CRP and diabetes mellitus: Diabetes (OR = 16.32, 95%CI 2.02-131.67, p = 0.009), renal colic (OR = 0.06, 95%CI 0.02-0.05, p < 0.001), HU value of effusion (OR = 1.14, 95%CI 1.06-1.23, p < 0.001), hemoglobin (OR = 0.97, 95%CI 0.95-1.00, p = 0.026) and CRP (OR = 1.02, 95%CI 1.01-1.04, p < 0.001) were the five independent risk factors.