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Abstract
Objective To investigate the status of the midwifery workforce and childbirth services in China and to identify the association between midwife staffing and childbirth outcomes.
Design A descriptive, multicentre cross-sectional survey.
Setting Maternity hospitals from the eastern, central and western regions of China.
Participants Stratified sampling of maternity hospitals between 1 July and 31 December 2021.
The sample hospitals received a package of questionnaires, and the head midwives from the participating hospitals were invited to fill in the questionnaires.
Results A total of 180 hospitals were selected and investigated, staffed with 4159 midwives, 412 obstetric nurses and 1007 obstetricians at the labour and delivery units. The average efficiency index of annual midwifery services was 272 deliveries per midwife. In the sample hospitals, 44.9% of women had a caesarean delivery and 21.4% had an episiotomy. Improved midwife staffing was associated with reduced rates of instrumental vaginal delivery (adjusted β −0.032, 95% CI −0.115 to −0.012, p<0.05) and episiotomy (adjusted β −0.171, 95% CI −0.190 to −0.056, p<0.001).
Conclusion The rates of childbirth interventions including the overall caesarean section in China and the episiotomy rate, especially in the central region, remain relatively high. Improved midwife staffing was associated with reduced rates of instrumental vaginal delivery and episiotomy, indicating that further investments in the midwifery workforce could produce better childbirth outcomes.
- Health Workforce
- Health Services
- Nursing Care
Data availability statement
The data are available upon request from the corresponding author.
This is an open access article distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited, appropriate credit is given, any changes made indicated, and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/.
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STRENGTHS AND LIMITATIONS OF THIS STUDY
The study employed a detailed descriptive multicentre cross-sectional investigation to assess the status and associations between hospital midwifery workforce and childbirth outcomes in China.
The study was carried out on a nationwide level, using a stratified sampling methodology rather than a comprehensive survey of the entire target population.
Due to the cross-sectional design, it was insufficient to establish causal relationships between midwife staffing and childbirth outcomes.
Introduction
Health workforce is the primary resource and a crucial factor within the healthcare system. It is defined by the WHO as ‘all people engaged in actions whose primary intent is to enhance health’.1 Nurses and midwives make up over 60% of the global health workforce.2 An adequate number of qualified nurses and midwives are the basis for improving patient satisfaction, meeting primary healthcare needs and contributing to better health outcomes.3 4 According to WHO and the International Confederation of Midwives, midwives are the primary caregivers for women in normal pregnancy and childbirth5 and can meet about 90% of the basic care needs for pregnant women and newborns.6
Maternity healthcare in current China is an obstetrician-led model. Pregnant women receive routine antenatal care from obstetricians at the clinics. During each antenatal visit, women can only spend a brief amount of time with their obstetrician due to the large number of women requiring assessment and time constraints. They usually receive fragmented care and lack individualised continuity of care from midwives throughout perinatal period.7 Over the years, the midwifery profession in China has declined as the country prioritised medical and technological advancements.8 Almost all midwives employed in hospitals are confined to work in labour and delivery units (LDUs), providing intrapartum care for labouring women.9
Globally, the chronic shortage and uneven distribution of midwives become the key barriers to high-quality maternal and newborn healthcare. The State of the World’s Midwifery (SoWMy) 2021 indicated a global shortage of 900 000 midwives.6 Strengthening the capacity of midwives has been highlighted as a current priority by the global health organisations.10 Currently, the density of midwifery personnel (per 1000 population) in China was only 0.05, which was far below those in other countries such as Ireland, Sweden, the UK and Malaysia. It is estimated that there is a shortage of 800 000 midwives in China according to the China Health Statistics Yearbook of 2022.11 The Chinese government has realised the pivotal role that midwives can play in a functioning health system and launched the 4-year bachelor degree midwifery programme since 2014, but still the majority of midwives in maternity hospitals had an initial educational level below a bachelor’s degree.12 13
In recent years, China has made remarkable progress in promoting maternal and child health over the generations.14 However, due to the continuous low birth rates and population ageing problems, the Chinese government officially announced the universal two-child policy in 2015 and the three-child policy in 2021. After the launching of these birth policies, the proportion of multiparous births increased from 34.1% in 2012 to 46.7% in 2016, and births in women with a uterine scar nearly doubled from 9.8% to 17.7% of all births.15 This has brought new challenges and burdens to the current midwifery workforce and quality of maternity care services, which may lead to adverse childbirth outcomes and negative experiences for women.16
