β2-Microglobulin, pulse pressure and metabolic alterations in hemodialysis patients.

BACKGROUND/AIM: Pulse pressure (PP) is a result of arterial stiffness seen in dialysis patients, but may be a consequence of fluid overload. We examined the role of β(2)-microglobulin (β(2)M) in PP in relation to metabolic alterations in patients on different hemodialysis (HD) modalities.

METHODS

We studied 76 hemodialyzed patients on regular HD (n = 34), predilution bagged hemodiafiltration (n = 19) and online predilution hemodiafiltration (n = 23). β(2)M levels were measured by radioimmunoassay, and the clearance of β(2)M was assessed by Kt/V for β(2)M. Arterial stiffness was measured as carotid-femoral pulse wave velocity, and PP was derived. Insulin levels were measured using immunoradioassay, and insulin resistance was calculated using homeostasis model assessment insulin resistance (HOMA-IR). Serum bicarbonate levels were measured using a blood gas analyzer, and percent sodium removal was calculated.

RESULTS

β(2)M levels predict increased PP (p = 0.02) adjusting for age, HD modalities, HD duration, HOMA-IR and percent sodium removal. β(2)M was positively associated with HOMA-IR (r = 0.306, p = 0.007). Serum bicarbonate levels and carotid-femoral pulse wave velocity were inversely associated (r = -0.719, p = 0.001).

CONCLUSIONS

β(2)M levels were positively associated with PP, which was influenced mainly by dialysis modality fluid and sodium balance and less by arterial stiffness. β(2)M levels were positively associated with insulin resistance. Uremic acidosis may contribute to arterial stiffness.