Poor Quality Sleep and its Associated Factors Among Iranian Patients Under Treatment for Cancer

Document Type : Original article

Authors

1 Department of Radiation Oncology, Faculty of Medicine, Iran University of Medical Sciences, Tehran, Iran

2 Department of Radiation Oncology, Faculty of Medicine, Imam Khomeini Hospital Complex , Tehran University of Medical Sciences, Tehran, Iran

3 Department of Psychiatry, Faculty of Medicine, Tehran University of Medical Sciences, Tehran, Iran

Abstract

Background: Sleep disorder is one of the main complaints of patients with cancer that could affect their quality of life and clinical outcomes. We aimed to investigate major contributors of poor quality sleep in patients with cancer that underwent treatment. 
Methods: We performed a cross-sectional study on 250 patients with cancer referred to the oncology department of Shohaday-e-Haftome-Tir Hospital, Tehran, Iran. Sleep quality as the main outcome of the study was evaluated using the Persian version of the self-report PSQI questionnaire. Global PSQI score >5 was categorized as the poor quality sleep. We also collected demographic and clinical data and physical performance status based on ECOG scale which grading is from 0:Fully active to 12:Death. Collecting the data regarding each patient was performed through medical records and face-to-face interviews.
Results: Mean age (±SD) of the study participants was 52.8 (±11.9) and 177 (70.8%) patients were female. The overall proportion of poor quality sleep was 66.8%. Sleep disorders were observed more frequent in patients with partial (OR=2.0, 95% CI=1.0, 3.8) and complete (OR=7.4, 95% CI=1.5, 36.4) physical dysfunction (p-value<0.05). There was also a strong association between a history of sleep disorder and cancer-related insomnia (OR=4.4, 95% CI=1.9, 10.1). No association was found between age, marital status, metastasis status, and cancer location with poor quality sleep.
Conclusion: Poor sleep quality had a high prevalence among our patients. Patients with physical functional impairment and those with psychiatric disorders (mood disorder) and pre-existing insomnia were the main groups of patients with a higher likelihood of cancer-related insomnia.

Keywords


Abstract
Background: Sleep disorder is one of the main complaints of patients with cancer that could affect their quality of life and clinical outcomes. We aimed to investigate major contributors of poor quality sleep in patients with cancer that underwent treatment. 
Methods: We performed a cross-sectional study on 250 patients with cancer referred to the oncology department of Shohaday-e-Haftome-Tir Hospital, Tehran, Iran. Sleep quality as the main outcome of the study was evaluated using the Persian version of the self-report PSQI questionnaire. Global PSQI score >5 was categorized as the poor quality sleep. We also collected demographic and clinical data and physical performance status based on ECOG scale which grading is from 0:Fully active to 12:Death. Collecting the data regarding each patient was performed through medical records and face-to-face interviews.
Results: Mean age (±SD) of the study participants was 52.8 (±11.9) and 177 (70.8%) patients were female. The overall proportion of poor quality sleep was 66.8%. Sleep disorders were observed more frequent in patients with partial (OR=2.0, 95% CI=1.0, 3.8) and complete (OR=7.4, 95% CI=1.5, 36.4) physical dysfunction (p-value<0.05). There was also a strong association between a history of sleep disorder and cancer-related insomnia (OR=4.4, 95% CI=1.9, 10.1). No association was found between age, marital status, metastasis status, and cancer location with poor quality sleep.
Conclusion: Poor sleep quality had a high prevalence among our patients. Patients with physical functional impairment and those with psychiatric disorders (mood disorder) and pre-existing insomnia were the main groups of patients with a higher likelihood of cancer-related insomnia.
Keywords: Neoplasms, Pittsburg sleep quality index, Sleep disorders, Sleep quality
Introduction
Cancer is a global public health challenge with a growing trend across the world (1). This upward trend is more intense in low and middle income countries and cancer also has more lethal outcomes (2,3). According to GLOBOCAN, two thirds of cancer death occur in such countries (3). Cancer affects various aspects of patients’ life. It comprises several mental and physical complications in cancer patients like pain, cancer treatment related fatigue, reduction of quality of life, immune system suppression and mental disorders (4). 
There are several evidences illustrating that quality of sleep in patients with cancer is also affected and it could be deteriorated due to cancer treatment and in one study conducted in Iran, it was shown that interventions focused on pain and fatigue management improve the patients sleep quality (5,6). Sleep disorder is known as a serious complaint in patients with cancer and is experienced by more than half of patients with cancer (4). Good quality sleep as a major need has strong relationship with quality of life and survival of patients with cancer (7). According to the previous studies, sleep deprivation is related to killer cell suppression that are essential part of immune system in combat against cancer cells and tumors (8). Therefore, in such circumstances, patients with cancer are more fragile against cancer and its consequences. It also makes them more vulnerable to infections and as a result, it can affect patients with cancer’s clinical outcomes through another pathway (9).  
Several studies with different approaches have been already performed and many different factors have been addressed in relation to sleep disturbance in patients with cancer. Pain, treatment side effects, sex, age, psychological causes, depression, cancer stage and cancer primary location have been already investigated as the predisposing factors for cancer-related insomnia in patients with cancer (9-11). Cancer-related insomnia is considered as a modifiable outcome, and determining the main factors of this phenomenon will be helpful to get a better comprehension considering its mechanism to prevent it (11). However, there is no consensus regarding risk factors of poor sleep quality in patients with cancer who underwent cancer treatment. In the current study we applied the PSQI self-report approach to evaluate the quality of sleep in patients with cancer. We also aimed to investigate risk factors of cancer-related poor quality sleep and performance status relation with sleep disorder in a sample of Iranian patients with cancer who underwent cancer treatment. There are few studies in this field in Iran addressing different types of cancer. Quality of sleep has a significant impact on a patient’s quality of life. Therefore, early diagnosis and referral to a psychiatrist and interventions are extremely important.

