The aim of this study was to determine whether renal function and renal parenchyma were affected in patients who had a continuously indwelling DJ tube for more than two years, and to identify and analyse potential causative factors.

A total of 74 cases with indwelling DJ tubes for more than two years were included in this study. Renal size/parenchymal width (PW) was measured based on CT coronal scans, and the mean PW value and the rate of change of PW were calculated before the initial placement of the DJ tube and at the last follow-up, respectively. Estimated glomerular filtration rate (eGFR), serum creatinine (Scr), blood urea nitrogen (BUN) and blood uric acid (UA) were also recorded at two time points before and after DJ tube placement.

During the mean retention time of 67.94 ± 48.26 months, the mean PW change rates of unilateral DJ tubular stenting kidney and healthy kidney/unilateral kidney were -39.01 ± 26.1% and 16.52 ± 25.4%, respectively, and the differences were statistically significant (P < 0.01). The mean PW rate of change in the isolated kidney group was -30.1 ± 16.2%, but was not statistically significant (P > 0.05). In addition, in the unilateral DJ tube retention group, DJ tube retention time was negatively correlated with the rate of change in mean PW percentage (Pearson correlation coefficient r = -0.470, P = 0.002) and positively correlated with the rate of change in eGFR (Pearson correlation coefficient r = 0.653, P < 0.01). In contrast, in the bilateral DJ tube retention group, there was no significant correlation between the duration of DJ tube retention and the change in mean percentage of PW, but there was a negative correlation with the rate of change in eGFR (Pearson correlation coefficient r = -0.443, P = 0.03).

In patients with unilateral or bilateral indwelling DJ tubes, kidney size may decrease over time despite the presence of an indwelling DJ tube, especially in patients with bilateral indwelling DJ tubes.