The Association of β2-Microglobulin with Physical Performance in Chinese Hemodialysis Patients with and without Diabetes.

Background: Higher β2-Microglobulin (β2-MG) is associated with aging, stroke and cognitive impairment, which are all connected with poor physical fitness. Poor physical function is ascribed to increasing mortality. However, there has been an academic dispute over the association of serum β2-MG with survival rate. Furthermore, diabetes mellitus (DM) has been well linked to poor physical function and a high level of β2-MG. We hypothesized that higher β2-MG could be associated with worse physical performance in hemodialysis (HD) patients, and that association could vary with diabetes.

Methods: We conducted a multicenter cross-sectional study at seven HD centers in Shanghai and Suzhou, respectively, in China, where a collection was made of the clinical characteristics, laboratory indicator, physical performance and DM assessment. The physical function was measured by the Short Physical Performance Battery (SPPB), and SPPB score ≤9 as the cutoff for low physical performance.The patients were divided into two groups of low and high physical performance, before categorized into four subgroups based on the absence of diabetes and SPPB scores. Logistic regression analyses were conducted to explore the association of β2-MG with physical performance.

Results: The final analysis involved a total of 780 patients, 251(32.2%) having diabetes. In the total population, β2-MG was lower in those with low SPPB than in those with high SPPB. Only in non-diabetic patients, β2-MG was lower in the low SPPB group, and positively associated with SPPB and its three compenents scores. Regardless of diabetes status, those who had low SPPB were prone to be older, accompanied by the poor nutritional status. Addtionally, the diabetes patients tended to have shorter HD duration and higher body mass index than the non-diabetic patients. Both before and after the covariates adjusted, β2-MG was significantly associated with physical performance in HD patients without diabetes.

Conclusions: Low level of β2-MG was significantly associated with poor physical performance in Chinese HD patients without DM.