Association of lower urinary tract symptoms with restless leg syndrome and impaired somnolence pattern in middle aged and elderly men

Abstract

BACKGROUND

Lower urinary tract symptoms (LUTS) are closely associated with sleep disturbances, with evidence suggesting a bidirectional relationship between urinary symptoms and impaired sleep. Restless legs syndrome (RLS), a common neurological disorder and a recognized cause of insomnia, has not been systematically evaluated in relation to LUTS despite their shared impact on sleep quality.

AIM

To investigate the association between LUTS and RLS in middle-aged to elderly men, with a focus on sleep quality parameters.

METHODS

A cross-sectional study was conducted in the Department of Urology, All India Institute of Medical Sciences (AIIMS) Raebareli, over a two-year period. Male patients aged > 50 years with clinically diagnosed LUTS were included (n = 263). Patients with congestive heart failure, chronic kidney disease, stroke, cognitive impairment, or psychiatric disorders were excluded. LUTS severity was assessed using the International Prostate Symptom Score, sleep quality using the Pittsburgh Sleep Quality Index (PSQI), and RLS severity using the Restless Leg Syndrome Rating Scale. Statistical analysis included the Mann-Whitney U test, χ² test, and Spearman’s correlation coefficient.

RESULTS

Among 263 patients, 113 (42.9%) were diagnosed with RLS. Patients with RLS had significantly higher mean total International Prostate Symptom Score scores compared to those without RLS (19.78 ± 6.73 vs 16.55 ± 7.38; P < 0.001). Significant differences were observed in LUTS domains including incomplete emptying (3.19 vs 2.33; P = 0.001), intermittency (2.85 vs 1.99; P = 0.002), weak stream (2.84 vs 1.87; P < 0.001), straining (2.30 vs 1.48; P = 0.005), and nocturia (3.16 vs 2.47; P < 0.001). Overall PSQI scores were comparable between groups (6.48 ± 7.17 vs 6.31 ± 5.23; P = 0.824). However, patients with RLS had significantly higher use of sleep medications (0.77 vs 0.38; P = 0.012) and greater daytime dysfunction (0.94 vs 0.52; P = 0.025). Among RLS patients, total LUTS severity showed a positive correlation with PSQI scores (r = 0.290; P = 0.002), whereas in non-RLS patients, nocturia was significantly associated with sleep quality (r = -0.277; P = 0.001).

CONCLUSION

RLS was present in 42.9% of men with LUTS and was associated with higher LUTS severity, particularly in voiding domains. While overall sleep quality scores were comparable between groups, differences were observed in sleep medication use and daytime dysfunction.

Key Words: Lower urinary tract symptoms; Restless legs syndrome; Sleep disorders; Benign prostatic hyperplasia; Nocturia; International Prostate Symptom Score; Pittsburgh Sleep Quality Index; Restless Leg Syndrome Rating Scale

Core Tip: This study identifies a high prevalence (42.9%) of restless legs syndrome (RLS) among middle-aged and elderly men with lower urinary tract symptoms (LUTS), an area that remains relatively underexplored in urology. A significant association was observed between RLS and greater LUTS severity, particularly obstructive symptoms and nocturia. Despite comparable global sleep quality scores, patients with RLS demonstrated greater functional sleep impairment, reflected by increased sleep medication use and daytime dysfunction. These findings reveal a clinically meaningful interaction between LUTS and RLS, underscoring the importance of routine RLS screening in men with LUTS to enable more comprehensive, multidisciplinary management strategies.to enable more comprehensive and outcome-oriented management.

