Isolated Hydronephrosis and Urinary Tract Infection by Two Years of Age: A Population-Based Study.

OBJECTIVE: To evaluate the risk for urinary tract infection (UTI) in infants with isolated hydronephrosis (IH). STUDY DESIGN: A retrospective, population-based study including all infants insured by Clalit Health Services and followed from birth to age 2 years in 3 regions of central Israel. Infants were divided into 3 groups based on electronic medical record diagnoses by age 6 months: (1) control: no urological diagnosis; (2) IH; and (3) complicated urological diagnosis (CUD): any additional nephrological/urological diagnosis with/without HN. The primary outcome was a diagnosis of UTI in the first 2 years of life. RESULTS: The cohort included 340 619 infants (52% male): 333 920 controls, 4369 with IH, and 2331 with CUD. Infants with IH were associated with a greater risk for UTI than control patients (17% vs 4%, P < .001). UTI risk for a male infant with IH was greater than for a female infant in the control group (12.6% vs 6.5%, P < .001). In a multivariable logistic regression analysis, both IH (OR 7.04; 95% CI 6.46-7.66) and CUD (OR 14.9; 95% CI 13.6-16.4) were independently associated with UTI. CONCLUSION: Infants with IH are at a greater risk for UTI in the first 2 years of life, supporting the recommendation for a high index of suspicion for UTI in this population.

Ambulatory Blood Pressure and Number of Subclinical Target Organ Injury Markers in Youth: The SHIP AHOY Study.

Background: Hypertension in adolescence is associated with subclinical target organ injury (TOI). We aimed to determine whether different blood pressure (BP) thresholds were associated with increasing number of TOI markers in healthy adolescents. Methods: 244 participants (mean age 15.5±1.8 years, 60.1% male) were studied. Participants were divided based on both systolic clinic and ambulatory BP (ABP), into low- (<75 th percentile), mid- (75 th -90 th percentile) and high-risk (>90 th percentile) groups. TOI assessments included left ventricular mass, systolic and diastolic function, and vascular stiffness. The number of TOI markers for each participant was calculated. A multivariable general linear model was constructed to evaluate the association of different participant characteristics with higher numbers of TOI markers. Results: 47.5% of participants had at least one TOI marker: 31.2% had one, 11.9% two, 3.7% three, and 0.8% four. The number of TOI markers increased according to the BP risk groups: the percentage of participants with more than one TOI in the low-, mid-, and high groups based on clinic BP was 6.7%, 19.1%, and 21.8% (p=0.02), and based on ABP was 9.6%, 15.8%, and 32.2% (p<0.001). In a multivariable regression analysis, both clinic BP percentile and ambulatory SBP index were independently associated with the number of TOI markers. When both clinic and ABP were included in the model, only the ambulatory SBP index was significantly associated with the number of markers. Conclusion: High SBP, especially when assessed by ABPM, was associated with an increasing number of subclinical cardiovascular injury markers in adolescents.

Blood Pressure Outcomes in NICU-Admitted Infants with Neonatal Hypertension: A Pediatric Nephrology Research Consortium Study.

OBJECTIVE: To describe the blood pressure outcomes of infants admitted to the neonatal intensive care unit (NICU) with idiopathic (nonsecondary) hypertension (HTN) who were discharged on antihypertensive therapy. STUDY DESIGN: Retrospective, multicenter study of 14 centers within the Pediatric Nephrology Research Consortium. We included all infants with a diagnosis of idiopathic HTN discharged from the NICU on antihypertensive treatment. The primary outcome was time to discontinuation of antihypertensive therapy, grouped into (≤6 months, >6 months to 1 year, and >1 year). Comparisons between groups were made with χ2 tests, Fisher's exact tests, and ANOVA. RESULTS: Data from 118 infants (66% male) were included. Calcium channel blockers were the most prescribed class of antihypertensives (56%) in the cohort. The percentages remaining on antihypertensives after NICU discharge were 60% at 6 months, 26% at 1 year, and 7% at 2 years. Antenatal steroid treatment was associated with decreased likelihood of antihypertensive therapy >1 year after discharge. CONCLUSIONS: This multicenter study reports that most infants admitted to the NICU diagnosed with idiopathic HTN will discontinue antihypertensive treatment by 2 years after NICU discharge. These data provide important insights into the outcome of neonatal HTN, but should be confirmed prospectively.

