Hypertension Canada's 2018 Guidelines for Diagnosis, Risk Assessment, Prevention, and Treatment of Hypertension in Adults and Children

Hypertension Canada provides annually updated, evidence-based guidelines for the diagnosis, assessment, prevention, and treatment of hypertension in adults and children. This year, the adult and pediatric guidelines are combined in one document. The new 2018 pregnancy-specific hypertension guidelines are published separately. For 2018, 5 new guidelines are introduced, and 1 existing guideline on the blood pressure thresholds and targets in the setting of thrombolysis for acute ischemic stroke is revised. The use of validated wrist devices for the estimation of blood pressure in individuals with large arm circumference is now included. Guidance is provided for the follow-up measurements of blood pressure, with the use of standardized methods and electronic (oscillometric) upper arm devices in individuals with hypertension, and either ambulatory blood pressure monitoring or home blood pressure monitoring in individuals with white coat effect. We specify that all individuals with hypertension should have an assessment of global cardiovascular risk to promote health behaviours that lower blood pressure. Finally, an angiotensin receptor-neprilysin inhibitor combination should be used in place of either an angiotensin-converting enzyme inhibitor or angiotensin receptor blocker in individuals with heart failure (with ejection fraction < 40%) who are symptomatic despite appropriate doses of guideline-directed heart failure therapies. The specific evidence and rationale underlying each of these guidelines are discussed.

Hypertension Canada's 2016 Canadian Hypertension Education Program Guidelines for Blood Pressure Measurement, Diagnosis, Assessment of Risk, Prevention, and Treatment of Hypertension

Hypertension Canada's Canadian Hypertension Education Program Guidelines Task Force provides annually updated, evidence-based recommendations to guide the diagnosis, assessment, prevention, and treatment of hypertension. This year, we present 4 new recommendations, as well as revisions to 2 previous recommendations. In the diagnosis and assessment of hypertension, automated office blood pressure, taken without patient-health provider interaction, is now recommended as the preferred method of measuring in-office blood pressure. Also, although a serum lipid panel remains part of the routine laboratory testing for patients with hypertension, fasting and nonfasting collections are now considered acceptable. For individuals with secondary hypertension arising from primary hyperaldosteronism, adrenal vein sampling is recommended for those who are candidates for potential adrenalectomy. With respect to the treatment of hypertension, a new recommendation that has been added is for increasing dietary potassium to reduce blood pressure in those who are not at high risk for hyperkalemia. Furthermore, in selected high-risk patients, intensive blood pressure reduction to a target systolic blood pressure ≤ 120 mm Hg should be considered to decrease the risk of cardiovascular events. Finally, in hypertensive individuals with uncomplicated, stable angina pectoris, either a β-blocker or calcium channel blocker may be considered for initial therapy. The specific evidence and rationale underlying each of these recommendations are discussed. Hypertension Canada's Canadian Hypertension Education Program Guidelines Task Force will continue to provide annual updates.

Hypertension Canada's 2017 Guidelines for Diagnosis, Risk Assessment, Prevention, and Treatment of Hypertension in Adults

Hypertension Canada provides annually updated, evidence-based guidelines for the diagnosis, assessment, prevention, and treatment of hypertension. This year, we introduce 10 new guidelines. Three previous guidelines have been revised and 5 have been removed. Previous age and frailty distinctions have been removed as considerations for when to initiate antihypertensive therapy. In the presence of macrovascular target organ damage, or in those with independent cardiovascular risk factors, antihypertensive therapy should be considered for all individuals with elevated average systolic nonautomated office blood pressure (non-AOBP) readings ≥ 140 mm Hg. For individuals with diastolic hypertension (with or without systolic hypertension), fixed-dose single-pill combinations are now recommended as an initial treatment option. Preference is given to pills containing an angiotensin-converting enzyme inhibitor or angiotensin receptor blocker in combination with either a calcium channel blocker or diuretic. Whenever a diuretic is selected as monotherapy, longer-acting agents are preferred. In patients with established ischemic heart disease, caution should be exercised in lowering diastolic non-AOBP to ≤ 60 mm Hg, especially in the presence of left ventricular hypertrophy. After a hemorrhagic stroke, in the first 24 hours, systolic non-AOBP lowering to < 140 mm Hg is not recommended. Finally, guidance is now provided for screening, initial diagnosis, assessment, and treatment of renovascular hypertension arising from fibromuscular dysplasia. The specific evidence and rationale underlying each of these guidelines are discussed.

