C-Reactive Protein as a Potential Peripheral Biomarker for High-Lethality Suicide Attempts

Abstract

The aim of the present study was to identify a cut-off of c-reactive protein (c-RP) potentially predictive of high-lethality suicide attempts (SA) in an inpatient psychiatric sample. After attempting suicide, subjects were admitted to the emergency ward of the IRCCS Ospedale Policlinico San Martino and later to the section of Psychiatry from 1st August 2013 to 31st July 2018. C-reactive protein was measured. The Area Under the Receiver Operating Characteristic (ROC_AUC) was used to assess the discriminative capacity of c-RP for high- vs. low-lethality SA, and a logistic regression was performed to detect the odds ratio, adjusted for age and sex. High-lethality suicide attempters were 133 (30.8%), while low-lethality suicide attempters were 299 (69.2%). The optimal cut-off threshold (and corresponding sensitivity and specificity values) for c-RP was 4.65 mg/L (68/71%). This cut-off corresponds to an AUC of 73.5%. An odds ratio of 4.70 was generated for current high-lethality SA after a logistic regression, adjusted for age and sex. Research on social and biological factors underlying the lethality of SA is crucial for a better understanding of this complex phenomenon. Identifying potential predictors of SA, especially those at high lethality, is essential to implement personalized preventive strategies.

High Serum Levels of IL-6 Are Associated with Suicide Attempt but Not with High Lethality Suicide Attempts: A Preliminary Case–Control Study

“…In this study, we did not observe differences between the degree of lethality in individuals with suicide attempts. One previous study reported an association between suicide attempt lethality and other biomarkers suggesting the C-reactive protein as a peripheral biomarker; however, measuring the IL-6 levels was not within the study objectives [ 6 ]. Similarly, the total cholesterol, high LDL-c, HDL-c, and triglycerides have been associated with the lethality of suicide attempts [ 46 ].…”

“…Each year, approximately 700,000 people die by suicide [ 3 ]. It is estimated that, for every completed suicide, there are around 20 suicide attempts worldwide; nonetheless, some reports indicate that some countries have higher rates of suicide fatalities, as 8.5–13% of all suicide attempts are fatal [ 4 , 5 , 6 ].…”