Cost-of-illness analysis of ulcerative colitis patients treated with biological therapy: a prospective observational study in Iran

Abstract

Background

No research has assessed the comprehensive annual costs of managing ulcerative colitis (UC) patients undergoing biological treatment. This study aimed to determine the annual costs and primary cost drivers for UC patients receiving biological therapy.

Methods

This prospective observational study was conducted in Iran from a societal perspective, employing the cost-of-illness method, grounded in human capital theory. A prevalence-based approach and bottom-up technique were used for cost estimation. Inpatient costs were extracted from hospital records, while outpatient service usage and direct non-medical costs over a one-year follow-up were collected through patient interviews. Indirect costs were evaluated using a standardized questionnaire. The average costs per patient were calculated, and the factors affecting patient expenses were analyzed using the Mann-Whitney and Kruskal-Wallis statistical tests.

Results

The study included 238 UC patients (50.8% male; mean age: 37.66 ± 12.13 years), with 32.8% receiving Infliximab (IFX) and 67.2% on Adalimumab (ADA), and an average disease duration of 9.29 ± 6.5 years. The total annual economic burden per UC patient was USD 2316.90. Of this, direct medical costs constituted 49.84%, direct non-medical costs 21.13%, and indirect costs 29.03%. Notably, higher expenses were significantly associated with patients under 20 years of age and those treated with ADA.

Conclusions

Biological therapies accounted for the largest share of direct medical expenses, while productivity losses, mainly resulting from temporary absenteeism, were identified as a major factor contributing to the economic burden of UC in Iran.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12913-025-12474-6.

Introduction

Ulcerative colitis (UC) is a chronic inflammatory bowel disease (IBD) that primarily affects the colon and rectum. It is characterized by alternating periods of remission and flare-ups, that may lead to symptoms which include abdominal pain, bloody diarrhoea, weight reduction, fatigue, and a frequent urge to defecate. UC symptoms vary in severity, often requiring ongoing management [1]. The prevalence and incidence of UC have been on the upward push globally, including in Iran, where it is far increasingly diagnosed as a widespread public health issue [2–4]. A previous study in Iran estimated the prevalence of UC to be 15 per 100,000 persons, with an annual incidence rate of 3.25 per 100,000 persons, indicating a marked boom in recent years [4]. Globally, the prevalence of UC ranges from 2.42 to 505.0 in 100,000 person-years, with higher rates discovered in Europe and North America compared to regions together with Asia [5].

Common symptoms of UC consist of bloody diarrhoea, abdominal cramps, fatigue, and weight loss, all of which significantly diminish a patient’s quality of lifestyle [6]. The unpredictable nature of flare-ups frequently ends in missed days at work and school, and at some stage in extreme exacerbations, patients may also face long-term disability. In extreme instances, UC can result in serious headaches like toxic megacolon, colorectal cancer, or intestinal perforation, which may necessitate surgical processes together with colectomy. These symptoms and complications contribute to great healthcare costs and lost productivity [7, 8].

Treatments for UC aim to control inflammation, alleviate symptoms, and maintain remission. Medical management normally entails aminosalicylates, corticosteroids, immunosuppressants, and biologic healing procedures [9]. Biological therapies have gained significant prominence in the treatment of ulcerative colitis, especially for patients who do not achieve satisfactory results with standard treatments [1]. In Iran, the use of biological therapy is mainly recommended for individuals with moderate to severe ulcerative colitis who have not responded to conventional therapies, including corticosteroids and 5-aminosalicylic acid (5-ASA) compounds [2, 3]. Currently, in Iran, various biological drugs are available for the treatment of UC. These include TNF inhibitors such as IFX and ADA. Additionally, JAK inhibitors like tofacitinib are also accessible to patients. It is noteworthy that IFX and ADA are widely available to patients [4, 6, 7]. Although biologic treatments have significantly more desirable UC management, they tend to be some of the most expensive remedies available. Besides medication, patients with UC can also need hospitalizations during flare-ups, surgical methods like colectomy for those with extreme or resistant disorders, and normal observe-up appointments for ongoing ailment monitoring and control [10–13]. The lifetime cost for UC is about USD 369,955 for patients diagnosed between the ages of 0 and 11 years, while it is estimated at USD 132,396 for those diagnosed at 70 years or older, leading to an average cost of USD 230,102 for a diagnosis regardless of age [14]. The results of a study in Shiraz, Iran, in 2019 showed the total annual economic costs of IBD per patient were estimated at 1229.74 USD, and especially for UC the mean of direct medical costs, direct non-medical, and indirect costs were 906.0059, 36.661, and 289.9718 USD per patient [15]. Studies show that 57.8% of total costs are related to indirect costs and 41.4% are for direct medical costs [16].