Regression of target organ damage in children and adolescents with primary hypertension

We assessed the effects of 12 months of non-pharmacological and pharmacological therapy on 24-h ambulatory blood pressure, regression of target organ damage (TOD) and metabolic abnormalities in 86 children (14.1 ± 2.4 years) with primary hypertension. Twenty-four hour systolic and diastolic blood pressure (BP) decreased (130 ± 8 vs 126 ± 8, 73 ± 7 vs 70 ± 7, p = 0.0001 and 0.004 respectively). Body mass index (BMI) did not change, but waist-to-hip (0.85 ± 0.07 vs 0.83 ± 0.05, p = 0.01) and waist-to-height ratio (WHtR; 0.49 ± 0.07 vs 0.48 ± 0.05, p = 0.008) decreased. Left ventricular mass index (LVMi; 38.5 ± 10.7 vs 35.2 ± 7.5 g/m(2.7), p = 0.0001), prevalence of left ventricular hypertrophy (46.5% vs 31.4%; p = 0.0001), carotid intima-media thickness (cIMT; 0.44 ± 0.05 vs 0.42 ± 0.04 mm, p = 0.0001), wall cross sectional area (WCSA; 7.5 ± 1.3 vs 6.9 ± 1.2 mm(2), p = 0.002), hsCRP (1.1 ± 1.0 vs 0.7 ± 0.7 mg/l, p = 0.002), and LDL-cholesterol (115 ± 33 vs 107 ± 26 mg/dl, p = 0.001) decreased. Patients who had lowered BP had a lower cIMT at the second examination (0.41 ± 0.04 vs 0.43 ± 0.04 mm, p = 0.04) and lower initial hsCRP values (0.9 ± 0.7 vs 1.5 ± 1.3 mg/l, p = 0.04) in comparison to non-responders. Regression analysis revealed that the main predictor of LVMi decrease was a decrease in abdominal fat expressed as a decrease in waist circumference (WC) (R (2) = 0.280, β = 0.558, p = 0.005), for WCSA-SDS a decrease in WC (R (2) = 0.332, β = 0.611, p = 0.009) and for a cIMT-SDS decrease the main predictor was a decrease in hsCRP concentrations (R (2) = 0.137, β = 0.412, p = 0.03). Standard antihypertensive treatment lowered BP and led to regression of TOD in hypertensive children. Lean body mass increase and decrease in abdominal obesity correlated with TOD regression.

Prevalence of complications in children with chronic kidney disease according to KDOQI

The Kidney Disease Outcome and Quality Initiative (KDOQI) Group recommended guidelines for the monitoring and treatment of chronic kidney disease (CKD) in 2002. These recommendations were based on the prevalence of known complications as seen in adults. In children, the exact prevalence of these complications is unknown. We therefore conducted a cross-sectional study of 366 patients with CKD in a single center to analyze the prevalence of these complications across all stages of kidney disease. Patients were categorized to their KDOQI stage of CKD according to their estimated renal function as determined from serum cystatin C. Fifty seven percent of patients had CKD stage 1, 29.0% stage 2, 10.4% stage 3 and 4.1% stages 4+5. Uropathies (31%) were the most prevalent causes of CKD. Glomerular disease accounted for 27%. The overall prevalence of complications was as follows: hypertension 70.2%, anemia 36.6%, proteinuria 11.5%, and metabolic bone disease 16.9%. Metabolic bone disease and anemia occurred frequently, even with a glomerular filtration rate >60 ml/min/1.73 m2. Growth failure (11.5%) was also common and is not a component of the KDOQI guidelines for CKD in children. The prevalence of all complications increased with worsening stage of kidney disease (all P-values significant). In summary, this study supports the KDOQI guidelines in defining and staging CKD in children. This study also highlights the differences in the causes and complications that occur in CKD between adults and pediatrics. We recommend modification of the KDOQI guidelines for children to reflect the differences described in this paper.

Is there really an increase in non-minimal change nephrotic syndrome in children?

BACKGROUND

Reports on the worldwide increase in focal segmental glomerulosclerosis (FSGS) in childhood may have been hampered by referral bias. A true increase in FSGS possibly could alter the current practice of withholding renal biopsy in childhood nephrotic syndrome (NS) unless the patient fails to respond to a 28-day course of corticosteroid therapy.

METHODS

With these questions in mind, we analyzed a 17-year database covering a 275,000-child population with mandatory referral. The incidence of NS per 100,000 childhood population per year was calculated, charts of 159 patients with NS seen between 1985 and 2002 were reviewed, and a receiver operating characteristic (ROC) plot analysis was performed to analyze the diagnostic performance of remission time.

RESULTS

Results show that 115 of 159 patients had minimal change NS, diagnosed either on the basis of corticosteroid response (n = 89), verified by renal biopsy (n = 14), or with minimal change plus mesangial immunoglobulin M on histological examination (n = 12). The remaining 44 patients underwent a renal biopsy showing FSGS (n = 29; 18.2%), diffuse mesangial hypercellularity (n = 8; 5%), membranoproliferative glomerulonephritis (n = 1; 0.6%), membranous nephropathy (n = 3; 1.9%), or other diagnoses (n = 3). The incidence of FSGS increased significantly (P = 0.0253) from 0.37 to 0.94/100,000-child population/y in the two 8(1/2)-year intervals of our study. ROC plot analysis confirmed diagnostic sensitivity and specificity greater than 80% for remission time between 21 and 28 days of therapy.

CONCLUSION

We confirm the increasing incidence of FSGS in children with idiopathic NS in a well-defined catchment area and, at the same time, find no reason to change the initial therapy and current indications to perform renal biopsy in childhood NS.

