Association of multimorbidity of non-communicable diseases with mortality: a 10-year prospective study of 0.5 million Chinese adults

Abstract

ObjectivesNon-communicable diseases (NCDs) account for seven out of 10 deaths worldwide, whereas the pattern of multimorbidity of NCDs and its long-term impact on all-cause mortality remains largely unknown, especially among the Chinese population. This study aimed to investigate the associations between the number and patterns of multimorbidity with long-term risks of mortality and to estimate the influence of age on the relationship between multimorbidity and mortality. Study designThis was a prospective population-based cohort study. MethodsData were obtained from the China Kadoorie Biobank study, which enrolled adults aged 30–79 years from 10 regions of China. The outcome was all-cause mortality, which was measured at a 10-year follow-up (9.93 ± 1.82 years). A principal component analysis (PCA) was used to identify patterns of individuals with multimorbidity based on 16 self-reported or baseline-detected chronic conditions. Cox proportional hazards models were used to examine the associations of both the number and patterns of multimorbidity of NCDs with all-cause mortality. Stratified analyses were carried out to explore whether the associations of multimorbidity with all-cause mortality were modified by age, number, and the patterns of multimorbidity. ResultsWe included 512,712 individuals in our analysis, of which 176,619 (34.5%) had only one long-term condition (LTC), and 81,360 (15.9%) had multimorbidity. The crude mortality rate was highest in those aged between 70 and 79 years who also had ≥4 LTCs (44.38 per 1000 person-years). In participants with at least four LTCs at baseline, fully adjusted HRs were 4.58 (95% CI 2.65–7.93) for people belongs to 1960s–1970s, compared to 2.73 (95% CI 2.50–2.97) for 1920s–1930s. Six multimorbidity patterns were identified, including cardiometabolic syndrome, respiratory diseases, digestive/renal/urologic diseases, articular/rheumatic diseases, and neuropsychiatric diseases. For the multimorbidity patterns of cardiometabolic syndrome, fully adjusted HRs for all-cause mortality were 1.60 (95% CI 1.55–1.65) in participants with one LTC and 8.19 (95% CI 6.45–10.40) in those with four LTCs compared with the reference group (no LTCs). ConclusionsThe observed higher risk of mortality in younger people with multimorbidity, as middle aged (30–49 years), calls for advocating primary prevention in the younger population and secondary prevention for the elderly to strengthen early detection and timely treatment. Health systems need to shift from single-disease models to more effective multimorbidity management.