C-reactive protein levels predict ED risk

By Nidhi Saha, BDSJun 27 2022Reviewed by Benedette Cuffari, M.Sc.

Erectile dysfunction (ED) is associated with negative effects on both the physical and mental health of men, as well as the life satisfaction of their companions. Although men at any age can be diagnosed with ED, it is much more common to occur in older men, particularly those over the age of 75. Throughout the world, ED-related comorbidities are projected to affect nearly 320 million men by 2025. 

Study: Novel predictive risk factor for erectile dysfunction: Serum high‐sensitivity C‐reactive protein. Image Credit: Wasan Tita / Shutterstock.com

Background

Multiple factors contribute to ED pathogenesis. Vascular ED, for example, is related to vascular endothelial dysfunction and is associated with lower nitric oxide production and limited blood flow which, taken together, inhibit erectile function. Thus, cardiovascular disease (CVD) is linked to ED. 

C-reactive protein (CRP) is expressed in humans during the acute immune response. Moreover, high-sensitivity CRP (hs-CRP) is a sensitive biomarker of inflammation that can independently predict CVD in its early phases. It has been hypothesized that CRP is strongly associated with ED and that ED may indicate early-phase CVD.

About the study

A recent meta-analysis published in Andrology aimed to describe the relationship between CRP and ED. This study followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) Statement. Herein, the researchers performed a systemic search on PubMed, Web of Science, and Cochrane Library to identify relevant republished literature before January 1, 2022.

Overall, 12 relevant articles were selected. These included nine studies comparing serum CRP levels in ED patients and controls, as well as three studies that analyzed CRP levels in ED patients on phosphodiesterase 5 inhibitor (PDE-5i) therapy. 

The nine studies that compared serum CRP levels in ED patients and controls consisted of 1,363 ED patients and 1,400 healthy controls. The results showed significantly higher CRP levels in ED patients than in healthy controls, thus indicating higher levels of inflammation in ED patients. 

Protective effect of PDE-5i therapy on CRP in ED patients

Previous evidence had depicted that on-demand PDE-5i could improve erectile function, as well as cavernous endothelial function. 

A comparative study of the changes among ED patients and their CRP levels before and after PDE-5i treatment indicated that CRP levels decreased by 0.38 mg/l in ED patients after the therapy was initiated. This decline was greater in ED patients who complied with the drug regimen.

In the present study, PDE-5is therapy was found to significantly reduce hs-CRP levels. This finding could expand current indications for evaluating the risk of ED in asymptomatic patients, as well as those who are not considered at risk for ED.

The results suggest that hs-CRP levels can be utilized for general risk assessment of patients with ΕD, as it provides information on the inflammatory risk profile of patients. However, the mechanism responsible for this association remains unclear. 

Conclusions

The current meta-analysis is the first to investigate the relationship between CRP and ED. Taken together, the study findings indicate that ED patients exhibit significantly higher CRP levels than healthy individuals. Furthermore, PDE-5i therapy could markedly diminish serum CRP levels in patients with ED.