Control of hypertension in children after renal transplantation

The aim of this cross-sectional single-center study was to investigate the efficacy of hypertension control in children who underwent transplantation using ambulatory blood pressure (BP) monitoring, and to determine the risk factors associated with poor control of hypertension. Thirty-six children fulfilled the inclusion criteria. The mean age was 13.9+/-4.4 yr; the mean time after renal transplantation was 2.7+/-2.4 yr (0.5-10.1). Hypertension was defined as a mean ambulatory BP > or =95th centile for healthy children and/or requiring antihypertensive drugs. Hypertension was regarded as controlled if the mean ambulatory BP was <95th centile in children already on antihypertensive drugs, or uncontrolled if the mean ambulatory BP was > or =95th centile in treated children. Hypertension was present in 89% of children. Seventeen children (47%) had controlled hypertension, and 14 (39%) had uncontrolled hypertension. One child (3%) had untreated hypertension, and only four children (11%) showed normal BP without antihypertensive drugs. The efficacy of hypertensive control was 55% (17 of 31 children on antihypertensive drugs had a BP<95th centile), i.e. 45% of treated children still had hypertension. Children with uncontrolled hypertension had significantly higher cyclosporine doses (6.1 vs. 4.3 mg/kg/day, p=0.01) and tacrolimus levels (9.2 vs. 6.1 microg/L, p<0.05), and there was a tendency toward use of lower number of antihypertensive drugs (2.0 vs. 1.5 drugs/patient, p=0.06) and lower use of angiotensin-converting enzyme (ACE) inhibitors (7 vs. 35%, p=0.09) and diuretics (29 vs. 59%, p=0.14) than in children with controlled hypertension. In conclusion, nearly 90% of our children after renal transplantation are hypertensive and the control of hypertension is unsatisfactorily low. The control of hypertension could be improved by increasing the number of prescribed antihypertensive drugs, especially ACE inhibitors, and diuretics, or by using higher doses of currently used antihypertensives.

Combined liver-kidney transplantation in primary hyperoxaluria type 1

Primary hyperoxaluria type 1 (PH1) is a rare autosomal recessive disorder characterised by an increased urinary excretion of calcium oxalate, leading to recurrent urolithiasis, nephrocalcinosis and accumulation of insoluble oxalate throughout the body (oxalosis) when the glomerular filtration rate falls to below 40-20 mL/min per 1.73 m(2). The disease is due to a functional defect of the liver-specific peroxisomal enzyme alanine: glyoxylate aminotransferase (AGT), the gene of which is located on chromosome 2q37.3. The diagnosis is based on increased urinary oxalate and glycollate, increased plasma oxalate and AGT measurement in a liver biopsy. AGT mistargeting may be investigated by immuno-electron microscopy and DNA analysis. End-stage renal failure is reached by the age of 15 years in 50% of PH1 patients and the overall death rate approximates 30%. The conservative treatment includes high fluid intake, pyridoxine and crystallisation inhibitors. Since the kidney is the main target of the disease, isolated kidney transplantation (Tx) has been proposed in association with vigorous peri-operative haemodialysis in an attempt to clear plasma oxalate at the time of Tx. However, because of a 100% recurrence rate, the average 3-year graft survival is 15%-25% in Europe, with a 5-10-year patient survival rate ranging from 10% to 50%. Since the liver is the only organ responsible for the detoxification of glyoxylate by AGT, deficient host liver removal is the first rationale for enzyme replacement therapy. Subsequent orthotopic liver Tx aims to supply the missing enzyme in its normal cellular and subcellular location and thus can be regarded as a form of gene therapy. Because of the usual spectrum of the disease, isolated liver Tx is limited to selected patients prior to having reached an advanced stage of chronic renal failure. Combined liver-kidney Tx has therefore become a conventional treatment for most PH1 patients: according to the European experience, patient survival approximates 80% at 5 years and 70% at 10 years. In addition, the renal function of survivors remains stable over time, between 40 and 60 mL/min per 1.73 m(2) after 5 to 10 years. In addition, liver Tx may allow the reversal of systemic storage disease (i.e. bone, heart, vessels, nerves) and provide valuable quality of life. Whatever the transplant strategy, the outcome is improved when patients are transplanted early in order to limit systemic oxalosis. According to the European experience, it appears that combined liver-kidney Tx is performed in PH1 patients with encouraging results, renal Tx alone has little role in the treatment of this disease, and liver Tx reverses the underlying metabolic defect and its clinical consequences.

Universal approach to pharmacokinetic monitoring of immunosuppressive agents in children

Current data indicate that pharmacokinetic (PK) monitoring of cyclosporin microemulsion (CsA) should be performed using the 2-h concentration (C2), that tacrolimus (Tac) is commonly monitored using the trough level, and mycophenolate mofetil (MMF) should be monitored using the 1-h (C1), 2-h (C2) and 6-h (C6) concentrations. The three differing time-point requirements are cumbersome, and we aimed to develop universal guidelines for all three drugs using a large number of full PK profiles in children. One-hundred and twenty two stable pediatric patients, receiving either CsA (165 PK profiles, 69 patients, 24 with concomitant MMF) or Tac (122 PK profiles, 53 patients, 18 with MMF) were analyzed retrospectively. Pearson r for the CsA C2 was 0.90 [95% confidence interval(CI): 0.86-0.92], for Tac C2 r was 0.86 (95% CI: 0.80-0.90), and for MPA C2 r was 0.77 (95% CI: 0.68-0.83), respectively. For MPA, at least three time-points are required to accurately estimate the area under the concentration-time curve (AUC), and C1, C2 and C6 serve as best markers. Excellent AUC estimations could be obtained from a limited sampling strategy from C1, C2 and C6 or C0, C1, C2 and C4 with clinically acceptable errors for all three drugs. The AUC can be estimated with great precision by using an identical approach for all three drugs. Target AUCs for a given time-point after transplantation remain to be established.