Another big challenge for China’s maternal and child healthcare system is the high rate of caesarean sections. In China, the overall annual rate of caesarean deliveries reached 34.9% between 2008 and 2014.17 In some urban areas like Shanghai, the caesarean section rate declined from 67% in 2009 to 52% in 201417 but still far beyond the recommended maximum level of 15% from WHO.18 For low-risk pregnancies, midwifery care in labour is associated with decreased intrapartum interventions, decreased caesarean deliveries and operative vaginal births.19 Renfrew et al pointed out that maternal and newborn care can be improved through access to acceptable and high-quality services through the presence of a competent workforce and adequate resources.20
Currently, vast advances in maternity care are still required to improve maternal and newborn outcomes and to ensure dignity and respect in pregnancy and childbirth.21 The internationally recognised midwife-led model of care emphasises a woman-centred philosophy. A cohort study conducted by Hua et al in Shanghai highlighted that the continuity of midwife-led care model is the preferred service for low-risk women, demonstrating its potential for widespread implementation throughout China.22 Evidence suggests that the provision of midwife-led continuity of care plays a vital role in improving childbirth outcomes and experiences and in reducing childbirth interventions.23–25 Meanwhile, several research studies have shown that adequate healthcare staffing is associated with better patient outcomes. Gerova found a significant association between increased number of full-time equivalent midwife staffing and more normal birth.26 Zbiri et al unfolded a positive association between an increase in midwife staff level and reduced intrapartum caesarean section rate.27 Sandall et al showed that births with bodily integrity and intact perineum were more common when more midwives were employed.28
To our knowledge, several previous studies on the midwifery workforce and childbirth services have been conducted in some local areas or on a small scale.29–31 Very few of them, however, have been carried out at the nationwide level. Currently, the existing evidence on the association between midwife staffing and childbirth outcomes is still scarce. Therefore, the aim of this study was to investigate, analyse and compare the status of the midwifery workforce and childbirth services among various regions of China and to explore the estimated outcomes associated with adequate midwife staffing under China’s new birth policy.
Method
Settings
A descriptive, multicentre cross-sectional survey was conducted in China between 1 July 2021 and 31 December 2021. Ethical approval was obtained from the Ethics Committee of the Obstetrics and Gynecology Hospital of Fudan University (OGHEC2021107). Maternity care in China is predominantly hospital based and obstetrician led. Currently, there is no nationally recognised direct registration system for midwives in China. Midwifery is a branch of nursing. All midwives have to be a registered nurse first with nursing licenses.32 Most of the midwives working in LDUs are nurses who are learning and gaining midwifery experience while on the job. They are required to follow obstetricians’ orders to provide intrapartum care. The majority of them have an initial educational level below a bachelor’s degree. Since 1991, the Baby Friendly Hospital Initiative has been launched by WHO to improve hospital maternity care practices that support breastfeeding. Most baby-friendly hospitals in China provide integrated labour and birth care for pregnant women. The data of this study were collected from maternity settings in the National Baby Friendly Hospital list.33 According to the National Development and Reform Commission, China is divided into eastern (11 provinces), central (9 provinces) and western (12 provinces) regions according to the geographic locations and economic development levels. In this study, the sample hospitals were selected from the above three regions.
Patient and public involvement
This study did not involve patients or the public.
Sampling methods
Maternity hospitals from the eastern, central and western regions of China were selected via stratified sampling. In total, there are 32 provinces (including 5 autonomous regions and 4 municipalities) in mainland China, which is divided into eastern, central and western regions. According to the baby-friendly facility list from the National Health Commission of China, there were a total of 7029 facilities providing maternity services, among which 3082 (43.9%) from Eastern China, 1541 (21.9%) from Central China and 2406 (34.2%) from Western China. The sample requirement for the survey was estimated at n=191 using 95% confidence level with a 7% margin of error. Therefore, we targeted a sample of maternity hospitals (n=200). Private hospitals and those who refused to participate in our survey were excluded. The recruitment targets for each region are shown in table 1. Finally, a total of 180 hospitals were enrolled in our study.
