Association of urinary sodium and potassium excretion with blood pressure.

BACKGROUND: Higher levels of sodium intake are reported to be associated with higher blood pressure. Whether this relationship varies according to levels of sodium or potassium intake and in different populations is unknown. METHODS: We studied 102,216 adults from 18 countries. Estimates of 24-hour sodium and potassium excretion were made from a single fasting morning urine specimen and were used as surrogates for intake. We assessed the relationship between electrolyte excretion and blood pressure, as measured with an automated device. RESULTS: Regression analyses showed increments of 2.11 mm Hg in systolic blood pressure and 0.78 mm Hg in diastolic blood pressure for each 1-g increment in estimated sodium excretion. The slope of this association was steeper with higher sodium intake (an increment of 2.58 mm Hg in systolic blood pressure per gram for sodium excretion >5 g per day, 1.74 mm Hg per gram for 3 to 5 g per day, and 0.74 mm Hg per gram for <3 g per day; P<0.001 for interaction). The slope of association was steeper for persons with hypertension (2.49 mm Hg per gram) than for those without hypertension (1.30 mm Hg per gram, P<0.001 for interaction) and was steeper with increased age (2.97 mm Hg per gram at >55 years of age, 2.43 mm Hg per gram at 45 to 55 years of age, and 1.96 mm Hg per gram at <45 years of age; P<0.001 for interaction). Potassium excretion was inversely associated with systolic blood pressure, with a steeper slope of association for persons with hypertension than for those without it (P<0.001) and a steeper slope with increased age (P<0.001). CONCLUSIONS: In this study, the association of estimated intake of sodium and potassium, as determined from measurements of excretion of these cations, with blood pressure was nonlinear and was most pronounced in persons consuming high-sodium diets, persons with hypertension, and older persons. (Funded by the Heart and Stroke Foundation of Ontario and others.).

Urinary sodium and potassium excretion, mortality, and cardiovascular events.

BACKGROUND: The optimal range of sodium intake for cardiovascular health is controversial. METHODS: We obtained morning fasting urine samples from 101,945 persons in 17 countries and estimated 24-hour sodium and potassium excretion (used as a surrogate for intake). We examined the association between estimated urinary sodium and potassium excretion and the composite outcome of death and major cardiovascular events. RESULTS: The mean estimated sodium and potassium excretion was 4.93 g per day and 2.12 g per day, respectively. With a mean follow-up of 3.7 years, the composite outcome occurred in 3317 participants (3.3%). As compared with an estimated sodium excretion of 4.00 to 5.99 g per day (reference range), a higher estimated sodium excretion (≥ 7.00 g per day) was associated with an increased risk of the composite outcome (odds ratio, 1.15; 95% confidence interval [CI], 1.02 to 1.30), as well as increased risks of death and major cardiovascular events considered separately. The association between a high estimated sodium excretion and the composite outcome was strongest among participants with hypertension (P=0.02 for interaction), with an increased risk at an estimated sodium excretion of 6.00 g or more per day. As compared with the reference range, an estimated sodium excretion that was below 3.00 g per day was also associated with an increased risk of the composite outcome (odds ratio, 1.27; 95% CI, 1.12 to 1.44). As compared with an estimated potassium excretion that was less than 1.50 g per day, higher potassium excretion was associated with a reduced risk of the composite outcome. CONCLUSIONS: In this study in which sodium intake was estimated on the basis of measured urinary excretion, an estimated sodium intake between 3 g per day and 6 g per day was associated with a lower risk of death and cardiovascular events than was either a higher or lower estimated level of intake. As compared with an estimated potassium excretion that was less than 1.50 g per day, higher potassium excretion was associated with a lower risk of death and cardiovascular events. (Funded by the Population Health Research Institute and others.).

Evaluation of serum vitamin B12 levels and its correlation with anti-thyroperoxidase antibody in patients with autoimmune thyroid disorders.

Vitamin B12 deficiency has been reported in patients with Autoimmune thyroid disorders. However there is limited data on exact prevalence of low B12 and its correlation with anti-thyroperoxidase antibody (anti-TPO) levels in these patients. The aim of our study was to estimate serum vitamin B12 levels in autoimmune thyroid disorders and to correlate B12 levels with anti-TPO. 350 patients were selected by convenient sampling. Vitamin B12 levels and thyroid parameters were estimated using fully automated chemiluminescence method on Access 2. Results of our study shows that using the manufacturer's cut-off of 145 pg/mL, the prevalence of low serum vitamin B12 was found to be 45.50 %. Higher prevalence (55 %) was seen based on the published cut-off of 200 pg/mL The study however did not demonstrate any significant correlation between vitamin B12 levels and anti-TPO (r = -0.11 and p value of 0.30).

A Study to Evaluate Lipid Profile in Treatment Naïve HIV Positive Patients.

