Platelet count: a simple measure of activity in Crohn's disease.

Platelet count: a simple measure of activity in Crohn's disease Thrombocytosis may occur in inflammatory bowel disease and probably represents a non-specific response to inflammation.1 2 We have observed raised platelet counts in patients with active Crohn's disease, and we therefore investigated whether the platelet count is a useful index of disease activity. We studied 57 patients with Crohn's disease attending a gastrointestinal clinic; diagnosis was based on conventional criteria. The patients comprised 27 men and 30 women aged (meant 1SD) 37±14 years. Mean duration of disease was nine years. Distribution of disease radiologically was diffuse small bowel (nine), ileocaecal (24), ileocolonic (eight), colonic (13), and anorectal (three). Thirty patients had undergone resections, and recurrent disease was present in 22. Twenty six patients were receiving prednisolone and 15 sulphasalazine. Disease activity was measured by a simple clinical index,3 scores of 5 or more representing active disease. Platelets were measured in all patients by an automated technique using a Clay Adams Ultra Flo 100 whole blood platelet counter (normal range 150-450x 109/1). In most patients serum orosomucoid concentrations were measured by rate reaction nephelometry with an automated Beckman rate nephelometer (normal range < 10 g/l). Statistical analysis was by unpaired Student's t test and Pearson's moment product correlation coefficient (r). Platelet counts were significantly higher in patients with clinically active disease (5114-177x 109/1; n= 19) than in those with inactive disease (379± 123 x 109/1; n= 38) (p < 0 01). Counts were similar irrespective of whether patients had undergone resection or had recurrence and irrespective of disease distribution and drug treatment. There was a strong positive correlation between platelet counts and serum orosomucoid concentrations (figure). All patients with platelet counts greater than 500x 109/1 had serum orosomucoid concentrations greater than 10 g/l.