Functional Status and Its Related Factors Among Stroke Survivors in Rehabilitation Departments of Hospitals in Shenzhen, China


 Background: Many stroke survivors have multiple chronic diseases and complications, coupled with various other factors which may affect their functional status. We aimed to investigate the factors associated with poor functional status in hospitalized patients with stroke in Shenzhen, China.Methods: This is a cross-sectional study. Data on 646 patients with stroke were recruited from four urban hospitals using cluster sampling. The Longshi Scale was used to assess the functional status of stroke survivors. Explanatory variables, i.e. factors affecting functional status, included demographic, lifestyle factors, complications, and chronic conditions. The ordinal logistic regression model was used to investigate factors associated with poor functional status. Results: Stroke survivors with poor functional status accounted for 72.14% and were assessed as the bedridden group based on the Longshi scale, 21.67% of patients with moderate functional limitation were assessed as the domestic group and 6.19% of the patients with mild functional restriction was assessed as the community group. The highest dependence was noted for feeding (73.39%), bowel and bladder management (69.74%), and bedtime entertainment (69.53%) among the bedridden group, and housework (74.29%) among the domestic group. In the adjusted model, patients who were in older age groups (odds ratio [OR] = 2.39, 95% CI: 1.55–3.80), female (OR = 1.73, 95% CI: 1.08–2.77), duration of stroke more than 12 months (OR = 1.94, 95% CI: 1.28–2.95), with pulmonary infection (OR = 10.91, 95% CI: 5.81–20.50), and with deep venous thrombosis (OR = 3.00, 95% CI: 1.28–7.04) had almost or more than two times the risk of poorer functioning.Conclusions: Our study found that 72.14% of stroke survivors had poor functional status, 21.67% and 6.19% of stroke survivors had moderate functional limitations and mild functional restrictions in rehabilitation settings. The older age bracket (age ≥ 60) and females were more likely to exhibit poor functioning. Pulmonary infection and deep venous thrombosis, both common post-stroke complications, were related to the increased chance of dependence. Therefore, interventions aimed at treating or preventing pulmonary infection and deep vein thrombosis need to contribute to addressing these circumstances and subsequent dysfunction after stroke.


Background
Over the past century, stroke had a dramatic increase and became the third leading cause of disability worldwide [1]. About 37 -45% of stroke survivors have functional disabilities [2,3]. More stroke survivors will be coping with functional disability and be dependent on others for one or more activities of daily living (ADLs) [1]. There is an urgent need to address the disability problems and change of functional status caused by stroke [1,4,5]. Limitations in ADLs stand for poor functional status and increased need for social support.
Most studies use the Modi ed Rankin Scale (mRS) to distinguish the patients' functional outcome, which helps to distinguish a wide range of disability categories, but mRS does not measure ADL-related functions and is insensitive to subtle differences in functional status between patients [6]. The Longshi scale (LS) is a visual-based scale that assesses abilities based on activity range and dependency and is used in China [7][8][9]. The participants/their family members/their caregivers report the real functional status and ADL manifestations of the patients with stroke, including people with cognitive impairment (National Standard of the People's Republic of China, No. GB/T 37103-2018) [10]. With the Barthel index as a reference, LS can better identify the disability of stroke survivors than mRS [10].
With the increasing prevalence and burden of multiple chronic conditions (MCC) in stroke survivors, MCC has a modest association with post-stroke functional outcome and contributes considerably to functional impairment [11][12][13][14][15]. As far as we know, In the Asia Paci c region,only one study in Singapore con rmed the relationship between MCC and post-stroke readmission [16], and a previous study of our team also found that the more MCC, the worse ADL ability of elderly stroke survivors, but it did not show the situation in young stroke survivors [13]. Therefore, due to the differences in individuals' characteristics, this study focuses on hospitalized stroke survivors in China's medical system settings.
The presence of chronic disease and demographic factors such as age, sex, complications, and lifestyle behaviors (e.g., smoking or use of alcohol) play an important role in the development of functional outcomes of patients with stroke [1,11,[17][18][19]. Pulmonary infection, deep vein thrombosis (DVT), urinary tract infection are the common complications after stroke [1]. Different studies have shown that the infection rate after stroke ranges from 5% -65%, pulmonary infection is 1% -33%, and urinary tract infection is 2% -27% [20,21]. Moreover, these complications in uence each other and are risk factors for each other. Pulmonary infection is an independent risk factor associated with DVT in hospitalized patients with stroke [17]. Even though functional outcome studies among stroke survivors, in general, have shown that the most powerful predictor of functional recovery is the initial severity of the stroke [22,23], but few studies detailed the clinical characteristics of hospitalized patients with stroke [23], especially in rehabilitation departments of urban hospitals in China.
It is important to note that a full understanding of the situation of stroke survivors is essential for planning current and future needs for healthcare resources and for identifying appropriate treatment strategies [23]. Hence, the knowledge of the factors related to poor functional status may help physicians to identify these factors and intervene as soon as possible, and it will help to highlight the demographic characteristics, lifestyle factors, complications, MCC, etc. of stroke survivors among rehabilitation departments of urban hospital settings in Shenzhen, China.

