| Objective and background:Primary aldosteronism (primary aldosteronism, PA) is due to adrenal cortical lesions, resulting in increased secretion of aldosterone and renin-angiotensin system (RAS) inhibition, demonstrated with high levels of plasma aldosterone and low plasma renin activity. It’s clinical manifestations is of hypertension with or without hypokalemia. The syndrome is one of the common causes of secondary hypertension. Its clinical manifestation is characterized with polydipsia, polyuria, nocturia, hypertension, hypokalemia, high urinary potassium, hyperlipidemia, high plasma aldosterone level and low plasma renin activity. The syndrome includs aldosterone-producing adenoma (APA) and idiopathic hyperaldosteronism (IHA) majorly.To know primary aldosteronism is a continous process. It was realized that primary aldosteronism is relatively rare, accounting for less than2%of patients with hypertension. Since aldosterone renin activity ratio (ARR) has been used to screened out the APA from the hypertensive patients successfully, ARR has gradually become a commonly used indicator to screen primary aldosteronism. The incidence and clinical features of primary aldosteronism has been realized again. The primary aldosteronism accounts for about10%of the hypertensive population, up to20%in patients with resistant hypertension.PA and primary hypertension(PH) have the main clinical manifestations of high blood pressure, and part of the PA is not associated with hypokalemia. However,the treatment and prognosis of PA and PH are diffrent completely. The treatment of PA rely mainly on surgery, part of the PA patients can be cured by surgery. While the etiology of PH has not been fully understood, the current treatment of PH is of changing lifestyle and medicine treatment. Therefore, to screen PA patients from hypertensive patients is of great significance.But so far, due to the the ARR can be influenced by many factors, the ARR determination is lack of standardization. Its cut point can be from20ng· dl-1/ng· ml-1h-1to122ng· dl-1/ng· ml-1h-1. For improving the accuracy of screening,most of laboratories require standardization of the test of ARR. The standardizations are made up of standardizing the inspection process, unifieding diagnostic criteria and standardizing diagnostic conditons. Standardizations require unifing the time and patients position of testing, the conditions of the patients taking medicine. We found a considerable number of patients can not tolerate the standardization, especially withdrawal or change anti-hypertension medicine. It leads to standardize the patients be very difficult, and cause the waste of medical resources and time. It is rare in literature report that the effectiveness of plasma aldosterone renin ratio screen primary aldosteronism from hypertensive patients without drug washout period. We wish to provide an easy, simple and affordable method that the patients can toletate well. At the same time, we wish to provide a detection methods of clinical laboratory basis for clinical diagnosis of primary aldosteronism. Materials and Methods:We use a retrospective study, diagnostic testing methods. We postoperatively study279cases of primary aldosteronism (PA) that confirmed by pathology evidence and70cases of primary hypertensions(PA) that selected randomly in the same period. All the patients plasma aldosterone renin activity ratio (ARR) were measured. As the range of10, the patiens were divided into11groups. During the measurement of the ARR, patients should maintain a normal sodium intake, and take supinal position at least8hrs in the night. At7:00of the next day, we collect the patients venous blood sample as they keep supinal position, then measured supinal PRA and ALD. Calculate the PA and PH number of cases of each group and the ARR value of diagnostic PA sensitivity, specificity and Youden index, then draw the ROC curve.Results:1. In the PA group,the patients with low plasma aldosterone level,normal plasmaaldosterone leve and high plasma aldosterone leve were7cases (2.51%),156cases (55.91%) and116cases (41.58%), respectively.2. In the PA group, the patients with low plasma renin activity level, normal plasma renin activity level and high plasma renin activity level were26cases (9.32%),225cases (80.64%) and28cases (10.04%), respectively.3. In the PA group, the patients with low potassium level, normal potassium level and high potassium level were0cases,153cases (54.81%) and126cases (55.2%), respectively.4. The sensitivity, specificity and Youdon index of diagnosis of PA were83.2%,82.9%,0.661,77.8%,88.6%,0.664and74.2%,92.9%,0.671repectively when the ARR were within30～,40～,50～60ng· dL-1/ng· mL-1· h-1groups. While the Youden index of the rest of the group segment were low.5. The best cut point of the ROC curve that primary aldosteronism can be diagnosised located in ARRwith in the range of30to60ng· dL-１/ng· mL-1· h-1.6. There was a significant difference of the level of ALD, PRA and ARR between PA group (P<0.05). There was not a significant difference of the level of ALD, PRA and ARR between APA group and IHA group (P>0.05). Conclusion:1. To screen primary aldosteronism from the hypertensive patients without medicine washout period,as the ARR is between30and60ng· dL-1/ng· mL-1· h-1, the sensitivity, specificity and Youden index of diagnosis of primary aldosteronism is pretty high. The best cut point of the ROC curve is located within this interval.2. The Youdon index of diagnosis of primary aldosteronism is high when ARR between30and60ng·dL-1/ng·mL-1·h-1in our hospital. It can be used as a clinical indicator of screening primary aldosteronism from primary hypertension patients, but it can not differential APA and IHA effectively.3. Such a detection method is simple and can be accepted by the patients easily. It can save health care resources significantly. The method is worthy of promotion clinically. |
