Eight RCTs were included (947 children enrolled; data were available for 859 children).
Five RCTs reported an adequate method of randomisation. Two RCTs reported that the radiologists were blinded to the treatment group. Three RCTs did not analyse data on an intention-to-treat basis and it was unclear whether any of the other RCTs has used intention-to-treat analysis. Studies reported low rates of losses to follow-up: 0 to 2% at 1 to 2 years, and 9 to 42% after 4 to 10 years.
Antibiotics versus antibiotics plus surgery (7 RCTs).
UTI: the meta-analysis showed no significant difference in UTI after 2 years or after 5 years between antibiotics alone and antibiotics plus surgery; the RR was 1.07 (95% CI: 0.55, 2.09) at 2 years (4 RCTs), and 0.99 (95% CI: 0.79, 1.26) after 5 years (3 RCTs). The meta-analysis showed that combined treatment reduced febrile UTI at 5 years compared with antibiotics alone; the RR (2 RCTs) was 0.43 (95% CI: 0.27, 0.70). No significant heterogeneity was detected for any of these meta-analyses (P>0.2). There was no significant difference in symptomatic UTI; the RR (European arm of 1 RCT) was 0.96 (95% CI: 0.67, 1.39).
Renal parenchymal abnormality: the meta-analysis showed no significant difference for new or progressive parenchymal abnormalities (detected using intravenous pyelography) at 2 years, or at 4 to 5 years. The RR of new defects was 1.06 (95% CI: 0.33, 3.42) at 2 years (2 RCTs) and 1.06 (95% CI: 0.77, 1.45) at 4 to 5 years (4 RCTs); the RR of progressive defects was 1.62 (95% CI: 0.25, 10.48) at 2 years (2 RCTs) and 0.97 (95% CI: 0.67, 1.40) at 4 to 5 years (3 RCTs). No significant heterogeneity was detected for any of these meta-analyses (P>0.1).
One RCT that also assessed renal parenchymal abnormalities using Tm-dimercaptosuccinic acid scintigraphy found that combined treatment increased new or progressive lesions compared with antibiotics alone, but the increase was not statistically significant (RR 1.05, 95% CI: 0.62, 1.77). Renal growth: it was not possible to perform a meta-analysis for studies reporting renal growth because of differences in the reported data. Four RCTs found no significant difference between treatments at 2 to 10 years.
End-stage renal failure (2 RCTs): three children in each treatment arm developed end-stage renal failure.
Hypertension (2 RCTs): five children treated with antibiotics alone developed hypertension compared with three who received combined treatment.
Glomerular filtration rate (4 RCTs): no individual study found any significant difference between the treatments.
Resolution of reflux (6 RCTs): the studies reported the results in different units (ureters or patients). Four RCTs found the resolution rates at 4 to 5 years were 93 to 99% after surgery and 16 to 49% for spontaneous resolution. One RCT found the resolution rate at 12 months was 69% after Dx/HA copolymer subureteric implantation compared with 38% with antibiotics alone.
Adverse effects: these were generally poorly reported. One arm of one RCT found postoperative urinary tract obstruction in 6.6% (10 out of 151) of children. One RCT (179 children) found no cases of obstruction after 5 years. None of the other studies mentioned obstruction.
Antibiotics compared with no treatment (1 RCT, 43 children entered, 29 analysed).
The RCT found no significant difference in UTI or renal parenchymal abnormality between treatments; the RR was 0.25 (95% CI: 0.03, 1.85) for UTI and 0.40 (95% CI: 0.02, 9.18) for renal parenchymal abnormality. The RCT might have been too small to detect a significant difference. The RCT did not report adverse effects.