Tawatchai Chaiwatanarat

The need for robust validation for MDRD-based glomerular filtration rate estimation in various CKD populations

BACKGROUND Currently, estimated glomerular filtration rate (eGFR) equations have been validated only in Caucasians and African-Americans and is not applicable to people of other races/ethnicities as shown in studies conducted in two Asian populations: Chinese and Japanese. Because of this, it is important that eGFR equations are validated in its prospective population before applying it in the clinical setting and in epidemiologic studies. Therefore, we examined all eGFR equations available: reexpressed isotope dilution mass spectroscopy (IDMS)-traceable Modification of Diet in Renal Disease (MDRD) equation, Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation, Chinese equation and Japanese equation. METHODS A total of 350 adult Thai CKD patients were studied. The (99m)Tc-DTPA plasma clearance was used as a reference for glomerular filtration rate (GFR). The serum creatinine was determined by IDMS reference enzymatic methods (Cr(Enz)) and Jaffes kinetic assay (Cr(Jaffe)) as indicated in each equation. RESULTS The disagreement between the reference GFR and eGFR (reference GFR minus eGFR) was 9.6 mL/min/1.73 m(2) for the reexpressed IDMS-traceable MDRD equation, 8.0 mL/min/1.73 m(2) for CKD-EPI equation, 1.9 mL/min/1.73 m(2) for eGFR equation from the Chinese study and 20.9 mL/min/1.73 m(2) for the eGFR equation from the Japanese study. The Thai coefficient for the reexpressed MDRD was 1.129. The reexpressed MDRD equation for Thais is as follows: 175 × Cr(Enz) ((-1.154)) × Age ((-0.203)) × 0.742 (if female) × 1.129 (if Thai). When stepwise multiple regression analysis was used, the Thai eGFR formula is: 375.5 × Cr(Enz) ((-0.848)) × Age ((-0.364)) × 0.712 (if female). CONCLUSIONS Differences in race/ethnicity can significantly affect the results obtained from MDRD-based eGFR equation. It is highly recommended that each population should validate eGFR equations before applying the equation in epidemiologic studies or clinical use.

Comparisons between validated estimated glomerular filtration rate equations and isotopic glomerular filtration rate in HIV patients

Objective:Understanding how best to measure renal function in HIV-infected patients is critical because estimated glomerular filtration rate (eGFR) in HIV-infected patients can be affected by ethnicity and body composition. We validated the available eGFR equations and compared them to the plasma 99mTc-diethylenetriaminepentaacetic acid (99mTc-DTPA) clearance in HIV-infected patients. Design:Test of diagnostic accuracy. Methods:One hundred and ninety-six HIV-infected patients underwent measuring of 99mTc-DTPA plasma clearance, five creatinine-based eGFR equations, cystatin-C GFR, and 24-h urine creatinine clearance (CrCl). Results:Mean (SD) 99mTc-DTPA GFR was 117.7 ± 29.2 ml/min per 1.73 m2. The re-expressed Modification of Diet in Renal Disease (MDRD), Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI), re-expressed MDRD formula with Thai racial correction factor, Thai eGFR equation, Cockcroft–Gault equation, cystatin-C GFR, and 24-h urine CrCl underestimated the reference GFR. The bias estimated by the mean of differences (SD) for the re-expressed MDRD equation, CKD-EPI, re-expressed MDRD formula with Thai racial correction factor, Thai eGFR, Cockcroft–Gault equation, cystatin-C, and 24-h urine CrCl can be expressed as 18.9 ± 27.3, 11.1 ± 25.5, 6.2 ± 28.8, 15.4 ± 27.0, 30.4 ± 28.0, 3.2 + 36.1, and 5.0 ± 12.1 ml/min per 1.73 m2, respectively. Conclusion:The available eGFR equations underestimated GFR in HIV-infected adults. However, the eGFR by cystatin-C GFR was the most precise and accurate. Among creatinine-based eGFR equations, re-expressed MDRD formula with Thai racial correction factor was the most precise and accurate. The racial factor for each ethnicity is important and the existing eGFR equation should be validated before using it in the HIV population.