In Iran, the rising burden of UC, in conjunction with escalating remedy costs, poses an enormous task for the healthcare system. While the advent of biologics and advanced treatment options has led to better patient outcomes, these remedies are frequently steeply priced, potentially restricting admission to a few individuals, particularly those in rural or economically disadvantaged areas [17, 18]. As the incidence and prevalence of UC keep growing globally and inside Iran, policymakers must address the direct and indirect costs associated with the ailment to lessen its monetary impact on sufferers and the healthcare system. By comprehensively understanding the economic burden of UC, policymakers can more effectively allocate resources and create interventions that lessen the financial strain on both patients and society at large. Therefore, this study aims to assess the economic burden of UC among Iranian patients receiving biological therapies.

Methods

Study design

This prospective, observational study took place in the Iranian provinces of Yazd, Bushehr, and Fars from 2019 to 2021. The economic burden of UC was assessed using the cost-of-illness method [19], incorporating a prevalence-based approach and a bottom-up technique, with the analysis being conducted from a societal perspective.

Study subjects and sampling design

The study included patients with moderate to severe UC who were treated with biological therapies, and monitored over one year. The diagnosis of UC was confirmed based on clinical, endoscopic, and histological criteria, as described in prior studies [20]. Patient records from the Iranian Health Insurance Office and the Social Security Insurance Office in each participant’s area of residence were used for data collection. These two major insurance funds, which cover over 90% of Iran’s population, provided extensive data for our study. In Iran, UC patients must present medical documentation, including a diagnostic report from a gastroenterologist and a prescription, to register for biological medications with the insurance office. The sample size was determined to be 268 patients for cost estimation, based on a 95% confidence interval and a 5% margin of error. A list of all patients using ADA and IFX was obtained from the Health Insurance and Social Security Insurance organizations and selected sample size through using stratified random sampling. Resource costs were derived from national tariffs, recorded in Rials, and converted to US dollars based on the 2021 average exchange rate of 252,000 Rials per US dollar.

Determining direct medical costs

Direct medical costs encompassed expenses for physician visits, psychological consultations, physiotherapy, nutrition consultations, surgeries, medications, inpatient care, imaging, laboratory tests, and nursing services. The cost for each service, excluding medications, was calculated by multiplying the quantity of services by the current tariffs set by the Ministry of Health and Medical Education (MoHME). MoHME establishes these tariffs annually for both private and public healthcare services, and for this study, a weighted average was applied based on the most recent national utilization survey [17]. Drug costs were determined by multiplying the quantity of each item by its unit price, as specified by the Food and Drug Administration (https://irc.fda.gov.ir/nfi#).

Determining direct non-medical costs

Non-medical costs included expenses for goods related to the condition, such as alternative medicine, special diets, assistive devices, and educational materials. Additional costs encompassed home nursing services (formal care), transportation, and accommodation for patients and their family members travelling to clinics, as well as informal care for dependents. All the mentioned items were collected from the patients every three months over one year. Then, transportation costs were calculated by combining public and private travel expenses: public transport costs were derived from average usage and municipal tariffs, while personal transport and other expenses were based on actual costs reported by patients in the questionnaire. Home nursing service costs were estimated by multiplying the number of service days by the current tariffs established by the MoHME. The average net hourly wage was applied for informal care provided by employed caregivers under the age of 65 [21].

Determining indirect costs

The human capital approach was applied to estimate indirect costs, with productivity losses from disability being a major component. In this study, disability was categorized into short-term and long-term categories.

Productivity losses due to short-term disability

Productivity losses from short-term disability were calculated based on temporary work absences of both patients and their caregivers. To estimate the productivity loss due to absences for therapy appointments, the hourly wage of the lowest-paid unskilled government workers (LPUGW), as defined by the Ministry of Labor, was multiplied by the total hours of absence for each caregiver and patient.

