Background Gout treatment relies heavily on urate-lowering therapies (ULTs). However, in patients with concurrent chronic kidney disease (CKD), choice of ULT may be complicated by the presence of polychronic disease (PCD), which can limit the utility of standard therapies, increase the risk of drug-drug interactions, and confound outcome evaluation.
Objectives To characterize PCD burden in gout patients with CKD initiating on two common ULTs, allopurinol (ALP) and febuxostat (FBX).
Methods Patients aged >18 years with gout (International Classification of Diseases, 9th Revision code CM 274.xx) and concurrent CKD (stage 3-4) were selected from the Truven Health Analytics MarketScan® databases (2008-2012) upon initiation of ALP or FBX if they had been continuously enrolled for ≥12 months prior to initiation and had no baseline claims evidence of malignancy, HIV/AIDS, organ transplant, or dialysis. PCD was defined as cardiovascular disease (CVD; e.g., ischemic heart or cerebrovascular disease), renal disease (e.g., nephritis, renal failure) and inflammatory arthritis (e.g., psoriasis, rheumatoid arthritis), as well as diabetes, chronic obstructive pulmonary disease (COPD), liver disease and other conditions. The baseline prevalence of 23 PCDs and 22 medication classes was assessed overall and by line of ULT.
Results A total of 5628 patients met eligibility criteria. Mean (SD) age was 68.3 (12.7) years; 63% of patients were male, and 39% were commercially insured. Three quarters had stage 3 CKD. In all, 4015 patients (71%) initiated on ALP, almost all (96.9%) in first-line settings; 1613 patients (29%) initiated on FBX, 49.5% in first-line settings.
Mean (SD) number of PCDs per patient was 4.5 (2.5). Eighty-three percent of patients had a diagnosis of CVD, 42.1% had diabetes, 29.2% had dyslipidemia, 16.1% had osteoarthritis, and 12.0% had COPD. The most common cardiovascular conditions were hypertension (69.0%); dysrhythmias/conduction disorders (23.7%); heart failure (22.2%); and ischemic heart (29.6%), cerebrovascular (8.7%), or peripheral vascular disease (8.7%). Among CVD patients, 57% had multiple cardiac conditions. Mean (SD) baseline healthcare expenditure per patient per year was $20,757 ($28,216).
Mean (SD) number of baseline medication classes per patient was 7.3 (2.6).Classes (percentage exposed) were antihyperlipidemic agent, diuretic, and glucocorticoid (68% for each), opiate analgesic or agonist (63%), β blocker (62%), calcium channel blocker (44%), angiotensin II receptor blocker (41%), ACE inhibitor (40%), prescription nonsteroidal anti-inflammatory drug (34%), anticoagulant (20%), antiplatelet (18%), antiarrhythmic (7%), and digitalis preparation (6%). Mean medication class count per patient in the 12 months before ULT initiation was significantly (p<0.0001) higher in second-line settings than in first-line settings, as were frequencies of tophi (p<.0001) and gout flare (p<.0001).
Conclusions Gout patients with moderate/severe CKD treated with ULT have numerous PCDs and are exposed to multiple medication classes. Clinical profiles and disease burden are more complicated in those treated in second-line settings. Controlling for both line of therapy and PCD should be considered in outcome evaluations.
Disclosure of Interest R. Turpin Employee of: Takeda Pharmaceuticals USA, Inc, G. Mitri Employee of: Takeda Pharmaceuticals USA, Inc, E. Wittbrodt Shareholder of: Takeda Pharmaceuticals USA, Inc, Employee of: Takeda Pharmaceuticals USA, Inc, B. Tidwell Consultant for: Takeda Pharmaceuticals USA, Inc, K. Schulman Consultant for: Takeda Pharmaceuticals USA, Inc