Materials and Methods 
The study was carried out on 250 cancer patients referred to the oncology department of Shohaday-e-Haftom-e-Tir Hospital, Tehran, Iran between April 2020 to December 2020.
The inclusion criteria were patients with solid tumors who are undergoing chemotherapy or radiotherapy or hormone therapy and are aged 20-80 years. The exclusion criteria included individuals over 80 years and under 20 years and a history of substance use disorder. 
Sleep quality was the main interesting outcome that was assessed using the validated Persian version of Pittsburgh Sleep Quality Index (PSQI) questionnaire. PSQI includes 19 items that evaluates sleep quality in 7 distinctive subdomains as following: subjective sleep quality (1 question), sleep latency (2 questions), sleep duration (1 question), habitual sleep efficiency (3 questions), sleep disturbances (9 questions), use of sleep medication (1 question) and daytime dysfunction (2 questions). Score for each question ranged from 0 to 3. In this scoring scale, 0 represents “very good”, 1 “fairly good”, 2 “fairly bad” and 3 “very bad”. Overall subjective sleep quality score was calculated through sum of all questions score and it ranged from 0 to 21. Higher score was associated with lower sleep quality and patients with score higher than 5 were categorized in bad sleep quality group. We also collected study participants demographic characteristics and their clinical history including age, sex, marital status, and physical performance status based on ECOG scale (The Eastern Cooperative Oncology Group scale). The ECOG Scale of Performance Status is one such measurement. It describes a patient’s level of functioning in terms of their ability to care for themself, daily activity, and physical ability (walking, working, etc.). The grading is from 0: Fully active, able to carry on all pre-disease performances without restriction to 5: Dead (12), cancer site, metastasis status, metastasis location, type of the received treatment, history of psychiatric disorder, history of sleep disorder, and history of taking sleeping peels using both face-to-face interview and their medical records.   
We used descriptive statistics to report our data. To evaluate the association between dichotomous variable, we applied Chi-Square test. Comparison of numerical variables was performed using Mann–Whitney U-test. Multiple logistic regression was also utilized to adjust the effect of confounding variables. We used Stata 14.1 to perform statistical analysis. Statistical significance level was p<0.05.
    
Ethics approval 
The current study was approved by the Iran University of Medical Sciences. The ethical code is: IR.IUMS.FMD.REC.1400.042. Informed consent was also taken from each participant before the interview.  

Results
The study was performed on 250 cancer patients who underwent either radiotherapy or chemotherapy at an educational hospital in Tehran. Mean age (±SD) of study participants was 52.8 (±11.9) and 177 (70.8%) patients were female. More than half of the patients (56.0%) were totally active (ECOG score=0) on ECOG scale, whereas only 2.0% were totally inactive (ECOG score=3). Breast cancer (45.2%) was the most prevalent cancer in the current study, followed by GI cancer (24.0%) and head and neck cancer (13.6%). Other clinical and demographic characteristics of the study participants were provided in table 1.  