Productivity losses due to long-term disability

Productivity losses from long-term disability were assessed by considering the early retirement of patients. The cost of early retirement was calculated by determining the difference between the reduced pension received by early retirees and the full pension they would have received upon retiring at the standard retirement age.

Measures

Alongside patients’ electronic records, data were collected using a custom-designed questionnaire composed of two sections.

Socio-demographic and clinical history section

This section gathered information on patients’ socio-demographic and clinical backgrounds, including age, residence, marital status, smoking history, education, gender, supplemental insurance, disease type and severity, disease duration, history of surgeries and hospitalizations, employment status, and medications taken.

Standard cost-of-illness questionnaire

This study employed a standardized cost-of-illness questionnaire, adapted from a previously used instrument [22] and customized to meet the specific objectives of this research. Interviews for this study were conducted using custom-designed questionnaires to assess direct and indirect costs associated with patient follow-ups. These questionnaires were administered every three months during the one-year follow-up period. The English version of the questionnaires is provided as supplementary material (Supplementary File 1).

Procedure for collecting the data

In coordination with the Social Security and Health Insurance offices of the targeted provinces, a list of patients diagnosed with UC was obtained. Following the specified sampling procedure, the list of selected study participants was compiled. Arrangements were made with these patients to participate in the study, and the research objectives were explained to them. After obtaining their informed consent, data collection tools were distributed along with instructions for completion. Patients were asked to submit the completed questionnaires every three months over one year, resulting in data collection across four phases. Inpatient and outpatient costs were collected prospectively during the follow-up period from patients’ insurance invoices available at the relevant insurance offices and hospitals. Additionally, through questionnaires, we inquired about any direct medical expenses not covered by insurance, recorded these costs, and added them to the total direct medical costs of the patients. The ethical committee of Iran University of Medical Sciences approved this study (IR.IUMS.MEDICINE.REC.1398.222).

Statistical analysis

Continuous variables were presented as means with standard deviations, whereas categorical variables were described using frequencies and percentages. Cost data were summarized as mean values accompanied by their 95% confidence intervals. Comparisons between independent groups were conducted using the Mann-Whitney U test and the Kruskal-Wallis test. All statistical analyses were carried out using SPSS version 26.0 and Stata version 13 (StataCorp, College Station, TX).

Results

Demographic clinical characteristics

A total of 268 patients with UC were enrolled in the study, with 238 continuing their participation throughout the research period. Table 1 presents an overview of the demographic and clinical characteristics of the participants. The average age of the participants was 37.66 ± 12.13 years and the mean duration of the disease was 9.29 ± 6.57 years. Most participants were male (50.8%), married (69.7%), and lived in urban areas (79.0%). Additionally, 35.3% of the patients were employed, and 52.9% had completed higher education. Among the participants, 160 (67.2%) were receiving ADA treatment, while 78 (32.8%) were undergoing IFX therapy (Table 1).

Table 1.

Demographic and clinical characteristics of study subjects

Variables	M±SD/ n (%)
Total	238
Age(yrs.)	37.66±12.13
≤20	6(2.52)
21–40	160(67.23)
41–60	54(22.69)
>60	18(7.56)
Duration of disease(yrs.)	9.29±6.57
≤5	86(36.13)
6–10	73(30.67)
11–15	45(18.91)
>15	34(14.29)
Gender
Men	121(50.8)
Women	117(49.2)
Marital status
Married	166(69.7)
Unmarried	62(26.1)
Separated /widowed	10(4.2)
Occupation status
Homemakers	73(30.7)
Retired	17(7.1)
Disabled	3(1.3)
Unemployed	46(19.3)
Student	15(6.3)
Employed	84(35.3)
Residential area
Village	50(21.0)
Urban	188(79.0)
Education
Illiterate	6(2.5)
Less than 6 years	14(5.9)
6–12 years	92(38.7)
More than12 years	126(52.9)
Complementary insurance
Yes	82(34.5)
No	156(65.5)
Use of tobacco products
Yes	33(13.9)
No	205(86.1)
Primary drug
IFX	78(32.8)
ADA	160(67.2)

