Estimates of patient population and data sources .Population-based incidence data were obtained from a central registry system in the Management Center for Transplantation and Special Diseases (MCTSD), affiliated to Ministry of Health (MOH) (
9). Prevalence data were not considered in this study. Tariffs and expenditure data of RTT and dialysis were extracted from insurance organizations` database. Regarding required probabilities, hospital-based registries, local clinical trials and national and international literature were reviewed.
Clinical data were obtained on the following key events: initial hospitalization for transplantation, immunosuppressive drug use, graft failure, acute rejection, delayed graft function, cytomegalovirus (CMV) infection and other important adverse events’ treatment.
Estimates on in-patient drug use, treatment duration and rate of rehospitalization were based on local standard protocol for RTT and dialysis, SSO and MSIO databases and hospital-based registries. Estimates on out-patient details of the immune suppressive regimen were obtained from Helal -e- Ahmar pharmacy records and SSO database.
According to MCTSD and database of insurance organizations, during the study year (2011- 2012), almost 17,000 patients were receiving RTT, out of which about 2,200 patients (aged between 18-70 years old) had their transplantation operation. There are two main semi-public hospitals in Tehran (capital city) performing renal transplantation which are in charge of almost half of the operations in the country (25% Baghiatollah Hospital and 25% Shahid Labbafinejad Teaching Hospitals).
Cost of initial hospitalization for transplantation
There is a global fixed tariff (GT) for transplantation provided by insurance organizations in both public and private hospitals with no co-payment or franchise for patients (except 10% for hospitalization in some hospitals). According to tariffs in the study year, a fixed amount of almost 39,000,000 IRR ($3,181US) was paid for each pair of operation (recipient and donor) for the whole hospitalization period (5 to 30 days). Total tariff was defined as 650 K, in which K was almost 60,000 IRR in the study year. Some drugs (e.g. ganciclovir) are not included in the GF. In some cases, real costs become greater than the compensation and patients should pay the difference as OOP. Considering the average annual number of patients having renal transplantation (2,200 patients), the total budget spent for initial hospitalization for transplantation was almost 86 billion IRR ($7,000,000).
Cost of immune suppressive agents
regarding maintenance therapy (MT) in RTT, the most costly and important immunosuppressive drugs are cyclosporine (CsA), mycophenolate mofetil (MMF) (
10), sirolimus (SRL) and tacrolimus. The mean CsA dose is 150 mg/d per patient and is available in three dosages (25, 50, 100 mg oral tablets); only the generic form is included in the insurers` formulary. The CsA cost was acquired from database of insurance organizations and calculated based on proportion of patients normally using different dosages (based on pharmacy records). Tacrolimous was usually used in patients who had their second or more transplantation (almost 10%) and the rest (90%) used CsA as the main immune surpressive agent. Rapamune
® (SRL) was only administered in special cases (less than 1%); however, it was not included in the analysis due to the fact that,over the study year, it did not have any insurance coverage (
Table 1).
| Maintenance Therapy | Dosage form | Dosage/day/ patient | Unit price (IRR) | Total cost/day /patient (IRR) | Nr. of Eligible patients | Duration (D.) | Total cost (IRR) | Total cost ($USD) |
|---|
| Cyclosporine (Generic) | Cap: 25, 100 ,50 mg | 150† mg qd | 300, 1200, 1500 | 5,167,800‡ | - | 365 | 1,886,247,000 | 153,854 |
| MycophenolateMofetil | Cap: 500 mg | 2 g qd | 11,000 | 44,000 | 2,200 | 365 | 35,332,000,000 | 2,881,892 |
| Prednisolone | Tab: 5 mg | 5mg/d qd | 130 | 130 | 2,200 | 365 | 104,390,000 | 8,515 |
| Tacrolimus | Tab: 0.5 mg | 0.2mg/Kg/d | 1,000 | 28,000 | 220§ | 365 | 2,248,400,000 | 183,393 |
| Total cost | | | | | | | 39,571,037,000 | 3,227,654 |
Cost of adverse events (AE) treatment major adverse events related to CsA-based regimens during 12 months posttransplantation are mainly acute rejection (18%) (
4), delayed graft function (17%) (
11), CMV infection (21%), graft failure (10.5%), thrombocytopenia (8%), hyperlipidemia (14%) (
12) and hypertension (67%) (
13-
17) Cost of each adverse event per patient and total cost of adverse events are summarized in
Tables 2 and
3.
