REN and diabetes mellitus: Comorbidity of HT and DM is common and it could be because both HT and DM have common factors involved in the pathogenesis of both conditions, such as increased levels of renin-angiotensin-aldosterone causing higher sodium reabsorption in the kidneys and stimulated sympathetic nervous system, which have an impact on vascular tonus, higher exposure to oxidative stress, and inflammation [37,38,39].