Disease-related and all-cause health care costs of elderly patients with gout

• Published in: Journal of managed care pharmacy 2008-03, Vol.14 (2), p.164-175
• Main Authors: Wu, Eric Q, Patel, Pankaj A, Yu, Andrew P, Mody, Reema R, Cahill, Kevin E, Tang, Jackson, Krishnan, Eswar
• Format: Article
• Language: English
• Subjects: Adolescent; Aged; Biomarkers; Female; Gout - drug therapy; Gout - economics; Gout Suppressants - economics; Gout Suppressants - therapeutic use; Health Expenditures; Health Services - economics; Health Services - utilization; Humans; Insurance Claim Review - statistics & numerical data; Male; Models, Econometric; Uric Acid - blood
• ISSN: 1083-4087; 1944-706X
• DOI: 10.18553/jmcp.2008.14.2.164

Gout is a common cause of inflammatory arthritis in the United States, and its prevalence has increased in recent decades, especially among older adults. Older adults with gout are of particular interest because they tend to experience higher rates of tophi, an advanced stage of gout, than do younger patients. For older adults with gout to (1) assess health care utilization and costs from a third-party payer perspective; (2) evaluate health care costs related to tophi; and (3) explore the relationship between elevated serum uric acid (UA) level, an indicator of disease control, and health care utilization. Data were extracted from the Integrated Healthcare Information Services (IHCIS) claims database (1999-2005), which includes approximately 40 private health plans in the United States for approximately 13 million beneficiaries, about 4% of whom are aged 65 years or older. Patients were included in the study if they: (1) had 2 diagnoses of gout (International Classification of Diseases, Ninth Revision, Clinical Modification [ICD-9-CM] code of 274.xx) on separate medical claims or 1 gout diagnosis plus at least 1 gout-related pharmacy claim (i.e., allopurinol, probenecid, colchicines, or sulfinpyrazone); (2) were at least 65 years old at the first diagnosis date (study index date); and (3) had 1 year of continuous eligibility both before and after the study index date. A comparison sample of elderly members without gout was selected using a 1:1 match to gout patients based on age, gender, and geographic region. Individuals in the comparison group also had 1 year of continuous eligibility both before and after the study index date, defined as the same index date as the respective matched gout patient. Patients with possible tophi were identified from at least 1 medical claim with an ICD-9-CM code 274.8x (274.81=gouty tophi of the ear; 274.82 = gouty tophi of other sites except ear; 274.89 = gout with other specified manifestations) during the 12-month study period following the study index date. Additionally, a subgroup of gout patients with at least 1 serum UA measure was selected. Patients were divided into 3 groups according to their serum UA level on the earliest test date (serum UA index date): low (< 6 mg per dL), moderate-high (6-8.99 mg per dL), and very high (> or = 9 mg per dL). Health care utilization was categorized into inpatient services, outpatient services, emergency room services, other medical services, and use of prescription drugs. Medica