A 3-year follow-up study of inpatients with lower limb ulcers: evidence of an obesity paradox?

Michelle Miller,¹ Christopher Delaney,² Deanna Penna,¹ Lilian Liang,¹ Jolene Thomas,¹ Phillip Puckridge,² James I Spark<sup>2

1</sup>Department of Nutrition and Dietetics, Flinders University, Adelaide, Australia; ²Department of Vascular Surgery, Southern Adelaide Health Service, Adelaide, Australia

Objectives: To determine whether body composition is related to long-term outcomes amongst vascular inpatients with lower limb ulcers.
Design: Prospective study with 3 years follow-up.
Materials and methods: Body mass index (BMI), fat, and fat-free mass were measured and associations with readmission to hospital (number, cause, length of stay) and all-cause mortality were explored.
Results: Thirty patients (22 men, 8 women) participated in the study. Ten patients (33%) had a BMI ≥ 30 kg/m². 18/20 (90%) patients with a BMI < 30 kg/m² and 9/10 (90%) patients with a BMI ≥ 30 kg/m² were admitted to hospital in the 3 years of follow-up. Patients with a BMI < 30 kg/m² were admitted more frequently, earlier and for longer compared to those with BMI ≥ 30 kg/m² but these did not reach statistical significance. The 3 year mortality rate for patients with BMI ≥ 30 kg/m² was 20% (n = 2/10) compared to 70% (n = 14/20) with a BMI <30 kg/m², P = 0.019.
Conclusion: This preliminary study suggests that higher BMI may have a protective effect against mortality in vascular patients with lower limb ulcers. These findings contradict the universal acceptance that obesity leads to poor health outcomes. Further work is required to confirm these findings and explore some of the potential mechanisms for this effect.

Keywords: body mass index, fat mass, obesity, overweight, vascular, ulcers