IFX Infliximab, ADA Adalimumab, M Mean, SD Standard deviation

Direct medical costs

Table 2 categorizes the cost items, also presenting the number (and percentage) of participants using each resource, along with the mean annual cost for each category. Medication accounted for the largest share of direct medical costs in UC patients, representing 38.04% (USD 881.44 per patient) of the total costs. Imaging costs, which were significantly lower than medication expenses, made up the second-largest portion at 3.38% (USD 78.32 per patient). Physician visit costs followed at 2.15% (USD 49.85 per patient), and surgery costs represented 2.06% ($47.83 per patient), making up the next largest shares of direct medical expenses. Hospitalization costs accounted for 1.61% (USD 37.38 per patient), outpatient nursing services 1.35% (USD 31.35 per patient), and laboratory tests 1.18% (USD 27.38 per patient) of the total direct medical costs, in that order. Consultations with physiotherapists, psychiatrists, and nutritionists incurred minimal costs for the UC patients in this study (Table 2).

Table 2.

Resource utilization and annual DMC of UC by types of costs per patient in 2021 (US$)

Cost categories	Participants using resources, n (%)	Mean (SD)	% of total costs
Physician visit	235 (98.7)	49.85(27.48)	2.15
General Physician	170 (71.4)	4.90(4.15)	0.21
Specialist	184 (77.3)	17.98(13.41)	0.78
Subspecialist	223 (93.7)	26.97(17.04)	1.16
Imaging	160(67.2)	78.32(82.91)	3.38
Laboratory tests	216(90.8)	27.38 (17.22)	1.18
Outpatient nursing services	78(32.8)	31.35(53.19)	1.35
Physiotherapy	3(1.3)	0.02(1.73)	0.01
Nutritionist Consult	13(5.5)	0.09(0.39)	0.00
Psychiatrist	14(5.9)	0.90(4.56)	0.04
surgery	10(4.2)	47.83(239.71)	2.06
Hospitalization	32) 13.4)	37.38(108.18)	1.61
Medication	238(100)	881.44(815.87)	38.04
Total direct medical costs	238(100)	1154.75(853.75)	49.84

UC Ulcerative colitis, DMC Direct medical costs, SD Standard deviation

Direct non-medical costs

Direct non-medical costs constituted 21.13% (USD 489.48 per patient) of the total UC patients. Within these direct non-medical costs, transportation and accommodation costs represented the largest share, making up 15.13% (USD 350.44 per patient) of the direct non-medical costs. The costs associated with medical-related goods accounted for a relatively notable portion, 2.87% (USD 66.56 per patient) of the direct non-medical costs (Table 3).

Table 3.

Resource utilization and annual DNMC of UC by types of costs per patient in 2021 (US$)

Cost categories	Participants using resources, n (%)	Mean (SD)	% of total costs
Transportation & Accommodation	236(99.16)	350.44(420.70)	15.13
Home nursing services	63(26.47)	10.22(25.78)	0.44
Medical related goods	46(19.33)	66.56(263.23)	2.87
Paid household help	22(9.24)	62.25(267.50)	2.69
Total direct non-medical costs	236(99.16)	489.48(644.82)	21.13

UC Ulcerative colitis, DNMC Direct non-medical costs, SD Standard deviation

Indirect costs

Indirect costs made up a significant portion of the total costs, representing 29.03% (USD 672.68 per patient) of the overall costs for UC patients. The largest share of indirect costs was due to temporary absenteeism among patients, which accounted for 16.20% (USD 375.36 per patient), followed by temporary absenteeism among caregivers, which contributed 11.95% (USD 276.90 per patient). Costs associated with early retirement had a minimal impact, accounting for just 0.88% (USD 20.42 per patient) of the indirect costs (Table 4).

Table 4.

Resource utilization and annual ID of UC by types of costs per patient in 2021 (US$)

Cost categories	Participants using resources, n (%)	Mean (SD)	Percentage
Temporary absenteeism for patients	237(99.58)	375.36(439.31)	16.20
Temporary absenteeism for caregivers	217(91.18)	276.90(461.96)	11.95
Early retirement	5(2.10)	20.42(143.87)	0.88
Total Indirect costs	237(99.58)	672.68(810.52)	29.03

UC Ulcerative colitis, ID Indirect costs, SD Standard deviation

Total economic burden

The economic burden of UC per patient in the study population for 2021 was estimated to be USD 2,316.90. Direct medical costs constituted the largest share, making up 49.84% of the total economic burden, while indirect costs, primarily due to reduced productivity of patients, accounted for 29.03% of the overall economic cost. Direct non-medical costs represented the smallest portion, at 21.13% of the total economic burden of UC (Table 5).

