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Clinical features and direct medical cost of splenic injury in China: a cross-sectional study

Objectives This study analyses the clinical features and direct medical cost (DMC) of splenic injury during 2000–2013 in China. Design This was a cross-sectional study. Methods We used ‘The No. 1 Military Medical Project’ information system to conduct a retrospective study. Patients’ information from 2000 to 2013 were identified. Demographic data, treatment, clinical data and DMC were collected. We performed a generalised linear method (GLM) using gamma distribution to assess the drivers of DMCs. Results We included 8083 patients with splenic injury who met the study criteria. Over the 14-year study period, 2782 (34.4%) patients were treated with non-operative management (NOM), 5301 (65.6%) with OM. From 2000 to 2013, the rate of NOM increased from 34.7% to 55.9%, while OM decreased from 65.3% to 44.1%. Mean per-patient DMC in both NOM and OM increased from 2000 to 2013. In GLM analysis, male, old age, length of stay, severe splenic injury grade, OM, intensive care unit, blood transfusion and tertiary hospitals were associated with higher DMC, while female and NOM was associated with lower DMC. Conclusions In China, management of splenic injury was the most important factor impacting the total DMC. Proper management and public policy could curtail the burden of splenic injury.


INTRODUCTION
The spleen is an organ found in all vertebrates. Similar in structure to a large lymph node, its function is to alternatively get rid of immune complexes, circulating pathogens and senescent, dysfunctional or infected red blood cell. 1 2 Trauma is a leading cause of death, with approximately 5 million deaths reported each year globally. According to reports, splenic injuries take up to 16%-23.8% of trauma, with a mortality rate of 9.3%, mainly in response to associated injuries and treatment. 3 Recently, management paradigms for splenic injury are always controversial. Although non-operative management (NOM) has been recognised as a standard of treatment in haemodynamically stable patients (an estimated success rate exceeding 80%-90%), 3 4 some literature contends old age, high grade of splenic trauma, the sign of a large haemoperitoneum, contrast extravasation on admission, high Injury Severity Score (ISS) value, low systolic blood pressure on admission, transfusion of more than one packed cells and the presence of brain injury associated trauma may increase the probability of failure of NOM. 5 6 At present most of the studies on splenic injuries focused on the comparison of the safe and clinical outcomes of operative vs NOM. 4 7 The direct medical cost (DMC) is a factor that cannot be neglected in evaluating if treatment strategies are proper from a healthcare economy point of view. The study of the cost of managing splenic injuries has rarely been reported in multicentre studies. [8][9][10] Moreover, there are no data on the cost of management of splenic injuries in China, and the studies on the characteristic of splenic injuries in Chinese hospitals were rarely reported.
The issues of medical cost in China are notably complicated due to its changing public medical insurance policy features. Therefore, it is necessary to understand the association of structure of medical cost with STRENGTHS AND LIMITATIONS OF THIS STUDY ⇒ We provided the most comprehensive description of clinical features of splenic injury and its related direct medical cost in China. ⇒ This study is useful for government and health administration services to reform the healthcare policies to contain trauma-related medical costs, and it provides useful evidence for management of splenic trauma in China. ⇒ This research cannot tell what type of non-operative management was adopted in patients due to the lack of related code in Chinese Trauma Databank. ⇒ The insurance types were not recorded in this database, we cannot estimate patients-related medical care utilisation or provide comprehensive cost analysis of patients with splenic injury.
Open access the different modalities of strategies, which may provide some useful data and evidence for healthcare workers and healthcare policymakers, to a certain extent. Until now, there is no study on DMC of splenic injury. To fill the gap, we explored the related factors of the total DMC of splenic injury based on a database. These results will provide an insight into the potential factors that contribute to DMC and support useful evidence for making a public policy to reduce the burden of splenic injury.

