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RLS prevalence and impact

Clinical bottom line

This large survey found that 2.7% of the adult population in western countries had RLS as diagnosed by standard criteria, with at least moderate severity and with symptoms at least twice a week. Quality of life is impaired in people suffering at least moderate symptoms at least twice a week.


Reference

RP Allen et al. Restless legs syndrome prevalence and impact. Archives of Internal Medicine 2005 165: 1286-1292.

Study

This was a prospective observational study conducted in five European countries (France, Germany, Italy, Spain, UK) and the USA. Participants were adults contacted by random methods with quotas set for age, sex, and working/social status to ensure that samples were nationally representative.

Participants were asked to complete questionnaires at telephone or face-to-face interviews. They were asked screening questions about RLS, using established diagnostic criteria. Those fulfilling RLS criteria were asked additional questions about the frequency and timing of symptoms, and distress caused.

Results

Of 16,000 people approached, 95% (15, 391) both agreed and provided a fully-completed questionnaire. Populations were similar to the overall population in each country, though younger people were slightly over-represented and older people slightly under-represented.

All four diagnostic symptoms were reported by 7.2%, with 5.0% having weekly symptoms (Figure 1). Moderate or severely distressing symptoms at least twice a week were experienced by 416 respondents (2.7%). Variations between countries were significant, with highest rates seen in France and lowest in Germany (Table 1).

Figure 1: Overall rates of RLS at various degrees of frequency and severity

Table 1: Largest differences between countries

RLS outcome
France (%)
Germany (%)
Any frequency
10.8
4.1
≥once a week
6.6
2.7
≥twice a week
5.5
2.0
≥twice weekly and at least moderate distress
4.2
1.3

 

RLS prevalence increased with age, but was lower in people aged over 80 years. Peak prevalence at about 6% was in people aged 60-80 years (Figure 2). Prevalence was generally twice as high in women than in men. Though most people with moderate or severe distress with frequent RLS had consulted physicians (60% in last 12 months, and 80% at any time), only 6% of these could recall having a diagnosis of RLS.

Figure 2: Prevalence with age

All eight domains of the SF-36 quality of life questionnaire had significantly lower scores than an age and sex adjusted US population for the 416 RLS sufferers. The actual values were very similar to those found for patients with type 2 diabetes or osteoarthritis.

Comment

This was another large, good study of RLS prevalence, confirming what was known previously, but updating it with information on quality of life. Quality of life is impaired in people suffering at least moderate symptoms at least twice a week.