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Saudi Journal of Kidney Diseases and Transplantation
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ORIGINAL ARTICLE Table of Contents   
Year : 2010  |  Volume : 21  |  Issue : 3  |  Page : 433-437
Assessment of sleep disturbance in renal transplant recipients and associated risk factors

1 Dr. Taheri Medical Research Group, Tehran; Baqiyatallah Research Center for Gastroenterology and Liver Disease, Baqiyatallah University of Medical Sciences, Tehran, Iran
2 Dr. Taheri Medical Research Group, Tehran, Iran
3 Dr. Taheri Medical Research Group, Tehran; Neurology Department, Tabriz University of Medical Sciences, Tabriz, Iran
4 Dr. Taheri Medical Research Group, Tehran; Orthopedics Department, Ahvaz University of Medical Sciences, Ahvaz, Iran

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Date of Web Publication26-Apr-2010


Sleep disturbances are highly prevalent in ESRD patients. In this study we sought to evaluate the associations of poor sleep with several genetic, laboratory, treatment and de­mographic factors in renal allograft recipients using a validated sleep quality questionnaire. A cross-sectional study was conducted on renal transplant patients over 18 years of age with stable current stable graft function. All patients completed PSQI and Ifudu questionnaires for assessment of sleep quality and morbidity measures. Kolmogorov-Smirnov test was used for evaluation of distributions besides Student's t-test, and Fisher's exact test for analyses. Mean total PSQI score for the whole patients was 6.5 ± 2.6. Overall 26 (67%) of patients were diagnosed as "poor sleepers" (PSQI total score ≥ 5) and the reminding 13 (33%) were "good sleepers". Compared to "good sleepers", "poor sleepers" significantly had higher serum phosphate levels and ESRD duration (P= 0.05). Hematological disorders were more seen in "poor sleepers" and musculo­skeletal disorders had a significant worsening impact on PSQI total score (β= 0.28, P= 0.05). In conclusion our study showed that sleep disturbance is common in renal transplant patients is sur­prisingly common, and ESRD duration prior to transplant was significantly associate with sleep quality. Future studies with larger sample sizes are necessary for confirming our results.

How to cite this article:
Pourfarziani V, Taheri S, Sharifi-Bonab MM, Mohammadzadeh M. Assessment of sleep disturbance in renal transplant recipients and associated risk factors. Saudi J Kidney Dis Transpl 2010;21:433-7

How to cite this URL:
Pourfarziani V, Taheri S, Sharifi-Bonab MM, Mohammadzadeh M. Assessment of sleep disturbance in renal transplant recipients and associated risk factors. Saudi J Kidney Dis Transpl [serial online] 2010 [cited 2021 Sep 22];21:433-7. Available from: https://www.sjkdt.org/text.asp?2010/21/3/433/62712

   Introduction Top

Disorders of sleeping and wakefulness are among the most prevalent complaints in pa­tients with ESRD. [1],[2]

Numerous studies have reported that sleep disturbances are associated with development of several mental and physical health dilemmas both in the general population and among ESRD patients. [3],[4]

Despite large number of surveys studying sleep disturbances in patients undergoing chro­nic dialysis; few studies addressed the kidney transplant recipients. In this study we aimed to evaluate the associations of sleep disturbance in renal allograft recipients using a validated sleep quality questionnaire.

   Materials and Methods Top

A cross-sectional study was conducted in sta­ble renal transplant patients attending an out­patient nephrology clinic after obtaining in­formed consent. 39 patients agreed to participate in the study. The following inclusion criteria were used: over 18 years of age, current stable graft function, and competence to give infor­med consent. Patients with an elevated serum creatinine level or any concomitant acute disease were excluded from analysis. We extracted all available demographic data, medical history, laboratory test results, and treatment strategies, from our local data registry and outpatient cli­nic records.

All patients completed two self-administered questionnaires for assessment of sleep quality and morbidity measures. Baseline assessment was determined using the Pittsburg Sleep Qua­lity Index (PSQI; 7 items; total score, 0 to 21; higher score indicating worse sleep quality). [5],[6] Patients were then divided into two groups based on the PSQI score: group I (poor sleepers, PSQI score ≥ 5) and group II (good sleepers, PSQI score < 5). Patients were also assessed for medical comorbidities (Ifudu comorbidity index; 42 items; total score range, 0 to 42; higher scores indicating more medical comor­bidities).

For statistical analysis, we used SPSS v.13.0. Kolmogorov-Smirnov test was used for eva­luation of distributions. We used Student's t-­test, and Fisher's exact test for comparing the demographic, laboratory, and clinical variables as well as the scores of comorbidity measures between the two groups. Univariate and multi­variate linear regression models were employed for assessing independent correlates of PS-QI total score.