MATERIALS AND METHODS Data source
Data for this study were obtained from 'The No. 1 Military Medical Project' information system, which is part of the Chinese Trauma Databank (CTDB). [11][12][13][14] It was built and maintained by the Information Centre of the Medical Department under the Ministry of General Logistics of the Chinese People's Liberation Army (PLA), possessing a lot of users' groups in China, and covering more than 200 military hospitals and 90 public hospitals. The database collects large amounts of trauma care data aiming to help the research, prevention and treatment of trauma.
Inpatients' information was included in the CTDB. Data handling in this system-based study are performed without revealing the identity of any participants and, therefore, obtaining ethical approval is not required.

Study design
This was a retrospective study using the data from the No. 1 Military Medical Project information system to identify 8038 inpatients with splenic injury (ICD9-CM 865.00-865. 19) in 8 hospitals (6 tertiary, 3 army medical hospitals of the PLA in Chongqing, the fourth people's hospital of Chongqing, affiliated hospital of Chengdu medical college, NO. 324 hospital of the army, and 2 secondary hospitals, No. 22 hospital of the army and NO. 477 hospital of the army) between January 2000 and December 2013. Patients who underwent splenectomy, splenorrhaphy and partial splenectomy were all defined as the OM group, while the others were identified as the NOM group.
Basic demographic data, DMC, the total length of hospital stay (LOS), injury pattern, trauma mechanism, transfusion, mortality, New Injury Severity Score (NISS) 15 and splenic injury grade 16 were collected. Exclusion criteria included patients who were dead on arrival at the hospital and those patients for whom complete data are unavailable (figure 1).

Estimation of costs
In our study, we extracted the DMC of each patient from the database, which includes medications, laboratory tests, imaging, surgery, transfusion, hospitalisation (medical consumables, diagnostic procedures, material, etc) and other costs (room costs, nursing care cost, etc). However, there were only records of total DMCs in 2010-2013, the expenses category was missing during that period in CTDB.
The total DMC from other years (2000-2012) was first converted into 2013 values in Renminbi (RMB) adjusting for inflation, 17 using the GDP deflator of China, 18 and was then converted to US dollars (USD) at the exchange rate equaling US$1=RMB6.196 for 2013.

Statistical analysis
Statistical analysis was performed using the RStudio, V.1.4.1717 (GNU General Public License) and SPSS V.22.0 (IBM). Mann-Whitney U test was applied for quantitative variables, the χ 2 test for categorical variables and the Kruskal-Wallis rank-sum test for continuous variables. Statistical significance was set at 0.05. We used the Bonferroni test for multiple corrections. Because DMC barely complies with the assumptions of the ordinary least squares regression, they, usually, are skewed to the right. Thus, a generalised linear method (GLM) with gamma family, log-link function was used to assess the factors impacting on the DMCs of splenic injury.

Patient and public involvement
No patients were involved. Table 1 shows the demographic and clinical characteristics of patients with splenic injury managed with NOM Open access or OM. In this study, a total of 8083 patients with splenic injury from 2000 to 2013 were included. Most of the patients managed with NOM or OM were men, 80% or 83.1%, respectively. Patients in the age group 18-40 years took up most of the population in NOM and OM. Car collision was the main factor that causes splenic injury. There was no difference between secondary hospitals and tertiary hospitals adopting the treatment strategies on patients. Compared with patients in NOM, patients in OM had longer LOS, more blood transfusion, higher splenic injury grade, NISS, mortality and total DMC.

Characteristics of patients by management
In  Figure 3 has shown that the distribution of various DMC by different management. Drug cost is the main expenditure in DMC, accounting for 46% (US$1612) of total DMC, followed by hospitalisation (18%, USD$633). Patients with NOM and OM had similar patterns structure of DMC, but transfusion and surgery costs are higher in patients with OM than patients with NOM. Table 2 shows the results of GLM with gamma distribution and the log-link function performed to determine

