Abstract
Objective
Identifying organizational factors affecting venous thromboembolism (VTE) incidence and variations between hospitals.
Methods
From a 2019 survey of VTE and live births in 113 hospitals, organizational factors: (hospital type, characteristics, live birth number), resource availability: (D-dimer, B-scan ultrasonography of lower extremity veins, computed tomographic pulmonary angiography [CTPA], and competency: [risk assessment, use of anticoagulants and patient education], data were collected and the associations, weighted by live birth number, analyzed.
Results
Of 113 hospitals in China, 770,828 live births and 526 cases of VTE (68.2 per 100,000 live births) were reported. Nine hospitals lacked B-scan ultrasonography of lower extremity veins and 22 lacked CTPA. Prevalence rates of VTE rates were higher in general hospitals (Odds ratio [OR] = 4.251, 95% CI: 3.373-5.357), hospitals with live births < 10,000 (OR = 1.650-2.193), and hospitals without B-scan ultrasonography (OR = 1.661, 95% CI: 1.096-2.518). Hospitals implementing patient education, had a lower risk of VTE (OR = 0.296-0.374), and VTE rate decreased with the annual increase in live births.
Conclusions
Improved hospital resource availability and competency, especially patient education, is vital for reducing VTE-related maternal mortality and morbidity risk.
Keywords: vein thromboembolism, pregnancy, hospital, China
Introduction
Thromboembolism in pregnancy is one of the most common causes of maternal morbidity and mortality worldwide.1,2 In pregnant women, venous thromboembolism (VTE) presents as deep vein thrombosis (DVT) or pulmonary embolism (PE).3,4 In recent decades, VTE has become a leading cause of sudden death, which occurs in every 1600 pregnancies, and PE accounted for 9% of overall maternal deaths.5,6 It is well recognized that pregnancy increases the risk of thromboembolism under conditions of hypercoagulability, decreased mobility, and compression of the inferior vena cava and pelvic veins.3,4 Therefore, there is an urgent need to recognize risk factors of pregnancy-related VTE.
The incidence of VTE varies worldwide, which is accounted for by both individual and organizational factors. In the United States and the United Kingdom, the incidence ranged from 0.5 to 2 and 0.85 per 1000 pregnancies, respectively.7–10 Among them, Asian women displayed a lower risk of VTE and death from VTE than black women.11,12 Besides individual heterogeneity, organizational factors in hospitals, including available D-dimer, B-scan ultrasonography, computed tomographic pulmonary angiography (CTPA), patient education, risk assessment and use of anticoagulants, are potentially key factors in pregnancy-related VTE. It has been reported that, with early detection and prophylactic managements, maternal death rate due to thromboembolic disease had declined from 14.8% in 2006 to 3.2% in 2014.13,14 Thus, these organizational factors may also play an important role in the varied incidence of VTE in pregnancy.
Here we hypothesized that the VTE rate differs in different hospital settings and that organizational factors, including resource availability and competency may have an impact on the incidence of thromboembolism in pregnancy. Considering the ethical issues of a prospective design or randomized controlled trial (RCT) on VTE prevention and management, an epidemiological investigation is a preferred alternative. Hence, we conducted a retrospective hospital-based point prevalence survey of 113 hospitals in mainland China. The purpose was identifying organizational factors and their roles affecting venous thromboembolism (VTE) incidence and variations between hospitals in the differing levels of maternal healthcare in hospital services.
Methods
Data Sources
We conducted a hospital-based point prevalence survey in 113 hospitals in 26 provinces throughout China. This cross-sectional survey collected registered data of thromboembolism during pregnancies from January 1st to December 31st, 2019. Participating hospitals included those across all levels that provided maternal healthcare services in mainland China. A survey request from the Chinese Women's and Children's Health Association was sent to the Chief of the Department of Obstetrics at each hospital. Hospitals that completed the survey and provided informed consent before February 29, 2020, were enrolled for the final analysis, and those with missing data of VTE were excluded. Trained staff members assigned for data quality control telephoned the point of contact in case of any queries. The Institutional Review Board of the Obstetrics and Gynecology Hospital of Fudan University approved the project (IRB 2020-147).
Data Collection
The participating hospitals completed the survey forms, and all data were uploaded to an e-questionnaire platform. This thromboembolism survey was designed to evaluate the hospital-related factors associated with VTE in accordance with Donabedian's framework.15,16 It covered the following aspects: organizational general information, resource availability and competency. The participating cases were all reported VTE cases in the puerperium period, covering before delivery and 42 days after delivery. DVT was diagnosed by the abnormal findings on B-scan ultrasonography of the lower extremity veins, and PE was diagnosed by abnormal findings of CTPA.
