Introduction

Faced with the challenge of an aging society, the demand for rehabilitation is predicted to increase due to shifting demographics and health conditions1,2,3. Anyone may need rehabilitation at some point, whether they have experienced an injury, disease, illness, or because their functioning has declined with age. As an essential part of achieving universal health coverage and goal 3 of the sustainable development goals (SDGs), WHO emphasizes the need for concerted and coordinated action by all stakeholders to strengthen the health system to provide quality and timely rehabilitation1,2,3. However, in low- and middle-income countries (LMICs), more than 50% of people do not receive the rehabilitation services they require4. WHO Rehabilitation Need Estimator indicated a greater need in China than other East Asian countries. The data showed that there are 490 million people who experienced conditions that could benefit from rehabilitation in China; the figures were 62 million, 23 million, 7.6 million, and 1.1 million in Japan, the Republic of Korea, the Democratic People’s Republic of Korea, and Mongolia, respectively5.

The rehabilitation patients usually have one or more dysfunctions, including cognitive impairment, speech disorders, dysphagia, cardiopulmonary disorders, and motor dysfunctions. Patient-specific strategies should be considered to capture different dimensions of functioning6. However, we found inconsistent results of sex differences in dysfunctions among rehabilitation patients. One Italy study explored sex differences among cardiac rehabilitation patients; results indicated that women following a CR program present more disability, depression, and worse quality of life than men7. Another Italy study explored sex differences in post-stroke functional outcomes at discharge from an intensive rehabilitation hospital; it found men and women presented a similar functional and clinical status8. One Spain study assessed the sex difference in social functioning in people with schizophrenia in psychosocial rehabilitation services; the study found that women showed better functioning than men9.

We believed that sex differences existed in dysfunctions and rehabilitation needs. Targeted rehabilitation management that clarifies the different needs of male and female patients would improve the treatment quality. However, to the best of our knowledge, no previous studies have investigated the sex difference in dysfunctions among rehabilitation patients in China. In the present study, we use the multicenter survey data to explore the role of patient’s sex on their dysfunctions. In particular, this study aimed to examine sex differences in dysfunctions among rehabilitation patients.

Methods

Design

We conducted a multicenter, cross-sectional, population-based study from September 12 to December 20, 2023, in 7 cities from 7 provinces in China. The inclusion criteria of participants were (1) they had dysfunctional problems; (2) they had visited rehabilitation doctors; (3) they were outpatients; (4) they would complete all evaluation procedures; and (5) they agreed to participate in our study. The exclusion criteria of participants were that they had visited rehabilitation doctors to help other family members take medicine.

Sampling

As detailed in Fig. 1, a 3-step multistage method was used to select the study’s sample. First, 7 cities in China were selected as sample cities. Second, we randomly selected 1 primary healthcare, 1 secondary hospital, and 1 tertiary hospital within each sampled city. A total of 21 medical institutions were enrolled from 7 cities. Third, a total of 3630 patients who visited doctors and met the inclusion criteria were invited to participate. Out of 3630 participants, 210 (5.79%) outpatient participants were deleted since they actually had no rehabilitation needs. 5 (0.15%) outpatient participants with missing values on study outcome (dysfunctions) were deleted. Therefore, the final analytical sample included 3415 participants.

Fig. 1
figure 1

Flowchart of sampling in the study (N = 3415).

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Measurement

General characteristics

Our study included general characteristics of patients on age (year), sex (since we focus on the biological sex-linked differences in our study, the option was male and female), educational level (not finished primary school, primary school, middle school, high school, bachelor or above), got married or not, and household income per year (thousands RMB) (less than 20, 20–50, 60–80, 90–130, 140–240, more than 240).

Diseases-related characteristics

The disease-related characteristics included patients’ dysfunctions, self-care ability, vital signs, disease status, and disease course. Doctors were invited to diagnose based on their own clinical experience and skill.