DISCUSSION
Using a large military fund database from China, we can obtain the clinical data of patients with splenic injury and calculate DMC resulting from the splenic injury. To our knowledge, this is the first description of the multicentre clinical features and DMC of splenic injury in China. Currently, NOM is the standard of treatment in haemodynamically stable patients with splenic injury, and the success rate of this produces exceeds 80%-90%. 3 In this retrospective study, we showed the changes in the treatment of splenic trauma and its related DMC in China from 2000 to 2013. Interestingly, the ratio of NOM had increased gradually in Chinese hospitals, while the DMC of patients with splenic injury had increased sharply after 2010.
In this study, the rate of patients with splenic injury with OM was higher than patients with NOM before 2010, which contrasted with many studies. 5 7 9 However, patients undergoing NOM vastly outnumbered patients with OM after 2010. We suppose there are several reasons for this phenomenon. First, before the reform of the Chinese healthcare system in 2009, the healthcare resources are seriously insufficient, and inequalities exist everywhere. Moreover, the relationship in China between doctors and patients is usually strained. 19 Thus, to avoid medical conflicts whenever possible, some Chinese doctors must choose a safe and conservative treatment to improve the one-time success ratio of treatment. Second, the Chinese government has introduced a new healthcare reform since 2009. Five main domains were reformed in China's health system reform: social health security, essential medicines, primary healthcare, basic public health service package and public hospitals. These measures improved access to healthcare and reduced health inequality, to a certain extent. Moreover, it, to some degree, reduced the contradiction between doctors and patients and promoted the progress of medical level. 20 However, in public hospitals, medical expenditure per-patient discharged increased by 22.1% between 2010 and 2013. 21 22 The proportion of out-of-pocket healthcare payments decreased, but the financial burden of healthcare did not fall much. The proportion of drug cost in total hospital expenditure has decreased, but total hospital expenditure is still rising. 22 Thus, splenic injury patients with low splenic grade and mild NISS were more likely to be adopted by NOM, but the per-patient DMC was higher than before whatever management doctors took. Previous studies have reported that nonsurgical treatment of blunt splenic injury is cost effective due to patients undergoing OM tend to have a longer LOS, drug, caregiving, more blood transfusions and more medical consumables, 9 23 which is similar to our results. Although the rate of patients with NOM is higher than OM in this study after 2010, the DMC of NOM in our study is much lower than OM.
China has already entered the ageing society since 1999 and is one of the fastest ageing countries in the world. 24 Injury is the fifth-leading cause of death in the elderly. Compared with younger patients, advanced age patients   In this study, drug cost was the main contributor to average splenic injury-related DMC in NOM or OM, followed by hospitalisation costs (figure 2). This phenomenon might be explained from two sides. From the supply side, Chinese doctors can obtain a 15% profit margin from the monetary values of drugs they prescribed according to the drug mark-up policy. 27 From 2009 to 2015, this policy was gradually ended in hospitals of all sizes, but overall hospital expenditure is still increasing. 25 From the demand side, patients in China are obsessed with medication therapy when they are ill. 28 Before 2009, pharmaceuticals accounted for above 40% of public hospitals' revenue in China. After healthcare system reforms in 2009, the rate of revenue began to slowly decline due to mark-up removal but still accounted for about 39% of public hospitals' revenue. 29 There are some limitations in our study. First, we cannot tell what type of NOM was adopted in patients due to the lack of related code in CTDB. Second, the categories of DMC cannot be extracted from 2010 to 2013 due to this part of the data was missing at that time in the datasets, we just extracted the total DMC of patients during that period. Third, patients' comorbidities and concomitant injury were not included in CTDB, so we cannot further evaluate the impact of these indicators on DMC. Fourth, because the insurance types were not recorded in this database, we cannot estimate patients-related medical care utilisation or provide a comprehensive cost analysis of patients with splenic injury. Despite these limitations, this study estimates to analyse DMCs of splenic injury and potential factors affecting the costs, as well as to provide evidence to develop specific and cost-effective interventions based on the cost estimations in this study.

CONCLUSIONS
This study is the first, to our knowledge, to describe DMC for splenic injury in China. China's health system always bears amounts of economic burden, coupled with a lack of effective incentives to improve health workers' motivation and laws to protect doctors from violence, which may have a significant influence on the management and cost of patients with splenic injury. This research will be useful for government and health administration services to reform the healthcare policies to contain trauma-related medical costs in the future and provides useful evidence for the management of splenic trauma in China.