First, organizational general information predominantly included general information (hospital type, characteristics and live birth number. Second, hospital resource availability included screening for VTE, using D-dimer for high risk screening, B-scan ultrasonography of the lower extremity veins and computed tographic pulmonary angiography [CTPA] for diagnosis. Risk assessment referred to the evaluation of VTE risk for the women during pregnancy and postpartum, based on the current clinical guidelines used in each hospital. Anticoagulant use was defined as therapeutic dosing. If the woman had no contraindication to anticoagulants, she would be prescribed these by obstetricians; if the woman had a contraindication, she would be transferred to a hematology specialist. Emergency transfer was medical transfer of critical patients to specialized hospitals or secondary hospitals, or for patients with suspicious symptoms, to those hospitals without use of further diagnostic methods. Patient education included the importance of early mobilization, use of stockings, risk classification, prophylactic and therapeutic anticoagulant use, and identifying early typical symptoms of VTE.
Statistical Analysis
We used numbers and percentages to describe the actual number and prevalence of VTE. Hospital related factors including hospital type, characteristics, and live birth numbers were analyzed as covariates. Patient individual information was unavailable in this questionnaire and thus not included. A multilevel regression was applied analyzing the association of organizational factors with the prevalence of VTE. “Hospital” was treated as a cluster and live birth number in each hospital was weighted. Poisson regression was conducted with hospital-level covariates to predict VTE event counts. Crude odds ratio (OR) and multivariable analyses after adjusting for hospital types, characteristics, region, live birth number, availability of B-scan ultrasonography of lower extremity veins and CTPA, risk assessment, anticoagulants’ use, patient education, are presented. Residual error was calculated by the variation between actual and adjusted prevalence of VTE. After adjusting the organizational factors, the variation of VTE prevalence was accounted for by individual factors. Statistical analyses were performed using SPSS version 26.0 (IBM Corp., Armonk, NY).
Results
Among the total of 124 hospitals completing our survey, 113 hospitals were included in the final analysis after excluding eleven hospitals with missing data (Supplemental Table 1). Of the total 770,828 deliveries in 113 enrolled hospitals, 526 VTE cases (68.2 per 100,000 live births) were reported. The number of VTE cases was 423, and the prevalence was 54.9 per 100,000 live births (95% CI: 54.6-55.1). For PE, the number of cases was 103, and the prevalence was 13.4 per 100,000 live births (95% CI: 13.3-13.4).
The majority of the enrolled hospitals were tertiary hospitals (79%) and located in the eastern region (75%). The proportion of general and specialized hospitals was 63% vs 37%, respectively. The number of live births varied from 600 to 373,00 per year, with median of 3500. Besides eight cases with missing information about maternal mortality (comprising two cases in tertiary hospitals and six cases in secondary hospitals due to lost follow-ups), there was one case of maternal mortality in a tertiary hospital and in the rest, 104 live cases were recorded. Of the physicians who responded, 80% were older than 40 years, 75% were at the position of an Associate Physician or above, and 53% had a Master's degree or more.
The general information of hospital-related factors with VTE rate is shown in Table 1. Besides availability of the D-dimer assessment, 9 (8%) of the hospitals lacked B-scan ultrasonography of the lower extremity veins and 22 (19.5%) lacked the CTPA. D-dimer test was available in 112 of our 113 hospitals. A small portion of hospitals reported insufficient competency, including lacking risk assessment (24.8%), anticoagulant use (18.6%), emergency transfer (3.5%), or patient education (4.4%).
Table 1.
Hospital factors in the 113 responding hospitals in mainland China.
