Tzoulis Ploutarchos, Yavropoulou Maria P
Department of Metabolism & Experimental Therapeutics, Division of Medicine, University College London Medical School, Gower Street, London, WC1E6BT, UK.
Department of Propaedeutic and Internal Medicine, Medical School of University of Athens, Endocrinology Unit, Athens, Attica, Greece.
Ther Adv Endocrinol Metab. 2023 Sep 18;14:20420188231197921. doi: 10.1177/20420188231197921. eCollection 2023.
Recent studies suggest a possible association of hyponatremia with osteoporosis, falls and bone fractures. The objectives of this narrative review were to further explore this association and the related pathophysiological mechanisms and to suggest a practical approach to patients with osteoporosis or chronic hyponatremia in clinical practice. We conducted an extensive PubMed search until October 2022 with the combination of the following keywords: 'hyponatremia' or 'sodium' or 'SIADH' and 'fractures' or 'bone' or 'osteoporosis', as MeSH Terms. Review of numerous observational studies confirms a significant independent association of, even mild, hyponatremia with two- to three-fold increase in the occurrence of bone fractures. Hyponatremia is a risk factor for osteoporosis with a predilection to affect the hip, while the magnitude of association depends on the severity and chronicity of hyponatremia. Chronic hyponatremia also increases the risk for falls by inducing gait instability and neurocognitive deficits. Besides the detrimental impact of hyponatremia on bone mineral density and risk of falls, it also induces changes in bone quality. Emerging evidence suggests that acute hyponatremia shifts bone turnover dynamics towards less bone formation, while hyponatremia correction increases bone formation. The key unanswered question whether treatment of hyponatremia could improve osteoporosis and lower fracture risk highlights the need for prospective studies, evaluating the impact of sodium normalization on bone metabolism and occurrence of fractures. Recommendations for clinical approach should include measurement of serum sodium in all individuals with fracture or osteoporosis. Also, hyponatremia, as an independent risk factor for fracture, should be taken into consideration when estimating the likelihood for future fragility fracture and in clinical decision-making about pharmacological therapy of osteoporosis. Until it is proven that normalization of sodium can lower fracture occurrence, correcting hyponatremia cannot be universally recommended on this basis, but should be decided on a case-by-case basis.
近期研究表明，低钠血症可能与骨质疏松症、跌倒及骨折有关。本叙述性综述的目的是进一步探讨这种关联及其相关的病理生理机制，并在临床实践中为骨质疏松症或慢性低钠血症患者提出一种实用的处理方法。我们在PubMed上进行了广泛检索，截至2022年10月，使用了以下关键词组合：“低钠血症”或“钠”或“抗利尿激素分泌失调综合征（SIADH）”以及“骨折”或“骨”或“骨质疏松症”作为医学主题词（MeSH Terms）。对大量观察性研究的回顾证实，即使是轻度低钠血症也与骨折发生率增加两到三倍存在显著的独立关联。低钠血症是骨质疏松症的一个危险因素，尤其易影响髋部，而这种关联的程度取决于低钠血症的严重程度和慢性程度。慢性低钠血症还会因导致步态不稳和神经认知缺陷而增加跌倒风险。除了低钠血症对骨密度和跌倒风险的有害影响外，它还会引起骨质量的变化。新出现的证据表明，急性低钠血症会使骨转换动态向骨形成减少的方向转变，而纠正低钠血症则会增加骨形成。关于低钠血症的治疗是否能改善骨质疏松症并降低骨折风险这一关键未决问题，凸显了进行前瞻性研究的必要性，以评估钠水平正常化对骨代谢和骨折发生情况的影响。临床处理的建议应包括对所有骨折或骨质疏松症患者测量血清钠。此外，在评估未来脆性骨折的可能性以及在骨质疏松症药物治疗的临床决策中，应将低钠血症作为骨折的独立危险因素加以考虑。在钠水平正常化可降低骨折发生率得到证实之前，不能普遍推荐基于此纠正低钠血症，而应逐案决定。