HIV infection is associated with lipid abnormalities in treatment naïve patients. CD4 count is used for monitoring the HIV infection. Primary objective was to evaluate and correlate lipid profile and CD4 counts in HIV infection. Secondary objective was to evaluate the feasibility of using Lipid profile to monitor the HIV infected treatment naïve patients instead of CD4 counts. 112 patients were selected based on a criteria from ART center in tertiary care center. CD4 counts were assessed and Lipid profile was evaluated enzymatically. A correlation study was done between the lipid profile and the CD4 count and clinical stages of infection. Cholesterol showed no significant correlation in any stage. HDL-C showed significant correlation (p < 0.05) with stage 2 and 4 disease. LDL-C showed no significant correlation in any stage. TGL showed significant correlation (p < 0.05) at stage 4 disease. Hence, HDL-C and TGL can be used as indicators of lipid status and for infection progression in treatment naive HIV patients, while Cholesterol and LDL-C has no role to play.

Usefulness of lipase / amylase ratio in acute pancreatitis in South Indian population.

This retrospective study was conducted to assess the serum lipase / amylase ratio in acute pancreatitis for South Indian population attending the clinics of Gastroenterology and Emergency medicine in the last five years. One thousand one hundred and thirty two patients (768 males and 364 females) with acute pancreatitis (AP) were selected for the study. The diagnosis of AP was based on clinical evaluation, Computed Tomography (CT) findings and biochemical parameters such as serum lipase and amylase. Based on the etiology, the groups were divided into alcoholic, biliary and miscellaneous AP. Based on CT findings, groups were divided into mild, moderate and severe AP. Serum lipase, amylase and lipase / amylase ratio were calculated and statistically analyzed. Serum lipase levels in alcoholic group (3226.3 ± 1384.7) were significantly lower in comparison to biliary (6064.5 ± 1640.8) group though the levels were not significantly different from miscellaneous group (2132.3 ± 1210). Serum amylase values were significantly lower in alcoholic group (923.4 ± 557.5) in comparison to biliary (1736.2 ± 390.7) and there was significant difference between alcoholic and miscellaneous group (535.8 ± 477.6). The serum lipase / amylase ratio > 4 occurred in alcoholic group than with biliary and miscellaneous group. The sensitivity and specificity to predict alcoholic AP with lipase / amylase ratio at >4.0 was 84 % and 59 % respectively. In conclusion the serum lipase to amylase ratio greater than 3.0 could be used to differentiate but keeping the cut off at 4.0 would be of higher sensitivity without much change in specificity. The serum lipase to amylase ratio with a cut off of 3.0 or greater is not useful to differentiate the severe AP from milder AP. Hence, serum amylase and lipase are important for evaluation of pancreatitis though it is not a gold standard for the diagnosis or assessment of severity of acute pancreatitis.

Validation and comparison of three formulae to estimate sodium and potassium excretion from a single morning fasting urine compared to 24-h measures in 11 countries.

BACKGROUND AND OBJECTIVES: Although 24-h urinary measure to estimate sodium and potassium excretion is the gold standard, it is not practical for large studies. We compared estimates of 24-h sodium and potassium excretion from a single morning fasting urine (MFU) using three different formulae in healthy individuals. METHODS: We studied 1083 individuals aged 35-70 years from the general population in 11 countries. A 24-h urine and MFU specimen were obtained from each individual. A subset of 448 individuals repeated the measures after 30-90 days. The Kawasaki, Tanaka, and INTERSALT formulae were used to estimate urinary excretion from a MFU specimen. RESULTS: The intraclass correlation coefficient (ICC) between estimated and measured sodium excretion was higher with Kawasaki (0.71; 95% confidence interval, CI: 0.65-0.76) compared with INTERSALT (0.49; 95% CI: 0.29-0.62) and Tanaka (0.54; 95% CI: 0.42-0.62) formulae (P <0.001). For potassium, the ICC was higher with the Kawasaki (0.55; 95% CI: 0.31-0.69) than the Tanaka (0.36; 95% CI: -0.07 to 0.60; P <0.05) formula (no INTERSALT formula exists for potassium). The degree of bias (vs. the 24-h urine) for sodium was smaller with Kawasaki (+313 mg/day; 95% CI: +182 to +444) compared with INTERSALT (-872 mg/day; 95% CI: -728 to -1016) and Tanaka (-548 mg/day; 95% CI: -408 to -688) formulae (P <0.001 and P = 0.02, respectively). Similarly for potassium, the Kawasaki formula provided the best agreement and least bias. Blood pressure correlated most closely and similarly with the 24-h and Kawasaki estimates for sodium compared with the other two formulae. CONCLUSION: In a diverse population, the Kawasaki formula is the most valid and least biased method of estimating 24-h sodium excretion from a single MFU and is suitable for population studies.