Serologic response to COVID-19 infection or vaccination in pediatric kidney transplant recipients compared to healthy children.

BACKGROUND: Differences in serologic response to COVID-19 infection or vaccination were reported in adult kidney transplant recipients (KTR) compared to non-immunocompromised patients. This study aims to compare the serologic response of naturally infected or vaccinated pediatric KTR to that of controls. METHODS: Thirty-eight KTR and 42 healthy children were included; aged ≤18 years, with a previously confirmed COVID-19 infection or post COVID-19 vaccination. Serological response was measured by anti-spike protein IgG antibody titers. Response post third vaccine was additionally assessed in KTR. RESULTS: Fourteen children in each group had previously confirmed infection. KTR were significantly older and developed a 2-fold higher antibody titer post-infection compared to controls [median (interquartile range [IQR]) age: 14.9 (7.8, 17.5) vs. 6.3 (4.5, 11.5) years, p = 0.02; median (IQR) titer: 1695 (982, 3520) vs. 716 (368, 976) AU/mL, p = 0.03]. Twenty-four KTR and 28 controls were vaccinated. Antibody titer was lower in KTR than in controls [median (IQR): 803 (206, 1744) vs. 8023 (3032, 30,052) AU/mL, p < 0.001]. Fourteen KTR received third vaccine. Antibody titer post booster in KTR reached similar levels to those of controls post two doses [median (IQR) 5923 (2295, 12,278) vs. 8023 (3034, 30,052) AU/mL, p = 0.37] and to KTR post natural infection [5282 AU/mL (2583, 13,257) p = 0.8]. CONCLUSION: Serologic response to COVID-19 infection was significantly higher in KTR than in controls. Antibody level in KTR was higher in response to infection vs. vaccination, contrary to reports in the general population. Response to vaccination in KTR reached levels comparable to controls only after third vaccine.

Hypertension in Pediatric Solid Organ Transplant Recipients.

PURPOSE OF REVIEW: To review the current literature regarding hypertension (HTN) following pediatric solid organ transplant (SOTx), including definition, prevalence, risk factors, outcomes, and treatment. RECENT FINDINGS: In recent years several new guidelines for the definition, monitoring, and management of pediatric HTN have been published, but with no specific recommendations regarding SOTx recipients. HTN remains highly prevalent, yet underdiagnosed and undertreated in kidney transplant (KTx) recipients, especially when ambulatory blood pressure monitoring (ABPM) is utilized. There are little data regarding its prevalence in other SOTx recipients. HTN in this population is multifactorial and is associated with HTN status prior to Tx, demographic factors (age, sex, and race), weight status, and immunosuppression protocol. HTN is associated with subclinical cardiovascular (CV) end-organ damage, including left ventricular hypertrophy (LVH) and arterial stiffness, yet there are no recent data regarding its long-term outcomes. There are also no updated recommendations regarding the optimal management of HTN in this population. Given its high prevalence and the young age of this population facing years at increased CV risk, post-Tx HTN requires more clinical attention (routine monitoring, frequent application of ABPM, better BP control). Additional research is needed for a better understanding of its long-term outcomes as well as its treatment and treatment goals. Much more research is needed regarding HTN in other pediatric SOTx populations.

Comparison of validation protocols for blood pressure measuring devices in children and adolescents.

Accuracy of blood pressure (BP) measurement is important for the evaluation of hypertension in children and adolescents, and it is critically dependent upon the accuracy of the BP measuring device. A device that could pass validated protocols with reliable accuracy would be desirable in clinical and research settings. Several scientific organizations have published recommendations on the validation of different BP measuring devices. Most of them focus on adults but separate recommendations and validation criteria for BP devices intended for use in children and adolescents are included in some validation protocols. In this review, we compare the validation criteria for BP measuring devices among consensus documents from different scientific organizations focusing on the pediatric population and we discuss the evidence gaps targeting the needs for validated BP measuring devices in children and adolescents. We also highlight common pitfalls in the validation studies of BP measuring devices in children and adolescents using the example of office BP devices.

[NEPHROTIC SYNDROME RECURRENCE POST-RENAL TRANSPLANTATION: 10 YEARS' EXPERIENCE AT SCHNEIDER CHILDREN'S MEDICAL CENTER IN ISRAEL].