   Results Top

Demographic characteristics of the study po­pulation as well as their clinical and laboratory data are presented in [Table 1]. Mean total PSQI score for the whole patients was 6.5 ± 2.6. Overall 26(67%) of patients were diagnosed as "poor sleepers" (PSQI total score > 5) and the remaining 13 (33%) were "good sleepers". [Table 2] shows frequencies of disorders in each PSQI & comorbidity (Ifudu) sub-categories. Mean scores for sub-scores of PSQI were as follow: subjective sleep quality: 1.0 ± 0.8, sleep latency: 1.2 ± 0.9, sleep duration: 1.3 ± 1.3, habitual sleep efficiency: (no case), sleep dis­turbances: 3.0± 1.4, use of sleeping medica­tion: 3.0 ± 0.2, and daytime dysfunction over the last month: 2.0 ± 1.4.

We evaluated the difference of all variables listed in [Table 1] between "good sleepers" and "poor sleeper". We found that "poor sleepers" significantly had higher phosphate levels (6.1 ± 2.6 vs. 4.0 ± 1.6, respectively; P= 0.05) and ESRD duration (48 ± 58 vs. 20 ± 18 months, respectively; P= 0.05) compared to "good slee­pers". Considering categories for sleep quality, the only comorbidity index which is more seen among "poor sleepers" is hematological disor­ders (P= 0.03). We also assessed the potential impact of all the mentioned variables [Table 1] and comorbidity sub-indices on the PSQI total score using univariate linear regression analy­sis. Only comorbidity indices: ischemic heart disease, musculoskeletal and hematological dis­orders and limb amputation represented signi­ficant relations [Table 3]. Multivariable linear regression model revealed only musculoske­letal disorders as the independent comorbidity sub-index affecting PSQI score (P= 0.05, β= 0.29).

   Discussion Top

The prevalence of poor sleep in the present study was 67%. This finding represents a rela­tively higher prevalence of sleep disturbance among renal transplant patients compared to study by Sabbatini et al [3] where 52% preva­lence of sleep disturbance was reported. On the other hand, our finding seems quite com­parable with sleep-wake complaints in dialysis patients reported in previous studies. [7],[8],[9],[10]

At least two other recent studies have evalua­ted this issue. [11],[12] Molnar et al [11] reported high risk for sleep apnea in the kidney transplanted population that was approximately equivalent to patients undergoing dialysis. Beecroft et al [12] in their survey found that sleep apnea impro­ves just in a minority of patients following successful kidney transplantation; however, spe­cific determinants of improvement were not identified in their survey.

Several factors including anemia, advanced age, sex, and hormone imbalance may contri­bute to sleep disorders in CRF patients. [13] A number of previous studies have reported that male gender, use of specific medications, co­morbidity, and impaired kidney function are associated with high risk for sleep apnea in this patient population. [11] In our study, no asso­ciation between sleep quality and age, sex, im­munosuppression type, presence of diabetes mellitus, and serum creatinine level was iden­tified. However, although total comorbidity score showed a significant relationship with total PSQI score [Table 3], only musculoske­letal disorders represented an independent risk factor for higher PSQI scores and therefore worse sleep quality. On the other hand, regar­ding quality of sleep categories, "poor slee­pers" were more likely to have hematological disorders compared to "good sleepers".

Iliesco et al[2] in their study on hemodialysis patients found that anemia is a risk factor for poor sleeping. In the present study, we did not detect any association between hemoglobin levels and quality of sleep in renal transplant patients. Disturbance in immune function; [15] metabolic changes, [15] low serum PTH levels [16] are known risk factors for poor sleep, how­ever, infection rate and metabolic profile was not different. We did not measure the PTH levels however; we found that elevated serum phosphate values in renal transplant patients are significantly common in "poor sleepers". Socioeconomic level and education level are established risk factors for health related qua­lity of life in ESRD patients. [2] However, we did not find any data on the potential association between these factors and quality of sleep in renal patients. In this study, we did not detect any impact for the abovementioned factors as well as area of residence, gender and marital status on the sleep quality in our kidney trans­plant population. Other assessed risk factors in­cluding cause of renal failure, history of rejec­tion episodes, rehospitalization due to infec­tion, type of transplantation, having family caregiver, immunosuppression type, and age also did not affect sleep quality in this study.

In this study, ESRD duration presented as a significant risk factor for poor sleeping in re­nal recipients. Iliescu et al [2] in their study on hemodialysis patients found no impact for the duration of ESRD on the patients' sleep quality. However, corroborating to our finding, Sabba­tini et al [16] found that being over one year and less than eight year on dialysis (ESRD dura­tion) is a significant risk for poor sleeping. We also found no association between sleep qua­lity and human leukocyte antigen haplotypes expression.

The low quality of sleep observed in trans­plant patients with a functioning allograft ob­viously shows that the poor quality of sleep in renal patients has some extra factors other than renal dysfunction. Polysomnographic evalua­tions and surveys with larger study population for a more precisely uncovering the associa­tions of specific sleep components seem nece­ssary.

