CHRONIC CONDITIONS AND PHYSICAL FUNCTIONING: DEVELOPMENT OF A NEW ICD-CODED MULTIMORBIDITY INDEX. (11th November 2018)

• Record Type: Journal Article
• Authors: Wei, M; Ratz, D; Kabeto, M; Langa, K
• Is Part Of: Innovation in aging. Volume 2(2018)Supplement 1
• Page Start: 316
• Page End: 316
• Publication Date: 2018-11-11
• Subjects: Aging -- Periodicals; Gerontology -- Periodicals; 612.67
• DOI: 10.1093/geroni/igy023.1156
• Languages: English
• ISSNs: 2399-5300

Abstract

Abstract: Most older adults have multiple chronic conditions (multimorbidity) that profoundly affect physical functioning. However, critical gaps remain in its measurement. We previously developed and validated a multimorbidity index that weights self-reported physician-diagnosed diseases by physical functioning. Herein, we linked Health and Retirement Study (HRS) and Medicare claims to develop a multimorbidity index of ICD-coded conditions (MWI-ICD) for administrative data. Medicare-eligible HRS participants with outpatient and inpatient claims contributed repeated measures of a modified Short Form (SF)-36 physical functioning scale and ICD-coded conditions between 2000–2012. Mixed effects models adjusted for age were used to obtain regression coefficients for conditions on physical functioning. MWI-ICD was calculated by summing the physical functioning-weighted conditions. We included 71, 756 observations from 17, 478 participants with mean age 70.98.2 years and 55.930.3 physical functioning units. Diseases varied several-fold in their impact on physical functioning (median 1.8, range 0–9.3). The top prevalent conditions were hypertensive disease (66%), metabolic disorders including hyperlipidemia and overweight/obesity (61%), eye disorders (57%), and connective tissue and joint disorders (55%). Neuroendocrine tumors, acquired hemolytic anemias, multiple sclerosis, and paralysis had the greatest impact on physical functioning. The mean MWI was 13.4 (median 11.7, range 0–43.5) and mean disease count was 6.6 (median 6, range 0–29). Chronic conditions from Medicare claims had wide-ranging associations with physical functioning. MWI had a wider distribution than simple disease count, suggesting that a simple disease count is unlikely to capture the full impact of multimorbidity on physical functioning. A newly-developed MWI-ICD is feasible and readily implemented in administrative data.