Study design and setting
The cross-sectional survey was conducted in the rehabilitation medicine departments of four hospitals in four districts of Shenzhen, China. These hospitals were selected through convenient sampling. Initially, the purpose of this study was to investigate the care needs of inpatients in rehabilitation hospitals. The study protocol was registered in China Clinical Trial Registration Center (ChiCTR -2000034067) and approved by the ethics committee of Shenzhen Second People's hospital.

Study participants
A total of 1019 hospitalized patients were screened, and 646 stroke survivors were recruited using cluster sampling between August 4 and August 22, 2021 (Fig.1). Stroke was diagnosed according to the 10th edition of the International Classi cation of Diseases (ICD-10) [24], and all patients in the selected hospitals who were diagnosed with stroke and older than 18 years old were included. The type of stroke is based on the rst diagnosis from the patients' medical history. Subarachnoid hemorrhage was not included. Before the recruitment, the investigator would explain the study contents in detail and obtain the informed consent of each subject or their family.

Dependent variable
The ADL measured by the LS scale is used to de ne the functional status as the dependent variable [9]. LS scale assesses participants' independence or dependence on two questions and nine activities: bowel and bladder control, feeding, entertainment, toileting, grooming, housework, community mobility, shopping, and social participation (Fig. 2) [7].
According to the LS, the activity levels were divided into three groups (bedridden, domestic, and community groups) depending on the activity range of the participants (Fig. 3) [10]. To determine the activity range of the participants, the participants/their family members/caregivers were asked "Can you/he/she get off the bed independently? And can you/he/she go outdoor independently?", with only two options available for the answer, "yes or no" [8]. The bedridden group represents those who cannot get off the bed independently. The subjects accessed as the domestic group can get off the bed independently but cannot go outdoor independently. The subjects in the community group can go outdoor independently [8]. In previous studies, we have proved that the LS was reliable and valid for disability assessment [9]. Notably, the LS indicates the level of the functional status of participants. The community group was considered to have a mild functional limitation, the domestic group indicates moderate functional limitation, and the bedridden group has poor functional status (having a severe problem performing everyday tasks).

Independent variables
In this study, we collected patients' age, sex, body mass index (BMI), smoking, alcohol consumption, and disease information of complications and multiple chronic conditions as the independent variables. Demographic data were obtained by online questionnaires from participants and their families. Questions about smoking and drinking were assessed as dichotomous (yes/no) responses. Our study considered nine common chronic diseases: (1) hypertension, (2) cardiovascular disease, (3) diabetes, (4) hyperlipidemia, (5) hyperuricemia, (6) chronic obstructive pulmonary diseases, (7) chronic renal insu ciency, (8) abnormal liver function, (9) chronic bronchitis, and three common complications: (1) pulmonary infection, (2) urinary system infection, (3) DVT. The assessment of stroke survivors was done by asking participants whether a health professional told them that they have this condition, and there are only two options (yes/no); a method widely used to assess MCC [25]. In addition, the history of any chronic disease or the use of related drugs or other treatment is also recorded as "yes". Ultimately, we de ned the chronic disease by using self-reports, medical history, and a combination of these two assessments. The sum of MCC and complications were classi ed as categories: 0, 1, and ≥ 2.

