Background/Purpose:

To comprehensively assess patient, comorbidity, physician, system, health care access and disease factors associated with the ability to achieve and maintain target serum urate (sUA) with allopurinol in patients with gout.

Methods:

We used National VA national databases from 2002-2012.  Patients were eligible if they had ≥2 outpatient or ≥1 inpatient encounters with an International Classification of Diseases-ninth version (ICD-9) code 274.xx for gout, and met 12-month observability rule.  Index allopurinol use was defined as the filling of a new allopurinol prescription with no allopurinol exposure in the previous 121 days.  Treatment successes were defined as the achievement of: (1) post-index sUA <6 mg/dl; and (2) post-index sUA <6 mg/dl that was sustained, as defined by achievement of: (1) post-index sUA <6 mg/dl and at least one more follow-up sUA that was <6 mg/dl.

Results:

41,153 unique patients with 47,072 episodes contributed to analyses of achieving target sUA ≤ (success 1) and 17,402 unique patients with 18,323 episodes to achieving and maintaining target sUA  (success 2).  In multivariable-adjusted models, the following were associated with significantly higher odds of achieving both successes 1 and 2: older age, normal BMI (18.5-25 kg/m2), female sex, black/african-american race, peptic ulcer disease, severe liver disease, hypertension, rheumatologist as the main provider rather than non-rheumatologist, Midwest location for the health care facility, a lower hospital bed size, service-connection conditions of 50% or more, longer distance to the nearest VA facility, lower pre-index sUA, higher allopurinol start and end dose, higher allopurinol adherence, previous use of allopurinol with in 1 year and normal/recommended or fast allopurinol dose escalation. Diabetes with complications and paraplegia,  were associated with increased odds of not achieving success 1 and 2. Additionally, increasing BMI and greater baseline sUA showed a  clear linear trend toward not achieving success 1 and success 2. 

Conclusion:

In this study, we identified several important factors associated with achieving and maintaining sUA <6 mg/dl.  This knowledge provides several new potential modifiable targets for improving the ability to lower serum urate with allopurinol pharmacotherapy and sustain a therapeutic target in patients with gout. 

Table 1. Multivariable-adjusted association of factors with the ability to achieve and maintain target sUA of < 6mg/dl*

ACR Meeting Abstracts - https://acrabstracts.org/abstract/effectiveness-of-allopurinol-in-achieving-and-sustaining-target-serum-urate-a-study-using-large-intergrated-national-health-network/