Stratified sampling of maternity hospitals (n=7029）
Instrument
A tailored structured questionnaire draft was designed on the basis of literature review and was pretested to form a finalised version. The questionnaire was mainly comprised of two parts. Part 1 included care providers’ demographic characteristics such as age, job role, educational level, professional title and years of working experience. Part 2 included information on childbirth services with 20 items: (1) basic information on facilities (eg, total number of delivery beds, number of single LDUs, number of qualified midwives and obstetric nurses without midwifery qualifications, and number of anaesthetists and obstetricians) and (2) situation of childbirth services at the LDUs (eg, total number of deliveries, number of caesarean sections, number of spontaneous vaginal deliveries and instrumental deliveries, number of episiotomies, midwifery service efficiency, and supportive midwifery care services including continuous labour support, midwife clinic, birth plan and pain management). We used the above questionnaire to measure and describe the characteristics of the midwifery workforce and the current situation of childbirth services in maternity settings of China.
Data collection
Survey data were collected from the 180 hospitals nationwide between 1 July 2021 and 31 December 2021 by self-administered questionnaires. The 180 sample hospitals received a package of questionnaires along with online invitation letters and consent forms. The LDU head midwives of the sample hospitals were approached by the research assistants who provided a verbal explanation and informed written consent information about the study. Signed, informed written consent was obtained from those who were willing to participate. A total of 180 LDU head midwives from the participating facilities were invited to fill in the questionnaires. Three research midwives were recruited and trained to contact the facilities surveyed, collect questionnaires and check for consistencies and completeness of filled questionnaires. The online questionnaires were directly sent back to the research team. Questionnaires with any problems were returned to the LDU head midwife for resurvey. Our data allowed us to investigate how the midwifery workforce was related to childbirth outcomes. No identifiable information of the sample hospitals was used in the study.
Data analysis
We used descriptive statistics (numbers and percentages) to describe the characteristics of the maternity facilities (including delivery beds, labour beds, and single delivery rooms), LDU staff (including qualified midwives, obstetric nurses, anaesthetists, and obstetricians) and childbirth services (including intrapartum continuous labour support, midwife clinic, birth plan, pain management, and freedom to move during labour) in the sample hospitals and to analyse midwives’ workloads across different regions of China. Kruskal-Wallis H test was performed to compare the differences of these variables among Eastern, Central and Western China. To measure the midwifery workloads, we used health service efficiency index (HSEI) in the study. It was calculated as an indicator measuring the workloads of healthcare providers in the facilities surveyed.34 The HSEI was defined as the number of service cases provided by each midwifery staff member. For childbirth services, the HSEI of midwives was estimated by dividing the total number of vaginal deliveries by the number of qualified midwives in the LDU, with a higher value indicating heavier workloads for midwives. In this study, we did not include the number of caesarean deliveries when assessing the impact of workloads on midwives. The study employed a linear regression model to investigate the association between the independent variable, the number of midwife staffing and the dependent variable which comprised the rates of hospital-level childbirth outcomes, including caesarean delivery, instrumental vaginal delivery, ICS, episiotomy, postpartum haemorrhage, shoulder dystocia, neonatal asphyxia and preterm birth. Each variable was entered separately into the model for analysis. All the collected data were entered into Epidata Info 3.1. The data were checked for accuracy and completeness prior to any analysis and then exported to IBM Statistical Package for the Social Sciences (SPSS) V.26.0 (Chicago Inc., USA). Statistical significance was set at p<0.05.
Results
Selected characteristics of LDUs and the midwifery workforce
Of the 200 maternity hospitals approached and invited to participate, 180 (90%) agreed (76 in the eastern region of China, 43 in the central region and 61 in the western region) to participate in the study (table 2). As for characteristics of the LDUs surveyed, the ratios of delivery beds, labour beds, single delivery rooms and obstetricians to nurses (including both obstetric nurses and qualified midwives) were as follows: 1 delivery bed for every 3.2 nurses, 1 labour bed for every 2.5 nurses, 1 single delivery room for every 6.3 nurses and 1 obstetrician for every 4.5 nurses. The ratios of delivery beds, labour beds and obstetricians to qualified midwives were 1 delivery bed for every 2.9 qualified midwives, 1 labour bed for every 2.3 qualified midwives and 1 obstetrician for every 4.1 qualified midwives.