Bone density and 25-hydroxyvitamin D level in extrahepatic biliary atresia.

Abstract. Biliary atresia (BA) represents a common cholestatic affliction of the gastrointestinal tract affecting infants and children. The objective of the present study was to evaluate 42 patients (20 with and 22 without jaundice) diagnosed with extrahepatic BA for bone mineral content and serum 25-hydroxyvitamin D (HVD) levels. Physical examination and anthropometric nutritional assessment were performed. The investigation included liver function tests and serum calcium (Ca), phosphate (P), magnesium (Mg), and 25-HVD levels. Dual-energy X-ray absorptiometry was used to measure the bone mineral density (BMD) of the lumbar spine (L1–L4). Our results showed that 16 jaundiced␣patients (80%) and only 3 nonjaundiced patients (13.6%) showed osteoporosis (P< 0.05). All patients had normal serum Ca and P levels. Only 1 nonjaundiced patient had a low serum Mg level. Serum 25-HVD levels (mean ± SD) were 20.71 ± 8.24, 16.12 ± 4.3, and 9.18 ± 5.84 ng/ml, respectively, in subjects with normal bone density (n=7), osteopenia (n=3), and osteoporosis (n=11). Bone disease represents a well-known complication among long-term survivors of BA. To date, the pathogenesis has remained unexplained. Since, as demonstrated in the present study, jaundiced patients develop osteoporosis more frequently than nonjaundiced patients, hyperbilirubinemia may have an influence. Bone-mineral deficiency can be detected earlier by means of BMD measurement (non-invasive method) than by measuring serum Ca, P, and Mg levels in these patients.

Normal Solid Gastric Emptying Values Measured by Scintigraphy Using Asian-style Meal:A Multicenter Study in Healthy Volunteers.

Background/Aims To report gastric emptying scintigraphy, normal values should be established for a specific protocol. The aim of this study was to provide normal gastric emptying values and determine factors affecting gastric emptying using Asian rice-based meal in healthy volunteers. Methods One hundred and ninety-two healthy volunteers were included at 7 tertiary care centers across Thailand. Gastric emptying scintigraphy was acquired in 45 degree left anterior oblique view immediately after ingestion of a 267 kcal steamed-rice with technetium-99m labeled-microwaved egg meal with 100 mL water for up to 4 hours. Results One hundred and eighty-nine volunteers (99 females, age 43 ± 14 years) completed the study. The medians (5–95th percentiles) of lag time, gastric emptying half time (GE T1/2) and percent gastric retentions at 2 and 4 hours for all volunteers were 18.6 (0.5–39.1) minutes, 68.7 (45.1–107.8) minutes, 16.3% (2.7–49.8%) and 1.1% (0.2–8.8%), respectively. Female volunteers had significantly slower gastric emptying compared to male (GE T1/2, 74 [48–115] minutes vs. 63 (41–96) minutes; P < 0.05). Female volunteers who were in luteal phase of menstrual cycle had significantly slower gastric emptying compared to those in follicular phase or menopausal status (GE T1/2, 85 [66–102] mintes vs. 69 [50–120] minutes or 72 [47–109] minutes, P < 0.05). All of smoking volunteers were male. Smoker male volunteers had significantly faster gastric emptying compared to non-smoker males (GE T1/2, 56 [44–80] minutes vs. 67 [44–100] minutes, P < 0.05). Age, body mass index and alcohol consumption habits did not affect gastric emptying values. Conclusions A steamed-rice with microwaved egg meal was well tolerated by healthy volunteers. Gender, menstrual status and smoking status were found to affect solid gastric emptying.

Circulating leptin levels and bone mineral density in children with biliary atresia

Aim: To investigate circulating leptin levels in biliary atresia (BA) patients and the association of leptin with bone mineral density (BMD) and the severity of BA.