For a more precise interpretation of this stu­dy's results, we should acknowledge and con­sider its limitations. Our study had a limited population size. Moreover, its exclusion and inclusion criteria may result in some types of selection bias and also make it difficult to compare it with other reports. Laboratory mea­sures were essentially not determined at the time of study and we used the last post-trans­plant available data for this purpose.

In conclusion, our study shows that sleep qua­lity in renal transplanted patients is surprisingly poor, and associated with duration of ESRD phosphate levels. The PSQI questionnaire seems an easy and feasible tool to investigate the qua­lity of sleep in renal transplant patients. Future studies with larger sample sizes are necessary for confirming our findings.

   Acknowledgement Top

Authors are thankful to colleagues from Clin­ical Research Unit, Baqiyatallah University of Medical Sciences for their kind help with the study. This study is co-funded by Dr. Taheri Medical Research Group and Baqiyatallah University.

   References Top

1.Iliescu EA, Yeates KE, Holland DC. Quality of sleep in patients with chronic kidney disease. Nephrol Dial Transplant 2004;19:95-9.  Back to cited text no. 1  [PUBMED]  [FULLTEXT]  
2.Iliescu EA, Coo H, McMurray MH, et al. Qua­lity of sleep and health-related quality of life in haemodialysis patients. Nephrol Dial. Transplant 2003;18(1):126-32.  Back to cited text no. 2      
3.Sabbatini M, Crispo A, Pisani A, et al. Sleep quality in renal transplant patients: A never investigated problem. Nephrol Dial Transplant 2005;20(1):194-8.  Back to cited text no. 3      
4.Kachuee H, Ameli J, Taheri S, et al. Sleep quality and its correlates in renal transplant patients. Transplant Proc 2007;39(4):1095-7.  Back to cited text no. 4      
5.Buysse DJ, Reynolds CF 3rd, Monk TH, Berman SR, Kupfer DJ. The Pittsburgh Sleep Quality Index: A new instrument for psy­chiatric practice and research. J Psychiatr Res 1989;28(2):193-213.  Back to cited text no. 5      
6.Cole JC, Motivala SJ, Buysse DJ, Oxman MN, Levin MJ, Irwin MR. Validation of a 3-factor scoring model for the Pittsburgh Sleep Quality Index in older adults. Sleep 2006;29(1):112-6.  Back to cited text no. 6      
7.Holley JL, Nespor S, Rault R. A comparison of reported sleep disorders in patients on chronic hemodialysis and continuous peritoneal dialysis. Am J Kidney Dis 1992;19:156-61.  Back to cited text no. 7  [PUBMED]    
8.Walker S, Fine A, Kryger MH. Sleep com­plaints are common in a dialysis unit. Am J Kidney Dis 1995;26:751-6.  Back to cited text no. 8  [PUBMED]  [FULLTEXT]  
9.Williams SW, Tell GS, Zheng B, Shumaker S, Rocco MV, Sevick MA. Correlates of sleep behavior among hemodialysis patients. Am J Nephrol 2002;22:18-28.  Back to cited text no. 9  [PUBMED]  [FULLTEXT]  
10.Mucsi I, Molnar MZ, Rethelyi J, et al. Sleep disorders and illness intrusiveness in patients on chronic dialysis. Nephrol Dial Transplant 2004; 19(7):1815-22.  Back to cited text no. 10      
11.Molnar MZ, Szentkiralyi A, Lindner A, et al. High prevalence of patients with a high risk for obstructtive sleep apnoea syndrome after kidney transplantation-association with decli­ning renal function. Nephrol Dial Transplant 2007;22(9):2686-92.  Back to cited text no. 11      
12.Beecroft JM, Zaltzman J, Prasad R, Meliton G, Hanly PJ. Impact of kidney transplantation on sleep apnoea in patients with end-stage renal disease. Nephrol Dial Transplant 2007;22(10): 3028-33.  Back to cited text no. 12      
13.Fletcher EC. Obstructive sleep apnea and the kidney. J Am Soc Nephrol 1993;4(5):1111-21.  Back to cited text no. 13      
14.Benz RL, Pressman MR, Hovick ET, Peterson DD. Potential novel predictors of mortality in end-stage renal disease patients with sleep disorders. Am J Kidney Dis 2000;35:1052-60.  Back to cited text no. 14  [PUBMED]  [FULLTEXT]  
15.Parker KP, Bliwise DL, Bailey JL, Rye DB. Polysomnographic measures of nocturnal sleep in patients on chronic, intermittent daytime haemodialysis vs those with chronic kidney disease. Nephrol Dial Transplant 2005;20(7): 1422-8.  Back to cited text no. 15      
16.Sabbatini M, Minale B, Crispo A, et al. Insom­nia in maintenance haemodialysis patients. Nephrol Dial Transplant 2002;17:852-6.  Back to cited text no. 16  [PUBMED]  [FULLTEXT]  

Correspondence Address:
Saeed Taheri
Dr. Taheri Medical Research Group, Postal Code 1447965744, Tehran
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  [Table 1], [Table 2], [Table 3]

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