Characteristics of LDUs and the midwifery workforce in the study sample
Overall, the 180 sample hospitals were staffed with 4159 qualified midwives (23.1 per hospital), 412 obstetric nurses (2.3 per hospital), 486 anaesthetists (2.7 per hospital) and 1007 obstetricians (5.6 per hospital) in the LDUs. The majority of participating midwives (n=2872, 69.1%) were under 36 years old across hospitals. A total of 2944 (70.8%) midwives held undergraduate degree, 2586 (62.2%) had junior professional qualifications and 2545 (61.2%) had <10 years of experience. Variables including midwives’ age, educational level, professional title and years of experience were statistically significant among the eastern, central and western regions of China (p<0.05).
Childbirth services in sample hospitals
The total number of births in the 180 sample hospitals was 2 055 692 between 2018 and 2020. The density of qualified midwives was 2.02 (4159×1000/2 055 692) per 1000 births, indicating that for every 10 000 births, there were 20 midwives available to provide care and support during childbirth. Midwives’ average HSEI was 272 deliveries per midwife (326 in the eastern, 121 in the central and 291 in the western region). The overall rates of childbirth medical interventions were 44.9% in caesarean delivery, 6.7% in ICS and 21.4% in episiotomy. The caesarean section rate in the western region was 48.1% (407 293/847 436), which was the highest among the three regions of China, compared with 42.7% (441 500/1 032 827) in the eastern and 42.3% (74 269/175 429) in the central region. The ICS rate and episiotomy rate in the central region were 7.2% and 28.6%, respectively, higher than those in the eastern region (6.4% and 20.0%) and western region (7.1% and 21.7%). The rates of instrumental vaginal delivery, continuous labour support, ICS, postpartum haemorrhage, placenta previa, shoulder dystocia and neonatal asphyxia were significantly different among the three regions (p<0.05).
Of the 180 hospitals, 138 (76.7%) provided intrapartum continuous labour support, 108 (60.0%) had antenatal midwife clinics and 116 (64.4%) made birth plans for pregnant women. In terms of labour pain management, the majority of hospitals offered both pharmacological and non-pharmacological pain management for labouring women, including epidural analgesia (97.2%, 175/180), Lamaze breathing (76.7%, 138/180), birth ball (91.1%, 164/180) and freedom to move during the first stage of labour (96.1%, 173/180) and the second stage of labour (69.4%, 125/180). The utilisation proportion of childbirth services including intrapartum continuous labour support, midwife clinic, and birth plan were all <80%. The childbirth services in sample hospitals are presented in table 3.
Childbirth services in 180 hospitals surveyed
Effects of midwife staffing on childbirth outcomes
Table 4 presents the estimated effects of midwife staffing on childbirth outcomes. Each potential associated factor was individually entered into a separate multivariable linear regression model. Midwife staffing was significantly related to two childbirth outcomes (the instrumental vaginal delivery rate and the episiotomy rate), indicating that increased midwife staffing was associated with reduced childbirth interventions including instrumental vaginal delivery (adjusted β −0.032, 95% CI −0.115 to −0.012, p<0.05) and episiotomy (adjusted β −0.171, 95% CI −0.190 to −0.056, p<0.001). The rates of caesarean delivery, intrapartum caesarean section, postpartum haemorrhage, shoulder dystocia, neonatal asphyxia and preterm birth were not significantly impacted by midwife staffing.
Effects of midwife staffing on childbirth outcomes
Discussion
To our knowledge, this was the first detailed descriptive multicentre cross-sectional study exploring the status and associations between the hospital midwifery workforce and childbirth outcomes in China. We found in this study that the Chinese midwifery workforce was handling heavy workloads and primarily consisted of junior midwives and that increased midwife staffing was associated with lower rates of instrumental vaginal delivery and episiotomy.
In our study, the LDU’s midwife-to-obstetrician ratio (4.1:1) was higher than the optimal nurse-to-doctor ratio of 2:1 recommended by WHO.1 This ratio was also higher than that in other countries as 2.4:1 in Japan and 3.9:1 in the UK but lower than that in Sweden (5.4:1) and Australia (9.6:1).35 However, the sample hospitals in our study had lower density of qualified midwives (2.02 per 1000 births), compared with France, Switzerland and Germany with 25 or even more midwives per 1000 births.36 The ratio of midwife-to-delivery beds (2.9:1) in our study was slightly lower than the recommendation for the allocation of three midwives per one delivery bed reported by the Ministry of Health of China. Usually, the LDU midwives may not only provide care for labouring women but also perform tasks at the obstetric emergency rooms and assist the doctors with caesarean deliveries in the operating theatres.37 Thus, more midwifery workforce still needs to be devoted into the maternity healthcare system.