  1. (1)

    Dysfunctions: dysfunctions were the outcome of this study, which was the clinical diagnosis from rehabilitation doctors. It consisted of five types of dysfunctions: ① Cognitive impairment: patients had cognitive impairments that affect their judgment of people, time, and place; ② Speech disorders: patients had speech impairments that affect their communication; ③ Dysphagia: patients had swallow impairments that affect their oral intake; ④ Cardiopulmonary disorders: patients had heart and/or lung function impairments that affect their limb mobility; ⑤ Motor dysfunctions: patients had motor impairments that affect their trunk, upper limb, or lower limb mobility. Each type of dysfunction was generated into the dummy variable (1 = yes; 0 = no).

  2. (2)

    Self-care ability: our research group developed a method for assessing self-care ability in daily life using a scenario diagram (the Longshi-scale), which was approved by the National Standards Commission of China in 2016 as an evaluation method of self-care ability concerning Activities of Daily Living (ADL) among disabled people (20162587-T-314)10,11,12. According to the Longshi-scale, the patient could be divided into three groups: ‘community group’, ‘domestic group’, and ‘bedridden group’. ①Community group: referred to the person who can actively move outdoors (including the use of assistive devices and the impact of the environment); ②Domestic group: referred to the person who can take the initiative to get out of bed, cannot take the initiative to move outdoors, and the scope of activity is limited to the family environment (including the use of assistive devices and the impact of the environment); ③Bedridden group: referred to a person who cannot voluntarily get out of bed and whose scope of activity is limited to bed (including the use of assistive devices and environmental influences). Self-care ability was a category variable in our study (1 = community group; 2 = domestic group; 3 = bedridden group).

  3. (3)

    Vital signs: included patients’ temperature, pulse, heart rate, and respiration. ‘Stable vital signs’ referred to these indicators being within the normal range. ‘Unstable vital signs’ mean these indicators are beyond the normal range and can threaten patients’ lives. The vital signs were dummy variables in our study (1 = unstable; 0 = stable).

  4. (4)

    Disease status: encompassed the patient’s basic disease, underlying conditions, complications, and comorbidities. ‘Disease had not been controlled’ refers to any of the following situations: ①Failing to achieve clinical ideal parameters; ②Developing new clinical symptoms; ③Requiring the use of new medications. If none of the above situations happened, it was considered ‘Disease had been controlled’. The disease status was a dummy variable in our study (1 = uncontrolled; 0 = controlled).

  5. (5)

    Disease course: doctors were asked to fill in the questions about the disease course of patients. According to medical insurance policies, medical insurance does not cover patients’ hospitalization expenses whose course of disease was longer than the duration limitation. The duration limitations were diverse in different sampled cities (the duration limitation was 12 months in Shenzhen, Changzhou, Chengdu, Haikou, and Linyi; the duration limitation was 6 months in Hangzhou; the duration limitation was 3 months in Mile). In our study, the continued variable of disease course would be coded to a dummy variable (1 = more than duration limitation; 0 = within duration limitation).

Statistical analysis

The empirical strategy included 3 parts. First, descriptive analyses were used to assess the statistical values of the variables that measured the general and disease-related characteristics. Continuous variables were expressed as mean and SD, and categorical variables as numbers and percentages. Second, we used the T-test and Chi-square tests of independence to assess sex differences in dysfunctions. Third, the logistic regression models were constructed to explore the sex difference of dysfunctions among rehabilitation patients. In the models, dysfunctions were the outcome variable, and the patient’s sex was the independent variable. P-values below 0.05 were considered statistically significant. All statistical analyses were conducted using STATA Statistical Software Release 14.1.

Ethic approval

Our studies were approved by the Second People’s Hospital of Shenzhen Ethical Review Board (approval number of studies: 2023-226-02PJ). The questionnaire survey was conducted in accordance with the Declaration of Helsinki. Before conducting the questionnaire survey, trained enumerators introduced the study aims, the process, the potential risks and benefits, the privacy measures that were taken, the rights and duties of the individual, and the contact for the study. Enumerators also presented each participant with a standardized document that outlined the same information. All participants provided informed consent to participate in the study.

Results

General characteristics of participants

Out of 3415 participants, the mean age was 45.3 years (SD: 24.9). 1844 (54.0%) were male, and 1050 (30.7%) had a bachelor’s degree or higher educational level. Most participants got married (82.3%). Regarding household income, more than half reported that theirs was less than 20 thousand RMB (51.7%) (Table 1).

