1 Introduction

Restless leg syndrome is a common sensory motor disorder of sleep wake cycle. It significantly impaired sleep and quality of life. An uncomfortable sensation to move the legs, worse at rest, and at night.¹ The urge to move often presents as leg discomfort, but may range from mild irritation to disruptive, painful sensations. The symptoms typically occur near bedtime but may be present throughout the day in severe cases. Patients with RLS obtain symptom relief with movement, although the relief is temporary with rapid return of symptoms. The prevalence of RLS varies between 4 % and 10 % in general population.²

In 1685, an English physician Thomas Willis gave the first description of Restless leg syndrome (RLS), describing a patient with difficulty in sleep due to the involuntary movement of limbs. In 1945, Karl-Axel Ekbom, who was unaware about the work done by Willis coined the term “Restless leg”. Restless leg syndrome is widely used term to describe this condition but as it can affect upper limbs as well so it was renamed to Willis-Ekbom disease.^3,4

In Europe and North America, it was about 5 %–10 %. However, RLS becomes less common in Asia with a prevalence of 1 %–4 % as showed by Ohayon et al., in 2012 ⁵.A Pakistani research showed RLS prevalence of 23.6 % in Karachi.The prevalence in females was twice as high as compared to males.⁶

People usually do not seek any medical consultation regarding RLS or even if they have reported any of their symptoms it gets misdiagnosed or overlapped with other medical conditions which are called “RLS mimics” such as such as positional discomfort, myalgia, vascular or neurogenic claudication, hypnic jerks or habitual foot tapping. Restless Leg Syndrome can only be diagnosed by considering its four classical symptoms, which are defined by the criteria established by the International Restless Leg Syndrome Study Group (IRLSSG).⁷

Restless leg syndrome can occur at any age, and the symptoms seem to be worsening with growing age. A smaller percentage, specifically 3 %, within the age group of 18–29 years, experienced less suffering, while as the age progresses this percentage increases as 10 % in age group 30–79 years and 19 % in 80 years and above .⁸

The pathophysiology of RLS has been interrelated to three components i.e. dopaminergic dysfunction, iron deficiency and gene involvement.⁹ The diencephalospinal dopaminergic tracts is considered to be an anatomical site of dopaminergic dysfunction. In RLS as this system projects in the limbic system this could be related with the circadian pattern of symptoms of RLS.¹⁰ Iron plays an important role in the synthesis of dopamine. Dopamine transporter is impaired with iron deficiency also.¹¹

Secondary restless leg syndrome can be caused by different underlying conditions such as: diabetes, kidney failure, Parkinson's disease, peripheral neuropathy, medications such as antihistamine, antipsychotics, antiemetic's and antidepressants. ^12,13

There are numerous rheumatological diseases, with the most common ones being rheumatoid arthritis and osteoarthritis. Restless leg syndrome in arthritis patients is also one of the factor that needs to be further studied. In Rheumatoid arthritis patients; the release of inflammatory markers will promote in increase the risk of RLS in these patients. Presence of other comorbid in RA patients will also lead to increased prevalence of RA. There is an increased frequency of RLS in RA patients. In 1986 a study over patients; who were hospitalized for RA patients compared with hospitalized patients for osteoarthritis (OA), it showed a finding of 30 % prevalence of RLS in RA in comparison with 3 % in OA.¹⁴

Osteoarthritis, is defined as a heterogeneous group of conditions that lead to joint symptoms and signs which are associated with defective integrity of articular cartilage, in addition to related changes in the underlying bone and at the joint margins.¹⁵ The prevalence of Osteoarthritis in relation to RLS is not been studied previously much. Our aim is to identify the prevalence of RLS in Osteoarthritis patients. To spread awareness about RLS can be an association with rheumtological diseases as well that physicians sometimes misdiagnosed it.

OBJECTIVES = A cross-sectional study: Prevalence of RLS in OA patients.

2 Methodology

After evaluating the patients’ eligibility to participate in the study and obtaining consent, study questionnaires, which were validated and were in the English language was used. Patients were interviewed to rule out other conditions that mimic RLS.