Bone mineral density after renal transplantation in children

Longitudinal bone mineral changes after renal transplantation were studied in 14 children aged 8 +/- 4 years. Combination immunosuppressive therapy was given to all patients (prednisone, azathioprine, cyclosporine). Bone mineral density (BMD) measurements of the first through fourth lumbar vertebrae by dual-energy X-ray absorptiometry were performed within 1 year preceding renal transplantation and 6, 12, and 24 months afterward (M0, M6, M12, and M24, respectively). The results of BMD obtained in grams of hydroxyapatite per square centimeter of spine projected area were subsequently transformed to standard deviation scores for a normal pediatric population. In addition, we used a mathematical spine volume correction to give the results in grams per cubic centimeter. All patients had a well-functioning renal graft at M6, M12, and M24 and a normal serum creatinine level. Significant decreases in BMD, standard deviation score, and spine volume-corrected BMD were observed 6 months after renal transplantation (p < 0.05, p < 0.01, and p < 0.01 respectively); the median loss of BMD and spine volume-corrected BMD was 9.2% and 15.6% at M6, respectively, and the median serum parathyroid hormone level dropped from 125 to 34 pg/ml. Between M6 and M12, BMD increased significantly up to 95% (median) of pretransplantation values and reached 97.2% (median) at M24. Similar but less marked improvement was observed in spine volume-corrected BMD results, reaching 87.7% and 87.4% at M12 and M24, respectively. A negative correlation was found between the cumulative prednisone dose and BMD in grams per square centimeter at M6 (r2 = 0.603; p = 0.006), M12 (r2 = 0.532; p = 0.015), and M24 (r2 = 0.40; p = 0.014). There was no correlation between cumulative prednisone dose and spine volume-corrected BMD or standard deviation score. Mean 6-month cyclosporine levels did not correlate with any measure of BMD. We conclude that after renal transplantation children have a significant decrease of BMD during the first 6 months after the operation, despite normal graft function and growth improvement.

Pharmacokinetics of mycophenolate mofetil for autoimmune disease in children

This study describes the pharmacokinetics of mycophenolate mofetil (MMF) in 15 pediatric patients with vasculitis and connective tissue disease involving the kidney. Patients included 10 with systemic lupus erythematosus (SLE), 1 with antiphospholipid antibody syndrome, 2 with Wegener granulomatosis, and 1 each with Goodpasture syndrome, Henoch-Schönlein-associated nephritis, and 1 with severe tubulointerstitial nephritis and uveitis. All patients were treated with steroids and additional therapy prior to treatment with MMF, which was administered for a median of 491 days. Mean starting dose of MMF was 974+/-282 mg/m(2 )in two divided doses. Pharmacokinetic monitoring of the active compound of MMF, mycophenolic acid (MPA), was performed using an EMIT assay. The mean MPA AUC after a median of 39 days was 61.8+/-31.0 micro gxh/ml, median time to maximum concentration was 60 min, and mean maximum concentration was 18.5+/-8.4 micro g/ml. At last follow-up, mean MMF dose was 900+/-341 mg/m(2) per day, and mean trough MPA concentration was 3.1+/-1.1 (range 0.6-4.6) micro g/ml. Therapy was effective in inducing remission in 4 of 9 patients with active disease. Only 1 of the 5 other patients relapsed. All 6 patients with controlled disease maintained remission. There were few side effects: one episode each of diarrhea and leukocytopenia and two viral infections. We conclude that MMF at 900 mg/m(2) per day appears to be effective in these patients.

Residual renal function in children on haemodialysis and peritoneal dialysis therapy

Residual renal function was studied in 28 haemodialysis (HD) and 31 peritoneal dialysis (PD) patients aged 1-20 years observed over 6-43 (median 19) months. After the start of dialysis urine volume (UV) decreased to 57%, 46% and 26% of initial mean values in HD patients after 6, 12 and 24 months, respectively. In PD patients the corresponding figures were 57%, 69% and 62%. Mean UV calculated from all individual mean UV measurements observed was higher in PD than HD patients (954 vs. 537 ml/m2 per 24 h, P < 0.01). A better conservation of diuresis in PD patients was also suggested by a significantly longer persistence of a UV greater than 500 ml/m2 per 24 h compared with HD patients. Cox proportional hazard analysis identified dialysis modality and pre-dialysis UV of less than 1,000 ml/m2 per 24 h as the only significant risk factors for UV survival. However, the decline of UV per time was similar in both modes of treatment. No significant changes of glomerular filtration rate were observed during both HD and PD treatment.

