Importance: Pyoderma gangrenosum (PG) is a rare neutrophilic dermatosis. Few studies have evaluated the mortality outcomes of patients with PG.
Objective: To investigate all-cause and cause-specific mortality in patients with PG.
Design, setting, and participants: This retrospective population-based cohort study used data from the National Health Insurance Service database of Korea and the National Death Registry of Korea from patients with incident PG (≥3 documented visits with an International Statistical Classification of Diseases and Related Health Problems, Tenth Revision [ICD-10] code of L88) during January 2003 to December 2019. For comparison, a 1:20 cohort of age-, sex-, insurance type-, and income level-matched controls without any documented visit with an ICD-10 code of L88 during the entire observation was included.
Exposures: Pyoderma gangrenosum.
Main outcomes and measures: The participants were observed from the index date to their death, emigration, or the end of the observation period to investigate all-cause and cause-specific mortality during the 17-year study period.
Results: In total, 3386 patients with PG (1450 women [42.8%]; mean [SD] age, 57.8 [16.4] years) and 67 720 controls (29 000 women [42.8%]; mean [SD] age, 57.8 [16.3] years) were analyzed. All-cause mortality risk was greater in patients with PG than in controls (adjusted hazard ratio [aHR], 2.122; 95% CI, 1.971-2.285) after adjustment for smoking, drinking, body mass index, and comorbidities. Patients experienced greater mortality of infectious disease (aHR, 3.855; 95% CI, 2.640-5.628), neoplasm (aHR, 1.618; 95% CI, 1.363-1.920), hematologic disease (aHR, 12.298; 95% CI, 3.904-38.734), endocrine disease (aHR, 6.322; 95% CI, 5.026-7.953), neurologic disease (aHR, 2.039; 95% CI, 1.337-3.109), cardiovascular disease (aHR, 1.979; 95% CI, 1.645-2.382), respiratory disease (aHR, 1.757; 95% CI, 1.365-2.263), gastrointestinal disease (aHR, 2.278; 95% CI, 1.522-3.408), connective tissue disease (aHR, 8.685; 95% CI, 4.963-15.199), and kidney/urogenital disease (aHR, 3.617; 95% CI, 2.488-5.259) than controls. Compared with idiopathic PG (aHR, 2.062; 95% CI, 1.897-2.241), PG that was associated with solid organ cancer (aHR, 2.313; 95% CI, 1.956-2.737) and hematologic cancer (aHR, 8.330; 95% CI, 5.473-12.679) showed greater mortality, whereas PG that was associated with inflammatory bowel diseases showed a slightly better prognosis (aHR, 1.742; 95% CI, 0.964-3.148).
Conclusions and relevance: The results of this cohort study suggest that patients with PG had a higher all-cause and cause-specific mortality risk than the general population.