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Abstract: TH-PO181

Utility of Serum β2-Microglobulin for Prediction of Kidney Outcome Among Patients with Biopsy-Proven Diabetic Nephropathy

Session Information

Category: Diabetic Kidney Disease

  • 702 Diabetic Kidney Disease: Clinical

Authors

  • Uemura, Takayuki, Nara Kenritsu Ika Daigaku, Kashihara, Nara, Japan
  • Nishimoto, Masatoshi, Nara Kenritsu Ika Daigaku, Kashihara, Nara, Japan
  • Eriguchi, Masahiro, Nara Kenritsu Ika Daigaku, Kashihara, Nara, Japan
  • Tamaki, Hiroyuki, Nara Kenritsu Ika Daigaku, Kashihara, Nara, Japan
  • Tasaki, Hikari, Nara Kenritsu Ika Daigaku, Kashihara, Nara, Japan
  • Furuyama, Riri, Nara Kenritsu Ika Daigaku, Kashihara, Nara, Japan
  • Fukata, Fumihiro, Yamatotakada Shiritsu Byoin, Yamato Takada, Nara, Japan
  • Kosugi, Takaaki, Nara Kenritsu Ika Daigaku, Kashihara, Nara, Japan
  • Morimoto, Katsuhiko, Nara Prefecture Seiwa Medical Center, Ikoma-gun, Nara, Japan
  • Matsui, Masaru, Nara-ken Sogo Iryo Center, Nara, Nara, Japan
  • Samejima, Ken-ichi, Nara Kenritsu Ika Daigaku, Kashihara, Nara, Japan
  • Tsuruya, Kazuhiko, Nara Kenritsu Ika Daigaku, Kashihara, Nara, Japan
Background

Little is known regarding the importance of serum β2-microglobulin (β2-MG) on subsequent decline in kidney function among patients with diabetic nephropathy (DN). Here, we aimed to examine whether the addition of serum β2-MG to known predictors could improve the prediction performance for incident kidney failure with replacement therapy (KFRT) among patients with biopsy-proven DN.

Methods

A retrospective observational study consists of patients with biopsy-proven DN between June 1981 and December 2014. Patients complicated with other kidney diseases were excluded. Exposure of interest was log-transformed serum β2-MG levels measured at the time of kidney biopsy. The outcome variables were KFRT. Multivariable Cox regression models and competing-risk regression models, with all-cause mortality as a competing event, were performed with adjustments for previously known risk factors. Model fit by adding serum β2-MG levels was calculated using the Akaike information criterion (AIC). The net reclassification improvement (NRI) and integrated discrimination improvement (IDI) indexes were examined based on the 5-year cumulative incidence of KFRT, and the improvement of predictive performance for KFRT by serum β2-MG levels was evaluated.

Results

Among 408 patients, 99 developed KFRT during a median follow-up period of 6.7 years. A higher serum β2-MG level (1-unit increase in log-transformed serum β2-MG level) was associated with a higher incidence of KFRT, even after adjustments for previously known clinical and histological risk factors (hazard ratio [95% confidence interval (CI)]: 3.30 [1.57–6.94] and subdistribution hazard ratio [95% CI]: 3.07 [1.55–6.06]). Subgroup analyses revealed no effect modification by creatinine-based estimated glomerular filtration rate or kidney histological findings. The addition of log-transformed serum β2-MG level reduced AIC, and improved the prediction of KFRT (NRI and IDI: 0.32 [0.09–0.54] and 0.03 [0.01–0.56], respectively).

Conclusion

Among patients with biopsy-proven DN, serum β2-MG was an independent predictor of KFRT and improved prediction performance. In addition to serum creatinine, serum β2-MG could be also evaluated for DN.