INTRODUCTION

Lower urinary tract symptoms (LUTS) may arise from a combination of obstructive or irritative causes. Obstructive causes include benign prostatic hyperplasia, obstructive prostate cancer, urethral stricture disease, dysfunctional voiding, detrusor-external sphincter dyssynergia, severe phimosis, and severe meatal stenosis. Irritative LUTS, such as urinary frequency, urgency, and dysuria, may result not only from chronic bladder outlet obstruction but also from overactive bladder, cystitis, prostatitis, bladder stones, or bladder cancer[1]. Several studies have highlighted significant associations between LUTS and impaired sleep quality. In the Complementary and Alternative Medicine for Urological Symptoms (CAMUS) cohort, nocturia showed a strong association with sleep disturbance, although other LUTS were also independent predictors of sleep dysfunction. The Reduction by Dutasteride of Prostate Cancer Events (REDUCE) study demonstrated that men with pre-existing sleep problems had a higher risk of developing LUTS even if asymptomatic at baseline[2]. Similarly, the Nagahama study found that baseline sleep disturbance was significantly linked with LUTS both cross-sectionally and with worsening symptoms over time[3]. The National Health and Nutrition Examination Survey (NHANES) study further reported that sleep disorders increased the risk of nocturia and daytime LUTS, independent of body mass index, diabetes, and multiple co morbidities[4]. Evidence from both cross-sectional and longitudinal population-based studies, including the CAMUS trial, confirmed that LUTS severity itself could act as a risk factor for severe sleep disturbance[5].

Restless legs syndrome (RLS) is a neurological disorder characterized by an uncomfortable urge to move the legs at rest, relief with movement or walking, and worsening symptoms at night. RLS is recognized as an important contributor to sleep disorders and is considered the fourth leading cause of insomnia. Its association with comorbid conditions such as idiopathic pulmonary fibrosis, end-stage renal disease, irritable bowel syndrome, attention-deficit/hyperactivity disorder, and insomnia has also been reported[6]. Given that sleep disorders are highly prevalent among patients with LUTS, it is plausible that RLS may represent an associated or causative factor contributing to their sleep disturbances. However, this relationship has not yet been systematically explored. Although several studies have examined the association of LUTS with sleep disorders, none to date have specifically addressed their link with sleep-related movement disorders, including RLS. Regulation of sleep, nocturia and urinary bladder functions involve important contribution of dopaminergic neuronal fibres. Low dopamine hypothesis as seen in RLS patients can also elucidate the predominance of LUTS seen in elderly population. RLS, as a sensorimotor disorder characterized by dopaminergic dysregulation, is hypothesized to exacerbate detrusor-sphincter dysfunction, thereby leading to increased severity of voiding symptoms. The present study was therefore designed to investigate the association between LUTS and sleep disorders, with a special focus on RLS, assessed using the RLS Rating Scale (RLSRS). Accordingly, this study aimed to determine the prevalence of RLS among middle-aged to elderly male patients presenting with LUTS.

MATERIALS AND METHODS

This was a cross-sectional study. The study was conducted in the Department of Urology, All India Institute of Medical Sciences (AIIMS), Raebareli, Uttar Pradesh. The study population included patients who attended the Urology Outpatient Department (OPD) of AIIMS, Raebareli, and were clinically diagnosed as cases of LUTS. The study was carried out over a period of two years. The sample size was calculated using the formula using Cochrane’s formulae[7]. Considering the prevalence to be 20.44% on the basis of a study on RLS in end-stage renal disease patients undergoing haemodialysis by Lin et al[8] with a confidence level of 95%, a 5% margin of error, and an infinite sample population, the calculated sample size was 256. A convenience sampling technique was employed to recruit middle-aged and elderly male participants attending the outpatient department during the study period. All eligible and consenting individuals meeting the inclusion criteria were consecutively enrolled until the required sample size was achieved.

Inclusion criteria

Male patients in the middle-aged to elderly age group (> 50 years); who attended the Urology OPD of AIIMS, Raebareli, and were clinically diagnosed as LUTS.

Exclusion criteria

Patients who did not provide consent, suffering from congestive heart failure, chronic kidney disease, stroke, Cushing’s disease, hypothyroidism, cognitive impairment, dementia, or bipolar affective disorders and those who had been taking second-generation antipsychotics for more than three months, did not have medical records of treatment for MDD, or met the criteria for any substance use disorder.

