HY Shi, FKL Chan, WK Leung, MKK Li, CM Leung, SF Sze, JYL Ching, FH Lo, SWC Tsang, EHS Shan, LY Mak, BCY Lam, AJ Hui, WH Chow, MTL Wong, IFN Hung, YT Hui, YK Chan, KH Chan, CK Loo, CKM Ng, WC Lao, M Harbord, JCY Wu, JJY Sung, and SC Ng, Therapeutic Advances in Gastroenterology. 07, 2016. 9: p. 449-456. [IF: 3.648]
Abstract
Background:
Whether low-dose azathioprine (AZA) is effective in maintaining remission in patients with steroid-dependent ulcerative colitis (UC) remains unclear. We assessed the efficacy and safety of low-dose AZA in a Chinese population with UC.
Methods:
We identified steroid-dependent UC patients in clinical remission on AZA maintenance therapy from a territory-wide IBD Registry. Standard- and low-dose AZA were defined as at least 2 mg/kg/day and less than 2 mg/kg/day, respectively. Relapse rates were analyzed by Kaplan–Meier analysis and compared using log-rank test.
Results:
Among 1226 UC patients, 128 (53% male, median duration on AZA 44 months) were included. Median maintenance AZA dose was 1.3 mg/kg/day. 97.7% of the patients were on concomitant oral 5-aminosalicylic acid. Cumulative relapse-free rates in patients on standard-dose and low-dose AZA were 71.2%, 52.8% and 45.2%, and 71.8%, 55.3% and 46.2% at 12, 24 and 36 months, respectively (p = 0.871). Relapse rate within 12 months was higher in patients who withdrew compared with those who maintained on AZA (52.6% versus 29.4%; p = 0.045). Mean corpuscular volume increased after AZA therapy in both of the low-dose [median (interquartile range, IQR): 88.2 (81.4–92.2) versus 95.1 (90.1–100.9) fl, p < 0.001] and standard-dose subgroups [median (IQR) 86.8 (76.9–89.9) versus 94.7 (85.9–99.7) fl, p < 0.001]. Leukopenia occurred in 21.1% of the patients. Patients on standard dose had a higher risk for leukopenia than those on low-dose AZA [odds ratio (OR) 3.9, 95% CI 1.9–8.2, p < 0.001].
Conclusions:
In the Chinese population, low-dose AZA is effective for maintaining remission in steroid-dependent UC patients. Standard-dose AZA was associated with more than threefold increased risk of leukopenia.