No abstract

Background. β 2 -Microglobulin (β 2 -M) is recognized as a surrogate marker of middle-molecule uraemic toxins and is a key component in the genesis of dialysis-associated amyloidosis. Few studies have evaluated the association of β 2 -M levels with clinical outcome in dialyzed patients. Methods. The prognostic implication of serum β 2 -M levels for the survival of haemodialysis patients was examined in 490 prevalent haemodialysis patients (60.1 ± 11.8 years, haemodialysis duration of 87.4 ± 75.7 months, 288 males and 202 females; 24% diabetics). The patients were divided into two groups according to their serum β 2 -M levels: lower β 2 -M group (n = 245) with serum β 2 -M <32.2 mg/L (the median serum β 2 -M) and higher β 2 -M group (n = 245) with that ≥32.2 mg/L. Results. During the follow-up period of 40 ± 15 months, there were 91 all-cause deaths, and out of them, 36 were from cardiovascular diseases. Kaplan-Meier analysis revealed that all-cause mortality in the higher β 2 -M group was significantly higher compared to that in the lower β 2 -M group (P < 0.001). Multivariate Cox proportional hazards analyses showed that serum β 2 -M level was a significant predictor for all-cause mortality (hazard ratio, 1.05; 95% CI, 1.01-1.08; P = 0.005), and for non-cardiovascular mortality (hazard ratio, 1.06; 95% CI, 1.02-1.10; P = 0.006), after adjustment for age, gender, haemodialysis duration, the presence of diabetes, serum albumin and serum C-reactive protein.Conclusion. These results demonstrate that the serum β 2 -M level is a significant predictor of mortality in haemodialysis patients, independent of haemodialysis duration, diabetes, malnutrition and chronic inflammation, suggesting the clinical importance of lowering serum β 2 -M in these patients.

In the present study we examined the relationship of bone mineral density (BMD) reduction with increased mortality in hemodialysis patients. A single-center prospective observational study was conducted on 269 male hemodialysis patients. The BMD in the distal third of the radius (DR1/3) and in the ultradistal radius (UR), which are enriched with cortical and cancellous bone, respectively, was measured twice using dual-energy X-ray absorptiometry (DXA) with a 1-year interval. Subjects were divided into two groups based on the presence or absence of BMD reduction. Survival was followed for 61.0 months, after which time 104 patients (39%) had died. A significant BMD reduction at the UR and DR1/3 occurred in 182 (68%) and 195 (72%) patients, respectively. Patients with BMD reduction in the UR, in contrast to the DR1/3, had a significantly lower survival rate than those without BMD reduction (P = 0.01). In Cox regression analysis, the rate of BMD change at the UR, in addition to patient age, diabetes mellitus, and serum albumin, emerged as an independent predictor for increased mortality (HR = 0.970, 95% CI 0.945-0.996). Our results suggest that BMD reduction at the UR might be a clinically relevant marker that predicts an increased risk of mortality in male hemodialysis patients.

Prevalent fracture of the lumbar spine is established as a predictor of increased mortality in the general population. To examine whether this association is retained in hemodialysis patients, we conducted a single-center prospective observational study in 635 hemodialysis patients (60.3 + or - 12.0 years old, male/female 369/266). Patients were divided into two groups (with and without lumbar fracture, assessed by simple lateral radiograph), and survival was followed for an average of 53.8 months. Lumbar fracture was present in 62 patients (9.76%; male 9.76%, female 9.77%). During the follow-up period, there were 176 all-cause deaths (27.7%; male 27.6%, female 27.8%), of which 72 were from cardiovascular diseases. In Kaplan-Meier analysis, all-cause and noncardiovascular mortality rates, but not cardiovascular mortality, were significantly higher in patients with fracture than in those without (P < 0.0001). In multivariate Cox proportional hazard analysis, the presence of lumbar fracture was significantly associated with increased noncardiovascular mortality (HR = 2.035, 95% CI 1.135-3.652, P < 0.05) after adjustment for age, duration of hemodialysis, presence of diabetes, body mass index, and serum calcium, phosphate, and albumin. Significantly higher all-cause and noncardiovascular mortality rates were also evident for patients with fracture in separate analyses in males and females, but multivariate analysis showed a significant association of lumbar fracture with increased all-cause (HR = 2.151, 95% CI 1.033-4.478, P < 0.05) and noncardiovascular (HR = 2.637, 95% CI 1.014-6.858, P < 0.05) mortality rates only in females. In conclusion, lumbar fracture is significantly associated with all-cause mortality in female patients.