Variations in multimorbidity measurement in studies evaluating hospitalisation in older adults: a systematic review

Abstract

Background Multimorbidity is the coexistence of two or more chronic diseases, and in older adults is more common which can lead to increased rates of hospitalisation and health care. Therefore, this review aims to identify the varia- tions in multimorbidity measurement in studies evaluating hospitalisation in older adults. Methods A systematic review was conducted using a comprehensive database search in the PubMed, Embase, and Scopus databases, and included papers that used multimorbidity to evaluate hospitalisation in later life (PROS- PERO register: CRD42021229328). Studies that employed multimorbidity measures with a simple count, weighted indices, Latent Class Analysis, Adjusted Clinical Groups System, Chronic Disease Score or Cumulative Index Illness Rat- ing Scale were included. There was no restriction of language and year of publication of the studies included. Results This review included 39 articles and was reported according to the PRISMA methodology. Analysing the vari- ations in multimorbidity measurement related to hospitalisation in older adults we found a wide range of number of diseases, from 6 to 40, however, most of them utilised from 10 to 14 diseases. Regarding the data source, 56% of studies used self-reports, and 77% the disease count as a measure to assess multimorbidity. Conclusions This review revealed enormous heterogeneity in the number and type of diseases and diverse meth- odological criteria applied in studies that assessed multimorbidity associated with hospitalisation in older adults. Furthermore, the disease group most used in the studies was those of the circulatory system and the five diseases frequently included were diabetes, hypertension, cancer, stroke, and coronary heart disease.