Data collection
All data were collected through face-to-face interviews by uniformly trained therapists and nurses. The data is recorded through electronic questionnaires and stored on the website (https://www.mikecrm.com). Without permission, deletion, modi cation, and sharing of data are prohibited. During the data collection process, the database is supervised by the data administrator. Once unreasonable data records are found, the data administrator will check with the assessor and correct the error based on the actual situation.

Statistical analysis
All analyses were performed using SPSS 23.0 (IBM SPSS statistical software, Windows version, version 23.0. Armonk, NY: IBM Corporation). The number and the frequency (%) distribution of functional state independent variables was reported, and the frequency difference between different functional status groups was tested by the chi-square test. The ordinal logistic regression model was used to carry out the multivariate analysis, including the patients' age, sex, body mass index (BMI), smoking, alcohol consumption, complications, and multiple chronic conditions as covariates. Firstly, simple linear regression is used to detect whether there is multicollinearity between independent variables. If the tolerance is less than 0.1 or the variance expansion factor (VIF) is greater than 10, it indicates that there is collinearity. Secondly, ordinal logistic regression models were used to explore the factors associated with patients' poor functional status, who were assessed as the bedridden group based on the LS scale. Adjusted odds ratio (OR) and 95% con dence intervals (95% CI) of the variables in the nal model were reported. A P-value < 0.05 for two-tailed was considered statistically signi cant.

Functional status
The overall prevalence of the bedridden group was 72.14%, the prevalence of the domestic group was 21.67%, and that of the community group was 6.19% (Table 1). Table 2 reports responses of stroke survivors to each item of the LS scale regarding functional status. In the bedridden group, participants reported inability to eat most frequently (73.39%), followed by bowel and bladder management (69.74%) and bedtime entertainment (69.53%), and 74.29% of the domestic group participants had a severe problem performing housework (Table 2). The complete model includes all variables listed in Table 1, except for the sum of MCC and complications. Therefore, the model is adjusted for all the variables in Table 3. The VIF of the variables included in the model is less than 3.0. In the nal model, gender, age, duration of the stroke, pulmonary infection, and DVT were signi cantly correlated with poor functional status ( Table 3). The risk of poor function (OR = 2.43, 95% CI: 1.56 -3.80) in the elderly group (≥ 60 years old) was more than twice that in the young group (< 60 years old). Those with a disease duration of more than 12 months had close to twice-odd risks of poor functional status (OR = 1.72, 95% CI: 0.97-3.07) than those disease duration within 12 months. The risk was also close to or greater than double among females than males (OR =