Assessment tools

The International Prostate Symptom Score (IPSS) was used to evaluate the severity of LUTS[9]. The IPSS is a validated questionnaire designed to assess LUTS related to benign prostatic hyperplasia. It consists of seven questions on incomplete emptying, intermittency, frequency, urgency, weak stream, straining, and nocturia. For each question, the patient chose one of six responses ranging from “not at all” to “almost always”. Responses were scored from 0 to 5, with higher scores indicating more severe symptoms. The total score ranged from 0 to 35, as per the American Urological Association. The Pittsburgh Sleep Quality Index (PSQI) was used to evaluate sleep quality[10]. It included 19 self-rated questions that generated seven component scores: Subjective sleep quality, sleep latency, sleep duration, habitual sleep efficiency, sleep disturbances, use of sleeping medication, and daytime dysfunction. Each component score ranged from 0 to 3, with higher scores indicating greater dysfunction. The sum of these seven component scores yielded a global PSQI score ranging from 0 to 21, with higher scores reflecting poorer sleep quality. The RLSRS questionnaire was used to assess the severity of symptoms in patients with RLS. This ordinal scale consisted of 10 items assessing the frequency, intensity, and duration of RLS symptoms, as well as their impact on sleep and daily activities. Each item was rated from 0 (no symptoms) to 4 (very severe symptoms). The total score ranged from 0 to 40, with higher scores indicating more severe symptoms[11].

Study procedure

Patients clinically diagnosed as LUTS in the Urology OPD were evaluated for demographic and clinical characteristics, including age, gender, educational level, marital status, comorbidities, and medication use. They were then assessed for LUTS using IPSS, for sleep quality using PSQI, and for RLS using RLSRS.

Statistical analysis

Data collected was entered in Microsoft excel. Before final analysis, missing data were assessed for extent and pattern; cases with substantial missing information were excluded, while minor missing values were handled using appropriate statistical imputation methods. Appropriate statistical tests were employed to analyze the data obtained from IPSS and PSQI scales among patients with and without RLS. The Mann-Whitney U test was used to compare the domain-wise scores of IPSS and PSQI between the two independent groups, as the data were ordinal and not normally distributed. The χ² test was applied to evaluate the distribution of categorical responses across IPSS symptom severity levels, as it is suitable for assessing associations between categorical variables. Additionally, Spearman’s rank correlation coefficient was used to assess the correlation between LUTS symptoms and sleep quality, as it is ideal for non-parametric and ordinal data. These tests ensured robust and appropriate statistical inference while addressing the study objectives.

RESULTS

Among 263 patients, those with RLS (n = 113) had significantly higher total IPSS scores than non-RLS patients (19.78 ± 6.73 vs 16.55 ± 7.38; P < 0.001), with greater severity in incomplete emptying, intermittency, weak stream, straining, and nocturia. No significant differences were observed in frequency and urgency, indicating RLS is primarily associated with more severe obstructive LUTS and nocturia (Table 1).

Table 1 Domain-wise comparison of International Prostate Symptom Score in lower urinary tract symptoms patients, mean ± SD/median (interquartile range).

IPSS score domains	RLS (n = 113)	Non-RLS (n = 150)	P value
Incomplete emptying	3.19 ± 2.025, 4.00 (1.00-5.00)	2.33 ± 1.785, 2.00 (1.00-4.00)	< 0.001a
Frequency	2.76 ± 2.084, 3.00 (0.00-5.00)	2.33 ± 1.786, 2.00 (1.00-4.00)	0.08
Intermittency	2.85 ± 2.151, 3.00 (0.00-5.00)	1.99 ± 1.753, 2.00 (0.00-3.00)	< 0.001 a
Urgency	2.61 ± 2.185, 3.00 (0.00-5.00)	2.31 ± 1.761, 2.00 (1.00-3.25)	0.322
Weak stream	2.84 ± 2.145, 3.00 (0.00-5.00)	1.87 ± 1.803, 1.50 (0.00-3.00)	< 0.001a
Straining	2.30 ± 2.057, 2.00 (0.00-5.00)	1.48 ± 1.625, 1.00 (0.00-2.00)	< 0.05a
Nocturia	3.16 ± 1.579, 3.00 (2.00-5.00)	2.47 ± 1.612, 2.00 (1.00-4.00)	< 0.001a
Total	19.78 ± 6.731, 20.00 (15.00-24.00)	16.55 ± 7.376, 16.00 (11.00-20.00)	< 0.001a

^aP < 0.05.