INTRODUCTION: A total of 30-50% of pediatric patients presenting with steroid resistant nephrotic syndrome (SRNS) will reach end stage renal disease (ESRD). In patients with primary SRNS, the risk of post-transplant recurrence is around 60% with poor graft outcomes. In the past decade new treatment modalities have emerged in an attempt to improve graft outcomes. AIMS: To describe the clinical experience at the Schneider Children's Medical Center in Israel in treating children with post-transplant recurrent SRNS in the past decade, and compare its results to a similar study conducted at the same center in previous years. METHODS: A retrospective chart review was conducted. Data regarding demographic characteristics, clinical course and treatment modalities of patients with post-transplant recurrent SRNS were extracted from patients' charts. RESULTS: Eight patients with post-transplant recurrent SRNS were identified. Median age at initial nephrotic syndrome presentation was 4 (range: 0.8-15) years. Median time to reach ESRD was 43 (range: 12-132) months. All patients were treated with plasmapheresis, seven patients were treated with Rituximab. Low-density lipoprotein (LDL) apheresis, Ofatumumab and Abatacept were used in 1-2 patients each. Median follow-up time post-transplant was 47 (range: 15-93) months. Four patients (50%) responded to treatment, two achieved complete and two partial remission. Four patients reached ESRD within a median time of 24 (range: 12-84) months. Lower rates of acute tubular necrosis and immediate graft loss were observed during the last decade compared to previous years (37.5% vs. 64%; 0% vs. 28.6% respectively). CONCLUSIONS: Post-transplant recurrence of SRNS continues to pose a significant treatment challenge. Similar to previous reports, only 50% of our patients responded to treatment while 50% were unresponsive to all treatment modalities and reached ESRD. Immediate post-operative management improved over the last decade, however long-term outcome continues to be grim. There is a need to better identify disease mechanisms that will allow us to tailor more effective treatment modalities to improve patients' outcome.

Clinical Outcomes and Antibody Response in COVID-19-Positive Pediatric Solid Organ Transplant Recipients.

We describe the clinical and laboratory manifestations and outcomes of 25 pediatric solid organ transplant recipients who tested positive for severe acute respiratory coronavirus-2. Twenty-one (84%) developed a mild disease; 22 of 23 (96%) had a positive serologic response. Two patients (8%), both kidney transplant recipients with additional comorbidities, developed a severe disease. The findings emphasize the need for close monitoring of this population.

Serological Response to the BNT162b2 COVID-19 mRNA Vaccine in Adolescent and Young Adult Kidney Transplant Recipients.

BACKGROUND: Initial reports in adult kidney transplant recipients (KTR) indicate low immunogenicity after 2 doses of the BNT162b2 COVID-19 mRNA vaccine. We describe the immunogenicity of this vaccine compared to the serologic response in naturally infected COVID-19 positive adolescent and young adult KTR. METHODS: For this prospective observational study, the study group included 38 KTR who received 2 doses of the tested vaccine, and the control group included 14 KTR who had a previous polymerase chain reaction-confirmed COVID-19 infection. RESULTS: The mean age was 18 ± 3 y. Positive serologic responses were observed in 63% and 100% of the study and control groups, respectively (P = 0.01). Antibody titers were almost 30-fold higher in the control than the study group (median [interquartile range (IQR)]: 2782 [1908-11 000] versus 100.3 [4.7-1744] AU/mL, P < 0.001), despite the longer time from the COVID-19 infection to serologic testing compared to time from vaccination (median [IQR]: 157.5 [60-216] versus 37 [20.5-53] d, P = 0.011). Among vaccinated patients, higher proportions of those seronegative than seropositive were previously treated with rituximab (50% versus 8%, P = 0.01). Time from the second vaccine dose to serologic testing was longer in seropositive than seronegative patients (median [IQR]: 24.5 [15-40] versus 46 [27-56] d, P = 0.05). No patient developed symptomatic COVID-19 disease postvaccination. CONCLUSIONS: The BNT162b2 COVID-19 mRNA vaccine yielded higher positive antibody response in adolescent and young adult KTR than previously reported for adult KTR. Antibody titers after vaccination were significantly lower than following COVID-19 infection. Longer time may be required to mount appropriate humoral immunity to vaccination in KTR.

Pediatric and Adult Ambulatory Blood Pressure Thresholds and Blood Pressure Load as Predictors of Left Ventricular Hypertrophy in Adolescents.

[Figure: see text].

[PRIMARY HYPERTENSION IN CHILDREN AND ADOLESCENTS].