Our findings illustrated that the midwifery workforce in the sample hospitals was composed mainly of junior midwives and with <10 years of experience, which was consistent with Hu et al’s finding.38 The average age of employed midwives in China seemed younger, in contrast to Australian midwives averaging 47 years of age and US midwives with 49 years of age.39 In our study, the majority of midwives held a bachelor’s degree of nursing.40 Experience and seniority are important elements for fulfilling women’s expectations and increasing their satisfaction with childbirth experiences.41 Higher-ranking midwives have more experience and expertise and are more likely to provide a positive birth experience for women.42 43 In contrast, due to lack of clinical experience and skills, junior midwives may encounter higher incidence of working error and are more likely to leave their position.44 45 Therefore, great importance should be attached to the development of higher education in midwifery. To ensure the delivery of high-quality care, it is essential to provide ongoing training opportunities for Chinese midwives to enhance their knowledge and skills and to keep them updated on best practices.
The HSEI is a key indicator of measuring the midwifery care workloads with a higher value indicating heavier workloads for midwives.34 46 According to WHO,47 a maximum of 175 deliveries a year for a midwife was recommended. However, our findings suggested that workload inequity existed among different regions of China, with the eastern region having the highest workload, followed by the western region and the central region. The inequity of midwives’ workload may arise from uneven social and economic development,48 midwife staff structures,49 demands for childbirth services50 and government investment in maternity care services within various regions.51 In addition, our study showed that each midwife’s workload per year (272 deliveries per midwife per year) was far greater than that in other countries such as Japan (42), Germany (37), Denmark (28), Singapore (144), Finland (14) and Korea (49).52 The excessive workloads of care providers would affect the quality of maternity care and increase the incidence of adverse outcome events of maternal and newborn (eg, neonatal asphyxia, postpartum haemorrhage, etc).50 Since the launching of China’s new birth policy, the proportion of women with advanced maternal age and high risks has been on the rise,53 which may further aggravate midwives’ workloads.54 Therefore, more efforts should be made to optimise the midwifery staff structure and allocation of their functions and responsibilities, to strengthen financial investment and to enhance training for more midwifery health workers.
In our study, the majority of sample hospitals provided supportive childbirth care services, which echoes the concept advocated by WHO.21 Continuous labour support has benefits to better childbirth outcomes and has been identified as a key element in the WHO vision of quality of care for pregnant women and newborns.55–57 In China, maternity care is generally led by obstetricians, resulting in a lack of midwifery autonomy and continuity of care. Empowering midwives as autonomous and continuous care providers enables them to apply their expertise and judgement independently. This approach results in more personalised care tailored to the specific needs and preferences of individual women. However, we found that over one-fifth of the sample hospitals were facing barriers to providing supportive childbirth care. These barriers are possibly attributed to shortages of midwifery staff, inadequate professional training and a lack of enabling environment.58 59 The task of providing caseload continuous support may lead to intensification of human resource shortages and have implications on the organisation of shifts at the LDU.60 Currently, the implementation of the caseload model of midwifery care in China may be limited due to a shortage of midwives. The Chinese government, however, has realised the pivotal role that midwives play in a functioning health system. Hence, this model has potential to be further explored and integrated into maternity services in China to enhance the quality and experience of care.
