Alaa Tealab, Abdallah Remeah, John Mulhall, David Ralph, Mohamed Elkhouly, Saleh Binsaleh, Zenhom Mekawi, Tarek Soliman, Osama Abdelwahab, Hatem Kamr, Saad Mahmoud, Raanan Tal, Mohammed Nassar, Mohamad Habous
Objectives
To explore the association between HbA1C level and penile implant infection rates and to define a cut-off value that predicted implant infection.
Patients and Methods
A multi center prospective study included all patients undergoing penile implant surgery between 2009-15. Preoperative, perioperative and postoperative management were identical for the entire cohort. Univariate analysis was performed to define predictors of implant infection. HbA1c levels were analyzed as a continuous variable and sequential analysis was conducted utilizing 0.5% increments to define a cut-off level predicting implant infection. Multivariable analysis was performed with the following factors entered the model: Diabetes, HbA1C level, patient age, implant type, vascular risk factor number, presence of Peyronie's disease (PD), BMI and surgeon volume. A ROC curve was generated to define the optimal HbA1C cut-off for infection prediction.
Results
902 implant procedures were performed over this period of time. The mean age was 56.6 years. The mean HbA1c level was 8.0, with 81% of men having a HbA1c >6%. 685 (76%) implants were malleable, and 217 (24%) were inflatable devices. 302 (33.5%) patients had also a diagnosis of PD. Overall infection rate was 8.9% (80/902 subjects). Patients who had implant infection had significantly higher mean HbA1c levels, 9.5% vs 7.8% (p<0.001). Grouping the cases by HbA1c level we found infection rates were: 1.3% with HbA1c <6.5%, 1.5% for 6.5-7.5%, 6.5% for 7.6-8.5%, 14.7% for 8.6-9.5%, 22.4% for >9.5%. (p<0.001). Patient age, implant type, and vascular risk factor number were not predictive. Predictors defined on MVA were: PD, increased BMI, high HbA1C while a high-volume surgeon had a protective effect and was associated with a reduced infection risk. Using ROC analysis, we determined that a HbA1c cut-off value of 8.5% predicted infection with a sensitivity of 80% and a specificity of 65%.
Conclusion
Uncontrolled DM is associated with increased risk of infection after penile implant surgery. The risk is directly related to HbA1C level. A threshold value of 8.5% is suggested for clinical use to identify patients at increased infection risk.
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