Unexpectedly high inter- and intrapatient variability of ganciclovir levels in children

Few studies report Ganciclovir or Valganciclovir levels in children. Single-center, retrospective study of all available Ganciclovir levels in transplanted children. Ganciclovir monitoring was performed as previously described [G. Filler (1998); Pediatric Nephrology, 12, 6]. For the normalization of dosing to GFR and target trough levels, we assumed first-order kinetics. We analyzed 57 Ganciclovir levels in 20 children (mean age 8.6 +/- 5.5 yr) treated with intravenous or oral Ganciclovir or oral Valganciclovir. Ganciclovir levels were drawn after IV therapy (n = 9), during oral Ganciclovir (n = 5), or during oral Valganciclovir (n = 15). Oral bioavailability of Valganciclovir was 42.0 +/- 21.8%. The dose-normalized intrapatient Valganciclovir variability was 83%. Mean GFR was 92 +/- 22 mL/min/1.73 m(2). Mean Ganciclovir concentration at last available measurement was 0.60 +/- 0.09 mg/L. While target trough Ganciclovir levels have not been established, possibly subtherapeutic Ganciclovir levels <0.5 mg/L on recommended IV doses were found in eight patients. This subset of patients was significantly younger (4.5 +/- 3.1 vs. 11.4 +/- 5.0 yr). Levels <0.5 mg/L were found in 24/57 instances and 10 patients subsequently had their dose increased. The last Valganciclovir dose adjusted to a GFR of 100 mL/min/1.73 m(2) was 842 +/- 323 mg/m(2)/day. A high proportion of patients had low Ganciclovir levels both on intravenous and oral therapy. The oral bioavailability of Valganciclovir was 42%. Our data suggest substantial inter- and intrapatient variability of Ganciclovir levels after pediatric renal transplantation and may support the need for pharmacokinetic monitoring of Ganciclovir and Valganciclovir therapy for the prevention and treatment of CMV disease after pediatric transplantation. It is currently unclear what target trough level would be most suitable.

Estimation of peritoneal mass transport by three-pore model in children

BACKGROUND

Computerized modeling is increasingly used to optimize the efficacy of peritoneal dialysis (PD). The Personal Dialysis Capacity (PDC) test is a new tool to model PD efficacy based on the three-pore model of peritoneal mass transport. We sought to evaluate (i) whether the PDC test is applicable to children on chronic PD, and (ii) whether the physiological mass transport coefficients defined in the three pore model are dependent on age or body size in childhood.

METHODS

A validation study was performed in 32 pediatric chronic PD patients. Twenty tests were performed using a standard CAPD regimen, and 22 tests using a simplified automated PD (APD) protocol. Test accuracy and precision were evaluated by comparison of predicted with measured 24-hour dialysate clearances of urea, creatinine, beta2-microglobulin and albumin and ultrafiltration rates. Long-term reproducibility was assessed in 16 patients by repeated clearance studies after a median time interval of 10 weeks.

RESULTS

While daily clearances of urea and creatinine were predicted with good precision and accuracy with both test protocols (concordance correlation coefficients 0.90 to 0.98, mean difference predicted-calculated -0.6 to +0.6 ml/min/1.73 m2), ultrafiltration rates were predicted more closely by the APD (r = 0.97) than by the CAPD test (0.80). Middle and large molecule clearances were predicted less precisely in both test settings (r = 0.48 to 0.83). Re-test reproducibility was slightly lower than the predictive precision observed in the original test (r = 0.80 to 0.91). The calculated total peritoneal pore area increased in absolute terms, decreased with body size when standardized to weight, and was independent of body size when normalized to body surface area. The body size-normalized fluid reabsorption rate was slightly increased in young infants compared to older children or adults.

CONCLUSIONS

The PDC test permits to model peritoneal solute and water transport with remarkable precision in children of all age groups. While the peritoneal pore area is a linear function of body surface area, fluid reabsorption appears to be slightly increased in young infants.

Skeletal findings in children recently initiating glucocorticoids for the treatment of nephrotic syndrome

SUMMARY

Eighty children with nephrotic syndrome underwent lumbar spine densitometry and vertebral morphometry soon after glucocorticoid initiation. We found an inverse relationship between glucocorticoid exposure and spine areal bone mineral density (BMD) Z-score and a low rate of vertebral deformities (8%).

INTRODUCTION

Vertebral fractures are an under-recognized complication of childhood glucocorticoid-treated illnesses. Our goal was to study the relationships among glucocorticoid exposure, lumbar spine areal BMD (LS BMD), and vertebral shape in glucocorticoid-treated children with new-onset nephrotic syndrome.

METHODS

Lateral thoracolumbar spine radiography and LS BMD were performed in 80 children with nephrotic syndrome (median age 4.4 years; 46 boys) within the first 37 days of glucocorticoid therapy. Genant semiquantitative grading was used as the primary method for vertebral morphometry; the algorithm-based qualitative (ABQ) method was used for secondary vertebral deformity analysis.

RESULTS

Six of the 78 children with usable radiographs (8%; 95% confidence interval 4 to 16%) manifested a single Genant grade 1 deformity each. All deformities were mild anterior wedging (two at each of T6, T7, and T8). Four of the 78 children (5%; 95% confidence interval 2 to 13%) showed one ABQ sign of fracture each (loss of endplate parallelism; two children at T6 and two at T8). Two of the children with ABQ signs also had a Genant grade 1 deformity in the same vertebral body. None of the children with a Genant or ABQ deformity reported back pain. An inverse relationship was identified between LS BMD Z-score and glucocorticoid exposure.

