Relationship between Sleep Disorders , Pain and Quality of Life in Patients with Rheumatoid Arthritis

ARTICLE INFO ABSTRACT Article Type: Original Article Introduction: Rheumatoid arthritis as one of the most common autoimmune diseases is known to be one of the leading causes of disability. Sleep disorders have direct influence on patient’s life. According to studies, sleep problems are known to have negative impact on well-being and functioning, but the exact nature of relationship between sleep disorders and Rheumatoid arthritis is not completely understood. This study aimed to investigate the relationship between sleep disorders, pain and quality of life in patients with rheumatoid arthritis patients. Methods: In a descriptive -correlative study, 210 patients with rheumatoid arthritis referred to Tabriz medical university clinics selected by convenience sampling and were assessed by Sleep Disorders Questionnaire (SDQ), Epworth Sleepiness Scale (ESS), SF-36 Quality of Life Questionnaire and Visual Analog Scale (VAS). Data were analyzed using SPSS-13 by descriptive statistics such as frequency, mean (SD) and inferential statistics including Spearman correlation analysis, linear regression, χ2, ttest and ANOVA. Results: The mean age of participants was 48.41(12.92) years in which most of them (74%) were female. The mean (SD) quality of life was 40.51(22.94), sleepiness 13.14 (5.6) and pain 6.09 (2.14). There was significant negative relationship between some sleep disorders such as (naps, apnea, asphyxia,...) and pain with quality of life but pain severity had more effect on QOL compared to sleep problems. Furthermore, participants had low quality of life with more restriction in physical (mean=34.71) and general health (mean=34.42). Conclusion: Sleep problems and pain were associated with poor quality of life in Rheumatoid Arthritis patients. Article History: Received: 19 May 2015 Accepted: 27 Jul. 2015 ePublished: 1 Sep. 2015


Introduction
Rheumatoid Arthritis (RA) is one of the common systemic inflammatory diseases, which is known as progressive chronic autoimmune illness with slow onset. 1 Clinically inflation causes tenderness, morning stickiness and limitation in joints.Global prevalence of this disease is one percent along the lifetime. 2In Iran RA is the common musculoskeletal chronic inflammatory disease. 3ich in most patients the disease have permanent changes with different severity of arthritis deformities as well as functional disturbances. 4In this regard evidences show that every painful condition, disturbs sleep, which can lead to mood and abilities disturbances. 5oreover, Quality of Life (QOL) in RA usually is affected by pain, dependency, fatigue, and sleep disorders. 6This problem accelerates with age and additional chronic diseases. 7In this regard, most of studies

Copyright © 2015 by Tabriz University of Medical Sciences
indicate that 50-70% of patients with RA suffer from sleep disorders 8 which is 2-3 times more than general population compared to other medical conditions such as obesity, hypertension and respiratory diseases. 9,10The possible reasons of the sleep disorders in patients with RA include restless leg syndrome, anxiety, depression and bone disturbances. 11leep as one of the basic human needs plays an important role in physical and emotional refreshment. 12Moreover, some disturbances during sleep cause cardiovascular diseases, 13 behavioral disturbances, depression 14 and anxiety. 15eduction of general health, pain and negative effects on quality of life are common in RA, 16 however fewer researches have been done on sleep disorders of patients with RA.Although new methods for RA have been presented with new medical technology, but there have not been significant outcomes in solving the psychosocial and sleep problems of these patients.According to studies, sleep problems are known to have negative impact on wellbeing and functioning, but the exact nature of the relationship between sleep disorders and RA disease is not completely understood.So even more research in this area is needed. 17,18Also evidences indicate that sleep in the chronic patients with pain is impaired, but the nature and severity of disturbances are unclear. 19So recognizing sleep problems in these patients would help to improve their general health.
This study has been conducted to determine the relationship between sleep disorders and pain with QOL in patients with Rheumatoid Arthritis.

