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 significantly associated with age [26–28]. Once stroke occurs, the regenerative potential decreases, and the inflammatory 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 1-month case fatality and lower 1-year survival after stroke [31–33]. 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 influences (especially as prethrombotic and autoimmune diseases are more common in women). Some risk factors, such as atrial fibrillation 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 final 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 significantly facilitate and accelerate the recovery process [40]. This is why the incidence of lung infections is also higher in stroke survivors with nutritional deficiencies [34], while a higher BMI is shown to significantly 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 [41–43]. 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 (Table 1), and the proportion of patients without MCC was too low, which influenced the results. Previous studies have shown that stroke survivors with MCC have weak physical and/or cognitive abilities, worse hemodynamics, and collaterals after arterial occlusion, which hinder functional recovery after stroke [46], and MCC affects post-stroke neuropsychological adaptation [46–49].
The strength of this study is that it considers the factors and environmental conditions related to hospitalized stroke survivors, as well as their relationship with the patient's functional status. This can enable physicians to perform early management to improve the functional status of stroke survivors, such as paying more attention to pulmonary infection and reducing the incidence rate of DVT among inpatients with stroke in the rehabilitation setting.
Our study has several limitations. As mentioned previously, this study could not determine causal relationships due to the cross-sectional design. Additionally, first, the researched population was recruited from four hospitals in Shenzhen, China, meaning that the findings may not be representative of other areas and may not be generalizable to other settings. Second, due to the hospital settings, the percentage of the bedridden group was the largest. This may have affected the statistical ability for relevant data comparison. Third, due to the retrospective and cross-sectional design, the stroke levels according to the NIH Stroke Scale were not available for analysis, which may have affected the functional status of patients with stroke.
In summary, our study found that 72.14% of inpatients with stroke had poor functional status ( diagnosed as the bedridden group based on the LS scale), 21.67% of inpatients with stroke had moderate functional limitations (assessed as the domestic group) and 6.19% had mild functional limitation in rehabilitation settings in Shenzhen, China. The older age bracket and females are more likely to show poor functional status. Pulmonary infection and DVT, both common post-stroke complications, lower BMI, and alcohol consumption were associated with increased probability of dependence. Therefore, the elderly should pay more attention to maintaining a healthy lifestyle (e.g. quitting alcohol) before stroke occurs. Once a stroke occurs, attention should be paid to maintaining nutrition and a normal BMI, and interventions may be applied for patients with stroke to prevent lung infections and DVT to address subsequent functional disability after stroke.