Value of radioimmunoscintigraphy with technetium-99m labelled anti-CEA monoclonal antibody (BW431/26) in the detection of colorectal cancer

This study was undertaken as part of a Coordinated Research Programme initiated by the International Atomic Energy Agency to evaluate the usefulness of radioimmunoscintigraphy (RIS) in the management of patients with colorectal cancer. Technetium-99m labelled BW431/26, a monoclonal antibody against carcino-embryonic antigen (CEA), was used. The study included 73 patients (31 females and 42 males). Sixty-eight patients were suspected of having recurrent colorectal adenocarcinoma while another five were suspected to have primary colorectal cancer. Images were acquired at 10 min and 4 and 24 h following the injection of radioantibody. The efficacy of RIS in tumour detection was evaluated by the findings at surgery, histological investigation and/or other diagnostic modalities and clinical follow-up. Four of five patients with suspected primary colorectal cancer gave true-positive results (three at primary sites, one at the site of a metastatic lesion) while one was false-positive. The overall accuracy of RIS in the diagnosis of recurrent colorectal cancer was 87%. Its sensitivity in the detection of locoregional or abdominal recurrence and liver metastases was 97% and 89% respectively. RIS was more accurate than computed tomography (CT) scan in the detection of pelvic recurrence and liver metastases while CT scan was far superior to RIS in detecting lung metastases. RIS proved most useful in patents who had rising CEA levels on clinical follow-up but in whom other work-up, including CT scan, was negative. The advantages of RIS include the ability to detect tumour recurrence prior to other investigations and to identify tumour recurrence in areas such as the pelvis, where CT and magnetic resonance imaging have their greatest weaknesses in diagnosing recurrent disease. The imaging accuracy is significantly increased when combined CT and antibody imaging is performed.

Increased serum sclerostin in postoperative biliary atresia

BACKGROUND We determined the relationship between serum sclerostin and disease severity of biliary atresia (BA). METHODS Seventy postoperative BA patients and 35 controls were recruited. Serum sclerostin, C-terminal telopeptide of type I collagen (CTX), and osteocalcin were analyzed using ELISA. Bone mineral density (BMD) of the lumbar spine was measured by dual energy X-ray absorptiometry. RESULTS BA patients had significantly higher serum sclerostin than controls. Serum sclerostin was markedly elevated in jaundice patients compared with jaundice-free patients. Serum osteocalcin was not different, whereas serum CTX was greater in BA patients than controls. BMD of jaundice patients was significantly lower than jaundice-free patients. Additionally, serum sclerostin was correlated with biochemical parameters and BMD in BA. CONCLUSION Increased sclerostin levels were associated with liver dysfunction and the severity of BA, suggesting that sclerostin may reflect the deterioration of hepatic function and the outcome in postoperative BA.

Low bone mineral density and the severity of cholestasis in biliary atresia

AIM To investigate the prevalence of osteopenia and osteoporosis in postoperative biliary atresia (BA) children and the association of bone mineral density (BMD) and biochemical parameters in postKasai BA subjects. METHODS A total of 70 patients with postKasai BA were enrolled in this prospective study. The patients were classified into two groups according to their jaundice status. BMD of the lumbar spine was analyzed using dual energy X-ray absorptiometry. RESULTS The prevalence of low bone mass (osteopenia and osteoporosis) in BA patients were 51.4% (36 out of 70). Ten patients (35.7%) in the jaundice group and 8 patients (19.0%) in the non-jaundice group had osteopenia. Sixteen patients (57.1%) in the jaundice group and 2 patients (4.8%) in the no jaundice group had osteoporosis. In addition, lumbar spine BMD Z-score was substantially lower in the jaundice BA patients compared with non-jaundice patients. BA subjects with persistent jaundice had significantly lower serum 25-hydroxyvitamin D than those without jaundice. Further analysis revealed that lumbar spine BMD was correlated with age (r = 0.774, P < 0.001), serum albumin (r = 0.333, P = 0.005), total bilirubin (r = -0.476, P < 0.001), aspartate aminotransferase (r = -0.583, P < 0.001), alanine aminotransferase (r = -0.428, P < 0.001), and alkaline phosphatase(r = -0.456, P < 0.001). CONCLUSION Low BMD was associated with biochemical parameters reflecting the severity of cholestasis in postKasai BA patients.