Table 1 General characteristics among participants (N = 3415).
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Disease-related characteristics among participants

Table 2 indicates the disease-related characteristics among participants. The majority (56.3%) were diagnosed with orthopedic diseases, nearly one-third (25.0%) were diagnosed with neurologic disease, part of the participants (18.9%) was diagnosed with a childhood disease, a smaller proportion of participants were diagnosed with geriatric diseases (9.3%), cancer (0.8%), and cardiopulmonary disease (3.2%). Regarding dysfunctions, less than one-third were diagnosed as having cognitive impairment (24.7%) and speech disorders (24.1%). Few were diagnosed with dysphagia (7.2%) and cardiopulmonary disorders (4.1%). Most were diagnosed as having motor dysfunctions (77.5%). Part of the participants (16.8%) had multiple dysfunctions. Regarding self-care ability, most were evaluated as a community group (72.7%). Only a few participants were divided into the domestic group (11.0%) and bedridden group (16.3%). Regarding the disease course, some participants (44.7%) reported that their disease course was more than the duration limitation of local medical insurance coverage on hospitalisation expenses (the duration limitation was 12 months in Shenzhen, Changzhou, Chengdu, Haikou, and Linyi; the duration limitation was 6 months in Hangzhou; the duration limitation was 3 months in Mile). Some participants’ disease status (including the patient’s basic disease, underlying conditions, complications, and comorbidities) had not been controlled (10.0%). A few participants were diagnosed with unstable vital signs (including patients’ temperature, pulse, heart rate, and respiration) (0.6%).

Table 2 Disease-related characteristics among participants (N = 3415).
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Sex difference in dysfunctions among participants

Univariate analysis

As shown in Fig. 2. Compared with female rehabilitation outpatients, male rehabilitation outpatients had a significantly higher percentage of cognitive impairment (female: 15.7%, male:32.5%, P < 0.001), speech disorders (female: 14.4%, male:32.3%, P < 0.001), dysphagia (female: 5.5%, male:8.6%, P < 0.001). Comparatively, there was a higher proportion of female rehabilitation outpatients than males having motor dysfunctions (female: 71%, male:85%, P < 0.001).

Fig. 2
figure 2

Sex differences in dysfunctions among rehabilitation outpatients (N = 3415).

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Multivariate analysis

Table 3 shows the sex difference in dysfunctions among rehabilitation outpatients. After controlling the other characteristics (age, educational level, marital status, household income, diagnosis, self-care ability, vital signs, disease status, and disease course), the male patients were more likely to have cognitive impairment (OR = 1.74; 95% CI = 1.42, 2.13), speech disorders (OR = 2.00; 95% CI = 1.62, 2.48), dysphagia (OR = 1.55; 95% CI = 1.12, 2.16), and multiple dysfunctions (OR = 2.00; 95% CI = 1.57, 2.54) than female. Female patients were more likely to have motor dysfunctions (OR = 0.63; 95% CI = 0.50, 0.78) than male.

Table 3 Sex difference in dysfunctions among rehabilitation outpatients (N = 3415).
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Sex differences in dysfunctions with different types of diseases

The relationship between diseases and dysfunctions

Table 4 shows the relationship between diseases and dysfunctions. For the participants who were diagnosed with orthopedic disease, most of them had motor dysfunctions (68.0%). For the participants who were diagnosed with neurologic disease, most of them had dysphagia (90.2%). Cardiopulmonary disorders were common for the participants who were diagnosed with cardiopulmonary disease (41.8%) or geriatric diseases (38.3%). Cognitive impairment was common for the participants who were diagnosed with childhood diseases (60.7%). All differences were significant (P < 0.001).

Table 4 The relationship between diseases and dysfunctions (N=3415).
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Sex difference in dysfunctions with different types of diseases

To further explore sex differences in dysfunctions with different types of diseases, we first conducted subgroup analyses of sex differences in dysfunctions on specific diseases. The results showed that, for geriatric diseases, there are sex differences in speech disorders (OR = 0.63; 95% CI = 0.50, 0.78) (Appendix Table 1). For neurologic diseases and childhood diseases, there are sex differences in motor dysfunctions (OR = 0.63; 95% CI = 0.50, 0.78) (Appendix Table 2 and Appendix Table 3).

