1. Introduction

Chronic kidney disease (CKD) is a progressive health condition characterized by reduced glomerular filtration rate (GFR) and/or proteinuria, with stages ranging from 1 to 5 based on severity [1]. Affecting approximately 10%–15% of the global adult population, CKD is increasingly prevalent due to aging populations and the growing burden of conditions such as diabetes and hypertension [2]. If untreated, CKD can advance to end-stage kidney disease (ESKD), requiring dialysis or kidney transplantation, imposing significant individual and healthcare system burdens [3]. Sleep disturbances, including insomnia, obstructive sleep apnea (OSA), and restless leg syndrome (RLS), are common comorbidities in CKD patients [4]. In patients with advanced CKD, particularly those on renal replacement therapy (RRT), sleep disorders are more prevalent due to factors such as uremia, metabolic abnormalities, and associated psychological distress [5]. Around 50%–75% of patients with kidney failure and 8%–36% of individuals in the earlier stages of chronic kidney disease (CKD) report experiencing symptoms of insomnia [6]. Globally, sleep disorders affect approximately 20%–40% of the general population, with the prevalence being significantly higher among patients with chronic kidney disease (CKD) [7]. Cross-sectional and longitudinal studies consistently show a significant association between OSA and CKD, independent of other comorbidities like hypertension, diabetes, and obesity [8]. The bi-directional relationship between sleep disorders and CKD involves multiple pathophysiological mechanisms. Sleep disturbances, such as OSA and insomnia, can exacerbate CKD progression through factors like intermittent hypoxia, sympathetic activation, and nocturnal hypertension [9]. In addition, poor sleep quality has been associated with increased inflammation, oxidative stress, and metabolic imbalances, all of which play a role in exacerbating kidney damage [10]. Conversely, CKD-related factors, including uremia and deranged electrolytes, contribute to sleep disturbances, creating a complex interplay between these conditions [5]. Additionally, awareness among patients and healthcare providers about the association between sleep disorders and CKD remains low, especially since early-stage CKD is often asymptomatic [11]. Sleep disturbances in patients with chronic kidney disease (CKD) not only negatively affect their overall quality of life but also contribute to higher rates of morbidity and mortality [12,13]. Poor sleep is associated with cognitive dysfunction, cardiovascular disease, and metabolic syndrome, all of which are common in CKD patients [14]. Moreover, the subjective nature of sleep assessments, such as the Pittsburgh Sleep Quality Index (PSQI), complicates the accurate evaluation of sleep quality in CKD patients [15]. Objective assessment of sleep quality typically involves polysomnography (PSG), a complex, time-consuming, and expensive procedure. This adds to the treatment burden for patients who already spend significant time in the hospital for dialysis sessions [14]. Addressing sleep disturbances in CKD patients is essential for improving overall outcomes and reducing disease burden. The aim of this study is to investigate the relationship between sleep disorders and chronic kidney disease (CKD), focusing on the prevalence and impact of poor sleep quality across different CKD stages.

2. Materials & Methods

This cross-sectional study was conducted on patients diagnosed with chronic kidney disease (CKD) at conducted at the Department of Nephrology, Medical College for Women & Hospital, Dhaka Bangladesh. During 1 year from January 2024 to December 2024. A total of 50 patients were recruited using purposive sampling to ensure representation across CKD stages and etiologies. Written informed consent was obtained from each participant, and the study was conducted in accordance with ethical guidelines set by the Institutional Review Board (IRB) of the hospital.

Inclusion Criteria:

• • Patients diagnosed with CKD at stages 3–5D.
• • Aged 18 years or older.
• • Willing to provide informed consent and participate in sleep quality assessments.

Exclusion Criteria:

• • Presence of comorbid conditions such as advanced cancer or neurodegenerative diseases.
• • Ongoing use of sedative medications not related to CKD management.

Data Collection

Demographic and clinical data were collected through structured interviews, medical records, and laboratory tests. Demographic variables such as age, gender, marital status, educational level, occupation, smoking habits, and coffee intake were recorded. Clinical characteristics including the duration of CKD, the stage of CKD, comorbid conditions (e.g., hypertension, diabetes mellitus), eGFR (estimated glomerular filtration rate), creatinine levels, and medications (e.g., antihypertensive agents, erythropoietin) were assessed. Biochemical parameters such as potassium, calcium, phosphorus, hemoglobin, ferritin, and iron levels were also measured.

Sleep disorders were assessed using two validated tools: the Pittsburgh Sleep Quality Index (PSQI) and the Epworth Sleepiness Scale (ESS). The PSQI was used to measure the quality of sleep over the past month, with scores >5 indicating poor sleep quality. The ESS was used to assess daytime sleepiness, with scores >10 indicating excessive daytime sleepiness. Based on the findings from clinical assessments and sleep scales, patients were categorized into different sleep disorder types, including insomnia, obstructive sleep apnea (OSA), restless legs syndrome (RLS), and daytime sleepiness.

