Purpose: The open, prospective Community-Based chronic Care Lesotho (ComBaCaL) cohort is the first study to comprehensively investigate socioeconomic indicators, common chronic diseases and their risk factors in a remote rural setting in Lesotho. It serves as a platform for implementing nested trials using the Trials within Cohorts (TwiCs) design to assess community-based chronic care interventions. Here, we present the cohorts sociodemographic and chronic disease risk factor profile, including self-reported HIV prevalence and hypertension and diabetes care cascades. Participants: Since February 2023, Community Health Worker (CHWs) supported by a clinical decision support and data collection application, have enrolled inhabitants from 103 randomly selected rural villages in Butha-Buthe and Mokhotlong districts in North-East Lesotho. As of May 31, 2024, the cohort includes 5008 households with 14735 participants (55% female, median age 19 years). The cohorts socioeconomic status is low with an International Wealth Index of 26, a monthly household income of 42.4 USD and low levels of formal education. Among the 7917 adult participants, 42.5% are overweight or obese, with higher rates among women, and 33.1% smoke tobacco, with higher rates among men. Self-reported HIV prevalence is 15.1% with a 98.4% treatment rate. Hypertension prevalence is 17% with a 56% control rate and diabetes prevalence is 4% with a 39% control rate. Findings to date: The cohorts low socioeconomic status is linked to multiple health risks including insufficient access to clean energy, essential healthcare services, adequate sanitary facilities and secure food supply. Besides the expected high HIV prevalence, we found significant hypertension, diabetes and cardiovascular risk factor prevalences. While treatment and control rates for diabetes and hypertension are higher than in similar settings, they remain below global targets. Future plans: Ongoing cluster-randomized TwiCs, which will be completed in 2025, are assessing the effectiveness of community-based, CHW-led care interventions for diabetes and hypertension. CHWs will continue to closely monitor the cohort and integrate additional measurements such as HIV testing. This will provide further insights into the dynamics and interactions of chronic diseases and inform the development of future nested trials on innovative community-based prevention and care interventions. Registration: NCT05596773

NDL reports having received travel grants to attend IAS, AIDS, and CROI conferences from Gilead Sciences Sarl and ViiV Healthcare. All other authors declare that they have no competing interests.

The ComBaCaL project is funded by the TRANSFORM grant of the Swiss Agency for Development and Cooperation (project number 7F-10345.01.01) and a grant by the World Diabetes Foundation (WDF-1778). FGs salary is funded through a personal MD/PhD grant by the Swiss National Science Foundation (grant number 323530_207035). AAs salary is funded through a career grant of the Swiss National Science Foundation (Postdoc mobility #P500PM_221961). The funders had no role in the design of the cohort and nested trials and will not have any role during the analyses, interpretation of the data, or decision to submit results.

I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.

Yes

The details of the IRB/oversight body that provided approval or exemption for the research described are given below:

The National Health Research Ethics Committee Lesotho and the Ethikkommission Nordwest- und Zentralschweiz in Switzerland gave ethical approval for this work

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