Background: We report the long-term follow-up of children with antenatally detected unilateral multicystic dysplastic kidney (MCDK) who were followed between 1985 and 2009.
Methods: Involution rates were documented over time based on the initial size of the MCDK, as documented on postnatal ultrasound (USS), as well as long-term complications and renal function.
Results: In 323 patients (182 male), 10 % of MCDK had involuted, as evidenced on the first postnatal USS, with survival function analysis showing the probability of complete involution to be 35 % in 249 patients by 2 years of age, 47 % in 180 patients by 5 years of age and 62 % in 94 patients by 10 years of age. There was a significant difference in the involution rates of MCKD at the 10-year follow-up between MCDK with an initial size of >5 cm versus MCDK with an initial size of ≤5 cm (p < 0.0001). No patients in the whole cohort developed sustained hypertension or malignancy during a median follow-up of 10.1 years (range 0.3-15.4 years). Median estimated glomerular filtration rate (eGFR) in 76 patients (7 at 5 years, 69 at 10 years) was 93 ml/min/1.73 m(2) (range 46-175 ml/min/1.73 m(2)), with 40 (53%) having an eGFR of between 90 and 140 ml/min/1.73 m(2). Twenty-three (30 %) of the 76 patients at 10 years had normal eGFR (90-140 ml/min/1.73 m(2)) as well as complete involution of the MCDK, compensatory hypertrophy of the contralateral kidney, no proteinuria and no hypertension.
Conclusions: Larger MCDK at birth are less likely to involute during the first decade of life. However, conservative management remains justified due to the lack of complications. A minority of patients fulfil current criteria for discharge from specialty follow-up at 10 years.