RLS: Restless legs syndrome; IPSS: International Prostate Symptom Score.

Although the global PSQI score did not differ significantly between RLS and non-RLS patients (6.48 ± 7.17 vs 6.31 ± 5.23; P = 0.824), both groups exhibited similarly poor sleep quality. However, RLS patients had significantly higher use of sleep medications and greater daytime dysfunction, indicating a higher impact on daily functioning (Table 2).

Table 2 Domain-wise comparison of Pittsburgh Sleep Quality Index score in lower urinary tract symptoms patients (n = 263), mean ± SD/median (interquartile range).

PSQI score domains	RLS (n = 113)	Non-RLS (n = 150)	P value
Subjective sleep quality	1.01 ± 1.184, 0.00 (0.00-2.00)	0.70 ± 0.749, 1.00 (0.00-1.00)	0.177
Sleep latency	0.89 ± 1.089, 0.00 (0.00-2.00)	0.84 ± 0.844, 1.00 (0.00-1.00)	0.709
Sleep duration	088 ± 1.103, 0.00 (0.00-2.00)	0.56 ± 0.719, 0.00 (0.00-1.00)	0.107
Habitual sleep	0.93 ± 1.208, 0.00 (0.00-2.00)	0.78 ± 0.866, 1.00 (0.00-1.00)	0.917
Sleep disturbances	0.84 ± 1.040, 0.00 (0.00-2.00)	0.69 ± 0.759, 1.00 (0.00-1.00)	0.734
Use of sleeping medication	0.77 ± 1.207, 0.00 (0.00-1.00)	0.38 ± 0.527, 0.00 (0.00-1.00)	< 0.05a
Day time dysfunction	0.94 ± 1.144, 0.00 (0.00-2.00)	0.52 ± 0.610, 0.00 (0.00-1.00)	< 0.05a
Total	6.48 ± 7.169, 0.00 (0.00-13.00)	6.31 ± 5.225, 7.00 (0.00-11.00)	0.824

^aP < 0.05.

RLS: Restless legs syndrome; PSQI: Pittsburgh Sleep Quality Index.

RLS patients demonstrated significantly greater severity and frequency of LUTS across IPSS domains, with higher proportions reporting severe symptoms (e.g., incomplete emptying, weak stream, and straining) and fewer mild symptoms compared to non-RLS individuals (Figure 1).

Figure 1 Symptom-wise comparison of International Prostate Symptom Score in lower urinary tract symptoms patients. RLS: Restless legs syndrome.

Among RLS patients significant positive correlation was found between frequency and PSQI (r = 0.195, P = 0.03) and between total IPSS score and PSQI (r = 0.290, P = 0.002), indicating worse sleep quality with more severe LUTS. Among non-RLS patients. A significant negative correlation was found between nocturia and PSQI (r = -0.277, P = 0.001), suggesting nocturia negatively affects sleep quality in this group. In RLS patients, overall LUTS severity and specifically urinary frequency are associated with poorer sleep quality. In non-RLS patients, nocturia appears to be a primary contributor to sleep disturbance (Table 3).

Table 3 Symptoms-wise comparison of correlation between International Prostate Symptom Score and Pittsburgh Sleep Quality Index.

