The benefits of estrogen or selective estrogen receptor modulator on kidney and its related disease-chronic kidney disease-mineral and bone disorder: osteoporosis.
An umbrella concept addressing the relationship between chronic kidney disease (CKD) and mineral and bone disorders has been developed in recent years. Given the high prevalence of osteoporosis-related fractures in postmenopausal women with CKD, especially those undergoing chronic hemodialysis, the strategy used in the prevention and management of CKD and its associated osteoporosis in these postmenopausal women has become a topic of substantial debate. This controversy has ongoing relevance because osteoporosis results in a significant economic burden secondary to increased morbidity and mortality. The perfect goal of treatment and prevention includes both bone protection and renal protection, or at least protection of one disease without compromising the other disease. Both CKD and osteoporosis are frequently observed in the same patients, and often have parallel progression in postmenopausal women. Estrogen, the main female hormone during reproductive age, has been reported to have a protective effect on kidney fibrosis in several animal models, and is also considered one of the most effective drugs in the management of postmenopausal women with osteoporosis and prevention of osteoporosis. However, due to the many adverse events associated with the use of estrogen with and without progestin, some of which have contributed to significant morbidity and mortality, drug modification, which has had fewer reported incidences of adverse events without compromising the protective effect on both the kidney and bone, may have an easier road to acceptance. Therapeutic alternatives, such as the selective estrogen receptor modulators (SERMs), have shown the benefits of estrogen on bone, serum lipid levels, and renal protection, without any adverse effects on the breast and endometrium. The Multiple Outcomes of Raloxifene Evaluation trial (MORE) and its extension-Continuing Outcomes Relevant to Evista (CORE), a double-blind, randomized clinical trial encompassing postmenopausal women with osteoporosis, showed promising results in both bone and renal studies. Raloxifene increased bone mineral density (BMD) in the spine and femoral neck and reduced the risk of vertebral fracture. In addition, raloxifene slowed the increase in the rate of serum creatinine and also significantly slowed the decrease in the estimated glomerular filtration rate; of most importance, raloxifene use was associated with significantly fewer kidney-related adverse events. Hemodialyzed women on raloxifene treatment demonstrated increased trabecular BMD, a decrease in bone resorption markers, and a decrease in the low-density lipoprotein-cholesterol value. Thus, raloxifene and, most likely, other SERMs could be better in place of estrogen in the management of postmenopausal women with CKD and its associated osteoporosis, although much evidence should be provided in the advanced-stage CKD, especially in the Stage 5 CKD patients on dialysis.