Ueda K, Takura T, Fujikoshi S, Meyers J, Nagar SP, Enomoto H. A claims database longitudinal study of the economic burden among patients with knee osteoarthritis in Japan. Poster to be given at the 34th Annual Research Meeting of the Japanese Orthopaedic Association; October 17, 2019. Yokohama, Japan.


OBJECTIVE: To compare health care resource utilizations (HCRU) and costs among patients in Japan with knee osteoarthritis (KOA) with and without other painful sites.

METHODS: A retrospective analysis of insurance claims data was conducted using the Japan Medical Data Center database. Adults (≥40 years and with five-year follow up data) with KOA from 1 January 2011, to 31 December 2012 were evaluated. First KOA diagnosis claim defined the index date and patients were divided into two mutually exclusive cohorts: 1. Patients with other painful sites [KOA+] and 2. Patients with KOA only [KOA]. OA-related HCRU and costs during the five-year follow-up period were reported.

RESULTS: A total of 2,542 patients met the study criteria; 967 in the KOA+ cohort and 1,575 in the KOA cohort. Mean age was higher among the KOA+ cohort (54.7 years) versus the KOA cohort (52.0 years) with more females in the KOA+ cohort (63.3% versus 50.2%). Among patients in the KOA+ cohort, spine (7978.7%) and hip (12.4%) were the most common sites of other OA diagnosed. Regardless of cohort, more than 98.7% of patients were prescribed any pharmacological treatment during the follow-up period. A significantly higher proportion of OA-related hospitalizations were observed among the KOA+ cohort (3.2%, 1.1%, 1.7%, 2.5%, 2.1%) compared to the KOA cohort (0.9%, 0.4%, 0.6%, 0.4%, 0.8%) during each year of the five-year follow-up period. Similarly, mean OA-related healthcare costs per patient were high among patients in the KOA+ cohort (¥281,098, ¥197,255, ¥204,561, ¥205,939, ¥216,350) compared to the KOA cohort (¥99,168, ¥55,339, ¥60,002, ¥63,487, ¥70,212) during each year of the five-year follow-up period.

CONCLUSIONS: This is the first study which showed the demographics and HCRU for the KOA+ patients in Japan. These results suggest that multidisciplinary and comprehensive treatment for not only KOA but also other OA would be important for the effective resource utilization in the aging society.

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