Association of serum complement levels with failure of low-density-lipoprotein-cholesterol target attainment in patients after acute coronary syndrome: A prospective, observational study.

BACKGROUND

The interplay between inflammation and atherosclerosis is well acknowledged. However, the role of the complement system in lipid-lowering therapy (LLT) is poorly understood.

OBJECTIVE

To investigate the association of serum-complement levels with low-density lipoprotein cholesterol (LDL-C) levels in patients with acute coronary syndrome (ACS).

METHODS

Adult hospitalized patients with ACS received rosuvastatin 40 mg with an LDL-C target of <55 mg/dL and a reduction of >50% of baseline. High-sensitivity C-reactive protein, complement C3c, C4, C5a levels, LDL-C, high-density lipoprotein cholesterol, triglycerides, and apolipoprotein B levels were measured before treatment initiation, 6 weeks, 6 months, and 12 months afterward. Patients were followed up for 12 months for major adverse cardiovascular events (nonfatal stroke, nonfatal myocardial infarction, cardiovascular death).

RESULTS

Among 130 patients (91.5% male; mean age 56 ± 9 years), 42 (32.3%) achieved the target at 6 weeks, 61 (46.9%) at 6 months, and 63 (48.5%) at 12 months. Serum C3c levels were lower at baseline in 6-week target achievers (median [Q1-Q3], 98.9 [86.9-107.3]) vs nonachievers (126.0 [112.0-136.0]; P < .001). Similarly, C4 levels were 21.4 (18.2-26.4) mg/dL in achievers vs nonachievers (26.8 [22.1-31.6] mg/dL; P < .001); C5a levels did not differ between groups. C3c predicted failure of target attainment at 6 weeks (area under the curve, 95% CI: 0.94, 0.90-0.98; P < .001). A cut-off value of 112.5 mg/dL demonstrated sensitivity 77.3%, specificity 92.3%, and independently predicted failure (adjusted odds ratio 52.54; 95% CI, 12.49-221.0).

CONCLUSION

In patients with ACS treated with rosuvastatin 40 mg, serum C3c levels are associated with failure of LDL-C target attainment. Further research is needed to determine if they may be used to guide LLT.