LUTS symptoms and IPSS score	RLS		Non-RLS
	Correlation coefficient1	P value	Correlation coefficient1	P value
Incomplete emptying	0.025	0.79	-0.123	0.13
Frequency	0.195	< 0.05a	-0.047	0.56
Intermittency	-0.043	0.65	-0.040	0.63
Urgency	0.108	0.25	0.015	0.85
Weak stream	0.057	0.54	-0.106	0.19
Straining	-0.047	0.62	0.112	0.17
Nocturia	-0.001	0.99	-0.277	< 0.05a
IPSS	0.290	< 0.05a	-0.144	0.07

¹Spearman correlation coefficient.

^aP < 0.05.

IPSS: International Prostate Symptom Score; LUTS: Lower urinary tract symptoms; RLS: Restless legs syndrome.

DISCUSSION

In the present study, nearly 43% of patients with LUTS were found to have RLS, and the presence of RLS was significantly associated with more severe LUTS. The mean IPSS score was substantially higher in RLS patients than in non-RLS patients, consistent with the hypothesis that RLS contributes to increased urinary symptom burden. Obstructive symptom domains, including incomplete emptying, weak stream, straining, and nocturia, were particularly more severe in the RLS group. These findings highlight a distinctive symptom profile in RLS patients, where obstructive LUTS predominate.

Previous research has consistently demonstrated strong associations between sleep disorders and LUTS. The CAMUS trial reported that nocturia was significantly associated with sleep disturbance, and overall LUTS severity independently predicted poor sleep outcomes[5]. Similarly, the REDUCE study showed that baseline sleep problems increased the risk of LUTS development and progression in otherwise asymptomatic men[2]. Our findings parallel these observations, as RLS patients with more severe LUTS also reported worse sleep outcomes, reflected in higher use of sleep medications and greater daytime dysfunction. However, unlike prior large cohort studies such as the NHANES and the Nagahama Study[3,4]; which demonstrated broad associations between sleep quality and LUTS, our results suggest that global PSQI scores were comparable between RLS and non-RLS groups. Instead, specific domains of sleep impairment namely, reliance on sleep medications and daytime dysfunction differentiated RLS patients, suggesting that sleep-related functional impairment may be more important than global sleep quality scores in this subgroup. Further the findings of the study should be considered on the fact that RLS often causes sleep fragmentation and nocturia (a LUTS symptom) also disrupts sleep. So, both conditions might worsen each other or share a common mechanism related to sleep disorders.

Therefore, the frequency distribution of symptom severity adds further insight into the compounded symptom burden experienced by RLS patients. A higher proportion of patients with RLS reported severe voiding symptoms, with “almost always” responses for incomplete emptying (46.0% vs 22.7%), weak stream (41.6% vs 16.0%), and straining (30.1% vs 12.7%). While these findings suggest a possible association between RLS and obstructive LUTS, the underlying mechanisms remain uncertain. It is plausible that shared neurophysiological pathways, including alterations in dopaminergic signaling, may contribute to both conditions; however, such interpretations should be made with caution. In contrast, irritative symptoms such as frequency and urgency did not differ significantly between groups, which differs from some prior studies linking overactive bladder and sleep disturbances[1,4]. This may indicate that the relationship between RLS and LUTS in our cohort is more pronounced for voiding symptoms, although causality cannot be established.

Correlation analyses demonstrated that, among patients with RLS, greater LUTS severity and urinary frequency were associated with poorer sleep quality, as reflected by higher PSQI scores. In contrast, nocturia appeared to be the primary contributor to sleep disturbance among non-RLS patients, consistent with findings from the REDUCE and NHANES studies[2,4]. These subgroup-specific patterns suggest that the interaction between LUTS and sleep disturbance may differ in the presence of RLS, though the directionality of this relationship remains unclear.

Our findings are broadly consistent with prior studies, including that of Chavoshi et al[12], which reported a high prevalence of RLS and its association with impaired sleep quality in hemodialysis patients. However, differences in associated comorbidities across studies, such as thyroid dysfunction and antihypertensive use, highlight potential population-specific variability.

