Relationships Between Body Mass Index, Diabetes Mellitus and Peripheral Haemodynamic Parameters: A Cross-Sectional Study

Background/Objectives: The ankle–brachial index (ABI) is a low-cost, non-invasive screening tool for peripheral artery disease (PAD) and an independent predictor of cardiovascular events, which makes it suitable for primary care. Peripheral haemodynamic data across body mass index (BMI) gradients remain scarce, and BMI and diabetes are seldom modelled together despite their frequent co-occurrence. We investigated their associations with peripheral haemodynamic parameters. Methods: We performed a cross-sectional study in 147 primary care users, twenty-seven of whom had a self-reported diagnosis of diabetes mellitus (DM). Systolic pressure was obtained by auscultation, with Doppler being unavailable. The ABI was calculated per leg from unrounded pressure, and the lower index was adopted and classified according to American Heart Association thresholds (abnormal: ≤0.90; borderline: 0.91–0.99; normal: 1.00–1.40; elevated: >1.40). Nested linear models with robust standard errors estimated the adjusted association of DM with each outcome. Results: The DM group was older (62 vs. 44 years; p < 0.001), with greater rates of excess weight (77.8% vs. 54.2%), hypertension (59.3% vs. 25.8%), dyslipidaemia (48.1% vs. 11.7%), and smoking (30.8% vs. 10.1%). Crude upper-limb systolic pressure was 10.1 mmHg higher in the DM group (95% confidence interval [CI]: −0.5 to 20.6) but fell to 1.3 mmHg upon adjustment for age (p = 0.82 fully adjusted). The ABI did not differ between the groups (mean difference of 0.02, 95%CI: −0.06 to 0.11; p = 0.59) and showed no gradient across BMI. An abnormal ABI was present in 14.4% of participants and a borderline ABI in 18.5%, so that 32.9% had an ABI below 1.00. Conclusions: The crude blood pressure difference was attenuated after adjustment, chiefly for age, and DM was not independently associated with any outcome; residual confounding cannot be excluded. No ABI difference was detected, but power reached 80% only for a difference of about 0.12 units. The fact that one-third of participants had an ABI below 1.00 warrants further investigation of risk-based vascular peripheral assessment in primary care.