Table 1.

Review of the evidence for observational studies with an evaluation of MBD in infants under 2 years with CKD

Authors	Year	Ref	Population	Study design	Aim	Outcome
Rees et al.	2011	[24]	153 infants from 18 countries starting chronic peritoneal dialysis < 24 months	Registry study	Associations of feeding practices and other dialysis-related factors with length and weight gain in children	PTH levels 222 (85 to 529) pg/mL No data on associations of PTH with growth
Borzych et al.	2010	[26]	890 children from 24 countries	Registry study	Assessments of CKD-MBD in peritoneal dialysis	6% < 1 year and 16% < 1–5 years had hypophosphatemia 15% < 1 year and 21% 1–5 years had PTH 9 × above normal (KDIGO) Clinical and radiological symptoms markedly increased when PTH exceeded 300 pg/mL, the risk of hypercalcemia increased with levels below 100 pg/mL, and time-averaged PTH concentrations above 500 pg/mL were associated with impair longitudinal growth Associations were not analyzed separately in infants
Seikaly et al.	2006	[27]	5165 children with GFR < 75	Registry study	Correlates of short stature (< − 1.88) at entry to the registry	0–2 years had a mean height SDS of − 2.3 Ca, P, and PTH were NOT associated with short statures at entry
Schmitz et al.	2021	[74]	41 children, median age 1.1 year, range 0.5–8.0, CKD stage 3 to dialysis	Retrospective multi-center study	To evaluate enteral Ca intake and its association with PTH levels in pre-school children with CKD	Severe Ca deficiency found in 26% of children (with a significant variation between the first and second dietary data collection); 10% of children received enteral Ca above the upper target for age. Negative correlation between dietary calcium intake and PTH levels
Cansick et al.	2007	[28]	35 children aged 0.25 to 8.9 years	Retrospective single center study	Association of growth with PTH in children on dialysis	17 children under 2 years, the median change in HtSDS in the first year on dialysis was + 0.31 (range − 0.78 to 3.13) Significant association of change in HtSDS with ALP but no association of height with PTH in the study population Infants 0–2 years were not analyzed separately
Vidal et al.	2017	[1]	1063 infants 12 months or younger who initiated dialysis therapy in 1991 to 2013	Registry study	The impact of different dialysis modalities on clinical outcomes in young infants with chronic kidney failure	Mean PTH at dialysis initiation 496 (438 to 555) pg/mL similar in PD and HD
Shroff et al.	2006	[30]	98 children (61 boys), twenty-one < 1 year of age and 54 under < 5 years	Single center study	Outcome since 1984 of all children receiving chronic dialysis for > 3 months with a minimum follow-up of 5 (median 7.2) years	The measured intact PTH level at the start of dialysis was less than twice the ULN in 15 (16%) children as compared to a considerably improved control with 80 (88%) children having a PTH level within twice the upper limit of normal at final follow-up or pre-transplantation Separate analysis for infants not available
Shroff et al.	2003	[31]	18 children under 2 years of age received chronic hemodialysis (HD)	Single center study	Morbidity and outcome of chronic HD in children under 2 years of age	Intact PTH was less than twice the upper limit of the reference range for the assay in 41% of the children when HD was started and in 69% (n = 11) after 3 months
Paglialonga et al.	2016	[32]	21 children < 2 yrs at initiation of HD	Registry study	Outcomes in HD	PTH 169 (76–628) pg/mL at baseline, 336 (136–1088) at 6 months, and 207 (64–900) at 12 months
Ledermann et al.	2000	[33]	20 infants with a mean age of 0.34 year (range, 0.02–1 year)	Single center study	Outcome in PD	Intact PTH was less than twice the upper limit of the reference range in 58% of the infants (n = 12) after 6 months of PD and 100% (n = 14) after 1 year, with the values falling within the normal range in 79% Associations with growth were not assessed
Dachy et al.	2020	[5]	17 infants with age 2.6 (0.1;5.9) months at peritoneal dialysis initiation	Retrospective study	Experience of two French tertiary pediatric nephrology centers on 17 infants who began chronic PD before 6 months of age	Before PD, median PTH levels were 212 (6;799) ng/L, decreasing to 130 (23;732) ng/L 3 months after the beginning of PD, and reaching 123 (44;1540) ng/L at the end of PD (p = NS between PD initiation and the end of PD) Associations of PTH with growth were not assessed
Vidal et al.	2012	[34]	84 infants who started CPD at < 1 year of age	Registry study	Growth data analysis was performed only in infants with complete auxological parameters at 0, 6, and 12 months of follow-up	No significant association of catch-up growth with PTH intact PTH at initiation of dialysis was 508 (10–1760) ng/L at t0 and 351 (33–1650) at t12 in those with catch-up growth vs. 683 (163–2000) at t0 and 398 (81–3500) at t12 in those without catch-up growth