Previous literature has proposed potential overlapping mechanisms between RLS and nocturia, including alterations in autonomic function, circadian rhythm disturbances, and central sensory processing[13]. Additionally, factors such as dopaminergic dysfunction and iron metabolism have been implicated in RLS pathophysiology. Prior studies have emphasized the interplay between nocturia, sleep disturbances and lifestyle factors[14]; nevertheless, the extent to which these mechanisms contribute to the observed association with LUTS remains speculative and cannot be directly inferred from the present study.

Collectively, our findings support the coexistence of RLS and LUTS and their combined impact on sleep quality. However, given the observational nature of the study and the potential influence of confounding factors, these associations should be interpreted cautiously. Further studies are required to clarify underlying mechanisms and establish causal relationships.

The findings of the study should be interpreted considering the facts that the observed association between LUTS and RLS may be significantly influenced by multiple confounding factors, particularly advancing age, associated comorbidities, and medication use. Both LUTS and RLS demonstrate an independent increase in prevalence with age, making age a key shared determinant that may overestimate their true association if not adequately controlled. In addition, systemic conditions such as congestive heart failure, Cushing’s syndrome, diabetes mellitus, and neuropsychiatric disorders including bipolar affective disorder are known to independently contribute to sleep disturbance, neurohumoral dysregulation, and dopaminergic imbalance, thereby predisposing to or exacerbating RLS while also influencing LUTS. Furthermore, pharmacological agents, particularly antidepressants used in major depressive disorders, may worsen or precipitate RLS symptoms through central neurotransmitter modulation and may also impact urinary symptoms and sleep architecture. The coexistence of these factors introduces potential bias by acting as shared or interacting determinants, thereby confounding the relationship between LUTS and RLS. Apart from that increased sympathetic tone can also affect LUTS (detrusor activity).

Limitations of this study include its cross-sectional design, which precludes causal inference, and reliance on self-reported questionnaires. Future research in this domain should prioritize well-designed longitudinal and interventional studies to better define the temporal and potentially causal relationships between LUTS, RLS, and sleep disturbance. Given the cross-sectional nature of most existing evidence, including the present study, there is a critical need for prospective longitudinal studies that can establish directionality and clarify whether RLS contributes to the progression of LUTS, vice versa, or whether both arise from shared underlying mechanisms. Such designs would also enable evaluation of symptom trajectories over time and their impact on patient-reported outcomes.

Equally important is the need for rigorously conducted interventional trials assessing whether targeted management of one condition (e.g., RLS-directed therapy or optimized LUTS treatment) leads to measurable improvements in the other, as well as in overall sleep quality. These studies would be instrumental in determining the clinical relevance and therapeutic implications of the observed associations, thereby moving beyond correlation toward actionable evidence.

Furthermore, the incorporation of objective sleep assessment tools, including polysomnography and actigraphy, should be strongly emphasized in future studies. Reliance on subjective instruments alone may underestimate or misclassify sleep disturbances, particularly in patients with overlapping symptomatology. Objective measures would provide more precise characterization of sleep architecture, periodic limb movements, and nocturnal awakenings, thereby strengthening the validity and interpretability of findings.

In addition, future investigations should adopt comprehensive methodological frameworks that adequately control for confounding variables such as age, comorbidities, and medication use. Advancing research along these lines will be essential not only for refining our understanding of the LUTS-RLS-sleep interaction but also for informing integrated, multidisciplinary management strategies aimed at improving patient outcomes and quality of life.

CONCLUSION

RLS is significantly associated with more severe LUTS, especially obstructive domains such as incomplete emptying, weak stream, straining, and nocturia. Although global sleep quality (PSQI) did not differ between RLS and non-RLS groups, RLS patients reported higher use of sleep medications and greater daytime dysfunction, reflecting worse functional outcomes. Correlation analysis suggests that LUTS severity drives poor sleep in RLS patients, while nocturia is the key determinant in non-RLS patients. These findings highlight the need for clinicians to actively screen for RLS in LUTS patients to optimize both urinary and sleep-related health outcomes.