ORIGINAL PAPER Allopurinol adherence among patients with gout: an Italian general practice database study S. Mantarro, 1 A. Capogrosso-Sansone, 1 M. Tuccori, 2 C. Blandizzi, 1,2 S. Montagnani, 1 I. Convertino, 2 L. Antonioli, 1 M. Fornai, 1 I. Cricelli, 3 S. Pecchioli, 3 C. Cricelli, 4 F. Lapi 3 SUMMARY Aims: Allopurinol is used as long-term therapy to reduce the occurrence of gout flares. This study estimated the impact of patient adherence to allopurinol on hy- peruricaemia (serum uric acid levels, sUA > 6 mg/dl) and the identification of non- adherence predictors. Methods: The Italian Health Search-CSD Longitudinal Patient Database was accessed to identify outpatients aged ≥ 18 years with gout and prescribed with allopurinol during the years 2002–2011. Patients with a pro- portion of days covered ≥ 80% were considered adherent to allopurinol. Data on sUA levels over the first year of therapy were categorised in three time-windows (30–89; 90–149; 150–365 days). Logistic regressions were used to estimate the association between adherence and hyperuricaemia, as well as non-adherence predictors. Results: A total of 3727 patients were included. In the interval 0–29 days, the proportion of patients adherent to allopurinol was 45.9%, while up to 89, 149 and 365 days the percentages were 16.7%, 10.0% and 3.2%, respectively. The proportions of hyperuricaemic patients for each time-window were 43.1%, 42.4%, 32.6% and 59.0%, 64.0%, 66.4% among adherent and non-adherent patients, respectively. In the multivariable analysis, adherence was associated with a significant lower risk of hyperuricaemia. The adjusted ORs were 0.49 (95% CI: 0.33–0.73), 0.40 (95% CI: 0.24–0.67) and 0.23 (95% CI: 0.15– 0.34) for the first, second and third time-window, respectively. Patients with hyper- tension (adjusted OR = 0.64, 95% CI: 0.42–0.99) and history of gout flares (adjusted OR = 0.55, 95% CI: 0.32–0.95) were significantly adherent to allopuri- nol. Conclusions: Adherence monitoring in patients with gout is pivotal to ensure the effectiveness of therapy. To gain a better patient adherence, the communica- tion between physicians and patients should be improved. What’s known • Adherence to long-term therapy with allopurinol is a major healthcare concern. • A scarce patient adherence to allopurinol could lead to an increased risk of gout exacerbations. What’s new • Few patients with gout are adherent to allopurinol over the first year of therapy. • There is an impact of allopurinol adherence in reducing hyperuricaemia in patients with gout. • A higher proportion of patients with comorbidities (i.e. hypertension, diabetes) and those with previous gout flares are adherent to allopurinol as compared with healthier patients with gout. • More communication should be encouraged between physicians and patients to understand the reasons of non-adherence to allopurinol, and implement consequent actions. Introduction Gout is a common joint and painful disease that seriously affects the quality of life, determined by deposition of monosodium urate crystals within joints and surrounding tissues, as a consequence of chronic high blood urate levels (1). Hyperuricaemia is defined as serum uric acid (sUA) greater than 360 mmol/l (6 mg/dl), and can be caused by an increased metabolic production or a reduced renal excretion of urate (2). Although hyperuricaemia is necessary for gout occurrence, it is not sufficient to cause gout. As previously demonstrated, gout devel- oped in 22% of hyperuricaemic patients (over 9.0 mg/dl) during a 5-year period (3). It has been estimated that the prevalence of gout was 3.9% in USA (4), 1.4% in UK and Germany (5), 2.7% in New Zealand (6), 2.3% in women and 8.2% among men in Taiwan (7). In Italy and China, the gout prevalence appears to be remarkably lower (0.9% and 0.5%, respectively) than in other countries (8,9). Several risk factors are known to affect the gout onset, including comorbidities, genetic varia- tions, dietary habits and long-term exposure to cer- tain drugs (1,10–14). Pharmacotherapy of gout is focused on treatment of acute attacks (non-steroidal anti-inflammatory drugs – NSAIDs, colchicine or corticosteroids), and reduction in serum urate levels (xanthine oxidase inhibitors and uricosuric medications) as long-term therapy. The most important urate-lowering agents are allopurinol and febuxostat, which inhibit xan- thine oxidase thus preventing the conversion of oxypurines into uric acid (15,16). The Italian ª 2015 John Wiley & Sons Ltd Int J Clin Pract, July 2015, 69, 7, 757–765. doi: 10.1111/ijcp.12604 757 1 Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy 2 Unit of Adverse Drug Reaction Monitoring, University Hospital of Pisa, Pisa, Italy 3 Health Search, Italian College of General Practitioners, Florence, Italy 4 Italian College of General Practitioners, Florence, Italy Correspondence to: Francesco Lapi, Health Search, Italian College of General Practitioners, Via Sestese 61, 50141 Florence, Italy Tel.: + 39 055 494900 Fax: + 39 055 77931166 Email: lapi.francesco@simg.it Disclosures The authors ICr, SP, CC, FL provided consultancies in terms of protocol preparation and data analyses to Menarini Industrie Farmeceutiche Riunite which supported the submitted work. The authors SMa, AC, MT, CB, SMo, ICo, LA, MF had no support from any organisation for the submitted work; no financial relationships with any organisation that might have an interest in the submitted work; no other relationships or activities that could appear to have influenced the submitted work.