| Total | Eastern | Middle | Western | ||||||
|---|---|---|---|---|---|---|---|---|---|
| Hospital, n% N = 113 |
Delivery, N N = 770828 |
Hospital, n% N = 82 |
Delivery, N N = 446667 |
Hospitals, n% N = 17 |
Delivery, N N = 189037 |
Hospitals, n% N = 14 | Delivery, N N = 135124 |
||
| Hospital type | Tertiary hospital | 89 (78.9) | 680658 | 61 (74.4) | 366291 | 14 (82.4) | 179243 | 14 (100) | 135124 |
| Secondary or primary hospital | 24 (21.1) | 90170 | 21 (25.6) | 80376 | 3 (17.6) | 9794 | 0 (0) | 0 | |
| Hospital characteristics | Specialized hospital | 42 (37.2) | 484111 | 28 (34.1) | 233014 | 7 (41.2) | 144490 | 7 (50) | 106607 |
| General hospital | 71 (62.8) | 286717 | 54 (65.9) | 213653 | 10 (58.8) | 44547 | 7 (50) | 28517 | |
| Number of live births, per year | Group 1 (>10,000) | 16 (14.2) | 276498 | 9 (11.0) | 154782 | 3 (17.6) | 67333 | 4 (28.6) | 54383 |
| Group 2 (5000-10,000) | 31 (27.4) | 322551 | 20 (24.4) | 159745 | 7 (41.2) | 99410 | 4 (28.6) | 63396 | |
| Group 3 (3000-5000) | 28 (24.8) | 107587 | 21 (25.6) | 80227 | 4 (23.5) | 15100 | 3 (21.4) | 12260 | |
| Group 4 (<3000) | 38 (33.6) | 64192 | 32 (39.0) | 51913 | 3 (17.6) | 7194 | 3 (21.4) | 5085 | |
| D-dimer test | Yes | 112 (99.1) | 760568 | 81 (98.8) | 436407 | 17 (100) | 189037 | 14 (100) | 135124 |
| No | 1 (0.9) | 10260 | 1 (1.2) | 10260 | 0 (0) | 0 | 0 (0) | 0 | |
| B-scan ultrasonography* | Yes | 104 (92.0) | 717367 | 73 (89.0) | 393206 | 17 (100) | 189037 | 14 (100) | 135124 |
| No | 9 (8.0) | 53461 | 9 (11.0) | 53461 | 0 (0) | 0 | 0 (0) | 0 | |
| CTPA | Yes | 91 (80.5) | 644735 | 62 (75.6) | 325359 | 16 (94.1) | 187037 | 13 (92.9) | 132339 |
| No | 22 (19.5) | 126093 | 20 (24.4) | 121308 | 1 (5.9) | 2000 | 1 (7.1) | 2785 | |
| Risk assessment | Yes | 85 (75.2) | 592703 | 63 (76.8) | 360549 | 11 (64.7) | 118847 | 11 (78.6) | 113307 |
| No | 28 (24.8) | 178125 | 19 (23.2) | 86118 | 6 (35.3) | 70910 | 3 (21.4) | 21817 | |
| Anticoagulant use | Yes | 92 (81.4) | 665850 | 63 (76.8) | 362489 | 16 (94.1) | 173037 | 13 (92.9) | 130324 |
| No | 21 (18.6) | 104978 | 19 (23.2) | 84178 | 1 (5.9) | 16000 | 1 (7.1) | 4800 | |
| Emergency transfer | Yes | 109 (96.5) | 751778 | 78 (95.1) | 427617 | 17 (100) | 189037 | 14 (100) | 135124 |
| No | 4 (3.5) | 19050 | 4 (4.9) | 19050 | 0 (0) | 0 | 0 (0) | 0 | |
| Patient education | Group 1 (no) | 5 (4.4) | 20358 | 3 (2.7) | 9958 | 2 (11.8) | 10400 | 0 (0) | 0 |
| Group 2 (postpartum) | 4 (3.5) | 40091 | 2 (2.4) | 8758 | 2 (11.8) | 31333 | 0 (0) | 0 | |
| Group 3 (inpatient) | 17 (15.0) | 137465 | 12 (14.6) | 66034 | 2 (11.8) | 8600 | 3 (21.4) | 62831 | |
| Group 4 (during pregnancy) | 32 (28.3) | 178917 | 25 (30.5) | 112751 | 5 (29.4) | 50666 | 2 (14.3) | 15500 | |
| Group 5 (at first antenatal visit) | 55 (48.7) | 393997 | 40 (48.8) | 249166 | 6 (35.3) | 88038 | 9 (64.3) | 56793 | |
B-scan ultrasonography of the lower extremity veins.
Association of organizational factors with the prevalence of VTE is reported in Table 2.
Table 2.
