BackgroundBoth obesity and type II diabetes mellitus are associated with insulin resistance and abnormal metabolic reactions. This study was conducted to evaluate resting metabolic rate in obese diabetic patients and to assess its relation to glycaemic control.ResultsThis is a case control study conducted in Gabir AbuEliz centre in Khartoum, Sudan. A random sample of 40 obese diabetic patients (cases) and 40 obese non-diabetic subjects (controls) were interviewed and examined clinically to exclude presence of acute or chronic medical illness. Haemoglobin A1c was measured for each participant using the “NycoCard Haemoglobin A1c test” (Axis -Shield/ Norway). Fasting blood sugar was measured using one touch(R) glucometer (LifeScan Canada Ltd). The PowerLab 8/35 with a gas analyzer (AD Instruments, Castle Hill Australia) was used for measurement of VO2, VCO2 and Respiratory exchange ratio (RER). Resting metabolic rate was calculated using the Weir equation. VO2 (mean+/-SD) ml/min was significantly higher among cases (209.9+/-42.7) compared to the controls (192.4+/-28.1), (P = 0.034). Similarly, VCO2 (mean+/-SD) ml/min was higher among cases (191.4+/-35.0) than controls (178.3+/-22.5), (P = 0.05). Resting metabolic rate “RMR” (mean+/-SD) kcal/day was higher in obese diabetic patients (1480.7 +/- 274.2) than obese non-diabetic subjects (1362.4+/- 184.8), (P = 0.027). Participants with high glycated haemoglobin had higher RMR than those with normal glycated haemoglobin (P = 0.016).ConclusionIt is concluded that resting metabolic rate is significantly higher in obese diabetic patients compared to obese non-diabetics, especially in those with poor glycaemic control.

The Oxylog, a portable device for measuring oxygen consumption, was evaluated under standard, laboratory conditions and with exercising human subjects. The difference in oxygen partial pressure between room air and a series of test gases measured by the Oxylog showed good agreement with results obtained using a paramagnetic analyser and stable values were obtained for at least 6 h. The measurement of oxygen consumption by the Oxylog was assessed under simulated conditions, with an anaesthetic ventilator, and in exercising human subjects. With a simulated steady-state oxygen consumption there was an initial delay of 2 min before any oxygen consumption was recorded. Subsequent increases in simulated oxygen consumption were detected within one minute. The oxygen consumption of exercising human subjects measured with the Oxylog showed very good agreement with simultaneous measurements obtained using the Douglas bag technique. The application of an appropriate conversion factor allows the individual's energy expenditure to be estimated from the oxygen consumption: in this study a factor of 20.08 kJ per litre oxygen consumption gave the best agreement with the Douglas bag estimate.