The multimorbidity in the elderly has become an important issue that needs urgent attention in the field of public health. Therefore, it is of great significance to explore the influencing factors of multimorbidity in the elderly.

To investigate the prevalence of multimorbidity and related influencing factors in the elderly population in northern and southern China, in order to better manage and intervene the development and prognosis of multimorbidity in the elderly in different regions.

PubMed, Embase, Web of Science, Cochrane Library, Scopus, China Biology Medicine Disc, China National Knowledge Infrastructure, Wanfang Data Knowledge service platform were searched for relevant studies on influencing factors of multimorbidity in the elderly. Two researchers independently searched, screened, extracted data, and cross-checked. Any disagreements were resolved through consultation with a third researcher for arbitration. The search time limit was from the establishment of the database to July 2024. Stata 18.0 software was used for meta-analysis.

The research incorporated 10 articles from the southern region and 10 from the northern region, with sample sizes of 2 342 507 and 75 871 cases, respectively. The prevalence of multimorbidity among elderly patients in the southern and northern regions was 34% (95%CI=29%-38%, P<0.001) and 36% (95%CI=22%-50%, P<0.001), respectively. Among them, the influencing factors of elderly patients with multimorbidity in southern China were age (OR=1.92, 95%CI=1.26-2.94, P=0.003), gender (OR=1.51, 95%CI=1.03-2.21, P=0.034), and household per capita monthly income (OR=1.62, 95%CI=1.03-2.54, P=0.036), education level (OR=1.47, 95%CI=1.25-1.73, P<0.001), BMI (OR=1.72, 95%CI=1.52-1.96, P<0.001), smoking (OR=1.53, 95%CI=1.11-2.11, P=0.009), drinking (OR=1.39, 95%CI=1.26-1.54, P<0.001), regular physical exercise (OR=0.67, 95%CI=0.55-0.80, P<0.001) ; age (OR=1.67, 95%CI=1.00-2.79, P=0.048), BMI (OR=2.39, 95%CI=1.80-3.18, P<0.001), drinking (OR=1.63, 95%CI=1.32-2.02, P<0.001), regular physical exercise (OR=0.84, 95%CI=0.71-0.99, P<0.037) were the influencing factors of elderly patients with multimorbidity in northern China. Sensitivity analysis showed that the results of Meta-analysis were stable, and Egger's test (multimorbidity prevalence: P=0.826; influencing factors: P=0.841) suggested that the risk of publication bias of the included literature was not significant.

The prevalence of multimorbidity among the elderly was relatively high in both the northern and southern regions. The risk factors for multimorbidity in both regions included: age≥70 years, overweight or obese BMI status, and alcohol consumption. Conversely, regular physical exercise served as a protective factor. In southern China, male sex, household per capita monthly income≥¥2 000, education below college level, and smoking were the risk factors for multimorbidity. These disparities may stem from dietary habits, economic levels, lifestyle pace, and uneven medical resource distribution. Enhancing inter-regional medical resource coordination and sharing is advised to improve health equity and resource balance, boosting elderly health overall. Additionally, healthcare providers should tailor interventions based on these factors to optimize disease management in elderly with multimorbidity.

老年群体中多重慢性病共病现象已成为当前公共卫生领域亟待关注的重要问题，因此深入探究老年群体共病相关影响因素具有重要意义。

了解我国不同地区老年群体共病患病率及其患病影响因素，以期更好管理和干预不同地区老年群体的共病发展和预后。

利用计算机检索PubMed、Embase、Web of Science、Cochrane Library、Scopus、中国生物医学文献服务系统、中国知网、万方数据知识服务平台中有关老年人共病患病影响因素的队列研究、病例对照研究、横断面研究等观察性研究，检索时限为建库至2024年7月。2名研究者独立检索、筛选文献、数据提取并交叉核对，出现分歧时请第3名研究者进行判定。用Stata 18.0软件进行Meta分析。

纳入来自南北方的文献各有10篇，样本量分别为2 342 507例和75 871例。南北方老年患者共病患病率分别为34%（95%CI=29%~38%，P<0.001）和36%（95%CI=22%~50%，P<0.001）。其中，南方老年共病患者的影响因素有年龄（OR=1.92，95%CI=1.26~2.94，P=0.003）、性别（OR=1.51，95%CI=1.03~2.21，P=0.034）、家庭人均月收入（OR=1.62，95%CI=1.03~2.54，P=0.036）、文化程度（OR=1.47，95%CI=1.25~1.73，P<0.001）、BMI（OR=1.72，95%CI=1.52~1.96，P<0.001）、吸烟（OR=1.53，95%CI=1.11~2.11，P=0.009）、饮酒（OR=1.39，95%CI=1.26~1.54，P<0.001）、经常进行体育锻炼（OR=0.67，95%CI=0.55~0.80，P<0.001）；北方老年共病患者的影响因素有年龄（OR=1.67，95%CI=1.00~2.79，P=0.048）、BMI（OR=2.39，95%CI=1.80~3.18，P<0.001）、饮酒（OR=1.63，95%CI=1.32~2.02，P<0.001）、经常进行体育锻炼（OR=0.84，95%CI=0.71~0.99，P<0.037）。敏感性分析结果表明Meta分析结果较稳定，Egger's检验（老年人共病患病率P=0.826、老年人共病影响因素P=0.841）提示纳入文献的发表偏倚风险不显著。

南北方老年人共病率均较高。年龄在70岁及以上、BMI达到超重或肥胖水平、饮酒是南北方老年人共病患病的危险因素；经常进行体育锻炼是南北方老年人共病患病的保护因素；性别为男性、家庭人均月收入在2 000元及以上、文化程度在大专以下、吸烟仅为南方老年人共病患病的危险因素。这种差异可能与饮食结构、经济发展水平、生活节奏及医疗资源分配不均等因素密切相关。建议加强区域间医疗资源的协调与共享，以促进健康公平性和医疗资源的均衡分配，从而提升老年人的整体健康水平。同时，医务或社区工作者应根据老年共病患者的影响因素，定制个性化干预方案，精准优化多重慢性病患者的疾病管理效果。