Ibandronate vs. Alendronate for Osteoporosis

Cost-Effectiveness of Ibandronate vs. Alendronate used in treatment of osteoporosis, in a specialized clinic in Tirana.

Dr. Mirela Miraçi¹; Msc.Arlinda Demeti²; Prof.as Zamira Ylli³; Prof.Mira Ziçishti³;

Prof.As Suela Kelliçi¹

1. Faculty of Pharmacy, University of Medicine, Tirana.
2. Bioparafarmacia Franceze
3. Neostyle Clinic

Abstract: Osteoporosis is “a systemic skeletal disease with a high prevalence. Biphosphonates are medicaments which are chosen for their efficacy in reducing fracture incidence, increasing bone density and improving bone microarchitecture. The aim of the study is to evaluate the effectiveness of the drugs (ibandronate and alendronate) used in osteoporosis treatment, in post-menopausal women over the age of 50 years at a specialized clinic in Tirana; to calculate the annual cost of treatment of osteoporosis and to perform a cost effectiveness analyze.

Methods: Retrospective. The patients were all female, in menopause or post menopause, with T-score -1 to -6, treated with alendronate or ibandronate. The effectiveness is calculated as the average percentage of change in bone mineral density (av. % of change in BMD) of year 2011 vs. 2010 baseline. The annual cost of the treatment of osteoporosis according to the protocols and the cost of the examination with DXA scan (dual x-ray absorptiometry) were calculated. Finally a comparison of the cost-effectiveness was performed.

Conclusion: Patients with osteoporosis treated with Ibandronate, at our clinic in Tirana, have an average change from baseline higher compared with patients treated with Alendronate, with statistically significant difference between them (Man Whitney U = 66.0, p < 0.01).

The annual cost of the disease when treated with ibandronate is 1.3 times higher than the annual cost of treatment with alendronate. Ibandronate is more cost – effective than all other alendronate .

Introduction: Osteoporosis is “a systemic skeletal disease characterized by low bone mass and micro architectural deterioration of bone tissue, with a consequent increase in bone fragility and susceptibility to fractures” ⁽¹⁾

The World Health Organization defines osteoporosis as “bone density 2.5 standard deviations (SDs) below the mean for young white adult women at lumbar spine, femoral neck or forearm”. ⁽²⁾

Osteoporosis leads to nearly 9million fractures each year worldwide and over 300,000patients with fragility fractures are registered in UK hospitals each year (British Orthopaedic Association, 2007).⁽³⁾

Osteoporoza, është një sëmundje me një prevalencë të lartë edhe në Shqipëri (7.28% e popullatës dhe 9.6% tek femrat)⁴, e njëjtë me atë të hasur për astmën apo sëmundjet e zemrës; ……………..

Direct medical costs due to fragility fractures in UK healthcare economy were estimated at £1.8billion in 2000, with the potential to increase to £2.2billion by 2025 and the major part of these costs were related to hip fracture care. ⁽⁵⁾

The annual cost of osteoporosis and fractures in the US elderly was estimated at $16 billion⁽⁶⁾

Osteoporosis is diagnosed by a T-score, which is the number of standard deviation (SD) that patient’s bone mineral density (BMD), measured using dualX-ray absorptiometry, differs from the mean BMD of 30-years old premenopausal women. Patients with T-score of between -1 and -2.5 SD are said to have osteoporosis.^7,8

Biphosphonates are medicaments which are chosen for their efficacy in reducing fracture incidence, increasing bone density and improving bone microarchitecture.^9-15

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Methods: Retrospective. The patients were all female, in menopause or post menopause, 50 years old or elder, with T-score -1 to -6, diagnosed for the 1rst time in 2010 (the 1rst BMD measurement), who have received treatment (alendronate or ibandronate) for 12 months and in 2011 have performed a 2nd BMD measurement.

The effectiveness is calculated as the average percentage of change in bone mineral density (av.% of change in BMD) of year 2011 vs. 2010 baseline. It was calculated the annual cost of the treatment of osteoporosis according to the protocols: with once monthly 150 mg oral ibandronate plus supplements (calcium, vitamine D) and once weekly 70 mg alendronate (4 times per month) plus supplements (calcium, vitamine D). There are also included other direct costs such as the examination with DXA scan (dual x-ray absorptiometry) to determine the diagnosis and the medical visits. Finally a comparison of the cost-effectiveness will be performed.

