Effect of Hypokalemia on Screening for Primary Aldosteronism

Context Primary aldosteronism (PA) is a common, underdiagnosed, and treatable cause of hypertension. Guidelines recommend testing for hypokalemia, but current practices and their impact are unknown. Objective To estimate the impact of hypokalemia on the results of PA screening in clinical practice. Methods We studied electronic health records for adults who received longitudinal care within a large, integrated health system between 2007 and 2017 and underwent paired blood aldosterone and renin testing. Patients were grouped based on concurrent blood potassium concentrations. Results We found that 2,940 (82%) of the 3,571 patients screened for PA had concurrent potassium testing. Among all patients with a negative PA screen, 18% of patients did not have concurrent potassium testing and 14% of those tested were hypokalemic. Of the screen-negative hypokalemic patients, 77% were not retested. Among patients with repeated screens, we found that initial potassium concentration was a predictor of PA screen positivity on repeat. A one standard deviation lower initial potassium concentration was associated with a 74% higher odds of screen positivity on repeat, independent of initial aldosterone and renin results. Conclusions In-practice clinical data demonstrate that unrecognized and uncorrected hypokalemia contributes to the underdiagnosis of PA. Universal potassium testing and rescreening for PA in the setting of hypokalemia would likely substantially improve the identification and thereby management of PA. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement This work was supported by Grant 2019084 from the Doris Duke Charitable Foundation. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: Institutional Review Board of the University of Pennsylvania gave ethical approval for this work. I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable. Yes Restrictions apply to the availability of some or all data generated or analyzed during this study to preserve patient confidentiality. The corresponding author will on request detail the restrictions and any conditions under which access to some data may be provided.