Does gestational diabetes increase the risk of maternal kidney disease? A Swedish national cohort study.

Background: Gestational diabetes (GDM) is associated with increased risk of type 2 diabetes (T2DM) and cardiovascular disease. It is uncertain whether GDM is independently associated with the risk of chronic kidney disease. The aim was to examine the association between GDM and maternal CKD and end-stage kidney disease (ESKD) and to determine whether this depends on progression to overt T2DM.

Methods: A population-based cohort study was designed using Swedish national registry data. Previous GDM diagnosis was the main exposure, and this was stratified according to whether women developed T2DM after pregnancy. Using Cox regression models, we estimated the risk of CKD (stages 3-5), ESKD and different CKD subtypes (tubulointerstitial, glomerular, hypertensive, diabetic, other).

Findings: There were 1,121,633 women included, of whom 15,595 (1·4%) were diagnosed with GDM. Overall, GDM-diagnosed women were at increased risk of CKD (aHR 1·81, 95% CI 1·54-2·14) and ESKD (aHR 4·52, 95% CI 2·75-7·44). Associations were strongest for diabetic CKD (aHR 8·81, 95% CI 6·36-12·19) and hypertensive CKD (aHR 2·46, 95% CI 1·06-5·69). These associations were largely explained by post-pregnancy T2DM. Among women who had GDM + subsequent T2DM, strong associations were observed (CKD, aHR 21·70, 95% CI 17·17-27·42; ESKD, aHR 112·37, 95% CI 61·22-206·38). But among those with GDM only, associations were non-significant (CKD, aHR 1·11, 95% CI 0·89-1·38; ESKD, aHR 1·58, 95% CI 0·70-3·60 respectively).

Conclusion: Women who experience GDM and subsequent T2DM are at increased risk of developing CKD and ESKD. However, GDM-diagnosed women who never develop overt T2DM have similar risk of future CKD/ESKD to those with uncomplicated pregnancies.