Chinese normotensive and essential hypertensive reference intervals for plasma aldosterone and renin activity by liquid chromatography-tandem mass spectrometry.

OBJECTIVES: The renin-angiotensin-aldosterone system (RAAS) regulates blood pressure. Plasma renin activities (PRA) and plasma aldosterone concentrations (PAC) are biomarkers related to RAAS. Liquid chromatography-tandem mass spectrometry (LC-MS/MS)-based measurements for PRA and PAC have become popular. Method-specific reference intervals (RIs) are required. METHODS: Routine PRA and PAC services in a Hong Kong teaching hospital were based on LC-MS/MS methods. PRA and PAC RIs were developed for normotensive subjects and essential hypertensive (EH) patients. Healthy volunteers were recruited to establish normotensive RIs. PRA and PAC results of hypertensive patients with urine aldosterone tests for primary aldosteronism (PA) screening were retrieved from the laboratory information system. Patients without PA were included. Patients with secondary hypertension and patients on medications affecting the RAAS were excluded. The central 95% RIs were established based on the recommendations of the Clinical and Laboratory Standards Institute guideline C28-A3. RESULTS: PRA and PAC of 170 normotensive volunteers and 362 EH patients were analysed. There was no sex-specific difference in PRA and PAC for normotensive and EH reference subjects. Differences for PRA and PAC were noted between normotensive subjects aged below 45 and their older counterparts. However, such a difference was only identified for PRA but not PAC in EH patients. Age-specific RIs were established accordingly. CONCLUSIONS: This study presented age-specific LC-MS/MS RIs of PRA and PAC for both normotensive and EH populations for local Chinese in Hong Kong.

Serial monitoring of nutritional status in Chinese peritoneal dialysis patients by Subjective Global Assessment and comprehensive Malnutrition Inflammation Score.

AIM: The Malnutrition Inflammation Score (MIS) has been proposed for the assessment of nutritional status in peritoneal dialysis (PD) patients. The MIS and the Subjective Global Assessment (SGA) for serial monitoring of nutritional status in PD patients were compared. METHODS: The change in the MIS and SGA overall score of 59 PD patients (28 male) over 12 months was studied. Clinical factors relating to the discrepancy between the two instruments were explored. RESULTS: The average patient age was 55.8+/-9.7 years. Thirty of the 59 patients (50.8%) had exact agreement in the changed MIS and SGA scores. Cohen's kappa score was 0.274, indicating a modest degree of agreement. For the detection of deterioration in nutritional status and using the MIS as the reference measure, the SGA had a sensitivity of 61.9% and specificity of 86.8%; serum ferritin level was substantially higher in the ones whose SGA did not detect a deterioration in nutrition (1464.1+/-873.3 vs 800.5+/-561.6 pmol/L, P=0.046). For the detection of improvement in nutritional status, the SGA had a sensitivity of 45.8% and specificity of 82.9%; patients whose SGA did not detect an improvement in nutrition were dialyzed longer (53.8+/-35.3 vs 27.6+/-18.9 months, P=0.038), had higher total iron binding capacity (TIBC) (45.6+/-5.5 vs 38.2+/-8.1 micromol/L, P=0.015), had higher total Kt/V (2.02+/-0.36 vs 1.75+/-0.23, P=0.048) and higher normalized protein nitrogen appearance (1.16+/-0.25 vs 0.95+/-0.23 g/kg per day, P=0.048). CONCLUSION: The longitudinal changes in the MIS and SGA score have modest agreement with each other. However, PD patients with a longer duration of dialysis, higher serum ferritin, TIBC, total Kt/V or normalized protein nitrogen appearance tend to have discrepancies between the longitudinal changes in the MIS and SGA overall score.