This cross-sectional study was conducted during September 2019 to February 2020, to evaluate the economic burden of CVDs in two periods: before (2013) and after (2016) the HTP implementation. The bottom-up approach, the cost of disease, and the human capital approach (HCA) were used to calculate the total costs.
Study design and setting
This cross-sectional study was conducted before and after the HTP implementation in the north-west of Iran. A 550-bed cardiovascular specialized hospital affiliated with MoHME was selected as the study site. At both time points (before and after the HTP), data on direct, indirect, and non-medical costs were collected from hospital-based cardiovascular inpatients records and compared. Baseline data were collected from households with CVDs at two intervals.
Eligibility criteria
Patients with one of the CVDs (coronary artery stenosis, heart failure, heart attack, and cardiac rheumatism) in two periods, before (March 2012 to March 2013) and after (March 2016 to March 2017) the HTP, were eligible to participate in the study. Given that most hospitalization costs occur in the early years of the diagnosis and treatment of CVDs, the diagnosis of the disease over the past year was the basis of inclusion.
Sampling methodology and sample size
Samples were collected from a specialized cardiovascular hospital the most extensive and only reference for patients with CVDs using a purposive random sampling method. Initially, a list of all patients admitted to the study during the two intervals was prepared, and data were collected from inpatients medical records through a checklist. If necessary, patients who were eligible to participate in the study were contacted, and additional information was obtained via telephone interview.
Four types of CVDs with high frequency (coronary artery stenosis, heart failure, heart attack, and cardiac rheumatism) were selected to estimate sample size. Then, the medical records of 40 discharged patients were randomly selected and evaluated for cost. Based on the mean and variance of hospital costs and using Cohen’s sampling method, the sample size was estimated to be 253 (n = 800) before and 284 (n = 1300) after the HTP.
Cohen’s d is simply a measure of the distance between two means, measured in standard deviations [23]. It is calculated using Eq. (1):
$$d=\frac{{M}_{1}-{M}_{2}}{{SD}_{pooled}}$$
(1)
where M1 and M2 are the means for the 1st and 2nd samples, and SDpooled is the pooled standard deviation for the samples. SDpooled is appropriately calculated using the following equation:
$${SD}_{pooled}=\sqrt{\frac{\sum {({X}_{1}-{\stackrel{-}{X}}_{1})}^{2}+\sum {({X}_{2}-{\stackrel{-}{X}}_{2})}^{2}}{{n}_{1}+{n}_{2}-2}}.$$
(2)
Accordingly, the total number of hospitalizations for CVDs was extracted from the hospital information system (HIS), then, 600 patients for both intervals (300 before and 300 after the HTP) were randomly selected using random number table.
A pilot study was conducted a month before (August 2019) on 30 inpatients with CVDs by a face-to-face interview to estimate indirect costs in the last month. The data were extracted using a checklist. Data were multiplied by 12 to estimate the total costs in the last year. Based on the mean and variance of hospital costs and using Cohen’s sampling method, the sample size was estimated to be 180 for both time points, before and after the HTP implementation. By telephone follow-up, patients were selected from the direct costs calculation phase (n = 300). Contact with all selected patients continued until the designated sample size was obtained.
Data collection
Data were collected using a researcher-made checklist included age, sex, length of hospital stay, hospitalization costs, and other related costs (visitation, diagnostic services, hoteling expense (bed-days expense), surgery, and medication), which were extracted from the patients’ medical records. A checklist used in other similar international studies was used to collect non-hospital and non-medical costs [24, 25]. The questionnaire consisted of two sections; the first section included demographic information (age, gender, marital status, education status, and the number of family members), duration of illness, and insurance information. Also, the second section included information on indirect costs (absenteeism, sick leave, disability, etc.).
Study variables and data sources
In this study, multiple data sources were used to estimate the economic burden of the disease. The most important data source used to estimate direct medical costs were the information extracted from the medical records of the patients with CVDs.