The study questionnaire was to be divided into four parts. First part consist of demographic information regarding age, gender, comorbidities, family history if any.

Second part inquired the essential questions of the RLS specified in IRLSSG criteria.¹⁶1.An urge to move the legs, usually accompanied or caused by uncomfortable and unpleasant sensations in the legs. (Sometimes the urge to move is present without the uncomfortable sensations, and sometimes the arms or other body parts are involved in addition to the legs.)2.The urge to move or unpleasant sensations begin or worsen during periods of rest or inactivity such as lying or sitting3.The urge to move or unpleasant sensations are partially or totally relieved by movement, such as walking or stretching, at least as long as the activity continues.4.The urge to move or unpleasant sensations are worse in the evening or night than during the day or only occur in the evening or night. (When symptoms are very severe, the worsening at night may not be noticeable but must have been previously present.

Third part included the rating scale in patients of osteoarthritis to rate severity of RLS in daily life by asking from participates 10 questions. By adding the sum of questions and grading the severity into mild, moderate, severe and very severe.

Fourth part includes BMI by measuring height and weight of subjects and label in criteria of normal, over-weight and in obese class.

Fifth part included the grading of osteoarthritis diagnosed by radiological grading system (Kellgren-Lawrence scale):¹⁷

Grade 0 = normal, Grade 1 = doubtful narrowing of joint space and possible osteophyte lipping, F = Grade 2 = definite osteophytes and possible narrowing of joint space, Grade 3 = Moderate multiple osteophytes, definite narrowing of joint space, some sclerosis, and possible deformity of bone ends, grade 4 = Large osteophytes, marked narrowing of joint space, severe sclerosis, and definite deformity of bone ends.

3 Results

Among osteoarthritis patient interviewed in rheumatology and orthopedic OPD; patients were recruited on basis of aforementioned inclusion and exclusion criteria were classified. 260 participants have responded to the questionnaire using IRLSS and Kellgren-Lawrence scale after taking informed consent. 74.9 % (193) of the OA patients were having RLS positive and 25.8 % (67) were not having RLS (Fig. 1).

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Fig. 1 Frequency of RLS in osteoarthritis patients.

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Multiple factors were analyzed in OA patients to assess the association with RLS (Table 1). The mean age was 48 years (SD = 14.75). 74.2 % (193) participants were RLS fulfilling the criteria of IRLSSG and 25.8 % (67) were not seems to be positive according to scoring criteria. A significant p-value of 0.001. BMI of the patients gives an overview that 28 % lie in normal grade of 18–24 kg/m² and 71 % are part of overweight scale that is 25–30 kg/m².A significant relation of RLS in osteoarthritis patients who are over-weight. RLS severity grade with p-value 0.001 shows significance with RLS positive in osteoarthritis patients. No correlation is been noted with family history of joint diseases and duration of symptoms.

Osteoarthritis was labelled in study participates according to Kellgren-Lawrence scale; which analyses significant p-value of 0.0001 with comparison to patients who had positive RLS (Table 2).

Comparing the RLS severity with comorbidities present in participants. The observed significant p-value of 0.001 ± standard deviation of 11.5 suggests a trend of increasing Restless Leg Syndrome severity among osteoarthritis patients with co-morbidities. On grading the osteoarthritis in participants; we analyze the significant p value of 0.001 with correlation to RLS severity. It gives an impression of severe the osteoarthritis higher will be the severity of RLS in participants. Among the participants, it was observed that RLS severity in males mean is 14.86 ± 12.03 S.D. and in females 16.87 ± 11.75 (Table 3).

4 Discussion

After a thorough examination of various research articles, it appears that our study represents the first effort to determine the prevalence of Restless Leg Syndrome in the osteoarthritis population. A review of multiple epidemiological studies documented prevalence of RLS ranges from 3.9 % to 14.3 %, influenced by the specific population under study and the criteria applied.¹⁸ A research conducted in Karachi, Pakistan revealed a 23.6 % prevalence of RLS, with females exhibiting a prevalence twice that of males.¹⁹ Multiple studies were conducted in relation to different age groups. One of the study conducted in medical students that analyzes 66.7 % females and 33.3 % males were positive for RLS. Whereas, our study analyses the results in large age groups covering young, middle age and old age population too. Our study analyzes 74.5 % prevalence of RLS in OA subjects fulfilling one of our study objective.