 

Table 1. The participants’ demographic and clinical characteristics 

Gender

N

%

  Male

73

29.2%

  Female

177

70.8%

Marital status

 

 

  Single

30

12.0%

  Married

220

88.0%

ECOG performance status

 

 

  0

140

56.0%

  1

89

35.6%

  2

16

6.4%

  3

5

2.0%

Cancer type

 

 

  Breast

113

45.2%

  Gastrointestinal

60

24.0%

  Urinary system cancer

12

4.8%

  Head and Neck

34

13.6%

  Brain

6

2.4%

  Female cancer

23

9.2%

  Skin

2

0.8%

Metastasis status

 

 

  Present

87

34.8%

  Absent

163

65.2%

Metastasis location

 

 

  Bone

16

18.6%

  Brain

11

12.7%

  Visceral

59

68.6%

Mood disorder

 

 

  No

188

75.2%

  Yes

62

24.8%

Total

250

100%

History of Sleep disorder

 

 

  No

177

70.8%

  Yes

73

29.2%

History of taking sleep pills

 

 

  No

201

80.4%

  Yes

49

19.6%

 

Table 2. Distribution of sleep quality based on the participants’ demographic and clinical characteristics

Variable

poor sleep

 

Gender

n (%)

p-value

  Male

40 (54.7%)

 

  Female

127 (71.7%)

0.010

Age group

 

 

  20-40

20 (55.5%)

 

  41-60

106 (70.2%)

 

  Over 60

41 (65.0%)

0.232

ECOG

 

 

  0

83 (59.2%)

 

  1

65 (73.0%)

 

  2

14 (87.5%)

 

  3

5 (100%)

0.013

Disease stage

 

 

  Local cancer

105 (64.4%)

 

  Metastatic cancer

62 (71.2%)

0.273

Cancer site

 

 

  Breast

81 (71.6%)

 

  GI

39 (65.0%)

 

  Other

47 (61.0%)

0.293

Mood Disorder

 

 

  No

115 (61.1%)

 

  Yes

52 (83.8%)

 

Sleeping pill

 

 

  No

124 (61.6%)

 

  Yes

43 (87.7%)

0.011

Sleep disorder

 

 

  No

104 (58.7%)

 

  Yes

63 (86.3%)

<0.001

Total

167 (66.8%)

-----

 

Table 3. Determining contributing factors in bad quality sleep in the cancer patients

Variable

Adjusted OR

95% CI

p-value

Gender

 

 

 

  Male

Reference

 

 

  Female

1.9

0.8, 4.1

0.100

Age group

 

 

 

  20-40

Reference

 

 

  41-60

1.9

0.8, 4.5

0.114

  Over 60

1.1

0.4, 3.2

0.741

ECOG

 

 

 

  0

Reference

 

 

  1

2.0

1.0, 3.8

0.031

  2

7.4

1.5, 36.4

0.013

Disease stage

 

 

 

  Local cancer

Reference

 

 

  Metastatic cancer

1.5

0.7, 2.8

0.232

Cancer site

 

 

 

  Breast

Reference

 

 

  GI

1.0

0.4, 2.5

0.916

  Other

0.7

0.3, 1.8

0.573

Mood Disorder

 

 

 

  No

Reference

 

 

  Yes

2.2

0.9, 4.9

0.054

Sleep disorder

 

 

 

  No

Reference

 

 

  Yes

4.4

1.9, 10.1

<0.001

 

Table 4. Distribution of sleep quality score in study participants based on Pittsburgh Sleep Quality index in general and by its domains by gender

 

Male, (n: 73)

Female (n: 177)

Total (n: 250)

 

Domain score

Median (IQR)

Median (IQR)

Median (IQR)

p-value

Subjective sleep quality

1 (1)

1 (1)

1 (1)

0.372

Sleep latency

1 (1)

2 (2)

2 (2)

<0.001

Duration of sleep

1 (2)

1 (2)

1 (2)

0.898

Habitual sleep efficiency

1 (2)

1 (2)

1 (2)

0.180

Sleep disturbances

1 (0)

1 (1)

1 (1)

0.011

Daytime dysfunction

0 (0)

0 (0)

0 (0)

0.610

Sleep medical use

0 (1)

0 (2)

0 (2)

0.232

Overall score

6 (5)

8 (6)

8 (6)