Materials and methods
In this descriptive-correlative study, 210 patients with RA were selected from those who referred to educational medical clinics of Imam Reza and Sina, affiliated to Tabriz University of Medical Science of Iran.In the period of April to June 2014, the participants were chosen by convenience sampling and assessed by interview.Research community included RA patients diagnosed by a rheumatologist based on American college of Rheumatology (ACR) criteria.Inclusion criteria included: at least 18 years old, consent to participate in the study, at least six months after the definite diagnosis.Exclusion criteria consisted of suffering from other chronic physical and mental diseases or treated with psychotropic medications as well as to have previous sleep problems before RA disease.
In order to estimate the sample size using G power software, a pilot study conducted upon 20 patients.So with r=0.23, power 0.95 and α=0.05, the sample size was calculated as 200 in which by adding sample loss of 10%, subjects were raised to 220 patients.However, 10 samples excluded due to other physical diseases, finally 210 patients participated.
Participants were assessed by sleep disorders questionnaire (SDQ), Epworth Sleepiness Score (ESS), Quality of Life (SF-36) and Visual Analogue Scale (VAS).Sleep disorders questionnaire consists of 37 questions related to sleep disorders with yes (1) or no (0) choices and open questions.Scores of each questionnaire has been calculated and analyzed separately.Last part of SDQ, Epworth sleepiness score consists of 8 items about probability of sleeping in different situations, which ranges from 0 (never) to 3 (high chance of dozing).The total score of ESS considered in a scale of 0-24, so final grade class has been calculated as 3-9 (Normal), 10-13 (mild), 14-19 (moderate) and 20-24 (severe sleepiness) 20,21 The validity of the questionnaire has been established in previous studies. 22In this study, the internal reliability of Cronbach Alpha was 0.86.
Short form 36 (SF-36) is a general health questionnaire consisting of 36 Likert questions with 8 health concepts that assess QOL in: (1)physical function, (2)the physical function limitation as result of physical injury, (3)the role due to emotional problems, (4)energy and vitality, (5)mental health, (6)social function, (7)physical pain, (8)general health. 22Results of SF-36 range from 0 (worse outcomes) to 100 (the best outcome) in which the higher scores shows a better quality of life.QOL and its aspects have been classified into 3 groups: appropriate (75-100%), pretty appropriate (50-75%) and inappropriate (less than 50%).Its reliability in present study has been estimated as Cronbach Alpha 0.89.Visual analogue scale is a 10-centimeter scale in which 0 represents no pain and 10 severe pain.Scores of 1-3 shows slight pain, 4-7 medium pain and 8-10 severe pain.This tool has been used in various studies and its validity and reliability have been confirmed. 23,24 nfidentiality of data, informed consent for participation, and the right to resign anywhere during the study were among the moral considerations respected in this research.This study was approved by ethics committee of Medical University of Tabriz (code 5.4.580).Data were analyzed using Statistical Package for Social Science (SPSS) version13 by descriptive statistics using frequency, mean (SD) as well as inferential statistics using Spearman correlation analysis, Pearson, linear regression, ANOVA, χ 2 and t-test.

Results
This study was performed by participation of 210 patients with RA.Demographic characteristics showed that most of the participants were female (74.8%), married (98%), elementary education (34.8%).
Majority of samples (33.3%) had low knowledge, and (74.3%) have had RA disease more than five years and most (61%) had hospitalization history (Table 1 In different domains of QOL, participants had highest mean (SD) in mental health 47.66 (19.60) and lowest mean (SD) in the physical function 34.71 (24.93) (Table 3).
Results of these analyses indicate that there were significant differences in QOL and different aspects of sleep disorders (Table 4).The impact of sleep problems and pain severity on QOL by linear regression shows significant differences (P<0.001),but pain severity has more effect on QOL (r 2 =0.650) compared to sleep problems (r 2 =0.586) and sleepiness scale (r 2 =0.568).(Figure1) The relation between QOL and gender has shown significant relationship (P<0.001).
ANOVA showed significant differences in QOL based duration of RA disease, time period and severity of morning signs (p<0.001)marital status (P=0.013).Pearson correlation test indicated significant relation between QOL with age (P=0.02),(r= -0.16).
χ 2 -test presented significant differences between apnea based gender, snoring (P<0.001) and difficulty in falling sleep (P<0.001).There was no significant difference in presence of apnea and overweight (P=0.139)but there was significant difference between apnea and drowsiness (P<0.001).Finally the Spearman test showed significant correlation between pain with all domains of QOL (P<0.001).

