Significance of urinary incontinence, age, and consciousness level on arrival among patients with stroke

Abstract

Purpose:

We retrospectively investigated prognostic factors including urinary incontinence on arrival among the patients with stroke.

Materials and Methods:

A medical chart review was retrospectively performed for patients with stoke admitted between January 2010 and December 2010 in Ken-o Tokorozawa Hospital which had stroke care unit. The subjects were divided into a control group (functional outcome with modified Rankin scale (mRS) 0-3 at 3 months) and a poor group (severe disability or death, mRS 4-6).

Results:

There were 160 cases that had favorable outcome (the Control group) and 77 cases that had poor outcome (the Poor group). There were no significant differences between the two groups concerning the sex ratio, systolic blood pressure, heart rate, temperature, ratio of diabetes mellitus. However, the average age, ratio of hemorrhagic stroke, ratio of patients with a previous stroke, ratio of urinary incontinence upon admission, and duration of hospitalization in the Poor group was significantly higher than in the Control group. The Glasgow Coma Scale upon admission and ratio of hypertension in the Poor group were significantly lower than that in the Control group. Using a multiple logistic regression analysis, urinary incontinence (odds ratio, 3.17; 95% confidence interval, 1.45-6.93; P = 0.002), age (odds ratio, 1.04; 95% confidence interval, 1.01-1.07; P = 0.003) and Glasgow Coma Scale (odds ratio, 0.87; 95% confidence interval, 0.78-0.97; P = 0.01) were found to be factors independently associated with a poor outcome.

Conclusion:

Among the patients with strokes, the presence of urinary incontinence on arrival, the old age, and the level of consciousness are important prognostic factors. Physicians should therefore check for these factors when evaluating a patient who has experienced a stroke or suspected stroke.

INTRODUCTION

Urinary incontinence (UI) is an important and common health problem, whose prevalence increases with age.[1–3] Common types of incontinence affecting the elderly are: stress incontinence, urge incontinence, overflow incontinence, and mixed type incontinence. Concerning stress incontinence, females are predominant in comparison with males because of their shorter urethral tract. In contrast, urinary incontinence with urge symptoms is mostly affected by neurogenic issues affecting geriatric detrusor function.

Patients who experience a stroke may have urinary and/or fecal incontinence. Both have been reported to be signs of a poor prognosis in patients with stroke.[4,5] However, these signs were judged in the subacute or chronic phase during hospitalization, and only Nakayama et al. reported the significance of UI on arrival.[4,6–11] Moreover, even Nakayama et al. evaluated 32% of the patients with stroke in the subacute phase together with those in the acute phase. In addition, most of all reports, including that by Nakayama et al., that have evaluated the relationship between stroke and urinary incontinence, have excluded the patients with subarachnoid hemorrhage (SAH), because SAH required a head CT examination to obtain a correct diagnosis.

At Ken-o Tokorozawa Hospital in Saitama prefecture, located near Tokyo, we perform CT examinations for all patients who have had a possible stroke, including those suspected to have a SAH, and we routinely record whether the patient had urinary incontinence upon arrival. Accordingly, we retrospectively investigated the prognostic factors including urinary incontinence among the patients with both ischemic and hemorrhagic stroke.

MATERIALS AND METHODS

The institutional review board of Ken-o Tokorozawa Hospital approved this retrospective study and waived the requirement of informed consent. Ken-o Tokorozawa Hospital is located in Saitama prefecture close to Tokyo, and has 100 beds including stroke care unit. This hospital had one CT and two MRI instruments, and stroke patients can be evaluated by CT or MRI at any time.

A medical chart review was retrospectively performed for patients with stoke admitted between January 2010 and December 2010. Stroke was defined clinically according to the World Health Organization criteria, and the pathological subtype classification as ischemic stroke (IS),[12] including transient ischemic attack, intracerebral hemorrhage (ICH) or subarachnoid hemorrhage (SAH), was confirmed by CT and/or MRI. The diagnosis of SAH was made based on the existence of SAH in the basal cistern on the initial CT without evidence of a contusion or fracture of the skin or skull. A transient ischemic attack (TIA) is a transient episode of neurologic dysfunction caused by ischemia which subsided within 24 h without any high intensity lesions in diffusion weighted image.

The subjects were divided into a control group (functional outcome with modified Rankinscale (mRS) 0-3 at 3 months) and a poor group (severe disability or death, mRS 4-6). The exclusion criteria were delayed arrival over 48 h from when the initial signs and symptoms started, or from the last moment confirmed by other people. Another exclusion criterion was preexisting micturition disturbances. The patients’ age, sex ratio, physical data on arrival (Glasgow Coma Scale, systolic blood pressure, heart rate and temperature), past history of hypertension, diabetes mellitus and stroke, duration of admission and the survival rate were all compared between the two groups.

The statistical analyses were performed using unpaired Student's t-tests and the χ² analysis. A P value < 0.05 was considered to indicate a statistically significant difference. All data are shown as the means + standard error. A multivariate analysis using a logistic regression analysis was used to evaluate the independent factors regarding the outcome (favorable vs. poor). The variables included in the multivariate analysis were those with significance levels of P < 0.05 based on a univariate analysis. The odds ratio and the corresponding 95% confidence intervals were also calculated.

