Correlation Between the Crohn's Disease Activity and Harvey–Bradshaw Indices in Assessing Crohn's Disease Severity

Abstract

Clinical trials of Crohn's disease generally use the Crohn's Disease Activity Index to assess disease activity; these calculations are complex, time-consuming, and impracticable. We investigated whether a simpler tool, the Harvey-Bradshaw Index, was equally effective in assessing disease severity. Crohn's Disease Activity and Harvey-Bradshaw Index scores were collected from 2 large multicenter Crohn's disease studies. The PEGylated antibody fragment evaluation in Crohn's disease: safety and efficacy (PRECiSE) 1 and 2 trials assessed efficacy and tolerability of certolizumab pegol (PEGylated, humanized, Fab' fragment of an antitumor necrosis factor alpha antibody). PRECiSE 1 and 2 data were analyzed to determine if results from the Crohn's Disease Activity Index correlated with those from the Harvey-Bradshaw Index criteria for defining response and remission. Analysis of almost 1000 data pairs showed a positive correlation between scores. The correlation between the indices for pooled data from PRECiSE 1 and PRECiSE 2 was 0.800 (Spearman correlation coefficient). The correlations between indices for the PRECiSE 1 or PRECiSE 2 were 20.698 and 0.716, respectively (Kronecker product variance). A 3-point change in the Harvey-Bradshaw Index score corresponded to a 100-point change in the Crohn's Disease Activity Index (clinical response); scores < or =4 points corresponded to a Crohn's Disease Activity Index score < or =150 points (clinical remission). Results from the Crohn's Disease Activity Index correlate with those from the Harvey-Bradshaw Index; use of the Harvey-Bradshaw Index might permit simpler Crohn's disease activity assessment in long-term clinical trials, and facilitate standardized disease activity measurements and cross-center comparisons.