#5342 association between longitudinal gfr trajectories and bmd decline rate in patients with ckd stage 2­–4

Abstract Background and Aims Bone mineral density (BMD) predicts fracture risk in patients with chronic kidney disease (CKD). However, there are few studies regarding BMD decline rates in CKD population. In this study, we investigated whether BMD decline rate is associated with baseline estimated glomerular filtration rate (eGFR) and further evaluated with longitudinal eGFR trajectories. Method A prospective cohort study of 1,006 patients with CKD stages 2 through 4 who enrolled in the KoreaN Cohort Study for Outcome in Patients With CKD between 2011 and 2016. BMD was measured using dual-energy X-ray absorptiometry at baseline and year 4. Estimated GFR was measured 2–5 times during 4 years of follow-up. Mixed linear regression model was used for the longitudinal analysis and trajectory analysis was performed using semiparametric group-based modeling using maximum likelihood. Results Declined renal function was associated with increased rate of decline in total hip BMD (Stage 2: −0.23, Stage 3A: −0.39, Stage 3B: −0.80, Stage 4: −1.20 in men; −0.86, −1.19, −1.20, −1.58% change/year respectively in women). Trajectory analysis revealed two distinct trajectories of eGFR for each CKD Stages 2 through 4: Class 1, stable group; Class 2, rapid decline group. Trajectory group that represented rapid eGFR decline showed consistent trends of increased rate of decline in total hip BMD. There was significant difference between stable and rapid decline group in Stage 3A, 3B (Stage 3A: −0.18 vs. −0.67 [p = 0.009], Stage 3B: −0.36 vs. −1.10 [p = 0.031] in men; Stage 3A: −0.79 vs. −1.67 [p = 0.006], Stage 3B: −0.60 vs. −1.52% change/year [p = 0.001] in women; p for interaction). Conclusion Declined renal function and faster GFR decline is associated with rapid BMD decline in CKD stage 2–4.