Abstract
BACKGROUND: Previous studies indicate a high comorbidity burden among patients with malignant neoplasms, but claims-based comorbidity patterns have not been systematically characterized at the regional multi-hospital level in China. METHODS: This study is a multi-center, hospital-based retrospective analysis of inpatient insurance claims. We analyzed anonymized inpatient medical insurance claims data (2016-2021) from 163 hospitals in Zhanjiang, China, focusing on hospitalized patients with a primary diagnosis of malignant neoplasms. Malignant neoplasms and comorbidities were identified using International Classification of Diseases, 10th Revision(ICD-10) codes. Disease spectrum was stratified by sex, age, and region. Comorbidity patterns were delineated using association rule mining and network analysis. RESULTS: Among 107,029 patients, the ten most common malignancies accounted for 75.96% of all cases. Hospitalizations were more frequent among rural populations, males, and individuals aged ≥65 years. The median number of co-diagnosed conditions across major malignancies was 5 (interquartile range [IQR]: 3-7). Network analysis revealed three major co-diagnosis clusters: 1) liver cancer with chronic viral hepatitis and hepatic fibrosis; 2) lung cancer with chronic obstructive pulmonary disease (COPD) and pneumonia; and 3) colorectal cancer with inflammatory bowel disease-related conditions and intestinal obstruction. Patterns varied across sex, age groups, and urban-rural residence. CONCLUSIONS: This study demonstrates a high comorbidity burden among hospitalized cancer patients, with distinct malignancy-specific co-diagnosis patterns. These findings support the need for integrated clinical management and targeted healthcare resource allocation, particularly for older, male, and rural patient populations.