Restless leg syndrome (RSL) is a neurological movement disorder that affects more than 37 million people worldwide. A recent epidemiology analysis on adult sufferers of RSL by GlobalData, a leading data and analytics company found that while a significantly high proportion of the general population in the West experience RSL, less than one third are getting an accurate diagnosis.
Kasey Fu, MPH, Director of Epidemiology at GlobalData commented: ‘’Many studies suggest that a lack of awareness and knowledge in physicians is causing underdiagnosis of restless leg syndrome. This is an area that deserves more attention, given how many people report uncomfortable sensations that can severely affect their sleep and daily life’’.
Restless leg syndrome sufferers feel uncomfortable sensations in their legs, such as tingling and numbing, and the feelings worsen at night. The sensations provoke a strong urge to move the legs, which makes it difficult to have restful sleep and can adversely affect productivity, quality of living, and mental and physical health.
In the seven major markets (7MM*), there is variation in the active total prevalence of restless leg syndrome. The UK had the highest proportion of the population that had positive symptoms of restless leg (around 11%) and Japan had the lowest (around 2%). However, GlobalData observed that diagnosis is extremely low, where only 5–25% of those with symptoms have previously been diagnosed.
It is not clear what is causing the low diagnosis rate in these countries. In a US-based study of 15,391 people, 81% of those who had positive symptoms fulfilling the IRLSSG criteria had discussed their symptoms with a primary care physician, but only 6.2% of those were diagnosed with restless leg syndrome. Similarly, in a UK-based study of 23,052 people, 65% had sought medical help for the strange sensations in their legs, but only 13% of those had been diagnosed.
The sparse landscape of the RLS marketplace:
There are currently two food and drug (FDA)-approved therapies for RLS, Mirapex (pramipexole dihydrochloride) and Neupro (rotigotine). Mirapex is delivered in tablet form, taken orally once daily, and Neupro is a patch that, when attached to the skin, delivers rotigotine, a dopamine receptor agonist, over a 24-hour period.
Magdalene Crabbe, MA, Neurology and Ophthalmology Analyst, at GlobalData adds: “The highest stage of development is Vifor Pharma’s Ferinject (ferric carboxymaltose), an intravenously administered iron replacement therapy in Phase III of the RLS pipeline. Many RLS sufferers experience anemia, caused by Iron deficiency. Fewer circulating erythrocytes reduce dopaminergic signaling capabilities, triggering restlessness and disordered involuntary movements. Iron replacement therapy has been proven to be effective in relieving RLS symptoms.
“However, the sparse landscape of the RLS marketplace mean that patients are sometimes left untreated and can suffer severe consequences resulting from electrolyte imbalances and deficiency of essential nutrients”.
*7MM = US, France, Germany, Italy, Spain, UK, and Japan