USUAL THERAPY IMPROVES PERIANAL CROHNS-DISEASE AS MEASURED BY A NEW DISEASE-ACTIVITY INDEX

Troublesome perianal disease occurs in similar to 35% of patients with Crohn's disease, yet conventional disease activity indices do not ref lect the severity of this feature. To assess the degree of impairment and response to therapy, we identified five simple elements and graded each on a 5-point Likert scale in 37 patients at 124 visits. At each visit a Crohn's Disease (CDAI) or Simple Activity Index (HBDAI), Peria nal Disease Activity Index (PDAI), and treatment were recorded. The PD AI was validated against physician (MDGA) and patient (PGA) global ass essments, and treatment was prescribed for the perianal disease. Measu rement error was evaluated in 19 patients who were clinically stable a t two consecutive visits. The ability of the PDAI to detect important clinical change was tested in 20 subjects exhibiting a change on PGA a t consecutive visits. There were strong correlations between PDAI, MDG A, and PGA scores at all visits (R = 0.66-0.72; p < 0.001), whereas th e CDAI and HBDAI correlated poorly with PDAI (R < 0.23). Physicians pr escribed more aggressive therapy for higher PDAI scores (r = 0.53). Me an PDAI scores between visits in clinically stable subjects were not s ignificantly different [5.58 +/- 2.79 (initial); 5.42 +/- 2.55 (follow -up); p = 0.63]. PDAI significantly improved between visits when the p erianal disease had improved (PDAI score difference 3.05 +/- 2.96; P = .0002). We conclude that the PDAI is simple and clinically useful for patient management. It should now be assessed in a clinical trial.