Influence of low birth weight on minimal change nephrotic syndrome in children, including a meta-analysis

Background. Low birth weight (LBW) has been shown to lead to a low nephron endowment with subsequent glomerular hyperfiltration. Additional renal disease can therefore be expected to have a more severe course. Minimal change nephrotic syndrome (MCNS) is a common chronic illness in childhood. As it is important to be able to predict prognosis in MCNS, we set out to study the effect of LBW on MCNS in a cohort of patients from our University Medical Center, and performed a meta-analysis. Methods. A retrospective chart review of children with MCNS treated at the VU University Medical Center was performed, identifying 55 patients of whom 4 had LBW. The meta-analysis was performed using Review Manager (The Cochrane Collaboration). Results. The meta-analysis consisted of 201 patients (25 LBW, 176 normal birth weight). More LBW patients were classified as steroid resistant [odds ratio (OR) 6.97 (95% confidence interval [CI] 2.02-24.04), P = 0.002]. The number of relapses per year of follow-up was significantly higher in the LBW patients with MCNS [weighted mean difference 0.93 (95% CI 0.71-1.15) relapse per year, P < 0.0001]. MCNS patients with LBW were significantly more likely to be treated with cyclosporine [OR 4.4 (95% CI 1.7-11.8), P = 0.003] or cytotoxic agents [OR 4.2 (95% CI 1.8-10.2), P = 0.001] during the course of their disease, and they had a higher chance of developing several complications during the follow-up period, including hypertension. Conclusions. This meta-analysis provides support for an adverse effect of LBW on the course and prognosis of MCNS in children, which can aid clinicians and parents in assessing the expected clinical course.