Direct costs
This type of costs is directly attributable to patients admitted to various types of health care facilities (Ministry of Health, Social Security, and private sector), as well as treatment costs, including different services, such as diagnostic, medical, and rehabilitation services [26]. To estimate direct costs, the costs of standard diagnostic services, such as electrocardiograms, echocardiography, exercise testing, nuclear heart scan, and angiography, were included. Sampling was performed among patients who had undergone open-heart surgery, angioplasty, and medication. Sample sizes for the three groups (undergone open-heart surgery, angioplasty, and medication) were 135, 251, and 221 people, respectively. Sampling was performed using simple random sampling method and Cochrane-Orcutt Procedure, which is applicable for a limited population, was used. The main drugs for CVDs were also extracted by reviewing 65 patients’ medical records and interviews with CVDs specialists. In this section, direct payments were considered as the patients’ OOP expenditure, which can be due to the difference between the patient’s share of the cost and share of the insurance cost, which was recorded as the patient’s share of the costs in their medical record.
Indirect costs
Indirect costs are a combination of the costs incurred to the patients and their families, such as the cost of medical travel, cost of time lost, and cost of patient in-home care [27].
Time costs
Time costs are calculated based on the mean number of days lost due to receiving health care services and hospitalization in the hospital. In this study, time costs were calculated by multiplying the number of hospitalization days by the average daily wage. Data for an average daily wage were obtained from the report of the Ministry of Cooperatives, Labor, and Social Welfare of Iran in 2018.
Premature death costs
The human capital approach was used as the primary method for the estimation of premature death costs in this study. In previous studies, HCA was used for the estimation of premature death due to non-communicable diseases, such as CVDs [28, 29]. Total numbers of deaths due to CVDs during last 5 years were obtained from documents of the hospital and deputy of the health of ARUMS. The data adopted to the data of the Institute for Health Metrics and Evaluation (IHME) and Global Burden of Disease (GBD), and then, registered.
Data sources and manipulation
Data were collected using structured interviews with patients, medical records, and valid data sources.
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Population, employment rate, and life expectancy were extracted from the latest report provided by the Iranian Statistic Center (ISC).
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CVDs morbidity and mortality data were extracted from the National and Subnational Burden of Diseases, Injuries, and Risk Factors (NASBAD) survey.
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The final report by the Central Bank of the Islamic Republic of Iran was used to identify and determine the exchange rate by year.
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The average daily cost (the daily minimum wage lost) was calculated according to the principles presented by the Ministry of Cooperatives, Labor, and Social Welfare of Iran.
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The difference between payments by patients (patient’s share) and the insurance liability was calculated to determine the OOP expenditure.
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Indirect costs identified by data extracting through interviews with patients and their relatives who were aware of patients’ diseases using the designed checklist.
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Given that, there were no precise statistics on the level of household income, their income was estimated based on the minimum declared incomes of the Ministry of Labor, Cooperatives and Social Welfare.
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Other information, such as disease incidence, occupancy rate, payroll, GDP, national health expenditures, and standardized life expectancy were extracted from previous studies, treatment guidelines, World Bank databases, Iranian Ministry of Health (MoHME), and Iranian Statistic Center (ISC).
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All costs were equalled and presented in Iranian Rials (IRR) in two periods (the average exchange rate in 2013 equals 1$ = 31,840 IRR and in 2016 equals 1$ = 36,429 IRR).
Data analysis
The human capital approach considers the valuation of waste resulting from premature death for the whole economy [30]. Individuals play an economic role in society by generating, earning, and consuming. Thus, by calculating production, income, or consumption, the extent of the impact of one’s economic activities can be estimated.
In the present study, the discount rate of 3% was used to obtain the present value of the lost production. The Present Discounted Value of Lifetime Earnings (PVLE) model developed by Max et al. (2000) was also used to calculate and estimate the present value of the patients’ income [31].
Data were analyzed using SPSS version 16 (SPSS Inc., Chicago, IL, USA) [32] and Excel software version 2013. Continuous variables are reported as means ± standard deviation. Categorical variables are reported as proportions (%). Continuous variables were compared using t‑test and one‑way ANOVA, and categorical variables were compared using the Chi‑square test.