Table 5.

Resource utilization and total economic costs of UC by types of costs per patient in 2021 (US$)

Cost categories	Participants using resources, n (%)	Mean (SD)	Percentage
Direct medical costs	238(100)	1154.75(853.75)	49.84
Direct non-medical costs	236(99.16)	489.48(644.82)	21.13
Indirect costs	237(99.58)	672.68(810.52)	29.03
Total economic costs	238(100)	2316.90(1420.71)	100

UC Ulcerative colitis, SD Standard deviation

Comparison of economic costs among UC patients

The average indirect and total costs for patients aged ≤ 20 were notably higher, amounting to USD 1438.62 and USD 2976.56, respectively, compared to other age groups (P < 0.05). Similarly, patients receiving ADA incurred significantly higher average direct medical costs (USD 1327.17) and total costs (USD 2456.58) than those treated with IFX (P < 0.05) (Table 6).

Table 6.

Comparison of economic costs among UC patients using Kruskal-Wallis tests and Mann-Whitney

Variables	DMC $	DNMC $	IC $	Total costs $
Total	Mean(95% CI)	Mean(95% CI)	Mean(95% CI)	Mean(95% CI)
Gender
Women	1084.61(924.48-1244.74)	496.26(367.37-625.15)	749.22(588.31-910.14)	2330.09(2057.79-2602.39)
Men	1222.57(1072.96-1372.18)	482.91(377.63-588.20)	598.67(466.44-730.89)	2304.15(2059.44-2548.86)
Age Group
≤20	1038.39(670.33-1406.45)	499.55(40.92-958.18)	1438.62(474.68-3351.93)*	2976.56(639.35-5313.77)*
21 – 40	1215.45(1064.83-1366.07)	474.96(383.03-566.88)	699.42(574.79-824.05)	2389.83(2170.45-2609.21)
41 – 60	1100.53(942.72-1258.34)	579.32(352.91-805.73)	603.33(411.24-795.41)	2283.18(1900.85-2665.50)
>60	816.61(588.72-1044.50)	345.63(71.53-619.74)	387.71(88.16-687.26)	1549.96(989.82-2110.10)
Marital status
Unmarried	1051.91(941.54-1162.28)	422.28(287.04-557.53)	585.40(384.24-786.57)	2059.59(1776.05-2343.13)
Married	1204.43(1054.69-1354.16)	535.05(428.89-641.21)	704.90(579.01-830.79)	2444.38(2210.36-2678.39)
Separated /widowed	967.73(606.51-1328.94)	149.48(22.52-276.45)	678.92(123.53-1234.32)	1796.13(1119.61-2472.66)
Occupation status
Homemakers	1029.77(898.29-1161.26)	523.69(366.44-680.95)	827.72(622.52-1032.92)	2381.19(2050.91-2711.46)
Disabled	1710.28(1106.70-2313.85)	273.15(687.46-1233.76)	330.29(724.67-1385.26)	2313.72(43.16-4670.60)
Retired	1096.78(710.38-1483.18)	471.73(152.10-791.36)	425.27(132.51-718.04)	1993.79(1221.53-2766.05)
Unemployed	1041.14(930.96-1151.31)	470.02(286.78-653.26)	623.36(417.26-829.46)	2134.52(1795.90-2473.14)
Student	1161.95(818.32-1505.58)	589.14(259.80-918.48)	767.24(103.70-1430.79)	2518.33(1697.74-3338.92)
Employed	1316.18(1050.67-1581.68)	463.91(319.39-608.44)	610.36(443.68-777.04)	2390.45(2051.68-2729.23)
Residential area
Village	1204.03(987.09-1420.96)	399.36(274.26-524.46)	734.10(515.30-952.89)	2337.48(1966.52-2708.44)
Urban	1141.64(1015.37-1267.92)	513.44(414.45-612.44)	656.35(538.05-774.64)	2311.43(2102.36-2520.50)
Education
Illiterate	1301.38(809.19-1793.58)	430.09(29.23-830.96)	510.91(197.38-824.44)	2242.39(1367.52-3117.25)
Less than 6 years	1438.37(979.41-1897.33)	587.06(250.49-923.62)	483.72(83.73-883.70)	2509.14(1692.36-3325.92)
6–12 years	1056.01(936.97-1175.05)	446.75(337.68-555.83)	772.98(608.77-937.18)	2275.74(2026.33-2525.16)
More than12 years	1188.35(1007.80-1368.89)	512.65(382.84-642.47)	628.15(478.56-777.73)	2329.15(2048.74-2609.55)
Complementary insurance
Yes	1193.57(968.04-1419.11)	519.98(350.60-689.35)	729.60(516.43-942.77)	2443.15(2061.42-2824.88)
No	1134.34(1015.70-1252.98)	473.44(383.35-563.53)	642.76(529.81-755.71)	2250.54(2057.09-2443.99)
Disease Duration
<=5	1197.32(1059.46-1335.18)	439.21(328.86-549.57)	761.29(564.33-958.25)	2397.82(2096.33-2699.31)
5 – 10	1044.24(927.62-1160.86)	440.40(287.43-593.36)	591.88(439.66-744.10)	2076.52(1795.96-2357.07)
11 – 15	1314.68(843.06-1786.30)	574.75(344.38-805.12)	582.92(367.98-797.86)	2472.35(1976.91-2967.80)
> 15	1072.66(892.89-1252.42)	609.11(351.44-866.79)	740.83(413.05-1068.62)	2422.60(1878.42-2966.78)
Use of tobacco products
Yes	1217.23(789.23-1645.23)	379.69(155.68-603.70)	341.35(241.02-441.69)	1938.27(1488.21-2388.33)
No	1144.69(1036.48-1252.90)	507.15(418.10-596.20)	726.02(608.36-843.68)	2377.85(2179.95-2575.75)
Primary drug
IFX	801.07(695.21-906.93) *	590.49(415.01-765.96)	638.83(478.00-799.66)	2030.39(1779.62-2281.16) *
ADA	1327.17(1180.00-1474.34)	440.23(352.05-528.42)	689.18(555.60-822.76)	2456.58(2217.24-2695.91)