Concurrently, the overall annual rate of caesarean deliveries (44.9%) was still at a relatively high level in our survey, far beyond WHO’s recommended maximum level of 15%18 but lower than the rate of 54.5% reported in another study conducted in China.61 The non-pharmacological techniques are usually offered during the early stages of labour. While 97.2% of hospitals implemented epidurals, there remained a lack of utilisation of non-pharmacological measures. Besides, our study revealed some regional variations among three distinct regions (eg, in terms of caesarean section rate and the episiotomy rate), which may be due to the inequities of healthcare infrastructure and resource allocation. The western and central regions of China have historically been more rural and less developed, resulting in poorer access to healthcare services and limited impact of midwifery. It is recommended by WHO that the episiotomy rate should be limited to 20% or less, with around 10%.62 Thus, care providers should help women meet their goals for labour and birth by using techniques that are associated with minimal interventions.63
Additionally, our research unveiled a correlation between improved midwife staffing and decreased rates of instrumental vaginal delivery and episiotomy. Previous studies also showed that midwife staffing levels were associated with birth outcomes including reductions in postpartum haemorrhage, maternal readmission and the need for neonatal resuscitation.64–66 In England, one study found that more midwifery staff were associated with better experience of care.67 With the sufficient amount of staff, a reasonable time and the information or explanations are always offered to the women when they needed. Moreover, our study did not find a significant correlation between caesarean section rates and midwife staffing. This could be attributed to the relatively small sample size and the presence of sample hospitals in certain areas where caesarean rates were already low. However, the lower instrumental vaginal delivery rate associated with higher midwife staffing may be shifted to caesarean delivery, which should also be taken into account. As such, in order to reduce unnecessary interventions during labour and childbirth, appropriate actions need to be taken to address the overloading of midwives’ workloads and the issue of staff shortages, including recruitment and development of more Chinese midwifery workforce and reinforcement of resource allocation.
Limitations
First, our study was a stratified sampling research rather than a comprehensive survey of the entire target population. Information about the accurate scale of the midwifery workforce was elusive, given that the data varied within different regions. However, the sample was randomly drawn from the three regions of China, which may well represent the current status of the midwifery workforce and childbirth services. Follow-up studies need to be conducted in other provinces to confirm the consistency of the results. Second, a cross-sectional design was applied in our study, which is insufficient to establish causal relationships between midwife staffing and childbirth outcomes. Third, we estimated a sample size of 191 hospitals, but ultimately 180 hospitals were included in the study, resulting in the actual research effect size being lower than the estimated one. In future studies, consideration will be given to increasing the sample size in order to improve the reliability of the study findings. Fourth, we only selected the hospitals based on the list of national baby-friendly facilities. Despite these limitations, the strength of our study is that the data were collected on a nationwide level. Previous studies have not evaluated the status and associations between the hospital midwifery workforce and childbirth outcomes in China. As such, our study generated new knowledge and insights in this field.
Conclusion
Currently in the context of China’s new birth policy, midwives’ lower educational levels and professional qualifications, heavy workloads, staff shortages and unnecessary birth interventions are bringing new challenges for providing high-quality midwifery care. Enhanced midwife staffing correlates with lower rates of instrumental vaginal delivery and episiotomy. Our research provides evidence that further investments in midwifery could be a promising way to improve the quality of maternity care. To promote better childbirth outcomes, further efforts should be made to optimise the structure and function of midwife staffing, to boost the country’s financial investment in midwifery and to intensify the training and educational opportunities for an expanded midwifery workforce.
Data availability statement
The data are available upon request from the corresponding author.
Ethics statements
Patient consent for publication
Ethics approval
This study was approved by the Ethics Committee of the Obstetrics and Gynecology Hospital of Fudan University (OGHEC2021107). Participants gave informed consent to participate in the study before taking part.
Acknowledgments
The study was supported by the National Natural Science Foundation of China and Shanghai Municipal Health Commission. The authors would like to thank all the maternity hospitals who participated in our study and pay tribute to the Obstetrics and Gynecology Hospital of Fudan University for supporting this study.
References
Footnotes
WZ and CZ are joint first authors.
XZ and CG contributed equally.
Contributors WZ and CG designed the study and did the literature search. WZ, HM, LL and CZ collected data. WZ, XW and JW analysed data. WZ, CZ, and CG wrote the manuscript. CG and XZ revised the manuscript. WZ, CG, XZ and HM accessed and verified the data. WZ and CG are responsible for the overall content. All authors had full access to all data in the study, and the corresponding author had final responsibility for the decision to submit for publication.
Funding The study was funded by the National Natural Science Foundation of China (Grant No.72004029) and Shanghai Municipal Health Commission (Grant No.202040097).
Competing interests None declared.
Patient and public involvement Patients and/or the public were not involved in the design, or conduct, or reporting, or dissemination plans of this research.
Provenance and peer review Not commissioned; externally peer reviewed.