CONCLUSIONS

Although we identified an inverse relationship between steroid exposure and LS BMD soon after glucocorticoid initiation for childhood nephrotic syndrome, there was only a low rate of vertebral deformities. The clinical significance of these findings requires further study.

Adding sirolimus to tacrolimus-based immunosuppression in pediatric renal transplant recipients reduces tacrolimus exposure

In adult renal recipients, coadministration of tacrolimus (TAC) and sirolimus (SIR) results in reduced exposure to TAC at SIR doses of 2 mg/day. Eight pediatric renal recipients (median age at transplant 2.0 years, range: 1.2-12.9 years) were converted to TAC- and SIR-based immunosuppression as a rescue therapy. All patients had biopsy-proven chronic allograft nephropathy. TAC levels were measured using a commercially available EMIT assay and SIR levels with a newly developed assay based on the LC-MS MS technology. SIR was started at 0.13+/-0.05 mg/kg/day (3.51+/-1.26 mg/m2/day) in two divided doses. TAC was given at 0.14+/-0.09 mg/kg/day, resulting in a trough level of 6.3+/-2.5 ng/mL. After the addition of SIR, the median dose required to keep TAC blood trough concentrations within the target range increased by 71.2% (range: 21.9-245.4%), dose-normalized TAC exposure (AUC) decreased to 67.1% and the dose-normalized C(max), a surrogate for absorption rate, to 53.8% (both geometric means) while terminal half-life (t1/2), a pharmacokinetic parameter characterizing systemic elimination, remained unchanged (p<0.93). Adding SIR to TAC-based immunosuppression in young pediatric renal transplant recipients results in a significant decrease of TAC exposure. TAC trough levels should be monitored frequently.

Comorbidities in chronic pediatric peritoneal dialysis patients: a report of the International Pediatric Peritoneal Dialysis Network

BACKGROUND, OBJECTIVES, AND METHODS: Hospitalization and mortality rates in pediatric dialysis patients remain unacceptably high. Although studies have associated the presence of comorbidities with an increased risk for death in a relatively small number of pediatric dialysis patients, no large-scale study had set out to describe the comorbidities seen in pediatric dialysis patients or to evaluate the impact of those comorbidities on outcomes beyond the newborn period. In the present study, we evaluated the prevalence of comorbidities in a large international cohort of pediatric chronic peritoneal dialysis (CPD) patients from the International Pediatric Peritoneal Dialysis Network registry and began to assess potential associations between those comorbidities and hospitalization rates and mortality.

RESULTS

Information on comorbidities was available for 1830 patients 0 - 19 years of age at dialysis initiation. Median age at dialysis initiation was 9.1 years [interquartile range (IQR): 10.9], median follow-up for calculation of hospitalization rates was 15.2 months (range: 0.2 - 80.9 months), and total follow-up time in the registry was 2095 patient-years. At least 1 comorbidity had been reported for 602 of the patients (32.9%), with 283 (15.5%) having cognitive impairment; 230 (12.6%), motor impairment; 167 (9.1%), cardiac abnormality; 76 (4.2%), pulmonary abnormality; 212 (11.6%), ocular abnormality; and 101 (5.5%), hearing impairment. Of the 150 patients (8.2%) that had a defined syndrome, 85% had at least 1 nonrenal comorbidity, and 64% had multiple comorbidities. The presence of at least 1 comorbidity was associated with a higher hospitalization rate [hospital days per 100 observation days: 1.7 (IQR: 5.8) vs 1.2 (IQR: 3.9), p = 0.001] and decreased patient survival (4-year survival rate: 73% vs 90%, p < 0.0001).

CONCLUSIONS

Nearly one third of pediatric CPD patients in a large international cohort had at least 1 comorbidity, and multiple comorbidities were frequently reported among patients with a defined syndrome. Preliminary analysis suggests an association between comorbidity and poor outcome in those patients. As this powerful international registry matures, further multivariate analyses will be important to more clearly define the impact of comorbidities on hospitalization rates and mortality in pediatric CPD patients.

Arterial HTN in children with T1DM--frequent and not easy to diagnose

INTRODUCTION

To evaluate the diagnostic efficacy of the office blood pressure (OBP) and ambulatory blood pressure monitoring (ABPM) in the assessment of hypertension (HTN) in children with diabetes mellitus type 1 (T1DM).

METHODS

We analyzed OBP and ABPM measurements in 84 diabetic children (43 boys) obtained at a median age of 14.9 yr and 6.3 +/- 3.5 yr after diagnosis of T1DM. OBP and ABPM results were converted into standard deviation scores (SDS). In addition, we analyzed blood pressure loads and nighttime dipping. The comparison between OBP and ABPM was performed using kappa coefficient and receiver operator curve (ROC).