| Adverse Events/ Treatment | Dosage form | Dosage/day/ patient | Nr. per day | Duration (D.) | Unit price (IRR) | Total cost /patient (IRR) | Total cost ($US) |
|---|
| CMV | | | | | | | |
| Ganciclovir | For inj: 500mg | For treatment: 5 mg/Kg q 12 hr until treatment | 2 | 7 | 250,000 | 3,500,000 | 285 |
| Hospitalization | | | | 7 | 1,600,000 | 11,200,000 | 914 |
| Acute Rejection | | | | | | | |
| Methylprednisolone | For inj: 500 mg | 250-1000 mg | 1 | 7 | 200,000 | 1,400,000 | 114 |
| ATG | Inj: 250mg/5mL | 10-20mg/Kg | 4 | 7 | 550,000 | 15,400,000 | 1,256 |
| Gancyclovir | For inj: 500mg | For prophylaxy: 5 mg/Kg q 24 hr until hospitalization | 1 | 7 | 250,000 | 1,750,000 | 143 |
| Hospitalization | | | | 7 | 1,600,000 | 11,200,000 | 914 |
| Graft Failure | | | | | | | |
| Dialysis | | | | 10 times | 743,200 | 7,432,000 | 606 |
| Re- transplantation | | | | | 650K§ | 39,000,000 | 3,181 |
| Delayed Graft Function | | | | | | |
| ATG | Inj: 250mg/5mL | 10-20mg/Kg | 4 | 10 | 550,000 | 22,000,000 | 1,794 |
| Gancyclovir | For inj: 500mg | For prophylaxy: 5 mg/Kg q 24 hr until hospitalization | 1 | 10 | 250,000 | 2,500,000 | 204 |
| Dialysis | | | | 3 times | 743,200 | 2,229,600 | 182 |
| Infections | | | | | | | |
| Co-trimoxsazole | Tab: 400/80mg | q.d. –b.i.d. | 2 | 180 | 210 | 75,600 | 6 |
| Cefazoline | For Inj: 1g | 3g | 3 | 2 | 6,000 | 36,000 | 3 |
| Nystatin | Tab: 500,000 U | t.i.d- q.i.d. | 4 | 180 | 450 | 324,000 | 26 |
| Fluconazole | Tab: 100mg | 100 mg | 1 | 180 | 1,200 | 216,000 | 18 |
| Hyperlipidemia | | | | | | | |
| Atorvastatin | Tab: 10, 20, 40 mg | 10-40 mg | 1 | 365 | 1,100 | 401,500 | 33 |
| Hypertension | | | | | | | |
| Amlodipin | Tab: 5 mg | 5-10 mg | 1 | 365 | 150 | 54,750 | 4 |
| Thrombocytopenia | | |
| Plasmapheresis | | | - | 10 times | 1,300,000 | 13,000,000 | 1,060 |
| Total | | | | | | 131,719,450 | 10,744 |
| Adverse Events | Probability | Unit cost per patient (IRR) * | Prob. Unit cost /patient | Total cost (IRR)(n = 2,200) | Total Cost ($US) |
|---|
| CMV | 0.21 | 14,700,000 | 3,087,000 | 6,791,400,000 | 553,948 |
| Other Infections | 1** | 651,600 | 651,600 | 1,433,520,000 | 116,927 |
| Delayed Graft Function | 0.17 | 26,729,600 | 4,544,032 | 9,996,870,400 | 815,405 |
| Acute Rejection | 0.18 | 29,750,000 | 5,355,000 | 11,781,000,000 | 960,930 |
| Hyperlipidemia | 0.14 | 401,500 | 56,210 | 123,662,000 | 10,087 |
| Hypertension | 0.67 | 54,750 | 36,683 | 80,701,500 | 6,583 |
| Graft Failure | 0.105 | 46,432,000 | 4,875,360 | 10,725,792,000 | 874,861 |
| Thrombocytopenia | 0.08 | 13,000,000 | 1,040,000 | 2,288,000,000 | 186,623 |
| Total cost | | | 19,645,885 | 43,220,945,900 | 3,525,363 |
Regarding CMV infection, ganciclovir was administered over a 7-day hospitalization with an average treatment dose of 5 mg/Kg every 12 hours. In the case of acute rejection episodes, Methylprednisolone (daily boluses of 250- 1000 mg), antithymocyte globulin (ATG) with a daily dose of 10- 20 mg/Kg and ganciclovir for CMV infection prophylaxis (5 mg/Kg every 24 hour over hospitalization duration) are administered in renal transplant recipients. ATG with quite similar dosage is also used in patients experiencing delayed graft function. Other adverse events along with their treatment details are explained in
Table 2. There are also miscellaneous medicines usually used after transplantation which are listed in
Table 4.
| Miscellaneous medicines | Dosage form | Dosage/patient | Nr. per day | Duration (D.) | Unit price (IRR) | Total cost /patient (IRR) | Nr. of eligible patients | Total cost (IRR) | Total cost ($US) |
|---|
| Calcitriol (Rocaltrol®) | Cap: 0.25 mcg | q.d. | 1 | 365 | 2300 | 839,500 | 2,200 | 1,846,900,000 | 150,644 |
| Ferrus Sulphate | Tab: 50 mg | q.d. | 1 | 365 | 55 | 20,075 | 2,200 | 44,165,000 | 3,602 |
| A.S.A | Tab: 80 mg | q.d. | 1 | 365 | 83 | 30,295 | 2,200 | 66,649,000 | 5,436 |
| Ranitidine | Tab: 150 mg | h.s. | 1 | 365 | 55 | 20,075 | 2,200 | 44,165,000 | 3,602 |
| Calcium Carbonate | Tab: 500 mg | q.d. | 1 | 365 | 155 | 56,575 | 2,200 | 124,465,000 | 10,152 |
| Total Cost | | | | | | | | 2,126,344,000 | 173,438 |
Analysis
The model was constructed using Microsoft Excel® 2010. The total cost included cost of initial hospitalization for transplantation, cost of immunosuppressive agents, cost of adverse events and miscellaneous medicines. Total cost was expressed in both Iranian Rials (IRR) and US dollars ($USD). According to the official exchange price in the study year, one USD was equal to 12,260 IRR.
Monte-Carlo simulation
In order to test the reliability of each individual AE probability used as the model input, a Monte-Carlo model was run, to simulate a random sampling of 2,200 patients out of total population.
The idea of the Monte-Carlo analysis is the generation of large number of (
e.g. 100 - 1000) synthetic datasets that are similar to the experimental dataset, but with different distributed noise. Each of these new datasets is analyzed, and the distributions are stored. The resulting set of distributions can then be studied, point by point, and the mean and probability contours could be calculated (
18,
19).