Association between renal failure and lower levels may be due to tight monitoring but could partly be due to a decreased insulin degradation with decreasing renal capacity, i.e. the patient remains on an unchanged insulin dose whilst the kidney function decreases, thus potentially indicating an increased risk of hypoglycaemia.[23] Insulin pump prescription was associated with higher levels which may be explained by indication bias (prescription of insulin pump is generally due to bad historic blood glucose control), although no externally valid conclusions can be drawn. Here, INS is linked to kidney failure.