RESULTS

HTN was diagnosed in 43/84 (51%) patients using OBP (>95th percentile), and in 24/84 (29%) patients using ABPM ( > or = 95th percentile during 24 h, day or night). Both methods were in agreement in 33 ABPM normotensive and 16 ABPM hypertensive patients (most had nighttime HTN); 32% patients had white-coat HTN and 9.5% patients had masked HTN. The kappa coefficient was 0.175 (95% CI from -0.034 to 0.384) suggesting poor agreement between OBP and ABPM. Diastolic OBP was a better predictor of ABPM HTN (ROC area under the curve (AUC) = 0.71 +/- 0.06) than systolic OBP (AUC = 0.58 +/- 0.07). The percentage of non-dippers ranged from 7 to 23% in ABPM normotensive patients, and 21-42% in ABPM hypertensive patients who also had significantly higher BP loads (p < 0.0001).

CONCLUSION

Children with T1DM often suffer from nocturnal, white coat- and masked HTN, which can not be assessed and predicted by the OBP.

Prednisone dosing per body weight or body surface area in children with nephrotic syndrome: is it equivalent?

The current guidelines recommend a dosage of prednisone of 60 mg/m(2) body surface area per day (BSA PRED) for the initial therapy of nephrotic syndrome (NS). Alternatively, a dosage of 2 mg/kg body weight per day (W PRED) can be used. We hypothesized that the BSA PRED and W PRED are not equivalent and analyzed the differences between BSA PRED calculated with various formulas for body surface area (BSA), W PRED and the dose of prednisone prescribed for our patients. We performed a retrospective chart review of the patients at their initial presentation of NS. Thirty-three children were included, of median age 3.34 years at presentation. The W PRED was significantly lower than BSA PRED (P < 0.05), with a median W PRED:BSA PRED ratio of 0.85 [interquartile range (IQR) 0.8 to 0.9]. The difference between W PRED and BSA PRED decreased proportionally to patients' weights up to 30 kg. No differences were noted between the various BSA formulas using both weight and height for the calculation of BSA. The Bland-Altman analysis showed a proportional error between W PRED and BSA PRED up to the average daily dose of 60 mg, with a mean bias of 0.86 (95% limits of agreement = 0.68 to 1.05). Ten out of the 33 patients (30%) were given a lower than recommended BSA PRED dose by more than 5 mg/day. In conclusion, the dosage of prednisone at 2 mg/kg per day versus 60 mg/m(2) per day is not equivalent for patients with weights <30 kg and/or dose <60 mg/day.

Blood pressure rhythmicity and visceral fat in children with hypertension

Primary hypertension is associated with disturbed activity of the sympathetic nervous system and altered blood pressure rhythmicity. We analyzed changes in cardiovascular rhythmicity and its relation with target organ damage during 12 months of antihypertensive treatment in 50 boys with hypertension (median, 15.0 years). The following parameters were obtained before and after 12 months of antihypertensive treatment: 24-hour ambulatory blood pressure, left ventricular mass, carotid intima-media thickness, and MRI for visceral and subcutaneous adipose tissue. Amplitudes and acrophases of mean arterial pressure and heart rate rhythms were obtained for 24-, 12-, and 8-hour periods. After 1 year of treatment, 68% of patients were normotensive, and left ventricular mass and carotid intima-media thickness decreased in 60% and 62% of patients, respectively. Blood pressure and heart rate rhythmicity patterns did not change. Changes in blood pressure amplitude correlated with the decrease of waist circumference (P=0.035). Moreover, the decrease of visceral fat correlated with the decrease of 24-hour mean arterial pressure and heart rate acrophases (both P<0.05). There were no differences in changes of blood pressure and heart rate rhythms between patients who achieved or did not achieve normotension and regression of left ventricular mass and carotid intima-media thickness. It was concluded that abnormal cardiovascular rhythmicity persists in children with primary hypertension despite effective antihypertensive treatment, which suggests that it may be the primary abnormality. The correlation between changes in cardiovascular rhythmicity and visceral obesity may indicate that the visceral fat plays an important role in the sympathetic activity of adolescents with hypertension.

Substantial practice variation exists in the management of childhood nephrotic syndrome

BACKGROUND

Practice variation is common for nephrotic syndrome (NS) treatment.

METHODS

A cross-sectional, web-based survey on NS treatment was administered to 58 Canadian pediatric nephrologists with the aim to document existing practice variation and compare practice with the recommendations of the Kidney Disease Improving Global Outcomes Clinical Practice Guideline for NS.

RESULTS

Of the 58 nephrologists asked to participate in the survey, 40 (69 %) responded. Among these, 62 % prescribed initial daily glucocorticoid (GC) therapy for 6 weeks, 26 % for 4 weeks by 26 %, and 10 % prescribed 'other'. Alternate-day GC was continued for 6 weeks by 63 % of respondents and for >6 and <6 weeks by 32 and 6 %, respectively. For biopsy-confirmed minimal change disease, 65 and 46 % of respondents chose oral cyclophosphamide for frequently relapsing and steroid-dependent phenotypes, respectively; calcineurin inhibitors or mycophenolate were the second most popular choices. Kidney biopsy was 'always' performed by 16, 39, and 97 % of respondents for frequently relapsing, steroid-dependent, and steroid-resistant patients, respectively. Rituximab had been administered by 60 % of respondents; 22, 56, and 72 % reported that they would consider rituximab for frequently relapsing, steroid-dependent, and steroid-resistant patients, respectively. Most notable differences between practice and Guideline recommendations were first presentation GC duration, GC-sparing agent choices in frequently relapsing and steroid-dependent patients, and biopsy practices.