Statistical Analysis

Descriptive statistics were used to summarize demographic and clinical characteristics, with means ± standard deviations (SD) for continuous variables and frequencies and percentages for categorical variables. The prevalence of different sleep disorders was calculated by categorizing patients based on their scores in the PSQI and ESS. The statistical software SPSS version 26.0 was used for all analyses.

3. Results

Table 1: Demographic Characteristics of the study population (N=50)

Table 2: Clinical Characteristics of study population (N=50)

Table 3: Prevalence of Sleep Disorders in CKD Patients (N=50)

Table 4: Sleep Quality Assessment Scores

4. Discussion

Sleep disorders are common but often underrecognized complications in patients with chronic kidney disease (CKD). These disturbances significantly impact the quality of life and overall health outcomes, contributing to increased morbidity and mortality [5]. Chronic kidney disease disrupts metabolic homeostasis, alters circadian rhythms, and elevates inflammatory markers, all of which negatively affect sleep patterns [16]. Early identification and management of sleep disorders can enhance patient care and reduce the progression of CKD-related complications. Our findings suggest that 40% of the study participants had insomnia, a common sleep disorder seen in CKD patients, consistent with previous studies that reported high rates of insomnia in this group [17]. In addition, 30% of our participants were diagnosed with obstructive sleep apnea (OSA), a prevalence that aligns with existing literature where OSA is often found in CKD patients due to factors like fluid retention, airway obstruction, and metabolic changes [18]. The prevalence of restless legs syndrome (RLS) in our study was 20%, which is comparable to other research indicating that RLS is common among CKD patients [4]. Furthermore, our findings revealed that 10% of the participants reported excessive daytime sleepiness, which is frequently observed in CKD patients, possibly due to factors such as nocturnal disturbances and uremia [19]. The remaining 20% exhibited normal sleep patterns. Interestingly, when we assessed overall sleep quality using the Pittsburgh Sleep Quality Index (PSQI), 80% of participants scored above the cutoff for poor sleep quality, emphasizing the severity of sleep disturbances in this cohort. This aligns with research by Gela et al. (2024), who demonstrated that poor sleep quality is a prevalent issue among CKD patients, often correlating with worse outcomes in terms of quality of life and disease progression [20]. In a recent study, researchers reported that 77.8% of chronic kidney disease (CKD) patients were classified as poor sleepers, indicated by a Pittsburgh Sleep Quality Index (PSQI) score greater than 5 [21]. Similarly, previous literature has documented that the prevalence of poor sleep among CKD patients falls within the 45% to 80% range, including sleep-wake disturbances, sleep-disordered breathing, and excessive daytime sleepiness within this population [22]. The Epworth Sleepiness Scale (ESS) also indicated a significant proportion (30%) of participants experienced excessive daytime sleepiness, a finding that is often linked to impaired kidney function and the underlying metabolic derangements in CKD. In a cohort of 168 patients with end-stage renal disease (ESRD) receiving daytime hemodialysis, 70% demonstrated an increased tendency for inappropriate daytime sleep, as indicated by elevated ESS scores [19]. Similarly, another study reported that 56% of CKD patients exhibited high ESS scores (ESS > 10), indicating a substantial prevalence of EDS, with a median ESS value of 10.0 [23]. Our study adds to the growing body of evidence that sleep disorders are a critical concern in CKD management. Notably, the mean age of participants in our study was 51.4 years, which may have contributed to the high prevalence of sleep disturbances, as aging is often associated with an increased risk of sleep disorders [5].  This finding is consistent with previous research, which reported a similar mean age of approximately 55.6 years for CKD patients experiencing poor sleep quality [17]. Additionally, the high incidence of sleep disorders in individuals with hypertension and diabetes mellitus (the most common etiologies in our cohort) supports the view that these comorbidities may exacerbate sleep disturbances [24].

Limitations of the study:

Every hospital-based study has some limitations and the present study undertaken is no exception to this fact. The limitations of the present study are mentioned.

• • The cross-sectional design of the study prevents causal inferences between CKD and sleep disorders.
• • The absence of a control group limits comparisons between CKD patients and the general population regarding sleep disturbances.
• • The data collected on comorbidities and medications was retrospective, which may have introduced recall bias.

5. Conclusion and Recommendations

Among lupus nephritis patients, the use of hydroxychloroquine, cyclophosphamide, MMF, and corticosteroids aligns with current clinical practice guidelines and demonstrates the effectiveness of these therapies in achieving favorable treatment outcomes. The significant associations between urine KIM-1 levels and disease severity, as well as its correlation with renal function markers, highlight its utility in clinical practice. Future research should focus on further validating urine KIM-1 as a biomarker and exploring its potential in guiding treatment decisions and predicting patient outcomes in lupus nephritis.

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