Men with vasculogenic erectile dysfunction (ED) have greater levels of serum high-sensitivity C-reactive protein (hs-CRP) than men with non-vasculogenic ED, and this might affect their response to tadalafil treatment, researchers report in the Journal of Sexual Medicine.
However, “the predictive accuracy of hs-CRP for this purpose is only modest and not independent of underlying risk factors and mechanism of ED,” they added.
The term vasculogenic refers to blood vessels. Vasculogenic ED occurs when blood flow to the penis is impaired. Blood flow is essential for a firm erection.
Vasculogenic ED may occur because of endothelial dysfunction – damage to the endothelium (tissue that lines blood vessels). Inflammation is associated with endothelial dysfunction, atherosclerosis (hardening of the arteries), and poor cardiovascular health.
Measurements of hs-CRP are often used to gauge inflammation in the body and are considered a “strong predictor of future risk for adverse [cardiovascular] events.”
Because of the links between ED and cardiovascular disease, scientists have been investigating whether hs-CRP could be helpful in diagnosing and predicting ED, especially since phosphodiesterase-5 (PDE5) inhibitors have been shown to decrease hs-CRP levels, thus reducing inflammation.
In the current study, scientists explored the relationship among hs-CRP level, erectile dysfunction, and response to tadalafil, a PDE5 inhibitor.
They worked with 282 men (average age 37 years) who had had ED for at least six months. None of the men had had pharmacological treatment for ED in the past, nor did any have any acute inflammatory conditions that could raise hs-CRP levels.
Each participant completed the erectile function domain portion of the International Index of Erectile Function (referred to as IIEF-6). Penile Doppler tests were used to evaluate blood flow. Levels of hs-CRP were measured as well.
Based on assessments, the men were divided into two groups. One was diagnosed with vasculogenic ED (67 men, or 24% of the group), the other with non-vasculogenic ED (215, or 76% of the group).
At baseline, the men with vasculogenic ED were older and were more likely to have high blood pressure, diabetes, coronary artery disease, and hypothyroidism. They also had higher hs-CRP levels compared to the men with non-vasculogenic ED. In addition, men in the vasculogenic group had had ED for a longer period of time and were less likely to have psychological problems.
For six weeks, the men took 10 mg of tadalafil once a day. After this period, they were re-assessed.
Follow-up data were available for 78% of the men. About 61% of that subgroup responded to treatment, which means their IIEF-6 scores had improved from baseline. Approximately 92% had been compliant with treatment. Headache and backache were reasons given for noncompliance.
Those who had success with tadalafil tended to be younger, with fewer cardiovascular risk factors. They were also more likely to have non-vasculogenic ED.
Men who responded to therapy had lower baseline hs-CRP levels. Both responders and non-responders saw their hs-CRP levels drop, but the difference was greater for responders. Men with non-vasculogenic ED had greater hs-CRP level decreases than those with vasculogenic ED.
“Serum hs-CRP level is higher in [men with] vasculogenic ED compared to [men with] non-vasculogenic ED, and is associated with poorer response to tadalafil therapy,” the authors wrote.
“However, this association is not independent of underlying risk factors and mechanism of ED,” they concluded.
The Journal of Sexual Medicine
Jamaluddin, MS, DNB Urology, et al.
“Role of Serum High-Sensitivity C-Reactive Protein as a Predictor of Therapeutic Response to Tadalafil in Patients With Erectile Dysfunction: A Prospective Observational Study”
(Full-text. Published online: October 24, 2019)