Progress in methods of treating chronic kidney disease (CKD) is being made worldwide. The purpose is to improve prognosis of the CKD patient and reduce the cost of medical care. To this end, the Japan Association of Chronic Kidney Disease Initiative was founded in 2006, and the Committee of Measures for Pediatric CKD within the Japanese Society for Pediatric Nephrology was founded in the same year.

Since urinalysis at schools was started in Japan in 1974, the incidence of chronic glomerulonephritis has decreased amongst children undergoing dialysis therapy by the induction method, and that of congenital diseases such as hypoplastic/dysplastic kidney and reflux nephropathy has increased. The latter now accounts for about 40% of end-stage renal disease. Therefore good communication and cooperation between pediatric nephrologists and pediatric urologists is indispensable in controlling childhood CKD.

To further advance CKD treatment measures it is important for pediatric nephrologists to know their CKD patients’ renal function. In Japan, measurement of serum creatinine in children is now performed by the enzyme method, making the establishment of a facility for renal function evaluation essential.

In our Children’s Health and Medical Center, we previously found a significant positive correlation between serum creatinine (Cr) concentration and body length in children aged 1–12 years, with body length (m) × 0.30 yielding a value similar to the reference serum Cr level. Muscle mass tends to be less correlated with body length and increases rapidly from puberty into adolescence and beyond, especially amongst males. Neonatal glomerular filtration rate (GFR) per body surface area is about 1/3 of that of adults. It becomes equal to that of adults at about 18 months old. When we evaluated renal function of under-1 year olds and over-12 year olds, we could not find a reliable correlation coefficient for body length, and thus further investigation of these age groups is necessary in the future. We found that reference serum cysC levels gradually decreased during the first year after birth, thereafter becoming constant. Mean serum cysC concentration in children aged 1 year (0.76±0.10 mg/L) was slightly higher than in children aged ≥2 years (0.70±0.09 mg/L).
For adults, pharmacotherapeutics such as angiotensin-converting enzyme inhibitors (ACE-Is) and angiotensin receptor blockers (ARBs) have been shown to be effective in non-diabetic nephropathy as well as diabetic nephropathy. These same treatments are generally adopted for childhood CKD, but there is no corresponding evidence of similar efficacy.

The Committee of Measures for Pediatric CKD has embarked on a multidisciplinary study to determine the reference value of serum creatinine and cystatin C, as well as on a randomized controlled trial to investigate methods of slowing progression of CKD in Japanese children.

The long-term survival of children on dialysis is similar to transplant patients during the first 5 years, however, cumulative survival after 10 years is significantly worse in children on dialysis. In fact, cardiovascular and cerebrovascular complications are the major causes of death in young adults with childhood onset chronic renal failure (CRF). Studies have shown the presence of advanced coronary and carotid arteriopathy in young adults with childhood-onset CRF. Coronary calcium scores and intima-media thickness have been shown to be associated with cumulative dialysis and ESRD time, and cumulative serum calcium-phosphate product.  Although long-standing hypertension is an important determinant of concentric left ventricular hypertrophy, hypertension also results in increase in arterial wall tension, contributing to the development of arteriosclerosis and myocardial ischaemia. However, anemia also worsens eccentric left ventricular hypertrophy, often seen in volume overload states, by increasing the left ventricular chamber size and stroke volume.  Anemia also increases the arterial diameter, and could conceivably lead to an increase in arterial wall thickness, worsening the arteriosclerosis.  In addition, metastatic calcification due to increased calcium-phosphate product will lead to progressive coronary calcification contributing to the myocardial dysfunction.  Therefore it is important to control blood pressure, correct anemia and control mineral bone disease as all these will contribute to the long-term cardiovascular morbidity. In a recent study aimed at determining the significant factors present during the period of chronic kidney disease (CKD) stages 2-5 in pediatric patients, which may affect cardiovascular status at the time of end-stage renal disease (ESRD), 46 pediatric patients, mean age 9.70±6.48 years at diagnosis of CKD and mean CKD duration of 3.65±3.74 years were retrospectively reviewed. 54.3% of patients had at least one echocardiographic abnormality at onset of ESRD, with severe left ventricular hypertrophy (left ventricular mass index; LVMI >51g/m2.7) occurring in 21.7%. Although systolic and diastolic blood pressure indices showed significant correlation with LVMI and cardiac functional status (fractional shortening and ejection fraction) respectively, only time-averaged uric acid was a significant predictor (p=0.002) of LVMI on multivariate analysis. This may be related to the long-term proinflammatory effects on vascular cells. Therefore control of uric acid in CKD patients may conceivably have a role in improving long-term cardiovascular outcomes.

AIMS OF THE STUDY
Not only physical development could be retarded in children with chronic illness, progress of chronic illness may also affect negatively on psychological development in those afflicted children. The current study aimed to examine the differences between the children with kidney diseases and the matched healthy children on their psychological development in terms of intelligence and self-concept. Our findings could assist medical experts and caregivers to understand mental needs of the children with kidney diseases and critical factors influencing their social and psychological development.

METHODS
Two hundred and fifty-three children were invited to participate in the study. Among them, 215 children were afflicted with kidney diseases (kidney group), and 38 healthy children were recruited from community (non-kidney group). Approximately one half (130 out of 253) of the subjects were assessed individually by Wechsler Intelligence Scales (IQs), and over 90% of the subjects (235 out of 253) were asked to respond the researcher-made self-concepts questionnaire. In sum, there were 110 children whom had been completely assessed by both IQs and self-concepts questionnaire.

MAIN RESULTS
Employing factor analysis method, the self-concepts were clustered into 12 factors, including having company, good friend, shy self, bad kid, rigid self, fat-and-short self image, bad habit, physical symptoms, optimist, talent, confidence, and not easy-going. When t-tests were used to examine the differences on the 12 factors between these two groups, the results showed that their scores on 5 factors were significantly statistically different. Specifically, children in the non-kidney group had significantly higher scores on the having company (t=2.57, p<.05), talent (t=2.69, p<.01), and confidence (t=3.48, p<.001) than had the kidney group. In contrast, the kidney group exhibited higher scores on the shy self (t=-2.12, p<.05), and bad habit (t=-2.56, p<.05) than did the non-kidney group. Moreover, t-tests revealed that their IQs differences were significantly different (t=5.47, p<.001). The non-kidney group (mean=109.63, n=38) displayed significantly higher total scores of IQs than them in the kidney group (mean=90.58, n=92). Furthermore, total scores of IQs were found to be correlated positively with “having company” (r=.267, p<.01) and “talent” (r=.38, p<.01) by correlation analyses. Nonetheless, total scores of IQs were correlated negatively with “shy self” (r=-.22, p<.05), “bad-kid” (r=-.19, p<.05), “fat-and-short self image” (r=-.21, p<.05), “ risk habit” (r=-.36, p<.01) and “physical symptoms” (r=-.25, p<.05).

CONCLUSIONS
Our findings suggest that Children afflicted with kidney diseases exhibit a profile of self concepts characterized by shyness and bad habit. More importantly, having company, gifted ability and skills could be protective factors against sluggish psychological development. In contrast, shyness, guilt and shame, bad physical image, risk habit, and obvious physical symptoms are risk factors in the retarded psychological development.