R.L.GURUNG1, Y.M1, L.RABINDRAN1, S. UMAIRAH1, A.LIU1, S.C.LIM1
Khoo Teck Puat Hospital1
Allopurinol is an efficacious urate-lowering drug for gout but is associated with life-threatening severe cutaneous adverse reactions (SCAR). Patients with HLA-B*58:01 allele and chronic kidney disease (CKD) are at greatest risk. We aim to evaluate the implementation outcomes of HLA-B*58:01 testing in CKD patients requiring Allopurinol.
This pragmatic study enrolled CKD patients with gout and requiring allopurinol. Clinical HLA-B*5801 testing was performed during their clinical visit at Yishun health. Main outcomes were 1) percent changes in serum uric acid (sUA) from baseline, 2) proportion of patients achieving sUA level of 360 µM, 3) proportion of patients for whom test results warranted deviation from standard dosing regimens. Safety assessment involved phone call every fortnight for a month.
The patients (n=57) were predominantly male (77%), with mean [SD] age 62  years, baseline sUA of 609  µmol/l. Nine patients (15.8%) tested HLA-B*58:01 positive and avoided Allopurinol. However, among 48 HLA-B*58:01 negative patients, only 35 were prescribed Allopurinol. During the mean follow-up of 12 months, patients on Allopurinol showed greater reduction in sUA level (P=0.041) and were more likely to achieve sUA target compared to those not on Allopurinol or other medications (29% vs 0%, P=0.066). No allopurinol-induced side effects were reported but the maximum average dose was <150mg per day.
Pre-emptive test identified high risk patients, consistent with population allelic frequency reducing potential risk of adverse event. However, future work should address challenges we experienced to facilitate clinical implementation to achieve maximal benefit, especially in low-risk CKD patients.