[The correlation of lipid profile and serum osmolality with kidney progression in patients with type 2 diabetes mellitus].

<b>Objective:</b> To investigate the correlation of lipid profile and serum osmolality (OsP) with kidney progression in patients with type 2 diabetes mellitus (T2DM). <b>Methods:</b> A nested case-control study was conducted. Inpatients with T2DM who visited Guizhou Provincial People's Hospital in 2019 were included. Demographic characteristics, laboratory indices, and kidney progression events were collected. The correlation of lipid profile and OsP with kidney progression in T2DM were analyzed using multivariable Cox proportional hazards regression models and causal mediation analysis. <b>Results:</b> A total of 1 219 patients (714 males and 505 females) were included, aged (59.7±14.6) years. The median (<i>Q</i>₁, <i>Q</i>₃) follow-up duration was 54 (51, 58) months, with a loss to follow-up rate of 11.9% (145/1 219). Kidney progression occurred in 21.3% (260/1 219) of the patients. Cox proportional hazards regression analysis revealed that elevated OsP (<i>HR</i>=1.02, 95%<i>CI</i>: 1.01-1.02, <i>P</i><0.001), remnant cholesterol (RC) (<i>HR</i>=1.12, 95%<i>CI</i>: 1.02-1.23, <i>P</i>=0.023), apolipoprotein B (ApoB) (<i>HR</i>=1.59, 95%<i>CI</i>: 1.02-2.46, <i>P</i>=0.040), and age (<i>HR</i>=1.02, 95%<i>CI</i>: 1.01-1.03, <i>P</i><0.001) were identified as risk factors for kidney progression in T2DM. Compared with OsP<310 mmol/L, patients with OsP≥310 mmol/L had a significantly increased risk of kidney progression (<i>HR</i>=1.94, 95%<i>CI</i>: 1.50-2.51, <i>P</i><0.001). Causal mediation analysis using bootstrap resampling (N=5 000) indicated that RC and ApoB mediated 3.39% (95%<i>CI</i>: 0.98%-5.00%, <i>P</i>=0.020) and 9.54% (95%<i>CI</i>: 8.28%-17.00%, <i>P</i>=0.048) of the effect of OsP on kidney progression, respectively. <b>Conclusion:</b> Elevated OsP level in T2DM patients is a risk factor for kidney progression, with RC and ApoB mediating the effect of OsP on kidney progression in T2DM.