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North–South Disparities in Multimorbidity Revealed by Association Rule and Sequential Pattern Mining: Evidence From the China National Health Survey (CNHS)

Year: 2026

Type: article

Abstract: BACKGROUND: North-south differences in context and lifestyle may shape multimorbidity patterns in China. We compared multimorbidity between two northern (Liaoning, Jilin) and two southern (Guangdong, Jiangsu) CNHS provinces in eastern China using association rule mining (ARM) and sequential pattern mining (SPM). METHODS: We analyzed 19,067 adults (≥20 years) and 20 chronic conditions. ARM identified co-occurrence rules and reported support (proportion with the combination), confidence (P(consequent|antecedent)), and lift (observed/expected co-occurrence; >1 indicates positive association). SPM summarized common diagnosis-order sequences using sequence support (percentage of participants exhibiting an ordered sequence). Sensitivity analyses were restricted to self-reported physician diagnoses. RESULTS: Multimorbidity prevalence was 37.85% (age-standardized 32.84%), higher in northern than southern provinces (41.39% vs 34.08%; standardized 35.41% vs 31.04%). Hypertension, hyperuricemia, and diabetes were most common. Cardiovascular/cerebrovascular conditions were more frequent in the north, whereas anemia and kidney stones were more common in the south. ARM suggested metabolic-renal clustering in the south (eg, CKD→gout, support = 1.18%, confidence = 26.14%, lift = 2.60; gout+anemia→CKD, support = 0.55%, confidence = 38.89%, lift = 3.71) and musculoskeletal-cardiovascular links in the north (eg, osteoarthritis→spinal disease, support = 0.52%, confidence = 24.69%, lift = 2.22; CTRD→CHD, support = 0.63%, confidence = 28.24%, lift = 1.26). Common SPM sequences included hypertension→hyperuricemia (24.22%) and hypertension→diabetes→hyperuricemia (5.32%); hypertension→hyperuricemia→CKD was more frequent in the south (2.28%), while hypertension→CHD→hyperuricemia was more frequent in the north (5.70%). Sensitivity analyses showed broadly consistent regional contrasts. CONCLUSION: Multimorbidity burden and structure differed between the northern and southern provinces, supporting province-tailored prevention and integrated care.

Source: Journal of Epidemiology

DOI: 10.2188/jea.je20260009