Effect of elevated blood pressure on quality of life in children with chronic kidney disease

BACKGROUND

Although hypertension is known to have an adverse impact on health-related quality of life (HRQoL) in adults, little is known about the effects of hypertension and use of antihypertensive medications on HRQoL in hypertensive children with chronic kidney disease (CKD).

METHODS

Cross-sectional and longitudinal assessment of impact of elevated blood pressure (BP) and antihypertensive medication use on HRQoL scores obtained in children enrolled in the Chronic Kidney Disease in Children (CKiD) Study. Blood pressure was measured both manually and by ambulatory blood pressure monitoring. HRQoL was assessed with the PedsQL survey.

RESULTS

The study sample included 551 participants with sufficient data for cross-sectional and longitudinal analyses. Cross-sectional analysis of presence of prehypertension or hypertension and impact on HRQoL found mild associations between elevated BP and HRQoL scores with overall PedsQL parent and child scores averaging 79 vs. 76.5 and 83 vs. 78.5, respectively. However, no associations persisted under longitudinal multivariate analysis.

CONCLUSIONS

Despite apparent small effects of elevated BP on HRQoL at baseline, no association was found between the presence of elevated BP and HRQoL over time in children with mild-to-moderate CKD. In addition, antihypertensive medication use did not appear to have an impact on HRQoL in this population.

Reliability of resting blood pressure measurement and classification using an oscillometric device in children with chronic kidney disease

OBJECTIVE

To compare the reliability of blood pressure (BP) readings obtained with an oscillometric device with those obtained by auscultation and assess for differences in BP status classification based on the 2 techniques.

STUDY DESIGN

Resting BP was measured by auscultation and with an oscillometric device at the same encounter in 235 subjects enrolled in the Chronic Kidney Disease in Children study. Resting auscultatory BP values were averaged and compared with averaged oscillometric readings. BP agreement by the 2 methods was assessed using Bland-Altman plots, and BP status classification agreement was assessed by calculation of kappa statistics.

RESULTS

Oscillometric BP readings were higher than auscultatory readings, with a median paired difference of 9 mm Hg for systolic BP (SBP) and 6 mm Hg for diastolic BP (DBP). Correlation for mean SBP was 0.624 and for mean DBP was 0.491. The bias for oscillometric BP measurement was 8.7 mm Hg for SBP (P < .01) and 5.7 mm Hg for DBP (P < .01). BP status classification agreement was 61% for SBP and 63% for DBP, with Kappa values of .31 for SBP and .20 for DBP.

CONCLUSIONS

Compared with auscultation, the oscillometric device significantly overestimated both SBP and DBP, leading to frequent misclassification of BP status.

A novel mutation in the complement factor B gene (CFB) and atypical hemolytic uremic syndrome

We report the case of an 8-year-old girl diagnosed with atypical hemolytic uremic syndrome (aHUS) with a complement factor B (CFB) gene mutation. aHUS is a disease of complement dysregulation. In approximately 50% of patients, mutations are identified in genes encoding regulators of complement-complement factor H (CFH), membrane cofactor protein or complement factor I (CFI)-or activators of complement-complement factor B (CFB) or C3. The mutation in this patient was identified in exon 12 of CFB and changes a lysine at amino acid position 533 to an arginine (c.1598A>G p.Lys533Arg). The two other mutations previously reported in CFB associated with aHUS are c.858C>G, p.F286L in exon 6 and c.967A>Gp.K323E in exon 7.

Polycystic kidneys and del (4)(q21.1q21.3): further delineation of a distinct phenotype

A three year-old boy was evaluated because of growth and developmental delay, hypotonia and dysmorphic features. G-banding analysis revealed a small interstitial deletion of the long arm of chromosome four described as 46,XY,del (4)(q21.1q21.3). This patient's findings on physical exam included relative macrocephaly, frontal bossing, short fingers with clinodactyly and were consistent with the phenotypes of previously reported deletions involving the 4q21--> 4q22 band region (Am. J. Med. Genet. 68 (1997) 400-405). To date there are 10 reported live-born cases with such deletions and similar features. The case reported here delimits a minimal critical region for this phenotype to chromosomal region 4q21. Our patient was also found to have cysts in both his kidneys. The gene for type II polycystic kidney disease (PKD2) has been mapped to chromosomal region 4q21--> 4q23. FISH analysis, with a probe including the PKD2 gene, demonstrated hemizygosity at this locus. Thus the absence of one of the PKD2 alleles in the case reported here is associated with early bilateral cyst development. Kidney ultrasound/autopsy studies were reported in seven of the patients with the characteristic phenotype, and were positive for cysts in four cases including the one presented here (Clin. Genet. 31 (1987) 199-205; Am. J. Med. Genet. 68 (1997) 400-405; Am. J. Med. Genet. 40 (1991) 77-790. Our report supports the presence of a distinct phenotype associated with a deleted chromosomal region within 4q21. Hemizygosity for the PKD2 gene is likely in such deletions and may lead to renal cyst formation.