large impact on patient quality of life (QoL) and the economic burden associated with RLS become more widely recognized. QoL in patients with RLS has been shown to be worse than that of many other chronic conditions, including type 2 diabetes, clinical depression, and osteoarthritis. Sleep disturbance, a cardinal feature of RLS, is the most common and most destructive of its symptoms. More than two-thirds of RLS patients experience serious insomnia, and waking up several times per night is typical for this patient population. Moreover, RLS disrupts rest during waking hours, such as when the patient is sitting or relaxing. Thus, whether awake or asleep, the RLS patient finds little opportunity for the general restorative behaviors necessary for healthy human functioning, resulting in high rates of comorbidities including depression, anxiety, and hypertension. The direct and indirect costs related to RLS have been evaluated in a few studies. Although the cost studies are associated with certain limitations (eg, use of questionnaires), the results show that costs related to RLS are substantial. Healthcare utilization, primarily in the form of doctor visits, constitutes the largest proportion of direct expenditures for RLS in the United States. Indirect costs are also large, primarily due to productivity losses, which are as high as 20% in RLS patients. Effective treatment of RLS is necessary to limit the negative effects of RLS on QoL and to reduce costs associated with the condition.

(Am J Manag Care. 2012;18:S207-S212)
Restless legs syndrome (RLS) is a highly prevalent sensorimotor disorder with the potential to exert a very substantial negative impact on the quality of life (QoL) of those affected.1,2 The 4 standard diagnostic criteria for RLS are: 1) an urge to move the legs, 2) such an urge, or unpleasant feelings, while in a state of rest or inactivity, 3) relief of the urge and unpleasant feeling through movement, and 4) experience or intensification of the urge/unpleasant feelings during the evening or night hours.3,4

The pathophysiology of RLS is not fully understood; however, dopaminergic dysfunction and brain iron deficiency are thought to play a role. RLS is categorized as either primary or secondary. Primary RLS is idiopathic, with no known cause. Secondary RLS is associated with particular medical conditions, for example iron deficiency or chronic renal failure, or the use of certain medications.5

Reports regarding the epidemiology of RLS provide somewhat variable prevalence estimates based on the particular countries in which prevalence is measured, and how RLS is reported visà-vis the threshold of symptom severity. The REST General Population study, which included interviews with 15,391 adults in the United States (n = 6014), France, Italy, Spain, and the United Kingdom, found that 7.2% of the total study population met all 4 diagnostic criteria with “any frequency” of symptoms, while 5% experienced symptoms at least once per week, and 2.7% were designated RLS “sufferers,” meaning they experienced moderately or severely distressing symptoms at least twice per week. Data from the United States showed that 7.6% experienced the 4 diagnostic symptoms of RLS with any frequency, 5.8% experienced the 4 symptoms once or more per week, and 3.1% were designated RLS sufferers.2

A recent systematic review by Innes et al of RLS epidemiology studies from North America and Western Europe—which included 34 papers comprising over 230,000 participants— found prevalence rates in adults ranging from 4% to 29%.6 The RLS Epidemiology, Symptoms, and Treatment (REST) General Population study found the prevalence of RLS approximately 2 to 3 times more common in women—depending on severity of symptoms—which was roughly consistent with the Innes findings.2,6 Other demographic risk factors for RLS have been identified in epidemiologic studies. A study published in 2012, for example, examined demographic and socioeconomic risk factors for RLS based on the results of 2 population-based cohort studies conducted in Germany. One of the studies included was conducted in Dortmund and included 1312 participants; the other study was conducted in Pomerania and included 4308 participants. The authors found that risk factors for RLS in the Pomeranian study, which had a mean follow-up of 5.2 years, included female gender, being retired, and being unemployed. The study from Dortmund, which had a mean 2.2 year follow-up, observed slightly different risk factors: being retired, not having an education beyond primary school, being unemployed, having a low income, and doing shift work. Both studies also found that increased age and having an overall lower socioeconomic status were both associated with elevated RLS risk.7

Underdiagnosis of RLS is common, with only 41% of those requiring medical treatment actually receiving an RLS diagnosis; less than one-third of those experiencing frequent RLS symptoms receive an appropriate diagnosis.1 In addition to underdiagnosis, misdiagnosis is common. Hening et al noted a high risk for confounding symptoms (“mimics”) in RLS and conducted a study that examined the risk of being misdiagnosed with RLS despite qualifying for a diagnosis based on the 4 standard diagnostic criteria.3 Of the 1232 participants in the Hening study, 126 were found not to have RLS and yet reported experiencing symptoms that were consistent with the 4 diagnostic criteria.3 The authors further identified 6 mimics that sufficiently resembled 1 or more of the 4 diagnostic criteria so as to provoke misdiagnosis. These 6 mimics were: leg cramps, peripheral neuropathy, radiculopathy, arthritic pain, positional discomfort (ie, a particular seated/lying position causing RLS-like symptoms rather than urge/discomfort while being at rest per se), and pronounced or frequent unconscious movement of the feet or legs (eg, foot tapping, hypnic jerks).3

