SAN FRANCISCO – Hospitalization rates for gout doubled between 1993 and 2011, while those for rheumatoid arthritis fell by 67%, Dr. Sian Yik Lim reported at the annual meeting of the American College of Rheumatology.
The trends reveal marked progress in the treatment of rheumatoid arthritis, but “also highlight a critical need to improve gout care” and to implement measures to combat its rising prevalence, said Dr. Lim, a research fellow in medicine at Massachusetts General Hospital, Boston.
The study is “a very nice piece of work,” added Dr. James Galloway, who helped moderate the session at the meeting and is a lecturer in rheumatology at King’s College Hospital in London. “It makes us wonder whether we should spend more time teaching our primary care physician colleagues more about gout than rheumatoid arthritis.”
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Gout and rheumatoid arthritis are the two most common inflammatory joint diseases, but few longitudinal studies have examined trends in related hospital admissions or costs, Dr. Lim said. Therefore, he and his associates extracted primary hospital discharge ICD-9 diagnosis codes from the National Inpatient Sample and also studied primary procedure codes for total knee replacement, total hip replacement, and other major joint surgeries for 1993 through 2011. In addition, they merged these with cost data from the Healthcare Cost and Utilization Project for 2001 to 2011.
Hospitalizations for gout and rheumatoid arthritis “crisscrossed” during the study period, Dr. Lim said. While there were more than three times as many hospitalizations for rheumatoid arthritis (26,712) as for gout (8,485) in 1993, by 2011, there were nearly twice as many admissions for gout (20,949) as for rheumatoid arthritis (11,015). Likewise, hospitalization rates for gout rose from 4.5 to 9 per 100,000 adults, while rheumatoid arthritis admissions fell by about two-thirds, from 14 to 5 per 100,000 adults. For the entire study period, hospital admissions for gout totaled 254,982, compared with 323,649 for rheumatoid arthritis, Dr. Lim added.
The investigators also documented a steady drop in admissions for total knee replacement, total hip replacement, and other major joint surgeries among rheumatoid arthritis patients, mirroring the results of recent multicenter studies in California (Ann Rheum Dis. 2009 Jul 5. doi: 10.1136/ard.2009.112474), the United Kingdom (Rheumatology [Oxford]. 2015 Apr;54[4]:666-71), and Germany (Ann Rheum Dis. 2015;74:738-45), Dr. Lim said. “This finding contrasts with the overall dramatic increase in these surgeries in the general United States population in recent years,” he added.
Inflation-adjusted hospital costs for gout and rheumatoid arthritis also converged during the study period, and by 2011, costs for gout actually exceeded those for rheumatoid arthritis, Dr. Lim said.
Overall, the findings reflect stark differences in care for gout and rheumatoid arthritis in the United States, he added. “New and potent drugs, effective combination regimens, and management strategies are increasingly being adopted for rheumatoid arthritis, but care for gout remains suboptimal, even though its prevalence and incidence are increasing,” he said. “Although the vast majority of gout patients are indicated for urate-lowering therapy, only a small proportion retrieve treatment, and the level of uric acid is not even measured in the vast majority of patients.”
Surveys also indicate that patients with gout often do not receive clear explanations about their disease, which may explain why as few as 10% follow treatment recommendations, according to Dr. Lim. He pointed to a hospital-based, retrospective cohort study reported at last year’s ACR annual meeting in which 89% of hospitalizations for gout were considered preventable. “These data support the need to improve gout prevention and care,” he said.
Dr. Lim had no disclosures. Dr. Hyon Choi, the senior author, reported having served on advisory boards for Takeda and AstraZeneca.