Author(s)

Bernard Kianu Phanzu^1*, Benjamin Longo-Mbenza², Jean Bosco Kasiam Lasion’kin³, Jody Mbuilu Pukuta⁴, Eleuthère Kintoki Vita¹, Nanoue Masolo Muze Kianu⁵

¹Department of Internal Medicine, Unit of Cardiology, University of Kinshasa Hospital, Kinshasa, Democratic Republic of Congo.
²Faculty of Health Sciences, Walter Sisulu University, Mthatha, South Africa.
³Department of Internal Medicine, Unit of Endocrinology and Metabolism, University of Kinshasa Hospital, Kinshasa, Democratic Republic of Congo.
⁴Department of Family Medicine, University of Witwatersrand, Johannesburg, South Africa.
⁵Faculty of Medicine, University of Technology, Bel Campus, Kinshasa, Democratic Republic of Congo.

Background: Hypertensive patients with insulin resistance (IR) are at greater risk of cardiovascular disease and may represent a particular subset of hypertension (HTN) requiring special medical attention. Quantitative measurements of the IR are not suitable for routine clinical practice. Met-abolic syndrome (MetS) or simply abdominal obesity (AO) is surrogate of IR. The performance of the recently proposed Sub-Saharan Africa cut-off point of abdominal obesity for identifying IR in hypertensive patients has never been evaluated. Aims: The main objective was to compare the performance of the newly proposed Sub-Saharan Africa specific threshold of abdominal obesity (AO-SSA) to that of IDF (AO-IDF) in identifying IR in Congolese Black Hypertensive Patients. Methods: A cross-sectional study was conducted at the Heart of Africa Cardiovascular Center, Lomo Medical Clinic, Kinshasa Limete, DR Congo, between January 2007 and January 2010. Homeostatic model assessment (HOMA) index was calculated to determine IR. Multivariate logistic regression analysis was used to assess the independent determinants of IR. The intrinsic (sensitivity and specificity) and extrinsic (positive predictive value and negative predictive value) characteristics of the AO-SSA, AO-IDF, AO-ATP III, MetS-SSA, MetS-IDF, and MetS-ATP III were calculated. The kappa statistic was determined for agreement between the ATPIII, IDF and SSA defined AO and MetS with HOMA-IR. Results: Men represented the majority of the enrolled patients: 105 (64.4%) and the mean age of all participants were 57 ± 11 years. Insulin resistance was found in 79.1% of the study population with 88.7, 79.3, 84.6, 71.4, 75.5, 91.1, 60.3 and 44.8 respectively among patient with MetS-ATP, MetS-IDF, MetS-SSA, AO-ATP III, AO-IDF, AO-SSA, diabetics and non-obese non-diabetic hypertensive patients. In multivariate analysis, the risk of IR was associated independently and significantly (p < 0.05) with cigarette smoking, low-HDL-C, hyperuricemia, and diastolic HTN, as shown in the following equation: Y = ﹣1.404 + 1.054 Cigarette Smoking + 0.872 low HDL-C + 0.983 hyperuricemia + 0.852 diastolic hypertension. The AO-SSA, with 87.7% sensitivity and 67.6% specificity, was the only surrogate who showed an acceptable agreement with the HOMA-IR index. Abdominal obesity defined according to other thresholds and the metabolic syndrome whatever the used diagnostic criteria have a slight agreement with the HOMA-IR index. Conclusion: IR was found to be prevalent in our study population. Cigarette smoking, low-HDL-C, hyperuricemia, and isolated diastolic HTN magnify IR. The AO-SSA is an easy and cost efficient method to diagnose IR in Congolese Black Hypertensive Patients. Further study in wider group is indicated to validate our findings.

Insulin Resistance, Hypertension, Sub-Saharan Africa, Abdominal Obesity

Phanzu, B. , Longo-Mbenza, B. , Lasion’kin, J. , Pukuta, J. , Vita, E. and Kianu, N. (2014) What Are the Determinants of Insulin Resistance (IR) and How Effective Is the Sub-Saharan Africa-Specific Threshold of Abdominal Obesity (AO-SSA) Identifying IR in Congolese Black Hypertensive Patients?. World Journal of Cardiovascular Diseases, 4, 642-654. doi: 10.4236/wjcd.2014.413076.