Cardiovascular disease prevention and mortality across 1 million urban populations in China: data from a nationwide population-based study.

BACKGROUND

China has been undergoing a rapid urbanisation. There are substantial disparities between old and new urban citizens in access to health care. We aimed to compare cardiovascular disease prevention and death risks among four distinct urban groups.

METHODS

Urban residents aged 35-75 years living in 96 prefecture-level cities from 31 provinces in mainland China were enrolled in the national population-based cohort China Patient-centered Evaluative Assessment of Cardiac Events Million Persons Project. They were categorised into four groups by their former and current places of residence as follows: old-urban in situ residents (local residents in established urban areas since birth), new-urban in situ residents (local residents in newly urbanised areas established during urbanisation), urban-to-urban migrants (migrants from other urban areas), and rural-to-urban migrants (migrants from rural areas). We excluded participants with missing data for former and current places of residence, medical history, socioeconomic status, or lifestyle information. After adjusting for demographic and socioeconomic characteristics, relative risks (RRs) of cardiovascular disease prevention indicators and hazard ratios (HRs) of cardiovascular mortality and all-cause mortality of the other three population groups were estimated by modified log-Poisson models with robust standard error and Cox proportional hazard models, with old-urban in situ residents as the reference group.

FINDINGS

From Sept 1, 2015, to Aug 17, 2020, 1 339 329 residents were enrolled, 270 606 were excluded for missing data in key variables, and 1 068 723 were subsequnetly included in the study. Compared with old-urban in situ residents, new-urban in situ residents were less likely to adhere to a healthy diet (RR 0·72 [95% CI 0·62-0·83]), while no significant results were observed in rural-to-urban migrants; new-urban in situ residents were less likely to use statins as primary prevention (RR 0·60 [0·46-0·79]), angiotensin-converting enzyme inhibitors (ACEIs) or angiotensin receptor blockers (ARBs; RR 0·78 [0·65-0·93]) and β-blockers (RR 0·68 [0·53-0·88]) as secondary prevention; and rural-to-urban migrants were less likely to use aspirin as a primary (RR 0·67 [0·46-0·96]) and secondary (RR 0·71 [0·54-0·94]) prevention and statins (RR 0·70 [0·51-0·97]) and ACEIs or ARBs (RR 0·68 [0·50-0·93]) as secondary prevention. Furthermore, in people diagnosed with hypertension, new-urban in situ residents were less likely to have their blood pressure controlled (RR 0·79 [95% CI 0·72-0·87]), while no significant results were observed in rural-to-urban migrants. New-urban in situ residents had higher risk of cardiovascular mortality (HR 1·16 [95% CI 1·05-1·29]; p=0·005) than did old-urban in situ residents, after a median follow-up of 2·7 years (IQR 2·0-4·2).

INTERPRETATION

New-urban in situ residents and rural-to-urban migrants both showed poorer utilisation of primary and secondary prevention medications than did old-urban in situ residents, while new-urban in situ residents also had lower adherence to healthy lifestyles and higher death risks. Comprehensive measures should be taken to strengthen the primary health-care system in newly urbanised areas, and promote interprovincial medical insurance reimbursement.

FUNDING

Chinese Academy of Medical Sciences Innovation Fund for Medical Science and the National High Level Hospital Clinical Research Funding.

TRANSLATION

For the Chinese translation of the abstract see Supplementary Materials section.