Greenfeld D, Mickley D, Quinlan D M, Roloff P
Department of Psychiatry, Yale University School of Medicine, New Haven, Conn.
Am J Psychiatry. 1995 Jan;152(1):60-3. doi: 10.1176/ajp.152.1.60.
The literature on the prevalence and importance of hypokalemia in persons with eating disorders in contradictory and confusing. The authors investigated the frequency of hypokalemia and its relationship to symptoms in a group of outpatients with eating disorders.
Diagnostic evaluations and electrolyte studies were performed for 945 outpatients meeting the DSM-III-R criteria for eating disorders at the time of their intake evaluations at a suburban clinic for eating disorders.
Clinically significant hypokalemia was comparatively rare. A total of 43 subjects (4.6%) were hypokalemic; of these, seven (0.7% of all subjects) were borderline hypokalemic (serum potassium = 3.4 mmol/liter). The hypokalemic subjects had a significantly lower mean weight and body mass index at entry than the normokalemic subjects. Significantly more of the hypokalemic subjects purged by abusing laxatives, either alone or with vomiting. The patients with restricting (nonpurging) anorexia nervosa, even those whose weights were very low, were generally normokalemic.
The low frequency of hypokalemia in this group of eating disordered outpatients suggests that routine electrolyte determination is a poor screening tool for occult or denied bulimia. Hypokalemia occurred almost invariably in lower-weight bulimic (or anorectic/bulimic) patients who were vomiting and/or abusing laxatives. Indeed, the study suggests that hypokalemia in a patient with an eating disorder is virtually certain evidence that the patient is purging at least daily. In addition, it appears that a patient with purely restricting anorexia nervosa is not at risk for hypokalemia even if his or her weight is very low.
关于饮食失调患者低钾血症的患病率及其重要性的文献相互矛盾且令人困惑。作者调查了一组饮食失调门诊患者中低钾血症的发生率及其与症状的关系。
对一家郊区饮食失调诊所945名在入院评估时符合DSM-III-R饮食失调标准的门诊患者进行了诊断评估和电解质研究。
具有临床意义的低钾血症相对少见。共有43名受试者（4.6%）存在低钾血症；其中7名（占所有受试者的0.7%）为临界低钾血症（血清钾 = 3.4 mmol/升）。低钾血症受试者入院时的平均体重和体重指数明显低于血钾正常的受试者。明显更多的低钾血症受试者单独或与呕吐一起滥用泻药进行清除行为。患有单纯性（非清除型）神经性厌食症的患者，即使体重很低，一般血钾也正常。
这组饮食失调门诊患者中低钾血症的发生率较低，这表明常规电解质测定对于隐匿性或否认的贪食症来说是一种较差的筛查工具。低钾血症几乎总是发生在体重较低且有呕吐和/或滥用泻药行为的贪食症（或厌食症/贪食症混合型）患者中。事实上，该研究表明饮食失调患者出现低钾血症几乎可以肯定证明该患者至少每天都在进行清除行为。此外，似乎患有单纯性神经性厌食症的患者即使体重很低也没有低钾血症的风险。
