The Kharameh cohort study (KHCS) is one branch of the ‘Prospective Epidemiological Research Studies in Iran’, located in the south of Iran. The enrolment phase of KHCS spanned from April 2015 to March 2017, during which urban and rural residents of Kharameh were enrolled in the study. KHCS aims to investigate the incidence of non-communicable diseases (NCDs) such as hypertension, diabetes mellitus, cardiovascular diseases and cancer, and its related risk factors in a 15-year follow-up.

KHCS was designed to recruit 10 000 individuals aged 40–70 years old from both urban and rural areas of Kharameh. Thus, a total of 10 800 individuals aged 40–70 years of age were invited and, finally, 10 663 subjects were accepted to participate, with a participation rate of 98.7%.

Of the 10 663 participants, 5944 (55.7%) were women, and 6801 (63.7%) were rural residents. The mean age of the participants was 51.9±8.2 years. 41.8% of the participants were aged 40–49, 35.2% were aged 50–59 and the remaining 23% were 60–70 years old. Until March 2020 (first 3 years of follow-up), the total number of patients diagnosed with NCDs was 1565. Hypertension, type 2 diabetes and acute ischaemic heart disease were the most common NCDs. Furthermore, the total number of deaths during the first 3 years of follow-up was 312, with cardiovascular diseases (38.7%) as the most common cause of death, followed by cerebrovascular diseases (11.8%) and cancer (16.2%).

The remaining 12 years of follow-up will inevitably shed light on the genetic, lifestyle/socioeconomic status, and environmental risk and protective factors of NCDs.

Multimorbidity is defined as the presence of two or more chronic diseases. Co-occurring diseases can have synergistic negative effects, and are associated with significant impacts on individual health outcomes and healthcare systems. However, the specific effects of diseases in combination will vary between different diseases. Identifying which diseases are most likely to co-occur in multimorbidity is an important step towards population health assessment and development of policies to prevent and manage multimorbidity more effectively and efficiently. The goal of this project is to conduct a systematic review and meta-analysis of studies of disease clustering in multimorbidity, in order to identify multimorbid disease clusters and test their stability.

We will review data from studies of multimorbidity that have used data clustering methodologies to reveal patterns of disease co-occurrence. We propose a network-based meta-analytic approach to perform meta-clustering on a select list of chronic diseases that are identified as priorities for multimorbidity research. We will assess the stability of obtained disease clusters across the research literature to date, in order to evaluate the strength of evidence for specific disease patterns in multimorbidity.

This study does not require ethics approval as the work is based on published research studies. The study findings will be published in a peer-reviewed journal and disseminated through conference presentations and meetings with knowledge users in health systems and public health spheres.

CRD42023411249.