Univariate and multivariate analyses of hospital factors affecting the prevelence of VTE in the 113 responding hospitals in mainland China.
| VTE, n (%) | Total, n | Univariate, OR (95% CI) | Multivariate*, OR (95% CI) | ||
|---|---|---|---|---|---|
| N = 526 | N = 770828 | ||||
| Hospital type | Tertiary hospital | 492 (0.072) | 680658 | Ref | Ref |
| Secondary or primary hospital | 34 (0.038) | 90170 | 0.486 (0.338-0.698) | 0.803 (0.530-1.216) | |
| Hospital characteristics | Specialized hospitals | 154 (0.032) | 484111 | Ref | Ref |
| General hospitals | 372 (0.130) | 286717 | 4.079 (3.380-4.922) | 4.251 (3.373-5.357) | |
| Hospital region | Western | 110 (0.081) | 135124 | Ref | Ref |
| Middle | 147 (0.078) | 189037 | 0.955 (0.746-1.223) | 0.821 (0.628-1.072) | |
| Eastern | 269 (0.060) | 446667 | 0.740 (0.593-0.924) | 0.465 (0.365-0.594) | |
| Number of live births, per year | Group 1 (>10,000) | 82 (0.030) | 276498 | Ref | Ref |
| Group 2 (5000-10,000) | 276 (0.086) | 322551 | 2.885 (2.255-3.692) | 2.193 (1.670-2.880) | |
| Group 3 (3000-5000) | 107 (0.099) | 107587 | 3.354 (2.515-4.472) | 1.438 (1.033-2.003) | |
| Group 4 (<3000) | 61 (0.095) | 64192 | 3.204 (2.300-4.464) | 1.650 (1.147-2.374) | |
| B-scan ultrasonography † | Yes | 497 (0.069) | 717367 | Ref | Ref |
| No | 29 (0.054) | 53461 | 0.783 (0.538-1.139) | 1.661 (1.096-2.518) | |
| CTPA | Yes | 456 (0.071) | 644735 | Ref | Ref |
| No | 70 (0.056) | 126093 | 0.785 (0.610-1.010) | 0.904 (0.684-1.195) | |
| Risk assessment | Yes | 456 (0.077) | 592703 | Ref | Ref |
| No | 70 (0.039) | 178125 | 0.511 (0.397-0.657) | 0.458 (0.307-0.683) | |
| Anticoagulant use | Yes | 463 (0.070) | 665850 | Ref | Ref |
| No | 63 (0.060) | 104978 | 0.863 (0.663-1.123) | 1.002 (0.751-1.338) | |
| Patient education | Group 1 (no) | 30 (0.147) | 20358 | Ref | Ref |
| Group 2 (postpartum) | 35 (0.087) | 40091 | 0.592 (0.364-0.965) | 1.075 (0.511-2.261) | |
| Group 3 (inpatient) | 67 (0.049) | 137465 | 0.331 (0.215-0.509) | 0.296 (0.148-0.593) | |
| Group 4 (during pregnancy) | 97 (0.054) | 178917 | 0.368(0.244-0.554) | 0.307 (0.157-0.603) | |
| Group 5 (at first antenatal visit) | 297 (0.075) | 393997 | 0.512 (0.351-0.745) | 0.374 (0.190-0.737) |
Adjusted for hospital types, characteristics, region, live birth number, risk assessment, patient education, availability of B-scan ultrasonography of the lower extremity veins and CTPA, and use of anticoagulants.
B ultrasound of lower extremity vein.
Of the general factors, a higher rate was observed in general hospitals than that of specialized hospitals (OR = 4.079, 95% CI: 3.380-4.922). A relatively lower prevalence in the eastern regions (OR = 0.740, 95% CI: 0.593-0.924) was noted. A higher prevalence of VTE was observed in hospitals with live birth numbers less than 10,000 (OR = 2.885-3.204). Availability of B-scan ultrasonography of lower extremity veins, CTPA and anticoagulants’ use was not associated with the prevalence of VTE. Hospitals implementing patient education showed lower VTE prevalence (OR = 0.331-0.592) compared to those hospitals without patient education. In multivariate analyses, the association between organizational factors and VTE prevalence was confirmed. In addition, hospitals with available B-scan ultrasonography of the lower extremity veins, had a lower VTE rate compared to their counterparts with unavailable B-scan ultrasonography (OR = 1.661, 95% CI: 1.096-2.518). To eliminate the bias in hospital resource availability, subgroup analysis of hospitals with accessible B-scan ultrasonography of lower extremity veins and D-dimer assessment was performed (Table 3). In this analysis, the association between patient education with VTE prevalence was significant in the multivariable analyses.
Table 3.
