The association between abnormal birth history and growth in children with CKD

Abstract

Background and objectives: Poor linear growth is a well described complication of chronic kidney disease (CKD). This study evaluated whether abnormal birth history defined by low birth weight (LBW; <2500 g), prematurity (gestational age <36 weeks), small for gestational age (SGA; birth weight <10th percentile for gestational age), or intensive care unit (ICU) at birth were risk factors for poor growth outcomes in children with CKD.

Design, setting, participants, & measurements: Growth outcomes were quantified by age-sex-specific height and weight z-scores during 1393 visits from 426 participants of the Chronic Kidney Disease in Children Study, an observational cohort of children with CKD. Median baseline GFR was 42.9 ml/min per 1.73 m(2), 21% had a glomerular diagnosis, and 52% had CKD for ≥ 90% of their lifetime.

Results: A high prevalence of LBW (17%), SGA (14%), prematurity (12%), and ICU after delivery (40%) was observed. Multivariate analyses demonstrated a negative effect of LBW (-0.43 ± 0.14; P < 0.01 for height and -0.37 ± 0.16; P = 0.02 for weight) and of SGA (-0.29 ± 0.16; P = 0.07 for height and -0.41 ± 0.19; P = 0.03 for weight) on current height and weight. In children with glomerular versus nonglomerular diagnoses, the effect of SGA (-1.08 versus -0.18; P = 0.029) on attained weight was more pronounced in children with a glomerular diagnosis.

Conclusions: LBW and SGA are novel risk factors for short stature and lower weight percentiles in children with mild to moderate CKD independent of kidney function.

Figure 1.

(Left) Histogram of 1393 age-sex-specific height z-scores with mean −0.68 and SD 1.16 with the density function from a Gaussian distribution with mean −0.68 and SD 1.16 superimposed. (Right) Histogram of 1383 age-sex-specific weight z-scores with mean −0.09 and SD 1.27 with the density function from a Gaussian distribution with mean −0.09 and SD 1.27 superimposed.

Figure 2.

Multivariate CKD diagnosis-specific repeated measures analyses of abnormal birth history exposures on age-sex-specific height z-scores. Point estimates of the mean differences (b_G) and 95% CIs in age-sex-specific height z-scores comparing those with the indicated abnormal birth exposure to those without the birth abnormality among those with a glomerular diagnosis of CKD are indicated by the diamond-shaped points and dashed vertical lines, respectively. Point estimates of the mean differences (b_NG) and 95% CIs in age-sex-specific height z-scores comparing those with the indicated abnormal birth exposure to those without the birth abnormality among those with a nonglomerular diagnosis of CKD are indicated by the diamond-shaped points and continuous vertical lines, respectively. The P values indicate the significance of any differential effects of the primary exposure on height z-score in those with a glomerular diagnosis of CKD compared with those with a nonglomerular diagnosis (i.e., is b_G ≠ b_NG). All analyses were adjusted for sex, race, age, percentage of life with CKD, and mid-parental height.

Figure 3.

Multivariate CKD diagnosis-specific repeated measures analyses of abnormal birth history exposures on age-sex-specific weight z-scores. Point estimates of the mean differences (b_G) and 95% CIs in age-sex-specific weight z-scores comparing those with the indicated abnormal birth exposure to those without the birth abnormality among those with a glomerular diagnosis of CKD are indicated by the diamond-shaped points and dashed vertical lines, respectively. Point estimates of the mean differences (b_NG) and 95% CIs in age-sex-specific weight z-scores comparing those with the indicated abnormal birth exposure to those without the birth abnormality among those with a nonglomerular diagnosis of CKD are indicated by the diamond-shaped points and continuous vertical lines, respectively. The P values indicate the significance of any differential effects of the primary exposure on weight z-score in those with a glomerular diagnosis of CKD compared with those with a nonglomerular diagnosis (i.e., is b_G ≠ b_NG). All analyses were adjusted for sex, race, age, percentage of life with CKD, and mid-parental height.