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RAPID REDUCTION OF SERUM PHOSPHORUS LEVELS BY LANTHANUM CARBONATE IN PATIENTS ON DIALYSIS Rosamund Wilson,1 Scharmen Confer,2 Raymond Pra1SPICA Consultants Ltd, Marlborough, UK; 2Shire Pharmaceuticals, Wayne, PA

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, USA Reducing serum phosphorus (SP) as rapidly as possible may improve patient perception of treatment requirement and avoid the need for additional titration steps. We investigated whether treatment with the non-calcium, non-resin phosphate binder, lanthanum carbonate (LC) resulted in a rapid reduction in SP by examining 4 randomized trials of patients with chronic kidney disease Stage 5 on dialysis (CKD5D). Two of the studies started dose titration at 750 mg of LC per day and the dose could increase to 3000 mg over the titration period. In the first study (n = 126), significant decreases in mean SP levels were observed after 1 week of treatment (p < 0.0001). Comparison of the mean baseline level of 7.8 mg/dL with each of the 6 titration weeks also showed significant reductions (p < 0.0001). In the second study (n = 73), mean baseline SP levels were similar to the first study (7.7 mg/dL) and there was a significant reduction in mean SP levels from week 1. In addition, 95% confidence intervals of the means for all visits did not include the mean baseline SP value. In a study with fixed LC doses for 6 weeks, patients randomized to doses > 750 mg experienced significant reductions in SP levels (p < 0.05) as early as week 1 of treatment (1350 mg: n = 30, mean baseline SP 6.81 mg/dL; 2250 mg: n = 26, mean baseline SP 7.42 mg/dL). Differences in SP levels between the LC and placebo groups at the end of treatment were –1.70 and –1.88 mg/dL for the 1350 mg and 2250 mg dose groups, respectively. A recently reported cross-over study comparing LC and sevelamer hydrochloride (SH) showed reductions in SP levels with initial LC and SH doses of 2250 mg and 4800 mg, respectively. The reduction was significantly greater in the LC group than in the SH group even at this titration dose after 1 week of treatment (–1.38 vs. –1.01 mg/dL; p = 0.024). LC has demonstrated rapid reductions of SP, even at low initial doses. These rapid reductions of SP may be advantageous to treat phosphate burden in patients with CKD5D.

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CHRONIC KIDNEY DISEASE AWARENESS IS LIMITED IN PATIENTS SEEN BY NEPHROLOGISTS Julie Wright MD, T. Alp Ikizler MD, Kerri Cavanaugh MD MHS, Vanderbilt University, Nashville Tennessee, U.S.A.

Purpose: Patient awareness of chronic kidney disease (CKD) is an important factor in the execution of successful disease self-care. Studies have shown low awareness of CKD in the general population, even in those who have seen a primary care physician in the past year. The aim of this study is to describe awareness of CKD diagnosis in patients seen by nephrologists, and characterize associations of level of awareness.

Methods: Four-hundred established adult patients with CKD (Stages 1-5), seen at least once previously in the Nephrology clinic, were enrolled from May 2009 to October 2009. They were asked about awareness of their diagnosis ("Do you have chronic kidney disease? Yes/No") and rated their perceived disease specific knowledge in nine areas on a scale of 1-4 (1=No knowledge, 2=A little knowledge, 3=A good amount of knowledge, and 4=A lot of knowledge). Measurements included demographics, visit information, and laboratory values. Health literacy was assessed with the Rapid Estimate of Adult Literacy in Medicine (REALM) survey.

Results: The mean age of this cohort was 56.7 years (SD 15.8), 83% were White, and 76% had CKD stage 3-5. Low literacy (<9th grade level) occurred in 18%. 28% were unaware they had CKD. 45% of stage 1-2 patients were unaware vs. 22% of those stage 3-5 (p=0.01). Low awareness was associated with increased eGFR [rho= -0.32; p=0.01], lack of attendance in a kidney education class [no attendance 36% unaware vs. attendance 19% unaware; p=0.01], less provider visits within the past year [≤ 2 visits 36% unaware, ≥3 visits 22% unaware; p=0.01], and lower overall perceived knowledge [2.36 (0.51) vs. 2.71(0.61); p=0.01]. Sex, race, age, and REALM scores were not associated with awareness of CKD in this cohort.

Conclusion: Awareness of CKD is limited even in patients seen by a nephrologist. Early and repeated communication regarding CKD may improve patient awareness of their diagnosis. Further study is needed to determine the impact of CKD awareness on self-care behaviors and clinical outcomes.