Univariate and multivariate analyses of hospital factors affecting the prevalence of VTE in 113 hospitals with VTE diagnosis competency in mainland China.
| VTE, n (%) | Total, n | Univariate, OR (95% CI) | Multivariate*, OR (95% CI) | ||
|---|---|---|---|---|---|
| N = 496 | N = 707107 | ||||
| Hospital type | Tertiary hospital | 463 (0.072) | 639190 | Ref | Ref |
| Secondary or primary hospital | 21 (0.031) | 67917 | 0.627 (0.434-0.908) | 0.944 (0.610-1.461) | |
| Hospital characteristics | Specialized hospitals | 151 (0.034) | 443850 | Ref | Ref |
| General hospitals | 345 (0.131) | 263257 | 3.852 (3.181-4.664) | 4.018 (3.164-5.104) | |
| Hospital region | Western | 110 (0.081) | 135124 | Ref | Ref |
| Middle | 147 (0.078) | 189037 | 0.955 (0.746-1.223) | 0.761 (0.580-0.998) | |
| Eastern | 239 (0.062) | 382946 | 0.767 (0.612-0.961) | 0.446 (0.348-0.571) | |
| Number of live births, per year | Group 1 (>10,000) | 80 (0.032) | 249645 | Ref | Ref |
| Group 2 (5000-10,000) | 274 (0.090) | 306117 | 2.793 (2.177-3.583) | 2.220 (1.683-2.929) | |
| Group 3 (3000-5000) | 81 (0.088) | 92487 | 2.733 (2.006-3.723) | 1.203 (0.843-1.715) | |
| Group 4 (<3000) | 61 (0.104) | 58858 | 3.234 (2.317-4.513) | 1.610 (1.062-2.442) | |
| Yes | 453 (0.073) | 621115 | Ref | Ref | |
| No | 43 (0.050) | 85992 | 0.686 (0.501-0.937) | 1.051 (0.556-1.984) | |
| CTPA | Yes | 428 (0.070) | 610467 | Ref | Ref |
| No | 68 (0.070) | 96640 | 1.004 (0.777-1.296) | 1.044 (0.788-1.381) | |
| Risk assessment | Yes | 431 (0.079) | 547742 | Ref | Ref |
| No | 65 (0.041) | 159365 | 0.518 (0.399-0.673) | 0.432 (0.285-0.655) | |
| Anticoagulant use | Yes | 443 (0.071) | 626396 | Ref | Ref |
| No | 53 (0.066) | 80711 | 0.929 (0.698-1.235) | 1.199 (0.884-1.627) | |
| Patient education | Group 1 (no) | 30 (0.147) | 20358 | Ref | Ref |
| Group 2 (postpartum) | 35 (0.098) | 35591 | 0.667 (0.410-1.087) | 1.823 (0.810-4.105) | |
| Group 3 (inpatient) | 54 (0.040) | 134365 | 0.273 (0.174-0.426) | 0.350 (0.169-0.724) | |
| Group 4 (during pregnancy) | 95 (0.063) | 150490 | 0.428 (0.284-0.646) | 0.501(0.224-1.029) | |
| Group 5 (at first antenatal visit) | 282 (0.077) | 366303 | 0.522 (0.358-0.761) | 0.573 (0.281-1.168) |
Adjusted by hospital types, characteristics, region, live birth number, risk assessment, patient education, CTPA availability and use of anticoagulants.
In addition, analysis of the variation between hospitals in VTE rate was also performed (Figure 1). The variation of VTE prevalence was reduced with the increase in the annual live birth numbers. After adjustment by organizational factors, the range of VTE prevalence was changed from 0 to 63.1 to 15.3 to 78.8 per 100,000 live births.
Figure 1.
Variation of VTE rate in 113 hospitals (A) crude VTE rate; (B) adjusted VTE rate, after adjusted by hospital types, characteristics, region, live birth number, risk assessment, patient education, availability of B-scan ultrasonography of lower extremity veins and the CTPA, and use of anticoagulants; (C) residual of VTE rate calculated by the variation between actual and adjusted prevalence of VTE.
Discussion
Principle Findings
This hospital-based point prevalence survey was one of the largest epidemiological multiple center surveys in China undertaken in a real-world setting. Of the total of 770,828 deliveries in 113 enrolled hospitals, 526 VTE cases (prevalence of 68.2 per 100,000 live births) were reported. The proportion of DVT cases was 423, with a prevalence of 54.9 per 100,000 live births (95% CI: 54.6-55.1). We also found a varied prevalence of thromboembolism in pregnancy that was related to organizational factors. These included resource availability and competency. These organizational factors appeared insufficient in some hospitals; and therefore, further effort towards strengthening the hospitals’ resource availability and competency, especially patient education, is warranted, to reduce VTE related maternal mortality and morbidity.
