The clinical effectiveness and cost-effectiveness of treatments for children with idiopathic steroid-resistant nephrotic syndrome: a systematic review

Abstract

To assess the clinical effectiveness and cost-effectiveness of treatments for children with idiopathic steroid-resistant nephrotic syndrome (SRNS). Electronic databases from inception to February 2006, bibliographies of studies, and experts in the field. Studies were selected, quality assessed and data were extracted using recognised methods agreed a priori. Meta-analysis was undertaken where appropriate using the random effects model. Where data allowed, subgroup analysis was undertaken according to renal histopathology. Two systematic reviews and 11 trials were included in the clinical effectiveness review; however, the quality of reporting and methodology of the included studies was generally poor. No economic evaluations were identified. No statistically significant difference in remission rates was found between cyclophosphamide plus prednisone and prednisone alone for all children or those with focal segmental glomerulosclerosis (FSGS), also the time to response was statistically significantly less with cyclophosphamide (38.4 days versus 95.5 days). Remission rates were not statistically significantly different between intravenous and oral cyclophosphamide. Vomiting was common with intravenous cyclophosphamide, while pneumonia and alopecia occurred in the oral group. Ciclosporin statistically significantly increased the number of children with complete remission compared with placebo or supportive treatment, but not for the FSGS subgroup, adverse effects including infection and hypertension differed little between groups. No differences were found between azathioprine and placebo, with about 13% of each group having remission. Complete or partial remission occurred in six out of seven patients on the 18-month methylprednisolone regimen and three out of five patients on the 6-month regimen, for both groups renal function improved and adverse events such as hypertension and frequent infections occurred. Intravenous dexamethasone and methylprednisolone produced similar complete remission rates, partial remission rates, median time to response (about 10 days) and total number of adverse events, with hypertension as the most common. Six-hour urinary albumin and urinary albumin to creatinine ratio decreased statistically significantly with high-dose but not low-dose enalapril. Tuna fish oil was not associated with any statistically significant improvements in proteinuria, creatinine clearance, serum creatinine or lipid profiles compared with placebo. A very limited literature was found on costs associated with SRNS in children. The pharmaceutical cost of treatment varied considerably: an 8-week course of cyclophosphamide cost less than 6 pounds, while a course of ciclosporin cost almost 900 pounds per year. Treatment with tacrolimus, an alternative to ciclosporin, was estimated to cost in excess of 3400 pounds per year. Healthcare medical management costs were estimated; varying by treatment strategy, they ranged from 250 pounds to 930 pounds per year in patients not experiencing complications. Other longer term costs may also be incurred. Lack of data meant that cost-effectiveness modelling was not feasible. The clinical effectiveness literature on treatments for idiopathic SRNS in children is very limited. The available evidence suggests a beneficial effect of ciclosporin on remission rates and of cyclophosphamide on time to remission; however, the strength of the conclusions drawn is limited by the poor quality of the included studies. The other treatments included in this review were each evaluated by only one study, and none found a statistically significant effect. There is insufficient evidence to determine whether or not there is a clinically significant difference. The available data on costs and outcomes are sparse and do not permit the reliable modelling of the cost-effectiveness of treatments for SRNS at present. A modelling framework is suggested, should more relevant data become available. A well-designed adequately powered randomised controlled trial comparing ciclosporin with other treatments in children with SRNS without genetic mutation is required.