INTRODUCTION: The prevalence of pediatric primary hypertension (HTN) has increased in the past few decades, most probably related to the increased prevalence of overweight/obesity in this population. According to various estimates 3.5-5% of children and adolescents have HTN. Children and especially adolescents with HTN are at an increased risk for HTN in early adulthood, and for early subclinical cardiovascular morbidity. Therefore, screening for and treatment of pediatric HTN is highly recommended, especially in high risk populations, such as overweight children. In the past few years, new guidelines for the diagnosis, evaluation and treatment of pediatric HTN were published by both the European Society of Hypertension and the American Academy of Pediatrics. The following review will discuss central aspects of the epidemiology, risk factors, definitions, and initial clinical approach of primary HTN in children and adolescents.

Association of Blood Pressure Level With Left Ventricular Mass in Adolescents.

Hypertension is associated with left ventricular hypertrophy (LVH), a risk factor for cardiovascular events. Since cardiovascular events in youth are rare, hypertension has historically been defined by the 95th percentile of the normal blood pressure (BP) distribution in healthy children. The optimal BP percentile associated with LVH in youth is unknown. We aimed to determine the association of systolic BP (SBP) percentile, independent of obesity, on left ventricular mass index (LVMI), and to estimate which SBP percentile best predicts LVH in youth. We evaluated SBP, anthropometrics, and echocardiogram in 303 adolescents (mean age 15.6 years, 63% white, 55% male) classified by SBP as low-risk (L=141, <80th percentile), mid-risk (M=71, 80-<90th percentile), or high-risk (H=91, ≥90th percentile) using the mean of 6 measurements at 2 visits according to the 2017 guidelines. Logistic regression was used to determine the sensitivity and specificity of various SBP percentiles associated with LVH. Results: BP groups did not differ by age or demographics but differed slightly by body mass index. Mean BP, LVMI, and prevalence of LVH increased across groups (BP: L=111/75, M=125/82, and H=133/92 mm Hg; LVMI: L=31.2, M=34.2, and H=34.9 g/m2.7; LVH: L=13%, M=21%, H=27%, all P<0.03). SBP percentile remained a significant determinant of LVMI after adjusting for covariates. The 90th percentile for SBP resulted in the best balance between sensitivity and specificity for predicting LVH (LVMI≥38.6 g/m2.7). Abnormalities in cardiac structure in youth can be found at BP levels below those used to define hypertension.

Hypertensive crisis in children and adolescents.

Hypertensive crisis is a relatively rare condition in children. However, if not treated, it might be life-threatening and lead to irreversible damage of vital organs. Clinical presentation of patients with hypertensive crisis can vary from very mild (hypertensive urgency) to severe symptoms (hypertensive emergency) despite similarly high blood pressure (BP). Individualized assessment of patients presenting with high BP with emphasis on the evaluation of end-organ damage rather than on the specific BP number is a key in guiding physician's initial management of a hypertensive crisis. The main aim of the treatment of hypertensive crisis is the prevention or treatment of life-threatening complications of hypertension-induced organ dysfunction, including neurologic, ophthalmologic, renal, and cardiac complications. While the treatment strategy must be directed toward the immediate reduction of BP to reduce the hypertensive damage to these organs, it should not be at a too fast rate to cause hypoperfusion of vital organs by an excessively rapid reduction of BP. Thus, intravenous continuous infusions rather than intravenous boluses of antihypertensive medications should be the preferable mode of initial treatment of children with hypertensive emergency.

Ambulatory blood pressure monitoring tolerability and blood pressure status in adolescents: the SHIP AHOY study.

BACKGROUND: Ambulatory blood pressure monitoring (ABPM) provides a more precise assessment of blood pressure (BP) status than clinic BP and is currently recommended in the evaluation of elevated BP in children and adolescents. Yet, ABPM can be uncomfortable for patients and cumbersome to perform. OBJECTIVE: Evaluation of the tolerability to ABPM in 232 adolescent participants (median age: 15.7 years, 64% white, 16% Hispanic, 53% male) in the Study of Hypertension In Pediatrics Adult Hypertension Onset in Youth and its potential effects on ABPM results. PARTICIPANTS AND METHODS: Ambulatory BP status (normal vs. hypertension) was determined by sex and height-specific pediatric cut-points. Participants were asked to rank their wake and sleep tolerability to ABPM from 1 (most tolerant) to 10 (least tolerant); those with tolerability score of at least 8 were considered ABPM intolerant. RESULTS: Forty-three (19%) participants had wake ambulatory hypertension (HTN), 42 (18%) had sleep ambulatory HTN, and 64 (28%) had overall (wake and/or sleep) ambulatory HTN. Forty (17%) participants were intolerant to ABPM during wake hours and 58 (25%) were intolerant during sleep. ABPM intolerance during wake (but not sleep) hours was independently associated with wake (odds ratio: 2.34, 95% confidence interval: 1.01-5.39) and overall (odds ratio: 2.94, 95% confidence interval: 1.21-7.18) ambulatory HTN. CONCLUSION: Poor tolerability to ABPM is associated with a higher prevalence of ambulatory HTN in adolescents, and should be taken into consideration at time of ABPM interpretation.