Clinical Implications
First, we found that the prevalence of VTE ranged from 625.0 to 0 per 100,000 live births among 113 enrolled hospitals, providing the baseline status of VTE across China. This large variation was consistent with previous reports in the United States (172 per 100,000 live births) 17 and United Kingdom (85 per 100,000 live births). 9 National epidemiological reports in China are scarce. In China, there were several regional reports providing VTE prevalence data, such as 257.8 per 100,000 live births in Liaoning 18 and 140 per 100,000 live birth in meta-analysis. 19 With the increasing usage of diagnostic methods, the prevalence of VTE must be updated to ensure earlier screening and diagnosis. Therefore, our study provides a real-world national prevalence of VTE during pregnancy and puerperium in China, which is necessary for updating the prevalence of pregnancy-related thrombosis events.
Second, the effect of organizational factors on the prevalence of VTE is complex, besides the individual heterogeneity. On one hand, sufficient resources including screening and diagnostic methods, potentially correlate with a higher reported prevalence of VTE, because substantial VTE cases are asymptomatic or unspecific with dyspnea or swollen ankles. In our study, D-dimer testing for screening and B ultrasonography of the lower extremity veins were commonly performed in more than 90% of the enrolled hospitals, together with 80% CTPA available. Thus, it is reasonable that ultrasonography of the lower extremity veins was associated with VTE prevalence in our multivariate analysis, and that D-dimer testing and CTPA were not statistically significant. This is partly due to the bias of missing diagnoses and the confounding effect of other related factors. On the other hand, organizational competency is critical in VTE prevention and treatment. In those hospitals with available resources, the prevalence of VTE could possibly be further reduced with high competency, since we found that those hospitals with risk assessment, anticoagulant use and patient education reported lower prevalence of VTE. Therefore, more attention should be paid to promoting risk assessments and the utilization of anticoagulants for further elimination of the risk of VTE in pregnancy and the related maternal mortality.
Furthermore, we found that patient education was significantly associated with a lower prevalence of VTE in pregnancy, which was initiated from early pregnancy to the postpartum period. Possible reasons could be: first, the initiation of early mobilization and use of stockings is an active response of pregnant women instead of their receiving passive treatment from the obstetricians. Second, prophylactic use of anticoagulants during pregnancy or in postpartum requires more understanding and the confidence of pregnant women, and then they would correctly use the anticoagulants following their doctor's advice. Third, consciousness of suspicious symptoms in the early phase in pregnant women is the key to timely screening and diagnosing VTE, which is necessary to reduce the related maternal mortality and morbidity. Thus, the provision of detailed health-related education is needed especially in terms of early mobilization, and the use of stockings and intermittent pneumatic compression devices, both after vaginal delivery and Cesarean section.
In addition, this study indicated that more attention is required for the construction of organizational resources and enhancement of competency. Since VTE is considered a preventable and modifiable disorder, our study indicated that the efficiency of implementation should be improved. In our study, the prevalence of VTE was less varied after being adjusted by the organizational factors. Organizations are beneficial for facilitating the work of patient-centered teams. 20 Besides individual factors, organizational effects should be considered in the macro-environment in hospitals. Second, in the whole course of VTE prevention and treatment, readiness is of great importance, which covers multi-levels of patient, doctor, department, and policy. Available resources and sufficient competency are an essential part of readiness. Thus, further efforts should be made towards improving these organizational factors as much as possible.
Strengths and Limitations
Our main strength is that it was a nation-wide hospital-based survey to evaluate the VTE status in China that accounted for potential hospital-related factors, including hospital types, resource availability, and competency. It covered 26 provinces in mainland China and enrolled 113 hospitals of varied types, characteristics, and scale. Due to the ethical considerations, our study design of a prevalence survey had the potential to explore the association between organizational factors and the prevalence of VTE. Moreover, multivariable analyses and adjustments were performed when investigating the association. Additionally, this survey covered alternative hospital-related factors that could be improved upon for the elimination of VTE risk. Thus, the findings are practical and indicate the potential for clinical implementation.
This study has some limitations. First, this survey was based on a questionnaire, and therefore, reporting bias should be considered. The numbers that emerged from the survey may not represent the true incidence of VTE in China. The incidence of VTE in those hospitals not responding may be lower, as this study recruited a high proportion of tertiary care hospitals. However, in the present case, the numbers represent the true positives out of all patients suspected of having VTE. Second, the hospitals participating in this survey were mainly tertiary and secondary hospitals, and only one primary hospital was enrolled. Since most of the hospitals were at a tertiary level of care (80%), there is possibly a bias as the findings do not represent the general situation and care for the patients. To eliminate this selection bias, the hospital characteristics, hospital type, and annual live birth numbers have been adjusted for, in the analysis. Third, the site of the enrolled hospitals was mainly the eastern region of mainland China, and the populations in different parts of China differ in their ethnic background as well as in their predisposition for VTE, based on other risk factors. Thus, subgroup analysis of the different regions was conducted. Fourth, whether resources are available and the hospital is competent were the main outcome parameters in this study, but the implementation has not been discussed. Organizational factors included resource availability and competency, but there was no information about false positive and false negative rates of diagnosis, with substantial variability due to different clinical suspicions, the modality being used and the expertise of the physicians. However, this survey was completed by the department Chief or senior physicians from the Department of Obstetrics from each hospital, and trained staff members were assigned for data quality control by telephoning the point of contact if there were any queries, which ensured the quality of the survey to some extent.