Statistical Analysis

Data were analyzed with SPSS 20 statistical package. It is used the non-parametric Man Whitney U test to compare the continuous variables, Fisher Exact test was used to compare proportions between variables and the the Odds Ratio OR for assessing the association between variables. Point estimations are accompanied with interval estimation by 95 % CI. For continuous variables is presented the average, the standard deviation and the minimum and maximum values. The level of statistical significance is defined at α ≤ 005. Statistical tests are two-sided.duhet te shihet gjuha e perdorur, a qendron ne anglisht?

Results of the study

In our study were included 70 patients who fulfill the inclusion criteria. 24 patients were treated with once monthly 150 mg oral ibandronate and 46 patients with once weekly 70 mg alendronate.There were not case of fracture among our patients.

Table 1 compares the frequency of pathologies (osteopenia and osteoporosis) in two groups of patients treated with alendronat or ibandronat.

OR= 1.3 95%CI 0.5 – 4.2 p=0.4

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Number of patients treated with alendronate is 1.3 times higher than the number of patients treated with ibandronate in the case of osteoporosis. (OR = 1.3, 95% CI 0.5-4.2, p = 0.4).

Chart 1

Calculation of efficiency

We have to calculate the average percentage of change of BMD (2011) to baseline (2010):

Table2. In the group of Alandronate (N=46) we have found this data:

*Fisher exact test p=0.3

There are 46 patients treated with alendronate. 18 ( 39.1 %) (95% ; CI 29.7 – 52.1) of them suffer from osteoporosis and 28 ( 60.9 % ) (95 % CI 47.8 – 74.2) from osteopenia, with no statistically significant difference between them, p = 0.9

Grupmosha 60 – 69 vjeç ka 1.6 herë më tepër gjasa që të vuajnë nga Osteoporoza sesa grupmosha 50-59 vjeç, por pa ndryshim sinjifikant ndërmjet tyre (OR=1.6; 95%CI 0.4–6.7; p=0.4)

Grupmosha >70 vjeç ka 2.8 herë më tepër gjasa që të vuajnë nga osteoporoza sesa grupmosha 50-59 vjeç, por pa ndryshim sinjifikant ndërmjet tyre (OR=2.8; 95%CI 0.4–25.2; p=0.3)

Pacientet me Osteopeni kanë peshë mesatare më të lartë krahasuar me pacientët me Osteoporozë, me ndryshim statistikisht të rëndësishëm ndërmjet tyre (Man Whitney U=376.5, p=0.01)

Pacientët me Osteoporozë kanë të njëjtën gjatësi mesatare me pacientët me Osteopeni, pa ndryshim statistikisht të rëndesishëm ndërmjet tyre (Man Whitney U=304.5, p=0.3).

The change from baseline for Alendronate group

The change from baseline is calculated:

Table 3

Patients with osteopenia have an average change from baseline higher compared with patients with osteoporosis, no statistically significant difference between them (Man Whitney U = 316.0, p = 0.2).

Table 4. In the group of Ibandronate (N = 24) we have find this data:

*Fisher exact test p<0.05

There are 24 patients treated with Ibandronate. 14 (58.3%), (95% CI 33.2-76.5) of them suffer from osteoporosis and 10 (43.7%), (95% CI 23.4-61.7) of osteopenia, no statistically significant difference between them, p = 0.9.

Pacientët me Osteoporozë kanë një moshë mesatare më të lartë krahasuar me pacientët me Osteopeni, por pa ndryshim statistikisht të rëndësishëm ndërmjet tyre (Man Whitney U=39.5, p=0.07). Pacientët me Osteoporozë kanë të njejtën gjatësi mesatare me pacientet me Osteopeni, pa ndryshim statistikisht të rëndësishëm ndermjet tyre (Man Whitney U=71.0, p=0.9)

Grupmosha 60 – 69 vjeç ka 3.7 herë më tepër gjasa që të vuajë nga Osteoporoza sesa grupmosha 50-59 vjeç, por pa ndryshim sinjifikant ndërmjet tyre (OR=3.7; 95%CI 0.6–27.8; p=0.2).