Prediction of Ambulatory Hypertension Based on Clinic Blood Pressure Percentile in Adolescents.

Ambulatory blood pressure (BP) monitoring provides a more precise measure of BP status than clinic BP and is currently recommended in the evaluation of high BP in children and adolescents. However, ambulatory BP monitoring may not always be available. Our aim was to determine the clinic BP percentile most likely to predict ambulatory hypertension. We evaluated clinic and ambulatory BP in 247 adolescents (median age, 15.7 years; 63% white; 54% male). Clinic BP percentile (based on the fourth report and the 2017 American Academy of Pediatrics clinical practice guidelines) and ambulatory BP status (normal versus hypertension) were determined by age-, sex-, and height-specific cut points. Sensitivity and specificity of different clinic BP percentiles and cutoffs to predict ambulatory hypertension were calculated. Forty (16%) and 67 (27%) patients had systolic hypertension based on the fourth report and the 2017 guidelines, respectively, whereas 38 (15%) had wake ambulatory systolic hypertension. The prevalence of ambulatory wake systolic hypertension increased across clinic systolic BP percentiles, from 3% when clinic systolic BP was <50th percentile to 41% when ≥95th percentile. The 2017 guidelines' 85th systolic percentile had similar sensitivity (86.8%) and better specificity (57.4% versus 48.1%) than elevated BP (≥90th percentile or ≥120 mm Hg) to diagnose ambulatory hypertension. When evaluating adolescents for hypertension, 2017 guidelines' clinic systolic 85th percentile may be the optimal threshold at which to perform ambulatory BP monitoring.

SHIP-AHOY (Study of High Blood Pressure in Pediatrics: Adult Hypertension Onset in Youth).

Although hypertension is identifiable in children and adolescents, there are many knowledge gaps on how to best define and manage high blood pressure in the young. SHIP-AHOY (Study of High Blood Pressure in Pediatrics: Adult Hypertension Onset in Youth) is being conducted to address these knowledge gaps. Five hundred adolescents will be recruited and will undergo ambulatory blood pressure monitoring, echocardiographic, vascular, and cognitive assessments, as well as epigenetic studies to identify mechanisms that underlie the development of hypertensive target organ damage. Details of the design and methods that will be utilized in SHIP-AHOY are presented here, as well as baseline characteristics of the first 264 study participants. The primary aim of the study is to develop a risk-based definition of hypertension in the young that will result in better understanding of the transition from blood pressure in youth to adult cardiovascular disease.

IGG3 anti-HLA donor-specific antibodies and graft function in pediatric kidney transplant recipients.

Anti-HLA DSAs are associated with ABMR and graft loss in KT recipients, yet the influence of DSA IgG subclass on outcomes in pediatric KT recipients is not completely understood. We performed a single-center retrospective chart review of pediatric KT recipients with anti-HLA DSAs, aiming to study the association between specific DSA IgG subclasses and graft outcomes, including ABMR and significant graft dysfunction (graft loss or 50% decrease in eGFR). Thirty-six patients (mean age 15.4y) with DSAs initially detected 1 month-14.3 years post-transplantation were followed for a median of 2.8 years. Rates of IgG1, 2, 3, and 4 subclass detection were 92%, 33%, 58%, and 25%, respectively. Twenty-two patients (61%) had clinical ABMR, whereas 19% had subclinical ABMR, and 13 (36%) experienced significant graft dysfunction. Patients with IgG3+ DSAs had a higher risk of graft dysfunction compared with IgG3- patients (52% vs 13%, P = .03). In a multiple Cox proportional regression analysis, the presence of IgG3+ DSA was independently associated with significant graft dysfunction (HR 10.45, 95% CI 1.97-55.55, P = .006). In conclusion, IgG3 subclass DSAs are associated with graft dysfunction and may be useful for risk stratification and treatment decisions in DSA-positive pediatric KT recipients.