Conclusions
In conclusion, organizational factors were observed to play an important role in the variation of prevalence of thromboembolism during pregnancy in China. This hospital-based point prevalence survey demonstrated that the prevalence of VTE was significantly influenced by organizational factors such as hospital resource availability and competency. Additional efforts should be accelerated towards the improvement of hospital resources and competency towards reducing the risk of VTE related maternal mortality and morbidity.
Supplemental Material
Supplemental material, sj-docx-1-cat-10.1177_10760296221076148 for Hospital Variation and Associated Organizational Factors of Pregnancy-Related Venous Thromboembolism in China by Qiongjie Zhou, MD, PhD, Zhekun Zhao, MD, PhD, Jinghui Xu, MD, Yu Xiong, MD, PhD, and Xiaotian Li, MD, PhD in Clinical and Applied Thrombosis/Hemostasis
Acknowledgments
The authors thank all 113 hospitals that completed the venous thromboembolism (VTE) survey in China.
Footnotes
Role of the funding source: The sponsor of the study had no role in study design, data collection, data analysis, data interpretation, or writing of the report. The corresponding authors had full access to all the data in the study and, along with the other authors, had final responsibility for the decision to submit for publication. The role of the sponsor in the design, execution, analysis, reporting, and funding is fully disclosed.
Disclosure of Interests: The authors have nothing to disclose. All authors have completed and submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest.
Contribution to Authorship: Dr Zhou QJ and Dr Li XT had full access to all of the study data and take responsibility for the integrity of the data and accuracy of the data analysis.
Concept and design: Zhou and Li.
Acquisition, analysis, or interpretation of data: Zhou and Li.
Drafting of the manuscript: All authors.
Critical revision of the manuscript for important intellectual content: All authors.
Statistical analysis: Zhou and Li.
Obtained funding: Li.
Administrative, technical, or material support: Li.
Details of Ethics Approval: The Institutional Review Board of the Obstetrics and Gynecology Hospital of Fudan University approved the project, and written informed consent was obtained from the participants (IRB202010, 20th January 2020).
Funding: This study was supported by the National Key Research and Development Program (2021YFC2701600, 2021YFC2701601), the Shanghai Key Program of Clinical Science and Technology Innovation (No. 17411950500, No. 17411950501 and No. 18511105602), Clinical Research Plan of SHDC (SHDC2020CR1047B and SHDC2020CR6021), the Shanghai Excellent Young Scholar Plan of Public Health (2020-2022, GWV-10.2-YQ13), Elite Young Scholar 2025 of Fudan University (2020-2023), National Science Foundation of China (81741047), Shanghai Medical Center of Key Programs for Female Reproductive Diseases (2017ZZ01016).
CONDENSATION: It is vital to improve hospital resource availability and competency towards reducing VTE-related maternal mortality and morbidity risk.
ORCID iD: Qiongjie Zhou https://orcid.org/0000-0003-1491-9870
Data Availability: The data used and analyzed during the current study are available from the corresponding author on reasonable request.
Supplemental Material: Supplemental material for this article is available online.
