Exploring disease interrelationships in older inpatients: a single-centre, retrospective study

Abstract

Background: Comorbidity is a common phenomenon in the older population; it causes a heavy burden on societies and individuals. However, the relevant evidence, especially in the southwestern region of China, is insufficient.

Objectives: We aimed to examine current comorbidity characteristics as well as correlations among diseases in individuals aged >60 years.

Design: Retrospective study.

Methods: We included records of 2,995 inpatients treated at the Gerontological Department of Sichuan Geriatric Hospital from January 2018 to February 2022. The patients were divided into groups according to sex and age. Diseases were categorised based on the International Classification of Diseases and their Chinese names. We calculated the age-adjusted Charlson Comorbidity Index (ACCI), categorised diseases using the China Health and Retirement Longitudinal Study questionnaire, and visualised comorbidity using web graphs and the Apriori algorithm.

Results: The ACCI was generally high, and it increased with age. There were significant differences in the frequency of all diseases across age groups, especially in individuals aged ≥90 years. The most common comorbid diseases were liver diseases, stomach or other digestive diseases, and hypertension. Strong correlations between the most common digestive diseases and hypertension were observed.

Conclusion: Our findings provide insights into the current situation regarding comorbidity and the correlations among diseases in the older population. We expect our findings to inform future research directions as well as policies regarding general clinical practice and public health, especially for medical consortiums.

Keywords: chronic diseases; comorbidity; disease visualisation; electronic medical records; older adults.

Figure 1

Web graph for “Liver diseases-Stomach or other digestive diseases.” This figure shows co-occurrence of diseases pairs by frequency visualization. Nodes represent diseases, and the size of nodes indicates the disease frequency. The thickness of the lines indicates the frequency of co-occurrence of the most common liver, stomach, or other digestive diseases.

Figure 2

Web graph for associations between diseases. This figure shows co-occurrence of disease pairs by frequency visualization. Nodes represent diseases, thick lines show strong connection between diseases, while normal and dotted lines show medium and weak connections, respectively. Strong connections are defined as a comorbidity frequency of >200 cases. All strong connections and co-occurrence frequencies are shown in Supplementary Table S4.