Predicting proteinuria in hypertensive pregnancies with urinary protein-creatinine or calcium-creatinine ratio.

OBJECTIVE: Evaluate the value of random urinary protein-creatinine (PrCr) and calcium-creatinine (CaCr) ratios to predict 24-h proteinuria in hypertensive pregnancies. STUDY DESIGN: Spot urine samples were collected before routine 24-h urine collections from consecutive pregnant women with hypertension (n=83). Reliability of spot urinary PrCr and CaCr to detect significant proteinuria (>or=300 mg/day) using 24-h urine protein as 'gold-standard' was assessed by receiver-operating characteristic (ROC) curve. RESULTS: Fifty-one patients (61.4%) had significant proteinuria (45 pre-eclampsia, 5 superimposed pre-eclampsia, 1 renal hypertension). Area under ROC curve to predict proteinuria was 0.82 (95% confidence interval (CI) 0.73 to 0.92, P<0.001) for PrCr and 0.55 (95% CI 0.43 to 0.68, P=0.2) for CaCr. A cutoff value of >0.19 for PrCr best predicted significant proteinuria with sensitivity, specificity, positive and negative predictive values and likelihood ratios (positive and negative), respectively, of 80.4, 68.8, 80.4, 68.8%, 2.57 and 3.51. CONCLUSION: Spot urinary PrCr predicts total urinary protein excretion in hypertensive pregnancies.

Plasma N terminal pro-brain natriuretic peptide levels and its determinants in a multi-ethnic population.

This study documents the determinants and plasma levels of N-terminal pro-brain natriuretic peptide (NT-proBNP) among hypertensive and normotensive subjects in a multi-ethnic population in the United Arab Emirates (UAE). We obtained demographic, anthropometric and clinical data, together with fasting NT-proBNP and biochemical indices from 128 hypertensive patients and 138 normotensive subjects matched for age, gender and ethnicity. Plasma NT-proBNP levels were significantly (P<0.001), and several-fold higher among hypertensives (median 5.92, inter quartile range (IQR): 1.79-18.48 pmol/l) than normotensives (median 1.78, IQR: 0.59-4.32 pmol/l) in the total study population, and the same was true for the ethnic groups separately. Similarly, plasma levels of glucose, blood urea nitrogen (BUN) and creatinine, but not insulin, were significantly (P<0.05) higher among hypertensives than normotensives. For all subjects combined, log NT-proBNP correlated positively and significantly with age (P<0.01), log glucose (P<0.05), systolic blood pressure (SBP, P<0.001), log BUN (P<0.001) and log creatinine (P<0.001). Multivariate regression analysis showed that NT-proBNP levels were independently and positively correlated with SBP, age, gender, log BUN, Emirati and South East Asian ethnic groups and inversely associated with current exercise. In conclusion, we found circulating levels of NT-proBNP to be significantly increased in hypertensive versus normotensive subjects in the UAE and independently related to SBP, age, gender, indices of renal function and possibly exercise. Our results further suggest a possible modulating effect of ethnicity on NT-proBNP levels.

Natriuretic peptide and adrenomedullin levels in chronic renal failure and effects of peritoneal dialysis.

Plasma levels of B-type natriuretic peptide (BNP) and its N-terminal propeptide (NT-BNP) are elevated in renal impairment and provide a robust prognostic index. The effect of peritoneal dialysis on plasma NT-BNP, however, is unknown. Furthermore, no information exists regarding levels of the N-terminal propeptide for C-type natriuretic peptide (NT-CNP) in renal failure and the effects of peritoneal dialysis. Accordingly, we documented venous levels of these peptides, and adrenomedullin, across peritoneal dialysis. We measured venous BNP, NT-BNP, NT-CNP, adrenomedullin, blood urea nitrogen (BUN) and creatinine before, during and after completion of overnight peritoneal dialysis in 11 patients, and identical sampling was carried out in eight patients (controls) but between peritoneal dialysis treatments. Peptide levels were measured using well-validated, published methods. Baseline levels of NT-CNP (212, 150-303 pmol/l, median and 25th and 75th percentiles) were much higher than recorded previously in healthy volunteers or in heart failure, and correlated with plasma creatinine (rs=0.53, P<0.05). Peritoneal dialysis had no effect on plasma NT-CNP, nor on NT-BNP, BNP or adrenomedullin (all elevated above normal), whereas both BUN and creatinine levels, as expected, declined (P<0.001). We conclude that plasma levels of NT-CNP are grossly elevated in chronic renal failure and correlated with plasma creatinine, but are not altered by peritoneal dialysis. Likewise, BNP, NT-BNP and adrenomedullin are elevated but are not altered by peritoneal dialysis. This information is needed if levels of these hormones are to be used as prognostic indicators or as a guide to the management of patients with chronic renal failure.