HAVCR1 and obesity due to melanocortin 4 receptor deficiency: Such associations are susceptible to confounding by shared risk factors (e.g., obesity, hypertension, and glycemic control) and the potential for reverse causality, in which impaired kidney function itself might alter lipid metabolism.[11,12] Consequently, the precise causal role of individual lipid fractions and their associated apolipoproteins in initiating or promoting kidney tubular injury, as reflected by KIM-1 levels, remains largely unknown.