Ambulatory Blood Pressure Control in Children and Young Adults After Kidney Transplantation.

BACKGROUND: Ambulatory blood pressure (BP) monitoring (ABPM) is the preferred method to characterize BP status, and its use in kidney transplant recipients is increasing. Data on longitudinal ambulatory BP (ABP) trends in pediatric and young adult kidney transplant recipients are limited. METHODS: Retrospective review of a large cohort of children and young adults following kidney transplantation and evaluation of their ABP status over time and its associations with any patient and clinical characteristics. RESULTS: Two hundred and two patients had baseline ABPM available for analysis, and 123 of them had a follow up (median time 2.3 years) ABPM. At the time of follow up, more patients were treated for hypertension (80% vs. 72%, P = 0.02), and less patients had ambulatory hypertension (36% vs. 54%, P = 0.005), uncontrolled or untreated, compared with baseline, with 45% of all patients classified as having controlled hypertension (compared to 26% at baseline, P = 0.002). Prevalence of ambulatory hypertension decreased only in patients who were less than 18 years old at baseline. High baseline mean 24-hour systolic BP was independently associated with persistent hypertension. CONCLUSIONS: In young kidney transplant recipients followed by ABPM, the prevalence of ambulatory hypertension decreases over time, mainly due to the increased number of patients with controlled hypertension.

Ambulatory Blood Pressure, Left Ventricular Hypertrophy, and Allograft Function in Children and Young Adults After Kidney Transplantation.

BACKGROUND: Hypertension is a common complication and is an important risk factor for graft loss and adverse cardiovascular outcomes in pediatric kidney transplantation. Ambulatory blood pressure monitoring (ABPM) is the preferred method to characterize blood pressure status. METHODS: We conducted a retrospective review of a large cohort of children and young adults with kidney transplant to estimate the prevalence of abnormal ambulatory blood pressure (ABP), assess factors associated with abnormal ABP, and examine whether ambulatory hypertension is associated with worse allograft function and left ventricular hypertrophy (LVH). RESULTS: Two hundred twenty-one patients had ABPM, and 142 patients had echocardiographic results available for analysis. One third of the patients had masked hypertension, 32% had LVH, and 38% had estimated glomerular filtration rate less than 60 mL/min per 1.73 m. African-American race/Hispanic ethnicity and requirement for more than 1 antihypertensive medication were independently associated with having masked hypertension. In a multivariate analysis, abnormal blood pressure (masked or sustained hypertension combined) was an independent predictor for LVH among patients not receiving antihypertensive treatment (P = 0.025). In a separate analysis, the use of antihypertensive medications was independently associated with worse allograft function (P = 0.002) although abnormal blood pressure was not a significant predictor. CONCLUSIONS: In young kidney transplant recipients, elevated ABP is frequently unrecognized and undertreated. The high prevalence of abnormal ABP, including masked hypertension, and its association with LVH supports the case for routine ABPM and cardiac structure evaluation as the standard of care in these patients.

Masked hypertension and allograft function in pediatric and young adults kidney transplant recipients.

Masked hypertension is a common complication of pediatric kidney transplantation. While office hypertension is known to be associated with worse short- and long-term graft function, the role of masked hypertension in allograft dysfunction is not clear. We conducted a retrospective cross-sectional analysis of 77 consecutive pediatric kidney transplant recipients who had routine 24-h ambulatory blood pressure monitoring with the aims to estimate the prevalence of masked hypertension and examine its association with allograft function. Masked hypertension was defined as a 24-h systolic or diastolic blood pressure load ≥25%. Twenty-nine percent of patients had masked hypertension. Patients with masked hypertension had significantly lower allograft function estimated using the creatinine-based Schwartz-Lyon formula, a cystatin C-based formula, and combined cystatin C and creatinine-based formulas than patients with normal blood pressure (all p values <0.05). In a multivariable analysis, masked hypertension remained independently associated with worse allograft function after adjustment for age, sex, race, time post-transplant, rejection history, antihypertensive treatment, and hemoglobin level. We conclude that in young kidney transplant recipients, masked hypertension is common and is associated with worse allograft function. These results support the case for routine ambulatory blood pressure monitoring as the standard of care in these patients to detect and treat masked hypertension.