Secondly, the path analysis was conducted to explore the association between sex, dysfunctions, and disease. The results showed that after controlling the covariates, the diseases were the mediators of the association between sex and dysfunction. For example, regarding neurologic disease, male patients were more likely to be diagnosed with neurologic disease (Standard coefficient = 0.129; 95% CI = 0.096, 0.162), and then had more cognitive impairment (Standard coefficient = 0.200; 95% CI = 0.167, 0.232) (Appendix Table 4). Regarding cardiopulmonary disease, male patients were more likely to be diagnosed with cardiopulmonary disease (Standard coefficient = 0.034; 95% CI = 0.000, 0.067), and then had more cognitive impairment (Standard coefficient = 0.084; 95% CI = 0.055, 0.113) (Appendix Table 5). Regarding childhood disease, male patients were more likely to be diagnosed with neurologic disease (Standard coefficient = 0.200; 95% CI = 0.168, 0.232), and then had more cognitive impairment (Standard coefficient = 0.658; 95% CI = 0.634, 0.681) (Appendix Table 6).

Discussion

Main findings

While targeted rehabilitation management is important, whether there is a sex difference in dysfunctions among rehabilitation patients is unknown. To bridge this research gap, our study conducted a multicenter survey to explore the sex difference in dysfunctions among rehabilitation outpatients in China. The study showed that sex differences existed in different dysfunctional problems. Male rehabilitation outpatients were more likely to have cognitive impairment, speech disorder, and dysphagia, and female rehabilitation outpatients were more likely to have motor dysfunctions.

Sex differences in dysfunctions

Cognitive impairment

We found that male rehabilitation outpatients had more cognitive impairment than females in our study. The finding was inconsistent with the evidence from surveys of elderly people. The Chinese Longitudinal Health Survey results from 2008 to 2011 showed that the oldest-old (aged 80–116 years) women had a significantly higher risk of cognitive impairment than men. However, these sex differences were insignificant among the old cohort (aged 65–79 years)13. Another Chinese study in rural areas also showed that females showed a significantly higher prevalence of cognitive impairment after age 7514. Cognitive impairment is a common dysfunctional problem among rehabilitation patients, which predominantly includes processing and psychomotor speed, attention, verbal and visual memory, working memory, executive functions, reasoning, visuospatial abilities, and metacognition14,15. We found that the age of the participants in our study could explain the contradictory findings. The outpatients were enrolled with an average age of 45.3 years, the relatively younger population in our study. Evidence indicated that in younger people, the male is likely to have brain trauma, an unhealthier lifestyle, and more cardiovascular disease, so male patients had more cognitive impairment than females. In older people, since the female is likely to suffer from Alzheimer’s disease, decreased estrogen, and more social isolation, they may have more cognitive impairment than the male13,16,17.

Speech disorders

We further found that speech disorders are more likely to be seen in men than female rehabilitation outpatients in our study. There are inconsistent results from previous evidence. A meta-analysis indicated that men presented more with dysarthria, which is similar to our results18. Other evidence of meta-analysis showed that men had higher aphasia rates than women in unilateral stroke patients since men have more lateralized language function than women19,20. However, another meta-analysis showed contrasting results that significantly larger aphasia rates were revealed in women than in men21. Regarding speech disorders, dysarthria or aphasia are frequently seen in rehabilitation22. Specifically, dysarthria is a neurological motor speech disorder due to the involvement of the muscles used for speech. Dysarthria is characterized by tongue, jaw, lips, and throat muscle weakness, incoordination in breathing control, articulatory and resonance disorder, and impairment of speech fluency22,23. Aphasia is an inability to formulate language and/or to comprehend because of damage to specific brain regions. The difficulties faced by people with aphasia can range from occasional trouble finding words to losing the ability to speak, read, or write22,23. In general, males are likely to suffer from cerebrovascular diseases such as stroke, which is the main reason for speech disorders, so they are more likely to have speech disorders than females18,19,20.

