Association between the Planetary Health Diet and foot ulcer size and renal biomarkers among diabetic patients with foot ulcers in a cohort study

Planetary Health diet index (PHDI) has been associated with chronic diseases and mortality. This study examines the relationship between PHDI and foot ulcer indices, as well as renal biochemical markers, in patients with type 2 diabetes and foot ulcers. We prospectively included 219 patients with type 2 diabetes and diabetic foot ulcers (DFUs) aged 25–75 years in Tehran, Iran. This study took place at the Diabetes Clinic of Tehran University of Medical Sciences. To assess dietary intake, three 24-h dietary recalls were conducted. We evaluated adherence to the PHDI based on EAT-Lancet guidelines. Length, width, and depth of ulcers and biochemical renal biomarkers were obtained from medical records at baseline. Participants were followed for 1 year. Multivariable linear regression models, adjusted for potential confounders, were used to assess the relationship between adherence to PHDI and the outcomes. Our findings revealed that higher adherence to the PHDI was related to lower serum creatinine (Cr) (β = −0.18, 95% CI: −0.33, −0.03), blood urea (β = −14.18, 95% CI: −22.89, −5.46), and higher estimated glomerular filtration rate (eGFR) (β = 17.18, 95% CI: 3.53, 30.82) in fully adjusted models. However, no significant relationship between PHDI and ulcer characteristics (length; β = −0.29, 95% CI: −1.15, 0.55, width; β = −0.07, 95%CI: −0.34, 0.49, and depth; β = −0.10, 95% CI: −0.60, 0.40) was observed. Each 10-point increase in PHDI was not significantly associated with ulcer indices. This study indicated inverse associations between adherence to the PHDI and Cr, urea, and eGFR in diabetic patients with foot ulcers. Further cohort research with larger sample sizes could yield more comprehensive insights.