Are serum concentrations of nitric oxide metabolites useful for predicting the clinical outcome of severe ulcerative colitis?

OBJECTIVE: To determine serum concentrations of nitric oxide metabolites (NOX) in patients with severe ulcerative colitis and to assess whether these concentrations predict clinical outcome. PATIENTS: Twenty-six patients (16 men and 10 women, mean age 46 years) with severe ulcerative colitis requiring hospitalization for parenteral steroid therapy. Thirteen patients had a complete clinical response and symptoms resolved after 5 days of parenteral steroid administration; 13 made an incomplete recovery and needed further treatment (six cyclosporin, seven colectomy). METHODS: Serum concentrations of NOX and C-reactive protein (CRP) were measured daily for 3 days in all patients and as clinically indicated thereafter. The normal range for NOX was established by measuring the concentration in 25 healthy controls. RESULTS: Mean serum NOX and CRP concentrations were significantly elevated in both the patients with a complete and those with an incomplete response compared with controls (P < 0.001) on day 1 and fell during the first 3 days of therapy. On day 3, mean serum concentrations of NOX and CRP were lower in the patients with a complete response, but only the difference in CRP attained statistical significance (P = 0.02). There was no correlation between NOX and CRP concentrations. CONCLUSIONS: In the majority of patients with severe ulcerative colitis, circulating concentrations of NOX are increased at presentation and fall promptly during parenteral steroid therapy, irrespective of clinical outcome. However, in a small number of patients NOX concentrations do not fall during steroid treatment and such patients will probably require additional medical therapy or surgery.