CONCLUSIONS

There is substantial Canadian practice variation in NS treatment. Assessment of factors driving variation and strategies to implement Guideline recommendations are needed.

Skeletal findings in the first 12 months following initiation of glucocorticoid therapy for pediatric nephrotic syndrome

Incident vertebral fractures and lumbar spine bone mineral density (BMD) were assessed in the 12 months following glucocorticoid initiation in 65 children with nephrotic syndrome. The incidence of vertebral fractures was low at 12 months (6 %) and most patients demonstrated recovery in BMD Z-scores by this time point.

INTRODUCTION

Vertebral fracture (VF) incidence following glucocorticoid (GC) initiation has not been previously reported in pediatric nephrotic syndrome.

METHODS

VF was assessed on radiographs (Genant method); lumbar spine bone mineral density (LS BMD) was evaluated by dual-energy X-ray absorptiometry.

RESULTS

Sixty-five children were followed to 12 months post-GC initiation (median age, 5.4 years; range, 2.3-17.9). Three of 54 children with radiographs (6 %; 95 % confidence interval (CI), 2-15 %) had incident VF at 1 year. The mean LS BMD Z-score was below the healthy average at baseline (mean ± standard deviation (SD), -0.5 ± 1.1; p = 0.001) and at 3 months (-0.6 ± 1.1; p < 0.001), but not at 6 months (-0.3 ± 1.3; p = 0.066) or 12 months (-0.3 ± 1.2; p = 0.066). Mixed effect modeling showed a significant increase in LS BMD Z-scores between 3 and 12 months (0.22 SD; 95 % CI, 0.08 to 0.36; p = 0.003). A subgroup (N = 16; 25 %) had LS BMD Z-scores that were ≤-1.0 at 12 months. In these children, each additional 1,000 mg/m(2) of GC received in the first 3 months was associated with a decrease in LS BMD Z-score by 0.39 at 12 months (95 % CI, -0.71 to -0.07; p = 0.017).

CONCLUSIONS

The incidence of VF at 1 year was low and LS BMD Z-scores improved by 12 months in the majority. Twenty-five percent of children had LS BMD Z-scores ≤-1.0 at 12 months. In these children, LS BMD Z-scores were inversely associated with early GC exposure, despite similar GC exposure compared to the rest of the cohort.

Association between obesity and the severity of ambulatory hypertension in children and adolescents

The goal of our study was to analyze the association between obesity and the severity of ambulatory hypertension in obese children. A total of 109 patients with primary obesity ages 7 to 18 years (mean ± SD age 14.1 ± 3.1) were enrolled. Patients were divided into three groups according to body mass index (BMI) Z-scores: group 1 (n = 27): BMI >1.65 and < 3.28 standard deviation scores (SDS); group 2 (n = 55): BMI >3.29 and <4.91 SDS; group 3 (n = 27): BMI >4.92 SDS. Definition and staging of ambulatory hypertension was based on blood pressure (BP) levels and BP load, obtained from ambulatory BP monitoring (ABPM). Only 24% had ambulatory normotension, 25% had ambulatory prehypertension, 3% had hypertension, and 48% had severe ambulatory hypertension. The severity of hypertension increased significantly with the degree of obesity (P = .0027). Daytime systolic, diastolic, and mean arterial BPs increased significantly with increased BMI, whereas the nighttime pressure remained elevated regardless of the degree of obesity. Isolated nighttime hypertension was observed in 25% of patients and 38% were classified as nondippers. Almost 50% of children with obesity and hypertension detected on ABPM suffer from severe ambulatory hypertension. BMI is associated with the severity of ambulatory hypertension and the increase of daytime BP.

White coat hypertension in children: not rare and not benign?

The clinical significance of white coat hypertension (WCH) remains uncertain. We aimed to evaluate the target organ damage (TOD) in children with essential hypertension (HTN) and WCH. We retrospectively analyzed the body mass index (BMI) and ambulatory blood pressure monitoring (ABPM) in 183 untreated children aged 5 to 19 years who were referred for assessment of hypertension and had secondary hypertension ruled out. Left ventricular mass index (LVMi) and carotid intima media thickness (CIMT) were analyzed in a subset of 106 children. WCH was found in 54/183 children (29.5%) who had normal mean arterial pressure (MAP), MAP load, and MAP day/night ratio. However, the mean+/-SD LVMi (g/m(2.7)) was identical in HTN and WCH patients (38.2+/-10.9 vs. 37.0+/-11.3, P=.59); it exceeded the 95th percentile in 40% HTN and 36% WCH patients (NS). The mean CIMT was significantly higher compared with normal, but not different between HTN and WCH; it exceeded the 95th percentile in 26% HTN and 29% WCH patients. WCH was found in up to 30% of children referred for HTN. Patients with WCH have TOD comparable to that found in HTN patients despite similar BMI, significantly lower average BP and BP load and a well-preserved BP dipping pattern.