Grupmosha >70 vjeç ka 13 herë më tepër gjasa që të vuajë nga osteoporoza sesa grupmosha 50-59 vjeç me ndryshim sinjifikant ndërmjet tyre (OR=13; 95%CI 0.5–33.0; p=0.03).

Pacientët me Osteopeni kanë peshë mesatare më të lartë krahasuar me pacientët me Osteoporozë, por pa ndryshim statistikisht të rëndësishëm ndërmjet tyre (Man Whitney U=90.5, p=0.2)

The change from baseline for Ibandronate group (N=24)

The change from baseline is calculated:

Table5

Patients with osteoporosis have an average change from baseline higher compared with patients with osteopenia, no statistically significant difference between them (Man Whitney U = 43.0, p = 0.1)

Comparison of change from baseline for patients with osteoporosis referring the two drugs.

Table 6.

Chart 2. The change from baseline for patients with osteoporosis

Pacientët me Osteoporozë të mjekuar me medikamentin Ibandronat kanë një ndryshim mesatar nga baseline më të lartë krahasuar me pacientet e mjekuar me Alendronat, me ndryshim statistikisht të rëndesishëm ndërmjet tyre (Man Whitney U=66.0, p<0.01).

Table 7. Percentages of the average change of BMD from baseline

Chart 3.

Nga figura rezulton se efikasiteti i medikamentit ibandronat (5.6) është dukshëm më i lartë se efikasiteti i medikamentit alendronat (1.8). Efikasiteti i medikamentit ibandronat tek pacientët me osteoporozë (7.3) është dukshëm më i lartë se efikasiteti i medikamentit alendronat (2.1). Efikasiteti i medikamentit ibandronat tek pacientët me osteoponi (3.3) është më i lartë se efikasiteti i medikamentit alendronat (1.7).

Cost analysis

We consider only direct costs such as: DXA scanner examinations, medical visits and medications costs (drugs and the supplements), according to a well-defined treatment protocol. In Albania, there is only one kind of ibandronate (only one brand) 150 mg / once a month, while there are lots of alendronate (different brands) 70 mg / 4 times per month, which we have called A1,A2,A3, A4,A5. We have calculated the costs of the only ibandronate and the costs of five types of alendronate, including the alendronate produced by a pharmaceuticals firm in the country, which has the lowest price in the market. In both cases the basic treatment is associated with calcium and vitamin D.

Table 8 Annual Cost of treatment and cost of examination

Table 9 Cost of illness according the type of medications

The annual cost of the disease when treated with ibandronate is 2.4 times higher than the annual cost of treatment with alendronate the alendronate produced by a pharmaceuticals firm in the country, which has the lowest price in the market, respectivly 537[1] euro versus 226 euro per patient in alendronate group.

Having all the annual costs and the efficiency for each drug, we can compare:

Table 10

Table11

The analyse of cost per efficiency unit (Table 10) shows that in the case of ibandronate the value obtained is 13.434 units and in alendronate “A1” case is 31.677 units.

Discussion of results

Patients with osteoporosis treated with Ibandronate, at our clinic in Tirana, have an average change from baseline higher compared with patients treated with Alendronate, with statistically significant difference between them (Man Whitney U = 66.0, p < 0.01). We find in the literature that once - monthly Ibandronate was shown to be clinically comparable to weekly alendronate at increasing BMD after 12 months in the lumbar spine and total hip¹⁶

The annual cost of the disease when treated with ibandronate is 1.3 times higher than the annual cost of treatment with alendronate “A1 and 2.4 times higher than the annual cost of treatment with the alendronate produced by a pharmaceuticals firm in the country, which has the lowest price in the market.

So as claimed, the cost for effectiveness unit is lower (about 2.3 times) in the case of ibandronate compared to alendronate “A1”. Well ibandronate results the most cost- effective. Ibandronate turns more cost – effective than all other alendronate including the alendronate produced by a pharmaceuticals firm in the country, which has the lowest price in the market