Discussion
This study aimed to assess the correlates of functional status based on the LS scale among patients with stroke in hospital settings in Shenzhen, China. We found that 74.12% of stroke survivors assessed as the bedridden group had poor functional status, 21.67% of patients assessed as the domestic group had moderate functional limitation and 6.19% of the patients had mild functional restriction and was assessed as the community group. This study built on observational research that showed that older age, sex, duration of a stroke, pulmonary infection, and DVT were associated with poor functional status among inpatients with stroke.
In the present study, compared with individuals aged < 60 years, the poor functional status of stroke survivors was 2.43 times higher among individuals aged ≥ 60 years. This is similar to studies about stroke functional outcomes, which have shown that stroke risk and poor outcomes were signi cantly associated with age [26-28]. Once stroke occurs, the regenerative potential decreases, and the in ammatory responses to this disease increase in the elderly [29,30]. We also noted that 75.3% of patients with a duration of more than one year had poor functional status, while 65.7% of stroke survivors with a duration of less than one year had poor functional status. It seems that the functional status of patients with a course of more than one year was worse than those with a duration of less than one year among hospitalized stroke survivors (Table 1 and Table 3). Not surprisingly, stroke survivors with good functional status were discharged after a year, while patients with poor functional status who needed continuous medical treatment were transferred to different rehabilitation hospitals in Shenzhen, China.
We observed that females were more likely to have a severe stroke, and were more likely to be assessed as the bedridden group, than males. The female group had more than double the odds of poor functioning (Table 3). This is similar to several previous studies, which show that women have higher 1month case fatality and lower 1-year survival after stroke [31][32][33]. In this study, the age was older in women (Supplementary Table 1), and the previous studies found that more severe strokes, less aspirin administration, and likely lower quality of care were attributed to contributing to the situation among female stroke survivors [34]. Another possible explanation is the physiological differences between females and males, such as hormonal in uences (especially as prethrombotic and autoimmune diseases are more common in women). Some risk factors, such as atrial brillation and hypertension, are more common in women [35,36]. This result indicated that a sex difference in functional status exists among stroke survivors.
Previous studies also showed that alcohol use was a complicated epidemiological risk factor of stroke [37]. Some studies have shown different results, that is, low-dose alcohol consumption may have a protective effect on stroke [27]. Even in the nal ordinal logistic model, the alcohol consumption was not included as a risk factor (Table 3), but the patients with stroke who were consuming alcohol had poorer functional status than those without alcohol use, and the proportion (86.84%) of stroke survivors with poor functional status among those who have alcohol consumption was higher than those (71.65%) without alcohol use ( Table 1). The results informed us that methods of lifestyle change (e.g. reducing alcohol consumption) may be prioritized to reduce the higher ADL dependence among stroke survivors.
Being underweight is associated with the highest risk of poor functional status after stroke. In the univariate analysis, The proportion of patients with poor functional status in the underweight group was 84.62%, which was much higher than 61.54% in the overweight group and 47.62% in the obese group (Table1), and the results are similar to previous reports [38 -39]. This may be because people with normal BMI or obesity have better nutritional status and good nutrition after vascular events, which can signi cantly facilitate and accelerate the recovery process [40]. This is why the incidence of lung infections is also higher in stroke survivors with nutritional de ciencies [34], while a higher BMI is shown to signi cantly reduce the risk for pulmonary infection. This is a reminder that lung infections can be prevented by maintaining a normal BMI with nutritional support. In the ordinal logistic analysis model, BMI is not a risk factor, which may be related to the small number of obese patients (21 people) in our study.
Previous studies have found that post-stroke infections can worsen stroke prognosis [41][42][43]. Pulmonary infection is considered the most common infection after stroke and was associated with a relative risk of mortality 3.0 [44]. In this study, the pooled overall infection rate of pulmonary infection was 35.3% and urinary tract infections occurred in 9.2% of patients. Pulmonary infection is associated with poor functional status with an OR of 10.91, similar to a previous study that included patients with a higher stroke severity who had higher infection rates, especially for the pulmonary infection [21]. That is because infections could lead to immobilization, general frailty, and a delay in rehabilitation, which in turn affect the outcome of stroke survivors [20,45]. This, in turn, leads to other complications, such as DVT. In this study, patients with thrombosis had poorer functional status than those without thrombosis. However, since this study was a cross-sectional study, it was impossible to determine the causal relationship between these risk factors and poor functional status, and only the correlation between these factors and poor functional status could be found.
Unlike in other studies, MCC was not a risk factor for poor functional status in the logistic analysis in the present study. A potential explanation is that almost 90% of the patients were with more than one MCC (

Declarations
This study was supported by the National Key R&D Program of China (Grant code: 2020YFC2008700) and a grant from the Sanming Project of Medicine in Shenzhen (No.SZSM202111010).

Availability of data and materials
All the summarized and analyzed data during this study are included in this published article; the original data in this study are available from the corresponding author upon reasonable request.
Ethics approval and consent to participate This study protocol was approved by the Medical Ethics Committees of Shenzhen Second People's Hospital. The study was registered in the Chinese Clinical Trial Registry on June 22, 2020 (No.: ChiCTR2000034067 http://www.chictr.org.cn/showproj.aspx?proj=54770 ). All inpatients or their proxies were invited to participate in this study after obtaining informed consent before collecting their information. All authors con rmed that all methods were carried out following the research protocol approved by the ethics committee.

Consent for publication
All inpatients or their proxies' consent to publish this study.

Figure 1
Flow diagram of selection of study subjects.  Flow chart of assessment using Longshi Scale.

Supplementary Files
This is a list of supplementary les associated with this preprint. Click to download. Additionaltable.docx