Hospitalization costs and their determining factors among patients undergoing kidney transplantation: a cross-sectional descriptive study

ABSTRACT BACKGROUND: Cost evaluation is a key tool in monitoring expenditure for budget management. It increases the efficiency of possible changes through identifying potential savings and estimating the resources required to make such changes. However, there is a lack of knowledge of the total cost of hospitalization up to the clinical outcome, regarding patients admitted for kidney transplantation. Likewise, there is a lack of data on the factors that influence the amounts spent by hospital institutions and healthcare systems. OBJECTIVES: To describe the costs and determining factors relating to hospitalization of patients undergoing kidney transplantation. DESIGN AND SETTING: Cross-sectional descriptive study with a quantitative approach based on secondary data from 81 patients who were admitted for kidney transplantation at a leading transplantation center in southern Brazil. METHODS: The direct costs of healthcare for patients who underwent kidney transplantation were the dependent variable, and included personnel, expenses, third-party services, materials and medicines. The factors that interfered in the cost of the procedure were indirect variables. The items that made up these variables were gathered from the records of the internal transplantation committee and from the electronic medical records. The billing sector provided information on the direct costs per patient. RESULTS: The estimated total cost of patients’ hospitalization was R$ 1,257,639.11 (US$ 571,010.44). Out of this amount, R$ 1,237,338.31 (US$ 561,793.20) was paid by the Brazilian National Health System and R$ 20,300.80 (US$ 9,217.24) by the transplantation center’s own resources. The highest costs related to the length of hospital stay and clinical complications such as sepsis and pneumonia. CONCLUSIONS: The costs of hospitalization for kidney transplantation relate to the length of hospital stay and clinical complications.


INTRODUCTION
Kidney transplantation is considered to be the best therapy for treating chronic kidney disease, which is increasing worryingly in the population. 1,2 It has been observed that kidney replacement therapies such as dialysis are costly and that transplantation is the most viable long-term cost-effective procedure. [1][2][3][4] In addition, kidney transplantation also implies improved quality of life. [5][6][7] The United States is the country in which the highest absolute numbers of kidney transplantations are performed. There were more than 400,000 procedures in the United States between 1988 and 2017. 8 Brazil is considered to be the country with the second highest absolute numbers of transplantations and has the best transplantation system in the world. 2 It has been estimated that 6,000 transplantations are performed in Brazil every year, i.e. approximately 30 kidney transplantations per million population. 2 However, since 2016, the numbers of kidney transplantations performed in many Brazilian states have been declining because the supply of donated organs from deceased donors has been decreasing. The exception to this is the states of Paraná, Rio Grande do Sul and São Paulo, where transplantation rates of more than 45 per million population have been maintained. 9 For the Brazilian system to remain a global reference, the professionals involved in it need to undertake a chain of successful actions, from identification of potential donors to execution of transplantations and outpatient follow-up. 10 Faced with the demands of society, managers need to have knowledge of the resources available and the strategies for qualifying patients and expanding access to organ transplants. 11 Such knowledge contributes towards cost management.
In this context, it is essential to know and evaluate the cost of transplantations from the perspective of public healthcare systems like the Brazilian National Health System. These systems are responsible for the costing of professional and hospital services and, hence, for identifying factors that influence expenditure 12 and adjusting this to the amounts paid to institutions. Furthermore, such knowledge contributes towards improvement of public policies and adjustment of the amounts paid by public healthcare systems for these procedures. In addition, cost evaluation is a key tool for monitoring expenditure and thus for managing the budget. This increases the efficiency of possible changes through identifying potential savings, estimating the resources required to make such changes and estimating the resources needed to extend the changes. 7 Research in Japan has recently identified a need to evaluate the cost of patient hospitalization and investigate the impact of clinical complications on the total cost of transplantation. 12 However, there is a lack of knowledge of the total cost of hospitalization up to the time of the clinical outcomes among patients who are admitted for kidney transplantation, along with the factors that influence the amounts spent by hospital institutions and healthcare systems. Therefore, the aim of this study was to describe the cost and its determining factors relating to hospitalization of patients undergoing kidney transplantation.

METHODS
This was a cross-sectional descriptive study with a quantitative approach, on the costs and determining factors relating to hospitalization of patients for kidney transplantation. The study was developed in a Brazilian transplantation center, based on secondary data from all patients (n = 81) who had been admitted for kidney transplantation between January 2007 and December 2016.
The inclusion criterion was that the transplantations needed to have been funded through the Brazilian public healthcare system. The institution where this study was conducted is a 335-bed philanthropic hospital that provides services for the Brazilian National Health System. In terms of the complexity and comprehensiveness of the services provided, it is a tertiary-care hospital and is considered to be a type II transplantation center. It has an internal committee responsible for management of transplantations; it emphasizes the role of nurses; and it attends patients from all over the state of Paraná. Furthermore, this institution is a reference center for performing kidney and heart transplantations.
Information was gathered between November 2016 and July 2017. We prepared a spreadsheet, with adjustments after the initial data-gathering, in order to record items from the electronic medical records, data from the internal transplantation committee, records from the institution's billing sector and information from the remuneration table of the National Health System that was in force and which is updated each year. 13 The direct costs of healthcare for patients who underwent kidney transplantation were considered to be the dependent variable. The direct costs included personnel, expenses, thirdparty services, materials and medicines. 14 They also included, as independent variables, the factors that interfered in the cost of the procedure. The items that made up these variables were gathered from the records of the internal transplantation committee and from the electronic medical records. These were divided into two groups: a) those relating to the patient, such as sex, age,   Table 1 shows the time distribution of hospitalizations and annual costs relating to patients who were discharged from the hospital (n = 77) (the four dead patients are not included). Table 2 shows the amounts paid to the institution for the total cost of hospitalizations through the Brazilian public healthcare system per year, according to the current table of costs and annual adjustments.
Among the variables that that were found to influence costs through multiple bivariate linear regression ( Table 3) The mean length of hospitalization (a variable that affects cost) was 17 days (± 11.02), with a range from three to 69 days and a median of 14 days. Out of the total number of patients, 64 had a long stay, consisting of more than 10 days of hospitalization.
The mean length of stay in the intensive care unit was seven days