In previous studies Evi Holzknecht shows the prevalence of RLS among females are much more common and worse than in males based on assessment by clinical, laboratory and poylsomonography.²⁰ A consistent similar results found in our study showing 55 % prevalence in females as compare to males of 47 %. The reason for the elevated incidence of RLS in females is not fully understood, but it could be attributed to the higher prevalence of vitamin D and iron deficiency in females compared to males.

Correlation of comorbidities (Diabetes, obesity, psychiatric illness and others) in different previous and recent studies have been noticed. One of the study shows the prevalence of RLS was 28.6 % among individuals with diabetes, whereas it was 7.1 % in the normal/non-diabetic population.²¹ Our study covered a wide range of comorbidities as well as normal participants to analyses the relation with RLS in them. And our study shows the higher the effect of RLS in comorbidities.

Multiple studies shows the percentage of RLS increases in rheumatoid arthritis as compare to other diseases. A study by Ishaq M. study describes that among patients with rheumatoid arthritis (RA), 20 % experienced Restless Legs Syndrome (RLS), while only 10 % of individuals in the control group with other rheumatic diseases reported RLS.²² One of the similar study by PadhanP. have done meta-analysis over prevalence of RLS which gives a picture of 2406 patients belongs to rheumatoid diseases; in which 26.6 % belongs to rheumatoid arthritis. It also mentions only 4.4 % prevalence in osteoarthritis patients.²³

Our study focuses the osteoarthritis patients and shows 74.9 % prevalence of RLS. Furthermore, analyses multiple associations of age, gender and BMI in osteoarthritis that shows its severity in them.

A study conducted in turkey analyses that patients with knee osteoarthritis (OA) exhibited longer duration of Restless Legs Syndrome (RLS), greater symptom severity, and higher pain scores, leading to more pronounced deterioration in both sleep quality and daily life activities compared to those with hip OA.²⁴ Our study focuses the different grades of OA on basis of X-ray's by using Kellgren-Lawrence scale. Correlating the fact that severe the grade of OA RLS severity will be increased.

A study conducted in United States revealed a substantial figure, with approximately 81 % of participants seeking consultations for Restless Legs Syndrome (RLS) from primary care doctors.²⁵ In contrast to that one of the study shows 96.6 % students did not report their symptoms of RLS to any doctor or did not seek any medical consultation regarding it even though all the students belong to different medical institutions.²⁶ This highlights the lack of awareness about Restless Legs Syndrome (RLS) in Pakistan, stemming from the absence of routine medical screening. Many individuals do not recognize it as a legitimate medical condition, leading to underreporting of symptoms to healthcare professionals. One of the objectives of our study is to raise awareness among the osteoarthritis population about Restless Leg Syndrome to prevent misinterpretation.

Our study had some limitations. As the sample size was small; which cannot represent the general population. The study conducted at two specific hospitals only. The effect of treatment given to the participates needs to follow in order to create more impact in society as this part was not conducted in our study.

5 Conclusion

It has been concluded that prevalence of Restless leg syndrome is higher in osteoarthritis. It needs to be further evaluated in our Asian population. Efforts should be directed towards avoiding the oversight of Restless Leg Syndrome in osteoarthritis patients and managing the condition appropriately.

Since the restless leg syndrome may exacerbate the symptoms, it should be considered as an underlying condition of the OA during clinical assessment. In the treatment and follow-up of restless legs syndrome, it should be aimed to increase the quality of life of the patients by following the treatment of OA.

Ethical statement

Ethical approval was obtained from the ethical review committee of Jinnah Medical and Dental College, Sohail University.

Patient consent

Patient consent has been obtained.

Author contribution

All authors had equal contribution in conception, data collection, preparing ,manuscript and reviewing manuscript.

Financial disclosure or funding

None.