ABSTRACT
Background: Most of the laboratories use previously published regression equations for estimation of calcium which may not fit for their population. So deriving locally a regression equation for albumin-adjusted calcium (CaAd) is a mainstay to avoid population-based differences. Aims & Objective: To derive regression equation for albumin-adjusted calcium in our laboratory and validate it for the local population. Material and Methods: Total 575 normal healthy individuals of 35-65 years were included in the present study and were estimated for serum total calcium (CaT), ionized calcium (Ca2+), and albumin. The linear regression equation for the binding of calcium and albumin was derived in a cohort of 450 normal healthy individuals of 35-65 years, and the albumin-adjusted calcium equation was internally validated in a separate cohort of 125 subjects. The performance of this equation was compared with a previously published equation: CaAd (mmol/L) = CaT (mmol/L) + 0.02 (40 - [albumin] (g/L). Results: The local adjustment equation obtained from the derivation subset was expressed by the relationship; CaAd (mmol/L) = CaT (mmol/L) + 0.03 (37.33 – [albumin] (g/L)). The equation was internally validated with an adjusted r2 shrinkage value of 0.0009 in a validation subset. Bland-Altman plot showed statistically significant difference (Mean = 0.13 mmol/L) when both formulae were compared for the population. Conclusion: A locally derived and internally validated albumin-adjusted calcium equation differed significantly from previously published equations. Individual laboratories should determine their own linear albumin-adjusted regression equation for calcium rather than relying on published formulas.
ABSTRACT
Context : To evaluate the usefulness of urinary albumin excretion rate (UAER) i.e. Albumin/Creatinine Ratio (ACR) in diagnosis and prognosis of essential hypertension (EHT). Objectives : To find out the association of urinary albumin excretion rate with the pathophysiology of essential hypertension. Study Design : A cross-sectional analytical study. Materials & Methods : Urinary albumin excretion (UAE), urinary creatinine (UC) and UAER were analyzed and compared between hypertensive cases and age & sex matched normotensive controls of age group 30-65 years using unpaired two-tailed Student ‘t’ test. All statistical analyses were done with PASW (SPSS) v.18.0. Results : Systolic BP (SBP) and diastolic BP (DBP) of cases were found to be significantly higher (p < 0.001) than controls. Urine MAlb level (p < 0.001) and ACR (p < 0.001) in cases were significantly higher compared to controls. Correlation studies showed that SBP and DBP was significantly positively correlated with urine MAlb (SBP: r = 0.859, DBP: r = 0.733; p < 0.001) and ACR (SBP: r = 0.830, DBP: r = 0.739; p < 0.001). Sex-wise comparison in cases revealed that males had statistically non-significant (p > 0.05) lower levels of urine MAlb as compared to females but had significantly higher (p < 0.001) levels of urine creatinine and lower (p < 0.001) ACR compared to females. Conclusion: Urinary MAlb levels and ACR are seen to be increased in hypertensive subjects compared to normotensive subjects. ACR was significantly higher in female hypertensives than males which can be credited to the physiologically observed lower urine creatinine levels compared to males. Both Microalbuminuria and ACR can serve as specific and well-established marker of cardiovascular and renal damage in EHT.