DISCUSSION
This study describes the costs and determining factors relating to hospitalization of patients who underwent kidney transplantation.
The results showed that male patients predominated and that the average age among the patients who underwent kidney transplantation was 37 years. Likewise, other studies have found that greater numbers of transplantations were performed on men and that the predominant age group was the adult and elderly public. 16 The data of the present study also indicated that the numbers of organ transplants from living and deceased donors were similar    kidney donors in order to increase the number of organs available for transplantation and reduce the costs relating to kidney replacement therapies. 17,18 In this case, kidney donors would receive a cash payment or other benefits established through healthcare programs, as recompense for the donated organ.
Regarding the data associated with the various stages of renal illness, comorbidities like arterial hypertension and diabetes mellitus are considered to be the dominant factors in this clinical condition.
These comorbidities have also been correlated with longer hospitalization and death 6,16 and are reflected in hospitalization costs. 19 The costs of carrying out hemodialysis prior to transplantation may result in costs that are higher than the cost of kidney transplantation. [3][4][5]7 Another study conducted in Brazil showed that over the four-year period studied, kidney transplantation from deceased and living donors gave rise to cost reductions per patient of approximately R$ 37,000 and R$ 46,000, in relation to hemodialysis, respectively. 7 It should be noted that in the present study, it was not possible to identify the cost savings generated through kidney transplantation from deceased and living donors, compared with hemodialysis. This was because there was a lack of information on previous transplantation care and treatment, since most of the patients had been followed up at other healthcare units.
In relation to the values established within the Brazilian public healthcare system, it was necessary to make annual adjustments to the National Health System hospital services ( Table 2).
This was because of refusal by the transplantation centers to pay for the expenditure on transplants. The annual adjustments served to offset the expenditure borne by these hospital institutions. 13 To identify the factors that made up the hospital costs, multiple linear regression was used. This showed that the length of the hospital stay was the main factor that influenced the total cost, as had been shown through the results from other studies. 12,20 The mean duration of hospitalization was longer than what had been estimated through the National Health System (17 days versus 10 days), including patient admission, surgical procedure and hospital discharge. 13 The factors that contributed to the length of stay in the intensive care unit and hospitalization units related to the predominant clinical complications after transplantation and to preventable or minor reasons, especially among patients who acquired healthcare-related infections and developed sepsis. A study investigating the total cost of treatment before and after transplantation showed that clinical complications due to urinary tract infection, sepsis or pneumonia had a significant influence on the total transplantation cost and gave rise to long hospital stays. Patients with pneumonia had hospital costs and lengths of hospital stay that were greater than those of patients without clinical complications (50 days versus 44 days; P < 0.01). 12 The results from the present study, along with those from other studies that investigated the hospital costs of other types of transplantation, such as liver transplantation, showed that complications after transplantation resulted in longer hospital stays, higher daily costs and more use of medication. 20 Infections are also a major cause of early hospitalization after hospital discharge. 21 Another study 22 showed that transplant recipients may be 6.4 times more likely to be hospitalized again after being discharged after transplantation.
The patients' clinical condition in relation to immunosuppression may also have influenced the outcomes and factors presented here. A study by Taminato 23 highlighted the challenge involved in management of infectious complications in patients who had received kidney transplantation, due to their compromised immune system. These results demonstrate that there is a need for the healthcare team to develop strategies for prevention of the more common clinical complications after the surgical procedure, such as healthcare-related infections, in order to reduce the costs incurred during hospitalization and after discharge.
Regarding the clinical outcome at discharge, approximately 90% of the patients were discharged with a functioning graft.
Over the long term, costs incurred during hospitalization may be lower than those of other surrogate renal therapies, thus indicating the importance of further studies to analyze the efficiency, cost-effectiveness and quality of life of this target population after kidney transplantation.
The present study had limitations in terms of the lack of information in the medical records, even though they were computerized. Since these patients' treatments are funded through the National Health System, the average cost per day of the stays in the intensive care unit and inpatient units was considered to be a single amount. Moreover, the data referring to the drugs and examinations were made available together, without separating the costs relating to each item.
However, because of the payment policy adopted in the National