DMC Direct medical costs, DNMC Direct non-medical costs, IC Indirect costs, CI Confidence interval, IFX  Infliximab, ADA Adalimumab, *Statisticvally significant

Discussion

This study prospectively assessed the economic burden of UC from a societal perspective in Iran, focusing on comparing the mean costs across different groups of UC patients receiving biologic therapies. To the best of our knowledge, it is the first research in Iran to comprehensively examine the economic impact of biologic treatments (IFX or ADA) for UC through a one-year patient follow-up, minimizing potential biases in data collection. This particular population is of significant interest, as it represents those with the most severe disease phenotypes, prolonged treatment durations, and a heightened risk of complications. Consequently, it imposes a substantial economic burden on the healthcare system.

Our findings indicate that the average annual total cost for UC patients was USD 2,316.90. This amount is notably higher than the costs reported in previous studies conducted in Iran [15, 16], primarily due to the inclusion of biologic therapies in this study, which are substantially more expensive than conventional medications. In contrast, most patients in earlier Iranian studies were treated with non-biologic drugs. On the other hand, cost estimates for UC in international studies were generally higher than those reported in our research [23–25]. However, due to significant fluctuations in the value of the Iranian Rial against foreign currencies, direct and meaningful cost comparisons are challenging. Additionally, differences in study perspectives and variations in healthcare utilization patterns among patients across countries may contribute to the observed discrepancies.

In this study, the mean annual direct medical costs per patient were USD 1,154.75, representing the largest proportion (49.84%) of the total expenses. This amount is considerably higher than those reported in previous Iranian studies [15, 16]. The main reason for this difference is the high costs associated with biologic medications used by patients in this study. Comparable figures have been reported internationally, with costs ranging from USD 6,217 to USD 11,477 in the United States and from €8,949 to €10,395 in Europe [26]. Biologic medications accounted for the largest share of expenses (38.04%), significantly surpassing the other cost categories. These findings emphasize the necessity for improved insurance coverage for biologic therapies to enhance its affordability. Beyond drug expenses, imaging costs (3.38%), physician visits (2.15%), and surgical procedures (2.06%) were the next most significant contributors. These results are consistent with the findings of many studies [16, 23, 24, 27], though they differ from a few others [15, 28]. Notably, the study also revealed that only a small proportion of participants accessed nutritional consultations or assessments. Considering the pivotal role of dietary support in the clinical management of UC patients [29, 30], it is strongly recommended to incorporate regular nutritional evaluation and monitoring into the care protocols for UC patients in Iran.