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AN ETHNIC CHINESE COEFFICIENT FOR THE RE-EXPRESSED MDRD EQUATION USING STANDARDIZED CREATININE Hui Xu, Boon Wee Teo, Borys Shuter, Danhua Wang, Jialiang Li, Arvind Kumar Sinha, Sunil Sethi, Evan Lee; National University Health System, Singapore

The MDRD glomerular filtration rate-estimating equation (eGFR) was modified with very different ethnic coefficients for ethnic Chinese (1.23) (Ma et al. JASN 2006:17,2937) and ethnic Japanese (0.81)(AJKD 2009:53,982) . We evaluated the validity of the Chinese coefficient using the same GFR measurement method as Ma et al.

To show a 20% difference between measured GFR (mGFR) and eGFR, we need >89 patients (Dupont et al; Controlled Clinical Trials 19: 589). We prospectively recruited 94 Chinese chronic kidney disease patients (51% male), and measured GFR using 3-sample plasma clearance of 99mTc-DTPA at 2, 3.5, and 5 hours, calculated by the slope-intercept method, with body surface area normalization (du Bois) and Brochner-Mortenson correction. We measured standardized serum creatinine by an enzymatic method and calculated eGFR with the re-expressed MDRD: 175 x Cr-1.154 x Age-0.203 x 0.742 (if female). To determine if methodology was a cause of the ethnic coefficient, we also calculated measured GFR as described by Ma et al with 2-samples. To simulate the MDRD population, we confined our sample (n=53) to mGFR <70 and age <70 years, boot-strap 50 random samples (n=60) to estimate the Chinese coefficient. We forced all MDRD coefficients to our mGFR to obtain the fitted Chinese coefficients.

Population means: age 58.1 ±13.5 years, creatinine 1.70 ±0.92 mg/dL measured GFR 54.2 ±28.7 mL/min/1.73m2.

Group (n) mGFR method

B-Mcorrection

Estimated ethnic coeff. (CI)

All (94) 3-samples Yes 1.14 (1.08-1.19)

All (94) 2-samples No 1.23 (1.17-1.29) Reduced (53) 3-samples Yes 1.15 (1.08-1.22)

Using standardized creatinine and Brochner-Mortenson correction, the Chinese coefficient for the MDRD equation is 1.14, and is significantly different from the previously reported Chinese coefficient of 1.23. A significant portion of the coefficient was contributed by the method of calculating and correcting measured GFR.

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STANDARDIZED SERUM CREATININE WITH CYSTATIN C IMPROVES ACCURACY OF GFR ESTIMATES IN ASIANS Hui Xu, Boon Wee Teo, Danhua Wang, Jialiang Li, Sunil Sethi, Evan Lee; National University Health System, Singapore We evaluated the performance of glomerular filtation rate estimating-equations (eGFR) with standardized serum creatinine (SCr) alone, serum cystatin C (cysC) alone, and in combination with demographic variables in a multi-ethnic Asian population.

We prospectively recruited 232 CKD patients (52% male, Chinese 40.5%, Malay 32%, Indian and others 27.5%) by gender, ethnicity, and eGFR. We measured SCr by enzymatic method and cystatin C by nephelometry. eGFR was calculated for SCr alone with revised MDRD: 175 x SCr-1.154 x Age-0.203 x 0.742 (if female); cystatin C alone and in combination from Stevens et al (AJKD 2008:51,395). No adjustment for ethnicity was made. We measured glomerular filtration rate (mGFR) using 3-sample plasma clearance of 99mTc-DTPA, calculated by the slope-intercept method, with body surface area normalization (du Bois) and Brochner-Mortenson correction. eGFR was compared overall and by ethnicity, and accuracy to within 15%, 30%, and 50% of mGFR, and mean bias ±SD (mL/min/1.73m2). Population means: age 58.4 ±12.8 years, SCr 1.73 ±1.04 mg/dL, cysC 1.48 ±0.69, mGFR 51.7 ±27.5 mL/min/1.73m2.

Group (n)

Equation type Accuracy (%) Mean bias ±SD

All (232) MDRD 50.5, 79.7, 95.3 0.95±15.2

All (232) cysC 40.5, 64.2, 84.9 11.1±16.2 All (232) cysC+demo 48.3, 74.1, 90.5 7.83±14.9 All (232) cysC+SCr+demo 59.1, 84.5, 95.7 4.51±14.2 Chinese cysC+SCr+demo 64.9, 88.3, 95.7 3.43±14.2 Malay cysC+SCr+demo 54.1, 87.8, 94.6 2.67±13.3 Indian+ cysC+SCr+demo 56.3, 75.0, 96.9 8.23±15.0 Cystatin C alone for estimating GFR was no better than

standardized creatinine alone. Performance was improved with both in combination with demographic variables but bias was noted. More research in ethnic variation of cystatin C is required.

NKF 2010 Spring Clinical Meetings AbstractsA112