Chronic renal comorbidities in pyoderma gangrenosum: a retrospective cohort study

The coexistence of pyoderma gangrenosum (PG) and chronic renal comorbidities has been reported anecdotally. We aimed to assess the bidirectional association between PG and the following chronic renal comorbidities: chronic renal failure (CRF), dialysis, kidney transplantation (KT), and other kidney diseases (OKD). That is to evaluate (i) the risk of the aforementioned diseases among patients with PG (ii) and the odds of PG after a diagnosis of renal comorbidities. A population-based retrospective cohort study was conducted comparing PG patients (n=302) with age-, sex-, and ethnicity-matched control subjects (n=1497) with regard to incident cases of renal comorbidities. A case-control design was additionally adopted to estimate the odds of PG in those with a preexisting history of renal comorbidities. Adjusted hazard ratios (HRs) and adjusted odds ratios (ORs) were estimated by Cox regression and logistic regression, respectively. Patients with PG demonstrated an increased risk of CRF (adjusted HR, 3.68; 95% CI, 2.72–5.97), dialysis (adjusted HR, 27.79; 95% CI, 3.24–238.14), and OKD (adjusted HR, 2.71; 95% CI, 1.55–4.74). In addition, the odds of PG were increased after the diagnosis of CRF (adjusted OR, 2.34; 95% CI, 1.33–4.11), KT (adjusted OR, 5.03; 95% CI, 1.01–25.12), and OKD (adjusted OR, 1.69; 95% CI, 1.04–2.74). Patients with a dual diagnosis of PG and renal diseases presented with PG at an older age and had a higher prevalence of comorbid conditions. In conclusion, a bidirectional association exists between PG and chronic renal conditions. Awareness of this comorbidity may be of benefit for physicians managing patients with PG.