In nearly 50% of the people, by the time they got diagnosed as Diabetes, at least one complication is already present. That can be any of the following Microvascular or macrovascular complication.

The mortality and morbidity due to DM is attributed to a range of complications, which includes both microvascular and macrovascular complications.

Renal/Kidney complications: Diabetic nephropathy is a microvascular disease, which is characterized by microalbuminuria, which over long period turns into macro albuminuria, causing overt nephropathy. The glomerular filtration rate (GFR) also deteriorates significantly in this process. If not treated, and addressed medically, nephropathy progresses into chronic kidney disease (CKD).

CKD in patients who have T2DM, is clinically defined as, elevated urinary albumin excretion ≥ 30 mg/g, a persistent reduction in the estimated GFR (eGFR) <60 ml/min/1.73 m2 , or both. The prevalence of CKD in patients with T2DM, is estimated to be approximately 50% worldwide. Also, the epidemiological changes in T2DM, are influencing or impacting the epidemiology of T2DM - associated CKD. This association of T2DM and CKD complicates the treatment of T2DM both clinically as well as financially. CKD in T2DM patients decreases the efficacy of oral antidiabetic drugs. This is indicative of the need for adjusting the dose of anti-diabetic drugs in T2DM patients who have CKD. CKD also significantly amplifies the risk of developing several complications if coupled with DM. These complications range from cardiovascular diseases, heart failure, renal failure, infections, adverse drug reactions to impaired quality of life and premature deaths

Cardiac Complications: People with diabetes tend to develop heart disease at a younger age than people without diabetes. In adults with diabetes, the most common causes of death are heart disease and stroke. Adults with diabetes are nearly twice as likely to die from heart disease or stroke as people without diabetes

The risk for CAD is two to four times higher in diabetic subjects, and in Indians, CAD occurs prematurely, i.e., one to two decades earlier than in the West. Thus there is an urgent need for studies on CAD in diabetic and nondiabetic subjects in India. ( Souce: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2825638/ )

People with diabetes are also at risk for heart failure. Heart failure is a chronic condition in which the heart cannot pump blood properly. Unfortunately, many of the cardiovascular problems start early in life in people with diabetes and can go undetected.

Those with diabetes sometimes suffer what is called "silent ischemia" or silent heart attack, which account for 25-30 percent of heart attacks. Silent, in this case, means the patient gets a heart attack without experiencing chest pain. Most of the cases realises very late and by the time they were diagnosed, the chances of treatment become narrowed down and survival chances become feeble.

Brain Stroke:

Diabetes is a well-established risk factor for stroke. It can cause pathologic changes in blood vessels at various locations and can lead to stroke if cerebral vessels are directly affected. Additionally, mortality is higher and poststroke outcomes are poorer in patients with stroke with uncontrolled glucose levels

Diabetic Retinopathies: When diabetic retinopathy among diabetics was assessed during the survey, the prevalence of any form of diabetic retinopathy in diabetic population aged up to 50 years was found to be 16.9%.

Peripheral vascular problems:

The various lower limb complications in diabetic patients are peripheral neuropathy, charcot arthropathy, foot ulcers, infections, and lower extremity amputations which may lead to hospitalization and disability among the diabetics.Foot ulcers are much feared complications of diabetes and recent studies have suggested that the risk of developing foot ulcer is as high as 25%.

The burden of diabetic foot disease may increase in the future due to the presence of peripheral neuropathy and vascular disease in more than 10% of patients during the diagnosis of diabetes and 1 st year after the initial diagnosis of diabetes is a period of danger for foot ulcer and amputation

A recent study from the famous institute from South India highlights the importance of foot care and relevance of early detection of diabetes and subsequent monitoring of the diabetic complications. With the rise in the prevalence of diabetes complications it becomes imperative to prevent foot problems at an early stage. Several prevention strategies including frequent foot examinations, appropriate patient education, and timely referrals, can help to ensure early diagnosis and treatment to prevent foot complications and lower extremity amputations. Targeting patients at increased risk for developing foot ulcers may be a cost effective strategy to control the progression to end stage complications.

In recent study, Burden of Diabetic Foot Ulcers in India: Evidence Landscape from Published Literature, Diabetic Foot Ulcers affect 15% of diabetics during their lifetime

Mono/polymicrobial etiology of diabetic foot infections was widely reported including high prevalence of Pseudomonas, E. coli, and S. aureus infections. Evidence from published literature showed 100,000 leg amputations/ year due to diabetes-related problems and an expense of approximately 1,00,000 rupees for complete treatment of Diabetic Foot Ulcers. Out of 62 million diabetics in India, 25% develop DFUs, of which 50% become infected, requiring hospitalization while 20% need amputation