0.025

    
According to the data, 167 patients (66.8%) were categorized in poor sleep. The prevalence of poor sleep was drastically higher in female (71.7%) than male (54.7%) (Table 2). However, after adjustment in multiple regression model, no statistically significant association was observed (p-value=0.100) (Table 3). An upward trend was observed when we compared proportion of poor sleep based on ECOG score where 59.2% patients with ECOG 0 score had low quality sleep, while it reached 100% at the 3 score of ECOG. Odds of poor sleep in patients with higher score of ECOG (score 2 and 3) was 7.4 times higher than the reference group (p-value=0.008). History of insomnia was addressed as the other contributing factor in the quality of sleep in cancer patients. Proportion of poor sleep in patients with history of sleep disorder was 86.3, which was considerably higher than patients without such history and the observed association was shown statistically significant (OR=4.7, 95% CI=1.9, 10.1) (p-value<0.001). No association between cancer stage, cancer location, age and sleep quality score was found. 
Besides, in table 4, we compared PSQI sleep quality score in overall and by its subdomains between male and female. Sleep disturbance, sleep latency and overall score of sleep quality on PSQI scale was highlighted significantly higher in female than male (p-value<0.05) (Table 4). 
   
Discussion
Poor quality sleep could affect several aspects of life and leads to a decrease in quality of life (7). It is estimated that prevalence of sleep disorders are virtually two times higher in patients with cancer  and it is known as one of the main complaints of patients who suffer from cancer (13). The current study was aimed at evaluating prevalence of poor quality sleep in a sample of Iranian patients with cancer and determining the main drivers of this phenomenon. 
Overall prevalence of poor quality sleep in our sample was pretty high, and around 66.0% of the patients have reported bad sleep. This high prevalence of bad sleep was supported by previous studies (5,11). The reported values for poor quality sleep in patients with cancer treated with chemotherapy ranges from 50% to 75% in previously published reports and these values were in line with our findings (14). High prevalence of poor quality sleep in patients with cancer might be referred to physical and mental complications arisen by life threatening nature of cancer. Cancer is known as a serious health condition that might finish the patient life; therefore, fear of death in cancer patients is linked to high level of stress and anxiety (15,16). Moreover, invasive treatment of cancer may lead to a couple of physical complications and adverse effects such as pain and physical performance status. Consequently, in presence of mental and physical problems in cancer patients’ poor sleep quality sounds logical (6).
Median score of overall sleep quality score was significantly higher in female than male. We also spotted a significant difference in sleep latency and sleep disturbances sub-domains when we compared men with women. However, after adjustment for confounding variables the association between gender and sleep quality disappeared. We also found no association between age and marital status as it has been already demonstrated in previous studies (6,10). Although we found no indication that poor quality sleep was related to age interpretation of such association is complicated. Age might be considered as an intermediate factor in the causal pathway since it is a predisposing factor for a couple of mental and physical health conditions such as mood disorder, insomnia, pain threshold, etc. that might increase risk of poor sleep quality (17).   
The results of the present study showed that patients with severe physical performance status were more likely to have poor sleep and quality of their night sleep was outstandingly lower than more active patients. The mentioned results were similar to previous published reports. However, generalizability of these findings is still controversial since many studies have shown that investigation of physical performance status is partially biased (17). However, it is argued that impaired physical performance status can result in prolonged absence from work and ultimately losing job in patients with cancer who underwent cancer treatment. It can also lead to psychological dysfunction due to unemployment and the further financial problems related to cost of cancer treatment particularly in communities with poor and unequal health system (17,18).     
We also found that mood disorders and history of insomnia were the other main contributors of poor quality sleep in cancer patients. Romito et al have already shown a strong correlation between mental health and quality of night sleep in cancer patients. They demonstrated that quality of sleep in patients with depression, distress and anxiety was strongly lower (19). The same finding was also reported by George et al that show an association between overall disturbed mood and poor sleep quality (11). 
We used a self-report approach to investigate the quality of sleep and it was our main limitation in the current study. Additionally, we had limitations in sample size and study power. Another limitation is lack of data regarding pain assessment, cancer treatment, related fatigue, and tobacco and opium use in the current study. However, we performed the study on a sample of cancer patients including both early and advanced cancer cases. A robust statistical method was also utilized in order to address the main contributing factor of cancer-related insomnia in cancer patients who underwent cancer treatment.

Conclusion
Poor sleep quality is shown a common and high prevalence problem affecting most of cancer patients. Patients with physically impaired function and those with mood disorders were the main groups of patients with higher likelihood of cancer-related insomnia. Thus, it is logical that we emphasized the role of mental and physical health of cancer patients and attempted to keep patients optimally healthy and functional during their course of cancer treatment.      
    
Acknowledgements 
None.

Conflict of Interest
The authors declare no conflict of interest.

Informed consent
Informed consent was obtained from all the participants included in the study.

Funding
The authors declare that the current study was not financially supported by any institution or organization.

 

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