Bladder volume at onset of reflux on initial cystogram predicts spontaneous resolution

Reflux grade is the factor most commonly used to predict spontaneous reflux resolution. We evaluated other potential predictive factors aside from reflux grade relative to spontaneous resolution.

We reviewed the records of 20 males and 98 females who were diagnosed with primary vesicoureteral reflux between ages 0 and 7 years between 1990 and 2000. Age, sex, height, weight, reflux grade, bladder volume at onset of reflux and laterality were recorded for the first, second and most recent voiding cystourethrogram or nuclear cystogram before spontaneous resolution or operative intervention.

Of 118 patients 75 (64%) had spontaneous resolution, 27 (23%) underwent corrective surgery and 16 (13%) are still being followed. Average age at diagnosis was 2.3 years (range 1 day to 7.7 years) and average followup was 4.3 years (range 0.2 to 14). Average time to spontaneous resolution was 2.2 years (range 0.5 to 10.3) vs a time to operative treatment of 3.6 years (range 0.2 to 11.2). There was a significantly higher spontaneous resolution rate for lower reflux grades (p = 0.0004). Reflux occurring at greater than 75% of predicted bladder capacity had a significantly higher resolution rate (p = 0.0005). The initial height and weight percentile was not significant for predicting spontaneous resolution. Breakthrough urinary tract infections were negative predictors of spontaneous resolution (p <0.0001).

In addition to grade, bladder volume relative to predicted bladder capacity at the onset of reflux appears to provide additional prognostic information regarding the likelihood of spontaneous resolution of primary vesicoureteral reflux.