C-reactive protein (CRP) is a predictor of high medical-care expenditures in a community-based elderly population aged 70 years and over: The Tsurugaya project Kaijun Niu a, *, Atsushi Hozawa b , Hui Guo a , Kaori Ohmori-Matsuda c , Yufei Cui a , Satoru Ebihara d , Naoki Nakaya e , Shinichi Kuriyama f , Toru Tsuboya c , Masako Kakizaki c , Takashi Ohrui g , Hiroyuki Arai g , Ichiro Tsuji c , Ryoichi Nagatomi a, * a Division of Biomedical Engineering for Health & Welfare, Tohoku University Graduate School of Biomedical Engineering, Sendai, Japan b Department of Public Health Yamagata University Graduate School of Medical Science, Yamagata, Japan c Department of Public Health and Forensic Medicine, Tohoku University Graduate School of Medicine, Sendai, Japan d Department of Internal Medicine and Rehabilitation Science, Tohoku University Graduate School of Medicine, Sendai, Japan e Department of Nutrition and Dietetics, Faculty of Family and Consumer Sciences, Kamakura Women’s University, Kamakura, Japan f Department of Molecular Epidemiology, Environment and Genome Research Center, Tohoku University Graduate School of Medicine, Sendai, Japan g Department of Geriatrics and Gerontology Division of Brain Sciences, Institute of Development, Aging and Cancer, Tohoku University, Sendai, Japan 1. Introduction CRP has received substantial attention in recent years as a promising biological predictor of atherosclerotic disease (Pearson et al., 2003). An evolving body of work suggests that even small increases in CRP within the normal range are predictive of future vascular events in apparently healthy, asymptomatic individuals (Ridker et al., 2002). A number of prospective studies have also demonstrated that high baseline levels of CRP are a strong independent predictor of cardiovascular risk (Koenig et al., 1999), recurrent events and/or increased mortality in patients with ischemic stroke (Di Napoli et al., 2001), peripheral vascular disease (Ridker et al., 2001) cancer (Heikkila et al., 2007), and all-cause mortality (Cao et al., 2007). CRP is also correlated with abdominal obesity and metabolic syndrome, and an elevated level increases the risk of developing type 2 diabetes (Barzilay et al., 2001; Pradhan et al., 2001). Total medical-care expenditures in Japan reached 33 trillion yen (approximately $290 billion) in 2006 (Accessed October 05, Archives of Gerontology and Geriatrics 54 (2012) e392–e397 ARTICLE INFO Article history: Received 25 October 2011 Received in revised form 8 November 2011 Accepted 31 January 2012 Available online 22 February 2012 Keywords: CRP Medical-care expenditure Inflammation ABSTRACT Because CRP is a strong independent predictor of various diseases, it was hypothesized that CRP may be a useful predictor or treatment target for medical-care expenditures. The aim of this study was to investigate the relationship between CRP and medical-care expenditures in a community-dwelling elderly population. This prospective cohort study was conducted including 925 Japanese subjects aged 70 years. A high-sensitivity CRP assay was used by applying the nephelometric method. Hospitalizations, outpatient visits, and expenditures were ascertained through computerized linkage with claims lodged between August 2002 and March 2008 with the Miyagi National Health Insurance (NHI) Association. Since medical-care expenditures were not normally distributed, the category of high medical-care expenditures (>75th percentile of medical-care expenditures: inpatient expenditures >$494/month; outpatient expenditure >$522/month; total expenditures >$1103/month) was used to examine the relation of CRP levels with medical-care expenditures. Multiple logistic regression analysis was used to examine the relationship between CRP cutoff points (low concentrations: <1.0 mg/L; intermediate concentrations: 1.0–3.0 mg/L; or high concentrations: 3.0 mg/L) and medical-care expenditures during 6 year-follow up period. After adjustment for potential confounding factors, a positive association of CRP with hospitalization, and total expenditures (p for trend = 0.03 and 0.02, respectively) was found. An elevated baseline CRP level is an independent predictor of increases in prospective medical-care expenditures among community-dwelling elderly. Further study is required to clarify whether reducing CRP by intervention is a cost-effective measure. ß 2012 Elsevier Ireland Ltd. All rights reserved. * Corresponding authors at: Division of Biomedical Engineering for Health & Welfare, Tohoku University Graduate School of Biomedical Engineering, 2-1 Seiryo- machi, Aoba-ku, Sendai 980-8575, Japan. Tel.: +81 22 717 8587; fax: +81 22 717 8587. E-mail addresses: nkj0809@gmail.com (K. Niu), nagatomi@med.tohoku.ac.jp (R. Nagatomi). Contents lists available at SciVerse ScienceDirect Archives of Gerontology and Geriatrics journal homepage: www.elsevier.com/locate/archger 0167-4943/$ – see front matter ß 2012 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.archger.2012.01.014