How likely is VUR to spontaneously resolve?

Spontaneous resolution of VUR occurs more often in lower grades

VUR may spontaneously resolve over time; though, there is no definitive test to predict in which children. It is more likely to do so in children with lower grades of reflux.¹

What is the likelihood of a child outgrowing VUR?

According to the American Urological Association (AUA):

A child who is between the ages of 2-5 years old with grade III VUR (unilateral) has between a 13.4% (at 1 year) and 51.3% (at 5 years) chance of spontaneous VUR resolution²
A child who is between the ages of 5-10 years old with grade III VUR (bilateral) has between a 2.6% (at 1 year) and 12.5% (at 5 years) chance of spontaneous VUR resolution²
In patients aged 25 to 60 months with bilateral VUR grade III, only 30.5% of cases were resolved at 5 years²

Antibiotic prophylaxis may be needed for a significant number of years in nearly half of the patients to protect them from a urinary tract infection (UTI) while their VUR persists. During this time, regular voiding cystourethrograms (VCUGs) are required to assess the condition. Also, the child is still at risk of breakthrough infections despite ongoing antibiotic treatment.

Age and gender matter in VUR resolution

The rate of spontaneous resolution of VUR decreases with increasing patient age. In a retrospective study, VUR resolved significantly slower in children over 13 months compared with children up to the age of 12 months (P<0.03).³

Boys with VUR have a greater likelihood of spontaneous resolution within the first year of life than girls.⁴ In one study, a resolution rate of 29% was reported in boys younger than 1 year with VUR grades IV and V. The same study reported that in both girls and boys after their first year of life, the annual reported resolution rate was only 9%.⁴

While high resolution rates have been reported for low grade VUR—one study reported spontaneous resolution rates of 82% for grade I VUR within 5 years⁵—resolution cannot be expected to occur universally. The longer a child goes without medical intervention, the more likely it is that he or she will suffer long-term consequences associated with VUR.

VUR may not resolve in time to prevent kidney damage

The longer the patient has had VUR, the less likely it is that VUR will resolve on its own, with or without antibiotic treatment.

Reflux does not usually cause renal injury in the absence of infection, but in situations with high-pressure reflux, as in children with posterior urethral valves, neuropathic bladder, and non-neurogenic neurogenic bladder, sterile reflux can cause significant damage¹
Children with high-grade reflux who acquire a UTI are at significant risk for pyelonephritis and new renal scarring¹
In one study, children experiencing a first UTI have a 70% risk of developing acute kidney infection⁶

References:

Elder JS. Vesicoureteral reflux. In: Kliegman R, Nelson WE, eds. Nelson Textbook of Pediatrics. 19th ed. Philadelphia, PA: Elsevier/Saunders; 2011:1834-1838.
American Urological Association. Management and screening of primary vesicoureteral reflux in children: AUA guideline. 2010.
Smellie JM, Jodal U, Lax H, et al. Outcome at 10 years of severe vesicoureteric reflux managed medically: report of the International Reflux Study in Children. J Pediatr. 2001;139(5):656-663. DOI: 10.1067/mpd.2001.117583
Sjöström S, Sillén U, Bachelard M, Hansson S, Stokland E. Spontaneous resolution of high grade infantile vesicoureteral reflux. J Urol. 2004;172:694-698. DOI: 10.1097/01.ju.0000130747.89561.cf
Arant BS Jr. Medical management of mild and moderate vesicoureteral reflux: followup studies of infants and young children. A preliminary report of the Southwest Pediatric Nephrology Study Group. J Urol. 1992;148:1683-1687. DOI: 10.1016/s0022-5347(17)37002
Lin KY, Chiu NT, Chen MJ, et al. Acute pyelonephritis and sequelae of renal scar in pediatric first febrile urinary tract infection. Pediatr Nephrol. 2003;18(4):362-365. DOI: 10.1007/s00467-003-1109-1