PTGS2 and peptic ulcer disease: In addition, PPIs (HR = 4.41, 95% CI 3.57–5.45, P < 0.001), H2-blockers (HR = 2.49, 95% CI 1.95-3.20, P < 0.001), aspirin (HR = 4.12, 95% CI 3.09–5.50, P < 0.001), NSAIDs (HR = 3.62, 95% CI 2.85–4.58, P < 0.001), COX-2-specific inhibitors (HR = 2.25, 95% CI 1.68–3.03, P < 0.001), and clopidogrel (HR = 1.46, 95% CI 1.07–1.99, P = 0.017) were independent risk factors for complicated recurrent peptic ulcer disease.