RLS has, in recent years, become the subject of intensifying study as the prevalence of RLS and the seriousness of an RLS diagnosis are becoming better recognized. The purpose of the present article is to examine the clinical and QoL burdens experienced by those who live with RLS symptoms as well as the economic burden borne by managed care organizations (MCOs) and the public at large.

Quality of Life

The burden on patient QoL arising from RLS can be severe, as has been observed in numerous QoL studies. Kushida et al, employing the SF-36 instrument for measuring QoL, found that across all 8 domains addressed by SF-36—including physical functioning, physical role functioning, bodily pain, general health perceptions, vitality, social role functioning, emotional role functioning, and mental health—participants with RLS scored significantly worse than published norms for the general US population. The authors also compared SF-36 scores for RLS with those scores observed in patients with type 2 diabetes, clinical depression, and osteoarthritis, and found that RLS patients had lower scores in nearly every domain, both physical and mental, compared with those other patient populations.8

These results are consistent with a study conducted by Abetz et al, which also employed the SF-36 and which also found significantly worse scores in each of the SF-36 domains for RLS patients compared with the general population. Similarly to the Kushida study, the study authors compared QoL scores in RLS participants with those of people with type 2 diabetes, clinical depression, chronic obstructive pulmonary disease (COPD) with hypertension, and osteoarthritis with hypertension. RLS patients were found to experience worse QoL scores for role-physical, bodily pain, and vitality compared with the other 4 groups, and worse scores for social function, role-emotional, and mental health than all but those with clinical depression. RLS patients also fared worse for general health compared with the type 2 diabetes and osteoarthritis groups.9

Sleep Disturbance

The burden of RLS on QoL can manifest in numerous ways, but much of the burden arises from the disturbance of sleep that the condition engenders. Sleep-related symptoms were by far the most commonly reported troublesome symptom experienced by patients with RLS in the REST Primary Care study, which included data from 23,052 patients in primary care centers in the United States and Western Europe (Figure).10 More than two-thirds (68.6%) of REST study participants required more than 30 minutes to fall asleep (diagnostic for insomnia), while 60.1% stated that they awoke at least 3 times every night, and the same percentage described difficulty sitting or relaxing.10,11 In addition, 57.2% of respondents reported that their activities of daily living (ADLs) were disturbed by RLS and 53.9% described depressive symptoms. When asked about the overall effect of RLS on their QoL, more than one-third of the study participants said that RLS had a high negative impact on their lives, and the remainder reported that it had some degree of negative impact.10

In the REST General Population study, which involved face-to-face or telephone interviews, more than three-fourths of study participants designated as RLS sufferers reported sleeprelated symptoms, 55.5% reported disturbance of daytime functioning, -59.4% reported pain associated with their RLS symptoms, and 26.2% reported mood disturbance (tendency to become depressed or “low”). The authors of a German study of patients with RLS diagnosed at movement disorder or neurological clinics observed that it took participants an average of 82.5 minutes to fall asleep and that patients averaged 4.3 awakenings per night.12

Sleep disturbance due to RLS has a negative impact on patient QoL, including performance. Many participants in the REST study reported daytime sleepiness and difficulty concentrating the next day, presumably due to sleep disturbance.2

Other Common Comorbidities in Patients With RLS

A variety of comorbidities are associated with RLS, including renal disease, iron deficiency, anemia, neuropathy, sleep apnea, pregnancy, and attention deficit disorder.13,14 It has been observed that people with Parkinson’s disease often have RLS, although this connection is not observed in untreated Parkinson’s; it is hypothesized that RLS in patients with Parkinson’s disease may be a consequence of treatment with certain drugs rather than the result of a direct pathological relationship.15

The psychological distress experienced by people with RLS can be quite severe, as RLS is a chronic condition in which rest, in both awake and sleeping states, is repeatedly and indefinitely disrupted. The extent and varieties of psychological distress associated with RLS were the subject of a recent study by Scholz et al. Psychological abnormalities commonly observed among the RLS participants were somatization (ie, the emergence of medical symptoms without a discernable organic cause), anxiety, compulsivity, and depression, all of which occurred at significantly higher rates than in members of the general population. In addition, a significant correlation was observed between psychological issues and disease severity.16

 
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