Mortality, disability, and healthcare expenditure of patients with seropositive rheumatoid arthritis in Korea: A nationwide population-based study.

In Ah Choi,Eun Young Lee,Jeong Seok Lee,Yeong Wook Song,Peter M. ten Klooster

doi:10.1371/journal.pone.0210471

Abstract

BackgroundWe investigated the mortality and disability rate, as well as the healthcare expenditure, for patients with newly diagnosed seropositive rheumatoid arthritis (RA) who were followed-up for up to 10 years, compared to the general population in Korea.MethodsWe conducted a nationwide population-based study using a National Health Insurance Service-National Sample Cohort of the Korean population, consisting of 1 million individuals who submitted medical care claims between 2002 and 2013. RA was identified using as the International Classification of Diseases code M05 (seropositive RA), with prescription of any disease-modifying anti-rheumatic drug (DMARD). Our analysis was based on the data of 1655 patients with incident seropositive RA and 8275 non-RA controls. The controls were matched to the RA cohort by sex, age at the time of diagnosis, duration of follow-up, geographic region, type of social security, and household income.ResultsThe most commonly used conventional synthetic DMARDs were hydroxychloroquine (71.30%) and methotrexate (69.5%), with adalimumab being the most commonly used biologic DMARD (2.54%). The mortality rate was significantly higher in the RA than the control group (incidence rate ratio [IRR] 1.29, 95% confidence interval [CI] 1.02–1.64) in the first 10 years after diagnosis. Specifically, mortality due to infectious diseases (IRR 4.41, 95% CI 1.60–12.17) and pneumonia (IRR 3.92, 95% CI 1.46–10.53) was significantly higher in the RA than control group. The disability rate was higher in the RA than control group over the first 10 years of the disease (IRR 2.27, 95% CI 1.77–2.92), which was attributed to a higher incidence of physical disability (IRR 3.81, 95% CI 2.81–5.15). Annual health expenditure was greater for the RA than the control group.ConclusionsTherefore, the rate of mortality and disability, as well as healthcare expenditure, are higher for patients with RA over the first 10 years of the disease onset, than the general population of Korea. The use of claim data has limited the quality of information and there is a limit to the observation period, and we expect the prospective national-wide multicenter cohort for longer period to overcome these limitations.

Highlights

Rheumatoid arthritis (RA) is a chronic inflammatory disease that leads to functional disability [1] and premature mortality [2,3,4]
The mortality rate was significantly higher in the rheumatoid arthritis (RA) than the control group in the first 10 years after diagnosis
The disability rate was higher in the RA than control group over the first 10 years of the disease (IRR 2.27, 95% confidence intervals (CI) 1.77–2.92), which was attributed to a higher

Summary

Introduction

Rheumatoid arthritis (RA) is a chronic inflammatory disease that leads to functional disability [1] and premature mortality [2,3,4]. The long-term prognosis of RA has improved dramatically following the introduction of effective disease modifying anti-rheumatic drugs (DMARDs), including biologic agents and treat-to-target approach for remission, the overall global burden of RA is increasing, owing to its chronic progressive course and the increasing life expectancy worldwide [5]. This burden is largely contributed by RA-associated mortality and disability, and includes the economic burden of RA treatment and management of its comorbidities. We investigated the mortality and disability rate, as well as the healthcare expenditure, for patients with newly diagnosed seropositive rheumatoid arthritis (RA) who were followed-up for up to 10 years, compared to the general population in Korea

Objectives

Methods

Results

Conclusion