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

Key Points In the patients on hemodialysis, β 2-microglobulin was lower in those with worse physical performance than in those with better physical performance. A significant association of higher β 2-microglobulin was discovered with better physical performance in the patients on hemodialysis without diabetes. Background Higher β 2-microglobulin ( β 2-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 β 2-MG with survival rate. Furthermore, diabetes mellitus (DM) has been well linked to poor physical function and a high level of β 2-MG. We hypothesized that higher β 2-MG could be associated with worse physical performance in patients on hemodialysis and that this association could vary with diabetes. Methods We conducted a multicenter cross-sectional study at seven hemodialysis centers in Shanghai and Suzhou in China, where a collection was made of the clinical characteristics, laboratory indicators, physical performance, and DM assessment. Physical function was measured by the Short Physical Performance Battery (SPPB), and SPPB score ≤9 was considered as the cutoff for low physical performance. The patients were divided into two groups of low and high physical performance before being categorized into four subgroups on the basis of the absence of diabetes and SPPB scores. Logistic regression analyses were conducted to explore the association of β 2-MG with physical performance. Results The final analysis involved a total of 780 patients, 251 (32.2%) having diabetes. In the total population, β 2-MG was lower in those with low SPPB scores than in those with high SPPB scores. Only in nondiabetic patients, β 2-MG was lower in the low-SPPB group and positively associated with SPPB and its three component scores. Regardless of diabetes status, those who had low SPPB scores were prone to be older, accompanied by poor nutritional status. In addition, diabetic patients tended to have shorter hemodialysis duration and higher body mass index than the nondiabetic patients. Both before and after the covariates were adjusted, β 2-MG was significantly associated with physical performance in patients on hemodialysis without diabetes. Conclusions Lower levels of β 2-MG were significantly associated with poor physical performance in Chinese patients on hemodialysis without DM.