Dysphagia

Moreover, we found that male rehabilitation outpatients had more risk of dysphagia than females in our study. Although no evidence has found the same results, several studies have explored similar sex differences among children. Chinese research focused on dysphagia among children with cerebral palsy, which did not find sex differences in dysphagia24. Regarding dysphagia, it is well documented in the literature that dysphagia is one of the most common challenges for the rehabilitation patient, especially a post-stroke patient25,26. Dysphagia, defined as difficulty in swallowing, is a common complication affecting many stroke patients in the first few hours and days after ictus. Dysphagia is associated with increased mortality and morbidity due in part to aspiration of ingested foods, liquids, or oral secretions27, pneumonia, and malnutrition28,29. Although many stroke patients recover swallowing spontaneously, 11–50% still have dysphagia at six months29,30; this persistent dysphagia independently predicts poor health outcomes31. Evidence showed that since the male is likely to have a stroke, decreased strength of the swallowing muscles, and an unhealthier lifestyle, so male patients had more dysphagia than females32,33.

Motor dysfunctions

Interestingly, we found the opposite direction of sex difference in motor dysfunctions. Female rehabilitation outpatients had more motor dysfunctions than males. We found mixed results from previous studies. Evidence from Australia explored the differential progression of motor dysfunctions between male and female fragile and premutation carriers; the results showed that the progression in women is less than in men34. A cross-sectional study from Korea focused on motor dysfunctions among Parkinson’s disease patients; this study found no sex difference in motor dysfunctions35. Motor dysfunctions were the most common dysfunctional problems in rehabilitation outpatients. Motor dysfunctions include slowing of gait36, declines in functional mobility37, reduced grip strength38, poor balance39, slower finger tapping speed40, and poor manual dexterity41, which may hinder the ADL of patients. Evidence showed that since women may have a higher prevalence of osteoarthritis, less muscle strength and muscle mass may lead to motor dysfunctions42,43.

Implications for rehabilitation practice

Overall, sex differences in different types of dysfunctions have yielded inconsistent results. These sex differences in dysfunctions could be due to differences in other characteristics between men and women, such as demographic characteristics, genetic factors, cardiovascular disease, psychiatric risk factors, and lifestyle44. Although we did not consider all the above characteristics, we need to admit that the sex differences of dysfunctions existed in rehabilitation outpatient after controlling their’ age, educational level, marital status, household income, self-care ability, disease course and status, and vital signs. For the health professionals working in rehabilitation medicine, more attention should be paid to the male outpatients who have cognitive impairment, speech disorders, and dysphagia. Similarly, for female rehabilitation outpatients, a greater emphasis on addressing motor dysfunctions may be warranted. More importantly, our further analysis indicated that the disease was the mediator between sex and dysfunction. When developing rehabilitation treatment strategies, tailoring rehabilitation approaches to account for sex differences and disease types could improve outcomes and enhance the effectiveness of rehabilitation programs.

Strengthen and limitations

To the best of our knowledge, this is the first study to examine the sex differences in dysfunctions among rehabilitation outpatients in China. The results of this study could better provide an empirical basis for developing rehabilitation treatment strategies and support the promotion of rehabilitation management. However, this study was subjected to several limitations. Firstly, this study used cross-sectional measurements. Therefore, the dysfunctions was only administered on a single occasion. We were unable to evaluate some of the potential changes. Secondly, because the data on dysfunctions were only based on outpatients, this study could not rule out the possibility of selection bias and could not generalized to the inpatients. Notwithstanding these limitations, our findings provide evidence for managing rehabilitation outpatients in clinical settings.

Conclusion

Clarifying the sex difference in dysfunctions among rehabilitation outpatients would help improve the target and personal treatment plan. However, it has not been comprehensively demonstrated so far whether this sex difference in dysfunctions. We carried out the multi-center study to explore the detailed sex difference in dysfunctions using first-hand data. Our findings show that cognitive impairment, speech disorders, and dysphagia were more likely to happen in male than female rehabilitation outpatients; in contrast, female rehabilitation had more motor dysfunctions than males. These sex differences may provide potential clinical value for the treatment of rehabilitation patients. Health professionals should pay attention to the sex differences affecting dysfunctions before planning the most suitable rehabilitation plan. More broadly, to provide better-individualized interventions and policy development in rehabilitation management in LMICs and other settings that struggle with improving the healthcare in rehabilitation, it is important to strengthen the effects of sex differences in dysfunctions to reach the different rehabilitation needs between males and females.