References
- 1.Friedman AM, Ananth CV. Obstetrical venous thromboembolism: epidemiology and strategies for prophylaxis. Semin Perinatol. 2016;40(2):81‐86. [DOI] [PubMed] [Google Scholar]
- 2.Liew NC, Alemany GV, Angchaisuksiri P, et al. Asian venous thromboembolism guidelines: updated recommendations for the prevention of venous thromboembolism. Int Angiol. 2017;36(1):1‐20. [DOI] [PubMed] [Google Scholar]
- 3.Liew NC, Chang YH, Choi G, et al. Asian venous thromboembolism guidelines: prevention of venous thromboembolism. Int Angiol. 2012;31(6):501‐516. [PubMed] [Google Scholar]
- 4.Voon HY, Chai MC, Hii LY, et al. Postpartum thromboprophylaxis in a multireligious cohort: a retrospective review of indications and uptake. J Obstet Gynaecol. 2018;38(4):493-497. [DOI] [PubMed] [Google Scholar]
- 5.Callaghan WM, Creanga AA, Kuklina EV. Severe maternal morbidity among delivery and postpartum hospitalizations in the United States. Obstet Gynecol. 2012;120(5):1029‐1036. [DOI] [PubMed] [Google Scholar]
- 6.Cantwell R, Clutton-Brock T, Cooper G, et al. Saving mothers’ lives: reviewing maternal deaths to make motherhood safer: 2006–2008. The eighth report of the confidential enquiries into maternal deaths in the United Kingdom. BJOG. 2011;118:Suppl1:1‐203. [DOI] [PubMed] [Google Scholar]
- 7.Berg CJ, Callaghan WM, Syverson C, et al. Pregnancy-related mortality in the United States, 1998 to 2005. Obstet Gynecol. 2010;116(6):1302‐1309. [DOI] [PubMed] [Google Scholar]
- 8.Sultan AA, West J, Grainge MJ, et al. Development and validation of risk prediction model for venous thromboembolism in postpartum women: multinational cohort study. Br Med J. 2016;355:i6253. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 9.Simpson EL, Lawrenson RA, Nightingale AL, et al. Venous thromboembolism in pregnancy and the puerperium: incidence and additional risk factors from a London perinatal database. BJOG. 2001;108(1):56‐60. [DOI] [PubMed] [Google Scholar]
- 10.Heit JA, Kobbervig CE, James AH, et al. Trends in the incidence of venous thromboembolism during pregnancy or postpartum: a 30-year population-based study. Ann Intern Med. 2005;143(10):697‐706. [DOI] [PubMed] [Google Scholar]
- 11.Blondon M, Harrington LB, Righini M, Boehlen F, Bounameaux H, Smith NL. Racial and ethnic differences in the risk of postpartum venous thromboembolism: a population-based, case-control study. J Thromb Haemost. 2014;12(12):2002‐2009. [DOI] [PubMed] [Google Scholar]
- 12.Chang J, Elam-Evans LD, Berg CJ, et al. Pregnancy-related mortality surveillance—United States, 1991–-1999. MMWR Surveill Summ. 2003;52(2):1‐8. [PubMed] [Google Scholar]
- 13.Say L, Chou D, Gemmill A, et al. Global causes of maternal death: a WHO systematic analysis. Lancet Glob Health. 2014;2(6):e323‐e333. [DOI] [PubMed] [Google Scholar]
- 14.Khan KS, Wogdyla D, Say L, et al. WHO Analysis of causes of maternal death: a systematic review. Lancet. 2006;367(9516):1066‐1074. [DOI] [PubMed] [Google Scholar]
- 15.Donabedian A. Evaluating the quality of medical care.1966. Milbank Q. 2005;83(4):691‐729. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 16.Ayanian JZ, Markel H. Donabedian's lasting framework for health care quality. Engl J Med. 2016;375(3):205‐207. [DOI] [PubMed] [Google Scholar]
- 17.James AH, Jamison MG, Brancazio LR, et al. Venous thromboembolism during pregnancy and the postpartum period: incidence, risk factors, and mortality. Am J Obstet Gynecol. 2006;194(5):1311. [DOI] [PubMed] [Google Scholar]
- 18.Zhang W, Shen J, Sun JL. Risk scores, prevention, and treatment of maternal venous thromboembolism. World J Clin Cases. 2020 Jun 6;8(11):2210‐2218. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 19.Meng K, Hu X, Peng X, Zhang Z. Incidence of venous thromboembolism during pregnancy and the puerperium: a systematic review and meta-analysis. J Matern Fetal Neonatal Med. 2015;28(3):245‐253. [DOI] [PubMed] [Google Scholar]
- 20.Institute of Medicine (US) Committee on Quality of Health Care in America. Crossing the Quality Chasm: A New Health System for the 21st Century. National Academies Press (US); 2001. [PubMed] [Google Scholar]
Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.
Supplementary Materials
Supplemental material, sj-docx-1-cat-10.1177_10760296221076148 for Hospital Variation and Associated Organizational Factors of Pregnancy-Related Venous Thromboembolism in China by Qiongjie Zhou, MD, PhD, Zhekun Zhao, MD, PhD, Jinghui Xu, MD, Yu Xiong, MD, PhD, and Xiaotian Li, MD, PhD in Clinical and Applied Thrombosis/Hemostasis