Risk factors for nonmelanoma skin cancer in renal transplant recipients: a case–control study from a reference outpatient clinic in Southeast Brazil

Background Nonmelanoma skin cancer (NMSC) is the most common tumor in humans, and its incidence increases among renal transplant recipients (RTRs). The aims of this study were to characterize the RTRs with NMSC, to identify risk factors, and to calculate the probability of this tumor in this population. Methods This was a hospital‐based case–control study. Epidemiological and clinical variables were evaluated. Hierarchical logistic regression was used, and a mathematical model was built. Results In total, 245 subjects were included. Possible associations were identified using a univariate analysis. Multivariate analysis identified risk factors with respective odds ratios and confidence intervals (95% CI): males 2.5 (1.3–4.7), age over 50 years 5.4 (2.3–12.9), Fitzpatrick's skin phototypes I–III 3.7 (1.6–8.7), occupational sun exposure 4.1 (2.1–8.1), timetable of recreational sun exposure all day 3.0 (1.4–6.1), and duration of transplantation (80 months or more) 3.3 (1.6–6.5). The Hosmer‐Lemeshow test and the receiver operating characteristics curve showed a strong fit and accuracy, respectively. The probability of an NMSC ranged from less than 1 to 92.5%. Conclusions This study characterized the RTRs with NMSC and identified risk factors. The multivariate analysis by hierarchical logistic regression proved to be a useful tool and allowed for the determination of the probability of NMSC in this population.