RESULTS

During the target period, there were 1540 patients who were admitted to Ken-o Tokorozawa Hospital, 258 of whom had experienced a stroke. Among them, 18 patients arrived over 48 h from the occurrence of stroke and another 3 patients had had urinary incontinence prior to the occurrence of stroke, so that 237 patients were finally included as study subjects. There were 37 cases of non-traumatic SAH, 72 cases of ICH and 128 cases of IS. All subjects who had a hemorrhagic stroke (SAH + ICH) underwent a CT examination. Concerning SAH, there were 34 cases of ruptured cerebral aneurysms, and 2 cases of dissecting aneurysms were confirmed by CT or conventional angiography. The other case became brain dead on the first hospital day, and the bleeding source of this case was not identified. All of the subjects with IS, except for this one, who became brain dead due to complications of hemorrhagic transformation confirmed by CT, underwent MRI examination. Among them, six cases did not show ischemic changes on diffusion weighted images which were re-evaluated over 24 h from the occurrence of signs and symptoms. All six cases who had no ischemic lesions showed the disappearance of their symptoms within 24 h from onset, and were considered to have had a transient ischemic attack. Among the subjects, there were 160 cases who had favorable outcome (the Control group) and 77 cases who had poor outcome (the Poor group).

The results of the analysis are shown in Table 1. There were no significant differences between the two groups concerning the sex ratio, systolic blood pressure, heart rate, temperature, ratio of diabetes mellitus. However, the average age, ratio of hemorrhagic stroke, ratio of patients with a previous stroke, ratio of urinary incontinence upon admission, and duration of hospitalization in the Poor group was significantly higher than in the Control group. The Glasgow Coma Scale upon admission and ratio of hypertension in the Poor group was significantly lower than that in the Control group. Concerning the outcome, the average modified Rankin Scale and mortality rate in the UI group was significantly higher than those in the Control group. Using a multiple logistic regression analysis, urinary incontinence (odds ratio, 3.17; 95% confidence interval, 1.45-6.93; P = 0.002), age (odds ratio, 1.04; 95% confidence interval, 1.01-1.07; P = 0.003), and Glasgow Coma Scale (odds ratio, 0.87; 95% confidence interval, 0.78-0.97; P = 0.01) were found to be factors independently associated with a poor outcome.

Table 1.

Results of the analysis

DISCUSSION

Among the patients with strokes, the presence of urinary incontinence on arrival, the old age, and the level of consciousness are important prognostic factors. Among factors, the urinary incontinence had the highest odds ratio. In addition, age and the level of consciousness had already reported to be risk factors for urinary incontinence.[13,14]

The mechanism of micturition is controlled by multiple pathways at many levels by brain, the spinal cord, and the peripheral nervous system, and is mediated by multiple neurotransmitters. Functional MRI studies that investigated which brain areas are involved in the regulation of micturition revealed that the thalamus, the insula, the prefrontal cortex, the anterior cingulate, the periaqueductal grey, the pons, the medulla, and the supplementary motor area are all activated during urinary storage. A preliminary conceptual framework, based on functional brain-imaging studies, suggested a mechanism wherein there are connections between various forebrain and brainstem structures that are involved in the control of the bladder and the sphincter in humans.[15,16] As age increases, the probability of the occurrence of asymptomatic or symptomatic cerebral infraction or minute hemorrhages increases.[13,15,17] The presence of these lesions could impair these neuronal pathways which regulate micturition. Accordingly, patients with a high age or a past history of stroke tended to be at higher risk for urinary incontinence. In addition, the arousal center is located in anascendingreticular activating system, which involves the medulla, pons, thalamus, and hypothalamus,[18] which also regulates micturition, so that consciousness disturbances also tended to be associated with urinary incontinence. Of interest, the patients with urinary incontinence who had good consciousness on arrival also had a poorer functional recovery in comparison with the patients without urinary incontinence. The impairment of the multiple neuronal pathways which regulate micturition may also have been associated with a poorer recovery of other functions. Previous reports also suggested that the presence of urinary incontinence during the subacute or chronic phase was an independent prognostic factor among stroke patients.[19–21]

There have been a few reports which investigated the relationship between SAH and urinary incontinence.[22–24] Patient with SAH often showed no focal signs, so that a correct diagnosis of SAH required CT examination. Another problem was the differential diagnosis of traumatic SAH. All of our cases of SAH except for one had a clearly identified bleeding source. The other patient had developed a sudden onset headache without trauma. In this study, all of cases with urinary incontinence in the SAH group had sum of Glasgow Coma Scaleunder 8, so the level of consciousness is an important factor that can contribute to the presence of urinary incontinence in patients with SAH. As a result, the prognosis of urinary incontinence in the patients with SAH was poor. Lee, et al. previously reported that the only 3.1% of the patients with SAH had urinary incontinence, and that urinary incontinence was not prognostic factor.[22] They retrospectively treated the data which was registered by multiple medical facilities. However, their study did not focus on urinary incontinence. In addition, many medical staff members did not know about the clinical importance of urinary incontinence, so they might have failed to record urinary incontinence, so the frequency of urinary incontinence in the patients with SAH was low.[10,25] Lawrence et al. prospectively collected data focusing on urinary incontinence at any time during hospitalization.[24] Their study demonstrated that 92% of the patients with SAH had urinary incontinence, and that the urinary incontinence in the patients with stroke was independently associated with death and severe disability.

CONCLUSION

Among the patients with strokes including SAH, the presence of urinary incontinence on arrival, the old age and the level of consciousness are important prognostic factors. Physicians should therefore check for these factors especially for urinary incontinence when evaluating a patient who has experienced a stroke or suspected stroke.