Low Birth Weight and Risk of Progression to End Stage Renal Disease in IgA Nephropathy--A Retrospective Registry-Based Cohort Study.
BACKGROUND
Low Birth Weight (LBW) is a surrogate for fetal undernutrition and is associated with impaired nephron development in utero. In this study, we investigate whether having been born LBW and/or small for gestational age (SGA) predict progression to ESRD in IgA nephropathy (IgAN) patients.


METHODS
Retrospective registry-based cohort study.


METHODS
The Medical Birth Registry has recorded all births since 1967 and the Norwegian Renal Registry has recorded all patients with ESRD since 1980. Based on data from the Norwegian Kidney Biopsy Registry we included all patients diagnosed with IgAN in Norway from 1988-2013. These registries were linked and we analysed risk of progression to ESRD associated with LBW (defined as birth weight less than the 10th percentile) and/or SGA (defined as birth weight less than the 10th percentile for gestational week) by Cox regression statistics.


RESULTS
We included 471 patients, of whom 74 developed ESRD. As compared to patients without LBW, patients with LBW had a hazard ratio (HR) of 2.0 (95% confidence interval 1.1-3.7) for the total cohort, 2.2 (1.1-4.4) for males and 1.3 (0.30-5.8) for females. Corresponding HRs for SGA were 2.2 (1.1-4.2), 2.7 (1.4-5.5) and 0.8 (0.10-5.9). Further analyses showed that as compared to patients with neither LBW nor SGA, patients with either SGA or LBW did not have significantly increased risks (HRs of 1.3-1.4) but patients who were both LBW and SGA had an increased risk (HR 3.2 (1.5-6.8).


CONCLUSIONS
Mean duration of follow-up only 10 years and maximum age only 46 years.


CONCLUSIONS
Among IgAN patients, LBW and/or SGA was associated with increased risk for progression to ESRD, the association was stronger in males.
Department of Internal Medicine, MUHAS, Dar es Salaam, Tanzania.|Department of Clinical Medicine, University of Bergen, Bergen, Norway.
Paschal
P
Ruggajo
Department of Clinical Medicine, University of Bergen, Bergen, Norway.|Department of Medicine, Haukeland University Hospital, Bergen, Norway.
Einar
E
Svarstad
Department of Clinical Medicine, University of Bergen, Bergen, Norway.|Department of Pathology, Haukeland University Hospital, Bergen, Norway.
Sabine
S
Leh
Department of Clinical Medicine, University of Bergen, Bergen, Norway.|Department of Medicine, Haukeland University Hospital, Bergen, Norway.
Hans-Peter
HP
Marti
Medical Birth Registry of Norway, Norwegian Institute of Public Health, Bergen, Norway.|Department of Transplantation Medicine, Rikshospitalet, Oslo University Hospital, Oslo, Norway.
Anna Varberg
AV
Reisæther
Department of Clinical Medicine, University of Bergen, Bergen, Norway.|Department of Medicine, Haugesund Hospital, Haugesund, Norway.
Bjørn Egil
BE
Vikse
D000328:Adult; D018450:Disease Progression; D005260:Female; D005865:Gestational Age; D005922:Glomerulonephritis, IGA / Q000209:etiology* / Q000473:pathology*; D006801:Humans; D007230:Infant, Low Birth Weight / Q000502:physiology*; D007236:Infant, Small for Gestational Age / Q000502:physiology; D007668:Kidney / Q000473:pathology; D007676:Kidney Failure, Chronic / Q000473:pathology*; D008297:Male; D009664:Norway; D047928:Premature Birth / Q000473:pathology; D012042:Registries; D012189:Retrospective Studies; D012307:Risk Factors; D055815:Young Adult