Background
Prostatitis is a common urologic disease
[1,
2], with studies reporting that during their lifetime, approximately 35–50% of men will suffer from prostatitis. The morbidity of prostatitis is higher in men who are not over 50-year-old
[3]. According to previous work, we know that the prevalence rate of chronic prostatitis in Chinese males is approximately 8.4%
[4]. Based on a proposal from the National Institutes of Health (NIH)
[5], prostatitis is divided into four categories; of them, Category III, which is defined as chronic prostatitis or chronic pelvic pain syndrome (CP/CPPS), accounts for most cases of prostatitis
[6]. CP/CPPS has a variety of clinical manifestations, such as pelvic pain or perineal pain, irritative or obstructive voiding symptoms, sexual dysfunction, or psychological disorders, and is without any evidence of urinary tract infection
[7,
8]. Commonly, chronic pelvic pain occurs with pelvic floor tenderness, thus the patients will feel pain at the time of palpation
[9].
Clinically, doctors always apply NIH-CPSI to judge the severity of chronic prostatitis. According to the subscores for pain, the pain levels are graded as mild (0 to 7), moderate (8 to 13), and severe (14 to 21). A recent study showed that the relationship between pain with the quality of life (QoL) in CP/CPPS patients was more important than urinary symptoms and the pain severity was more important than pain localization/type
[10]. So, studying the risk factors for pain severity and clarifying the pain severity are helpful in improving the strategy of individualized phenotypically guided treatment. Although recent studies had found several risk factors related to the pain of CP/CPPS patients, results were inconsistent. Some studies had shown that a sedentary lifestyle, smoking, and stress were potential risk factors for the pain in patients with CP/CPPS
[11]. But other studies showed that cigarette smoking was not related to the pain in patients with CP/CPPS
[12]. Therefore, studying the risk factors for the pain severity in patients with CP/CPPS is particularly important for designing the personalized treatment plan.
In this study, we recorded the NIH-CPSI scores and other parameters from the outpatients with CP/CPPS to explore the risk factors related to the pain severity in patients with CP/CPPS and establish a predicting model of it.
Discussion
Prostatitis is a common outpatient disease in urology. Recent research has shown that the prevalence rates of prostatitis in Europe and the USA are 10% to 14%
[21]. In the USA, this health problem motivates 8% of urology consultations
[1]. Among all types of prostatitis, CP/CPPS accounts for most cases. As shown in previous studies, men of all ages and ethnic origins can suffer from CP/CPPS, but the morbidity of the disease is more common in men who are younger than 50 years old
[1]. Although the clinical presentations are diverse, the main clinical features of prostatitis are pelvic pain and lower urinary tract symptoms
[22]. Thus, CP/CPPS is defined as pelvic pain that has presented for at least three months and for which no apparent cause has been found
[23].
From recent research, we found that engagement in sedentary work and alcohol consumption had a negative influence while marriage had a positive impact on the prognosis of CP/CPPS
[24]. Therefore, the questionnaire we designed included age, BMI, white cells in the urine, NIH-CPSI scores, sedentary, urinary retention, anxiety or irritability, sex life, contraception, past medical history, alcohol consumption, and smoking. Currently, nomograms are prognostic methods that can increase accuracy and make prognoses easier to understand, resulting in better clinical decision making; they are widely used in oncology and medicine
[25]. Therefore, in our study, we used multivariate logistic regression analysis to figure out the risk factors for the pain severity in patients with CP/CPPS and used a nomogram device to predict pain severity in CP/CPPS patients. Through using logistic regression analysis to measure the variables, we found that age, urinary retention, anxiety or irritability, contraception, and smoking were related to the pain severity in patients with CP/CPPS and enrolled those variables in the predictive model. Incorporating these five variables into the nomogram allowed the prediction of pain severity in CP/CPPS patients and resulted in the construction of an accurate prediction model of pain severity in CP/CPPS patients. The validation cohort demonstrated good discrimination and calibration power.
For many diseases, age is a potential risk factor. Previous research showed that CP/CPPS was more prevalent in older people
[26,
27]. Other research showed that younger age had been associated with more CP/CPPS symptoms
[28] and worse QoL
[29]. In our study, we found that age is a risk factor for pain severity in CP/CPPS patients, but the age ranges from 40 to 50 years had a higher risk for pain severity in CP/CPPS patients. In some opinions, sedentary and urinary retention could not cause CP/CPPS, but these variables could intensify pain severity among CP/CPPS due to the distention of the venous plexus of the prostate peripheral zone or chronic congestion of the pelvic cavity when in a sitting position
[30]. In our study, we found that urinary retention had a significant correlation with the pain severity in CP/CPPS patients. In previous studies, alcohol consumption was related to unchanged or worse symptoms in CP/CPPS patients
[24]. In our research, through the logistic regression analysis, we found that alcohol consumption was not connected with the pain severity in CP/CPPS patients.
Some researches showed that the frequency of sexual activity, especially the excessive number of sexual intercourse, was related to CP/CPPS
[31]. So, we investigate the influence of sexual activity and contraception. In our study, we did not find the relationship between sexual activity with the pain severity in CP/CPPS patients. But we found that contraception was significantly related to the pain severity in CP/CPPS patients. According to previous research, condoms could delay ejaculation resulting in sex lasting longer
[32]. In the process of a sexual impulse in humans, the pelvic congestion will regress in about 15–30 min after an orgasm or may last longer without an orgasm
[30]. Prolonged sexual activity could increase pelvic congestion. So, one of the possible reasons that condoms could intensify pain severity among CP/CPPS may be due to increased pelvic congestion. Smoking tended to enhance pain sensitivity. However, whether smoking affects CP/CPPS is still controversial. In Chen’s study, they found that smoking is a harmful factor for CP/CPPS
[11], but another study found that smoking resulted in a better symptom relief rate
[24]. In our research, we found that smoking is a risk factor for pain severity in CP/CPPS patients.
The correlation between stress and pain severity in CP/CPPS patients has been rarely reported. One study showed that people who are under stress at home or work are 1.5-fold more likely to suffer from CP/CPPS than unstressed people
[30]. Recently researches showed that biopsychosocial stress had a significant association with chronic pelvic pain in men
[33]. In our study, we found that stress is a risk factor for pain severity in CP/CPPS patients. However, whether stress causes or results from the pain in CP/CPPS patients was difficult to decide in the present study.
A 2009 revision of the NIH-CPSI called the GU problem index (GUPI) is now the recommended index as it includes questions on pain with bladder filling and bladder emptying
[34]. The questions on pain with bladder filling and bladder emptying did not include in the questionnaire we used according to the previous vision of NIH-CPSI. Then, we will add these two questions in our follow-up research.
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