Evidence for the atherogenic index of plasma as a potential biomarker for cardiovascular disease in schizophrenia

Background: Schizophrenia is known to be accompanied with increased cardiovascular mortality, which causes reduced life expectancy. Aim: The aim of the current study was to investigate if atherogenic index of plasma (AIP) could be a good marker in assessing cardiovascular disease (CVD) risk in patients with schizophrenia. Methods: Patients with schizophrenia ( n = 328) and healthy controls ( n = 141) were recruited. Schizophrenia patients were evaluated according to the presence of antipsychotic (AP) drug use as AP(+)Sch group and AP(−)Sch group. Atherogenic indices, such as AIP, Castelli’s risk index-I (CRI-I), Castelli’s risk index-II (CRI-II), and atherogenic coefficient (AC), were calculated according to the laboratory examination of serum lipid parameters. Results: According to the comparison of serum lipid levels, triglyceride (TG) levels were found to be highest and high-density lipoprotein–cholesterol levels were lowest in AP(+)Sch group than AP(−)Sch group and control group (CG) ( p < 0.001). AIP, CRI-I, and CRI-II scores were found to be significantly higher in AP(+)Sch group than AP(−)Sch group, and in AP(−)Sch than healthy controls ( p < 0.001). Mean AC scores were higher in AP(+)Sch group than both AP(−)Sch and CG and were similar in AP(−)Sch and control subjects ( p < 0.001). According to the correlation analysis, AIP scores were positively correlated with duration of disease ( r = 0.235; p = 0.002) and age ( r = 0.226; p = 0.003) in AP(+)Sch group but not in drug-free subjects. In all groups, atherogenic indices of CRI-I, CRI-II, and AC scores were found to be positively correlated with AIP scores ( p < 0.001). Conclusion: Our results suggest that AIP is an easily calculable and reliable marker for determining the CVD risk in both drug-free schizophrenia patients and patients under AP treatment.