The mean annual direct non-medical costs per UC patient in this study were USD 489.48, accounting for 21.85% of the total costs. These findings revealed a notable difference compared to other studies [15, 16, 27]. The higher costs observed in our study can be attributed to the inclusion of patients with moderate to severe UC who have not responded to standard treatments. This likely resulted in more frequent visits to treatment clinics, thereby increasing direct non-medical expenses. In contrast, the comparison studies included a broader range of patients, from mild to severe cases. Furthermore, a higher percentage of rural residents in our study may have contributed to elevated non-medical costs, such as transportation and accommodation expenses.

We also evaluated productivity losses resulting from work absenteeism by both patients and caregivers, as well as early retirement. Our findings indicated that productivity losses due to disability accounted for 29.03% of the total costs associated with UC. This result aligns with previous studies, which reported productivity losses ranging from 16 to 49% [15, 16, 31, 32]. However, variations in methodologies used to assess productivity losses related to disability present limitations for making more detailed comparisons with the findings of other studies.

We also analyzed the influence of demographic and clinical variables on the costs incurred by UC patients. Our findings showed that the indirect and total costs for UC patients under the age of 20 were significantly higher compared to other age groups. This is consistent with results reported by Kappelman et al. in a study conducted in the United States [24]. The significantly higher indirect and total costs for UC patients under the age of 20 may be attributed to factors such as increased caregiver dependency, educational disruptions, and the potential for more severe disease progression requiring intensive medical interventions. Additionally, early-onset UC might be associated with more severe disease activity, leading to increased healthcare utilization and, consequently, higher total costs. Our analysis revealed that the patients using ADA incurred significantly higher direct medical and total costs compared to those using IFX. In contrast, Lawton et al. found no significant cost difference between patients treated with IFX and ADA [33]. Further studies similar to ours are needed in other regions of the world to provide a clearer understanding of the costs associated with managing UC patients in diverse and specific settings. The strengths of this study lie in its one-year duration and the comprehensive data collection process, which combined electronic medical records with supplemental questionnaires. While differences in healthcare systems make it challenging to generalize our findings to other countries, they provide valuable insights into global trends in the era of biologic therapies.

Conclusion

Biologic medications were found to be the primary contributor to total costs. Expanding insurance coverage for these therapies is crucial to enhancing patients' affordability. Productivity losses resulting from absenteeism by both patients and caregivers, along with transportation and accommodation expenses, were significant components of the economic burden of UC in Iran.

Abbreviations

UC

Ulcerative colitis

IFX

Infliximab

ADA

Adalimumab

IBD

Inflammatory bowel disease

USD

United States Dollar

MoHME

Ministry of health and medical education

LPUGW

Lowest-paid unskilled government workers

Authors’ contributions

Conceptualization, Visualization, and Methodology: HK, FEFA, MSH. Supervision, and Project administration: HK, FEFA, MSH. Investigation: HK, MSH, MN. Writing, reviewing, and editing: HK, MSH, AM, MN, RT. Data curation, and Software: AGH, HK. All authors have reviewed and approved the final manuscript.

Funding

This article is derived from Hassan Karami’s PhD thesis and was financially supported by the Iran University of Medical Sciences (IUMS), Tehran, Iran (Grant number: 14606).

Data availability

The data underlying the findings of this study are available from the corresponding author upon reasonable request.

Declarations

Ethics approval and consent to participate

The ethical committee of Iran University of Medical Sciences approved this study (IR.IUMS.MEDICINE.REC.1398.222). The study was conducted in full compliance with the ethical principles outlined in the Declaration of Helsinki and adhered to all applicable national guidelines. Informed consent was obtained from all participants before their inclusion in the study.

Consent for publication

Not applicable.

Competing interests

The authors declare no competing interests.