Prognostic Significance of Interleukin-34 (IL-34) in Patients With Chronic Heart Failure With or Without Renal Insufficiency

Renal dysfunction, commonly associated with cardiac dysfunction, has predictive value for adverse long-term outcomes in heart failure (HF). We previously identified a novel renal biomarker, interleukin-34 (IL-34), elevated in HF patients and associated with kidney dysfunction and coronary artery disease during HF. However, the prognostic value of IL-34 in HF remains unclear, so that the present study aimed to determine it. This prospective, observational study included 510 consecutive HF patients with their serum IL-34 as well as other variables measured at baseline, and they were followed up for 2 years. The primary end point was a composite of cardiovascular death or a first HF hospitalization, with cardiovascular death, HF hospitalization, and all-cause mortality as secondary outcomes. There was a significant and gradual increase in risk as IL-34 increased, determined by log-rank tests with Kaplan-Meier curves. Serum IL-34 was also a significant prognostic predictor of the primary end point (1.301 [1.115-1.518]; =0.001), cardiovascular death (1.347 [1.096-1.655]; =0.005), HF hospitalization (1.234 [1.018-1.494]; =0.032), and all-cause mortality (1.343 [1.115-1.618]; =0.002) in HF as per SD increase in the log IL-34 level after adjusting for age, sex, traditional risk factors, and N-terminal pro-brain natriuretic peptide. Especially, IL-34 had a more-significant prognostic value in HF patients with kidney impairment than those without. IL-34 is a significant predictor of cardiovascular death, HF hospitalization, and all-cause mortality in chronic HF, especially when concomitant with renal dysfunction. Serum IL-34 measurement may provide new insights linking kidney impairment to poor HF outcomes beyond other renal markers.