The immunosuppressive drug azathioprine has been proven as an effective treatment for maintaining remission in inflammatory bowel disease (IBD).
It has not been established, however, whether neutropenia is also required during azathioprine therapy, to achieve more effective disease remission.
A study by Simon Campbell and Subrata Ghosh from the Gastrointestinal Laboratory at the University of Edinburgh, Scotland, has therefore evaluated whether neutropenia during azathioprine therapy reduces relapse rates in IBD patients.
The retrospective study was based on a total of 173 IBD patients, comprising 96 Crohn's disease (CD) sufferers, and 77 ulcerative colitis (UC) patients.
| Neutropenia does not reduce IBD relapse rates.|
| European Journal of Gastroenterology and Hepatology |
All the patients recruited into the study had been in a stable state of disease remission, following administration of azathioprine, for a minimum of 6 months.
The study followed-up patients for a median duration of 4 years (range 0.6 to 21 years). The lowest neutrophil counts during treatment were recorded.
Relapse rates per year of follow-up were compared in non-neutropenic patients (neutrophil count > 2.5 × 109, n = 129) and neutropenic patients (neutrophil count ≤ 2.5 × 109, n = 44). Survival curves for cumulative remission rates were also compared by log-rank test.
The mean relapse rate per year of follow-up, for the non-neutropenic group, was 0.19 per year, compared with a slightly higher rate of 0.28 per year in the neutropenic patients.
When analysis was performed on the CD and UC subgroups, there was found to be no significant difference in rates of relapse.
The cumulative remission percent, determined by Kaplan-Meier survival analysis, showed no difference between non-neutropenic and neutropenic groups by log-rank analysis. This was true for CD and UC, as well as for all IBD patients.
The researchers conclude from their findings that neutropenia, while on azathioprine, does not reduce the relapse rates of IBD patients, compared to those with neutrophil counts greater than 2.5 × 109.