Wolf Peter, Beiglböck Hannes, Smaijs Sabina, Wrba Thomas, Rasoul-Rockenschaub Susanne, Marculescu Rodrig, Gessl Alois, Luger Anton, Winhofer Yvonne, Krebs Michael
1 Division of Endocrinology and Metabolism, Department of Internal Medicine III, Medical University of Vienna , Vienna, Austria .
2 IT Systems and Communications, Medical University of Vienna , Vienna, Austria .
Thyroid. 2017 May;27(5):611-615. doi: 10.1089/thy.2016.0597. Epub 2017 Apr 19.
Hypothyroidism is referred to be a rare but possible cause of hyponatremia. However, there is only poor evidence supporting this association. Since hyponatremia and hypothyroidism are both common conditions themselves, co-occurrence does not have to be causal.
To address a potential relationship, a retrospective analysis of data from the Division of Endocrinology of the Medical University of Vienna from April 2004 to February 2016 was performed. A total of 8053 hypothyroid patients (48 ± 18 years of age; 71% female) with thyrotropin >4.0 μIU/mL and available blood tests for free thyroxine and sodium (Na) within maximal ± seven days were included and screened for hyponatremia. Patients' records were searched for concomitant disease and medication when Na concentration was <135 mmol/L.
Hyponatremia was present in 448/8053 (5.56%) patients. Analysis of medical history revealed potential alternative causes of hyponatremia in 442/448 (98.88%) patients (i.e., side effects of medication, concomitant underlying disease, or other endocrine disorders). This distribution did not differ between patients suffering from clinical or subclinical hypothyroidism. No case of clinically relevant hyponatremia (Na < 130 mmol/L), present in 111/448 (24.78%) patients could be attributed only to hypothyroidism. There was a very weak but statistically significant trend toward a positive association between thyroid function and serum Na levels (Na/thyrotropin: R = 0.022, p = 0.046; Na/free thyroxine: R = -0.047, p < 0.001).
The results suggest that hypothyroid patients with moderate to severe hyponatremia often have other potential explanations for their low serum Na concentrations in routine care.
甲状腺功能减退被认为是低钠血症的一种罕见但可能的病因。然而，仅有不足的证据支持这种关联。由于低钠血症和甲状腺功能减退本身都是常见病症，二者同时出现不一定存在因果关系。
为探究潜在关系，对维也纳医科大学内分泌科2004年4月至2016年2月的数据进行了回顾性分析。纳入了8053例促甲状腺激素>4.0 μIU/mL且在最多±7天内有游离甲状腺素和钠（Na）血液检测结果的甲状腺功能减退患者（年龄48±18岁；71%为女性），并对其进行低钠血症筛查。当Na浓度<135 mmol/L时，在患者记录中查找合并疾病和用药情况。
448/8053（5.56%）例患者存在低钠血症。病史分析显示，442/448（98.88%）例患者存在低钠血症的潜在其他病因（即药物副作用、合并基础疾病或其他内分泌紊乱）。临床甲状腺功能减退或亚临床甲状腺功能减退患者之间的这种分布无差异。111/448（24.78%）例患者中存在的临床相关低钠血症（Na<130 mmol/L），没有一例可仅归因于甲状腺功能减退。甲状腺功能与血清Na水平之间存在非常微弱但具有统计学意义的正相关趋势（Na/促甲状腺激素：R = 0.022，p = 0.046；Na/游离甲状腺素：R = -0.047，p<0.001）。
结果表明，在常规治疗中，中度至重度低钠血症的甲状腺功能减退患者血清Na浓度降低往往有其他潜在原因。