Discussion
In this study, different aspects of sleep disorders with QOL have been assessed in patients with RA by self-reported.Results indicated that 78.6% of patients reported sleep disorders.The mean of QOL in patients was 40.5 indicating poor level of QOL among these patients.This represents high rate of dysfunction in physical and general health.In assessment of various domains of QOL, patients reported better mental health compared to other aspects of QOL.In addition, findings demonstrated that sleep problems and pain were associated with poor quality of life in RA patients.
These findings are in line with the literature.Parvan et al., in a study on relation between QOL and sleep showed that poor level in general health had inverse relations with sleep. 25  Furthermore, Alishiri et al., in Tehran showed an inappropriate general health in RA patients, also they found a significant relationship between general health with sleep and pain severity. 26n the current study, 59.5% of the participants had low awareness about nature and complications of illness.In regard to significant relationship between duration of disease and QOL in participants, Masayo kojima et al., indicated a significant relation between duration of disease and number of surgeries related to illness and the QOL. 27urthermore, Monjamed found that 50% of patients had disrupted sleep in her survey about the effect of symptoms on quality of life in patients with RA. 28 Rupp and his colleagues who studied on disability and health-related quality of life, pointed to RA as an effective factor interferes with normal daily activities and sleep. 29lso individual character is one of those factors which can be aligned with sleep rhythm and rest, also can be effective on QOL.For instance, results showed that age as an individual character can influence the QOL.In addition, in this study gender had significant relation with QOL.As well as Yardim-Akaydin and collogues indicated this correlation more apparent in females than males. 30t seems that marriage could play an effective role in improving their QOL.In this study 91% were married and significant relation obtained between marital status and the QOL.Also Slatkowasky et al., in a study on health-related quality of life in women with symptomatic hand osteoarthritis, indicated significant relation between marriage and QOL. 31 One of the effective variables on QOL in this study was period of illness, that 40% of patients had more than 10 years history of RA which have had lower QOL comparing to other people with less history of illness.
Masayo kojima indicated that high duration of having the illness could be an independent risk factor in decreasing QOL. 27Most of patients (83.8%) reported taking a nap during daytime that could interfere with influence night sleep pattern.
Furthermore, changes in night sleep pattern are along with alteration in QOL of people.Sariyildiz et al., were concerned with impact of useful and sufficient sleep on physical function and QOL, indicated that disturbance in each stage of sleep had negative influence on QOL and reduces it. 32n the other hand pain due to illness, is one of the factors influencing sleep pattern and rest which is significantly effective on people's QOL.This results are consistent with Lee and et al., findings on assessing the role of sleep problems in central pain processing in rheumatoid arthritis. 33Also a study on sleep and its relationship to pain and disease activity in juvenile idiopathic arthritis indicated meaningful correlation between sleep apnea and insomnia with pain. 34Night sleep deprivation and pain could be playing a role in reducing the QOL as a factor with interaction effects.In a survey on the relationship between RA activity, sleep, psychiatric distress and pain sensitivity indicated no significant relation between pains with QOL but the sleep disorders had direct and significant relation with pain. 16n this study we observed significant difference between QOL with various aspects of sleep.Our findings indicated that there were significant relations between apnea, twitch leg during sleep, numbness of legs with the QOL.It means that increasing the apnea during sleep, night terror and any disturbance in process of night sleep reduces the QOL.Also Neven Fouda indicated that there was significant relationship between sleep apnea and period of illness and patients with RA more suffers from apnea during sleep.It seemed improving sleep conditions could raise QOL of people. 35inally, results indicated that sleep disorders in RA patients are more common, and these results were consistent with Gjever et al., studies who revealed that most patients with RA have sleep disorders. 10urthermore, in this study patients had restless legs syndrome and apnea, which it could be related to the cervical instability. 36he important aspect is the effects of two factors sleep and pain on QOL which could affect other health related patterns.We investigated what could worsen the QOL: sleep disturbance or pain, that pain severity had more effect.On the other hand, pain severity could impair sleep.In addition sleep disturbances would increase pain.So pain control in RA patients would help to promote their sleep thereupon promotion of the QOL.

Conclusion
Results of this study indicated that pain severity would worsen sleep disorders, which may increase the disease process as well as having negative relations with QOL.
Further studies with large sample size, as well as more careful tools of sleep disorders, would help to generalize results and suggestions.By providing adequate health care, and recognition of the patients' pain conditions we would increase the QOL of RA patients.

Table 1 .
Distribution of participants according to demographic characteristics (N=210)