Dynamics in the Prevalence of Insulin Resistance between 2005 and 2023 in Type 2 Diabetics in South Kivu in the East of the Democratic Republic of Congo: Cross-Sectional Studies

AIM: Sub-Saharan Africa is undergoing an epidemiological transition responsible for a change in the metabolic profile in favour of insulin resistance. The aim of this study was to assess the dynamics of the prevalence of insulin resistance and associated risk factors in diabetic patients in the Democratic Republic of Congo between 2005 and 2023. METHOD: We measured fasting blood glucose and insulin levels and looked for metabolic syndrome parameters (2009 criteria) in type 2 diabetes patients in 2005-2008 (n = 176) and in 2018-2023 (n = 303). The HOMA model was used to measure insulin sensitivity and islet β-cell secretory function. RESULTS: Between 2005 and 2013, the trend was towards an increase in the prevalence of insulin resistance (from 13.1% to 50.8%; p < 0.0001), obesity (from 17.0% to 31.7%; p = 0.0005) and abdominal obesity (from 32.4% to 49.8%; p = 0.0002). Diabetes mellitus without insulin resistance remained more prevalent in rural than in urban areas (60.2% vs. 24.5%; p < 0.0001). Finally, the Triglycerides/HDL-C ratio [AUC = 0.513 (0.46 - 0.56); p = 0.64] and the metabolic syndrome [AUC = 0.539 (0.49 - 0.58), p = 0.12] were not predictive of insulin resistance. CONCLUSION: This present study shows an increase in insulin resistance in Congolese urban areas and a persistence of atypical diabetes mellitus in Congolese rural areas, confirming the particularity of the pathophysiology of the disease in African areas currently influenced by the epidemiological transition. Further studies using an appropriate methodology are required.