DISCUSSION
Osteoporosis is considered to be the one of the leading health care problem and hence with our ageing population the prevalence and cost of osteoporosis is increasing [43]. Osteoporosis is a common skeletal disease characterized by bone mass reduction and bone micro architecture deterioration including bone fragility and high risk of fractures. Osteoporosis is diagnosed using several tests such as calcium test, vitamin D test and DEXA scan. Among these tests calcium and vitamin D tests are easily affordable however Dual Energy X-rays Absorptiometry (DEXA) scan is not affordable for majority of patients particularly in Pakistan. Furthermore DEXA scan and vitamin D tests are performed following the treatment duration of three months to check whether the treatment strategy is efficacious or not. Among the treatment strategies non-pharmacological treatment as well as pharmacological treatment is available for osteoporosis.
Non-pharmacological treatment includes the life style modifications, tobacco use and excessive use of alcohol and caffeine should be discouraged, promotes intake of balance diet with calcium and vitamin D, regular physical exercise and preventing minor accidents like fall, etc.
Pharmacological treatment of osteoporosis include anti-resorptive agents such as bisphosphonates (Alendronate, Alendronate plus D, Risedronate and Zoledronic acid ), estrogen, calcium and vitamin D supplements, calcitonin and selective estrogen receptor modulators (Raloxifene) and bone anabolic agents including recombinant human Para-thyroid Hormone (rhPTH).
In current study among 120 patients 69% patients were treated with bisphosphonates and 31% were treated with rhPTH. However more significant increase in Bone Mineral Density was observed in patients using Para-thyroid hormone. Lumber spine BMD was greatly increased in patients using Para-thyroid hormone as compared with the patients using bisphosphonate. In the first year of treatment rhPTH increase BMD by 8-9%, while bisphosphonates and estrogen therapy increase BMD 3-5% during the same time period. The results are comparable with the study conducted by Shen.L (2011) who reported that Parathyroid hormone therapy show areal BMD than therapy with bisphosphonnates. His result showed that as compared to treatment with bisphosphonates lumbar spine BMD increase significantly by use of PTH. Duration and dose dependent increase in hip BMD as compared to bisphosphonates treatment is induced by PTH. Distal radius BMD was significantly lower by treatment with PTH as compared to alendronate.
Bisphosphonates (the anti-resoptive agents) include the drugs etidronate, tiludronate, alendronate, and risedronate, etc. Among them the first generation bisphosphonate i.e.; etidronate (20mg/kg daily for 2 weeks followed by 10mg/kg for 10 weeks, a total of 12 weeks followed by 11 to 13 weeks of calcium supplementation) somehow decrease the rate of vertebral fractures but its long term use lead to prolong bisphosphonates retention and impaired mineralization thus causing adverse effects. Tiludronate (400mg daily oral dose for 3 months), alendronate (10mg once daily or 70mg once weekly and could be used upto 10 years however can be withdrawn after 5 years in some women), and risedronate (5mg once daily taken orally for up to7 years), Ibendronate (100-150mg every 3 months) that are the second and third generation bisphosphonates are much more potent and have greater therapeutic window then etidronate. Etidronate (Disodium); 400mg in a packing of 10s costs for about 290 Rs, Alendronadte(Na); 70mg with a packing of 10s is available in the cost for about 1500 Rs, Risedronate(Na); 35mg in packing of 4s price ranges from 400-700 Rs. Ibendronate; 150mg comes in price of about 400 Rs (Table.3).
Recombinant human Para-thyroid Hormone (the anabolic agent) include teriparatide with the brand name; Forteo is given as a subcutaneous injection in thigh or abdominal wall, in a dose of 20-mcg daily in a 2.4-ml prefilled delivery device and should not be used for more than 2 years. Price of one Forteo injection 20mcg in Pakistan is about 27000 Rs, which makes it unaffordable for majority of the osteoporotic patients.
In the current studies it has been observed that risks of vertebral fractures are reduced by long term use of bisphosphonates as compared to those patients who withdrew bisphosphonate therapy earlier. In a previous study conducted by Robert A. Adler (2016) showed that post-menopausal women receiving alendronate for 10 years had fewer clinical vertebral fractures than those who after 5 years were switched to placebo. Whereas few morphometric vertebral fractures were found in women who received zoledronic acid’s 6 annual infusions as compared to those who after 3 years were shifted to placebo.
In our study we found rhPTH to be more effective in improving bone architecture and reducing the risk of osteoporosis associated fractures when analyzed in comparison to bisphosphonates. Whereas in a previous study conducted by Hodsman.A (2005) reported fracture risks are significantly reduced by bone mineral architecture improvement as well as overall bone mass enhancement by use of teriperatide. In patients with severe osteoporosis for prevention of fractures PTH should be considered as an alternative therapy to existing anti-resorptive agents. In improving BMD of lumbar spine teriperatide is superior to anti-resorptive therapy (alendronate).
As we have compared bisphosphonates and rhPTH in curing osteoporosis or osteoporotic fractures we find rhPTH to be more efficacious then bisphosphonates but unfortunately due to high cost of rhPTH therapy in Pakistan patients does not afford rhPTH therapy and physician prefer prescribing bisphosphonates keeping in view patient’s affordability, as a result of which bisphosphonates are more recommended and prescribed in Pakistan.