INDIA HAS BEEN unfortunate to lose some of its most loved leaders to the ravages of diabetic kidney disease recently. Almost 30-40 per cent of diabetics face kidney complications. Often diabetics do not realise the ill-effects of uncontrolled sugar, since they do not feel any symptoms in the early stages. But prolonged elevations of blood sugar, especially if accompanied by high blood pressure, slowly and silently corrode your kidneys. By the time water retention/swelling is discernible, the damage is advanced. An early diagnosis can be made by blood and urine tests. The earliest sign is increased protein in the urine, which can precede kidney failure by years and must be checked yearly at the very least. Later, as blood levels of urea and creatinine start creeping up, symptoms start appearing. These include nausea, vomiting, loss of appetite, weakness, itching and muscle cramps. Anaemia and reduced requirement of anti-diabetic agents with episodes of low blood sugar can be other signs.
Why do kidneys give way if diabetes is uncontrolled? One of the chief effects of diabetes is injury to small blood vessels. The tiny arteries that flush our kidney and allow toxic dirt to be expelled while retaining nourishing fluids and electrolytes can get choked in diabetes. This reduces the ability of kidneys to throw out waste, which then accumulates in our body with water and salt. At the same time kidneys start leaking protein. Nerve involvement is also common in diabetes: this leads to weak bladder muscles, urine accumulation, back flow and frequent infections. Repeated infections also damage kidneys, at times irreversibly.
High blood pressure is central to diabetes-related kidney complications and as dangerous as uncontrolled blood sugar. Diabetes and high blood pressure usually go hand in hand. Unfortunately, both show no symptoms until complications occur. Once kidney involvement starts, blood pressure and sugar levels move oppositely. While sugar levels often decline with progressive renal damage, blood pressure becomes harder to manage. A family history of diabetic renal disease also predisposes us to it, as does smoking.
What can diabetics do to protect their kidneys? Apart from managing blood sugar and pressure from the very beginning, treating intercurrent infections of the urinary tract is essential, since infections may be a reversible cause of declining kidney function. Achieving the right targets for blood sugar and pressure is crucial to this. Typically, an HbA1c (that reflects the level of diabetes control for the preceding three months) should be at or below 7 per cent, though this can vary based on the age, duration of diabetes and presence of complications. Blood pressure should be below 130/80, in no case above 140/90. Good control from the start can ensure we do not face small-vessel complications such as of eyes and kidneys.
An important factor in accelerating kidney damage is unregulated use of painkillers in India. These are poison for kidneys and their use should be restricted to unavoidable situations. Giving up smoking is mandatory. Use of blood pressure-lowering drugs that protect kidneys from damage, like ACE inhibitors (the ‘prils’) and ARBs (the ‘sartans’) and now the new anti-diabetics like empa- or canagliflozin, is recommended. Use of alternative therapies is dangerous, especially since some may contain heavy metals that are toxic for kidneys.
Planning a diet for patients with diabetes and kidney disease requires consultation with a nutritionist. Fresh, home-made food is preferable to processed or restaurant food. Contrary to what you read, most Indian patients do not require protein restriction as our protein intakes are already low. Restricting proteins will only encourage muscle breakdown. Reduction of salt—and at times fluid—intake is important, but the modern fashion of using low-sodium salt is dangerous as many such salts are potassium-based. Potassium-rich food like fruit juices, coconut water, potatoes and tomatoes may have to be avoided. Phosphorus also tends to accumulate if kidneys are not functioning well and can have toxic effects. Dairy, beans, nuts, colas and most packaged foods are high in phosphorus and should not be consumed.
Protecting kidneys from the effects of diabetes is very much possible with these measures. Regular monitoring of renal function including urine protein is a must. At an advanced stage, where kidney function is reduced to 10-15 per cent, you may need dialysis or a transplant. According to renowned nephrologist Dr Vijay Kher, dialysis is much more convenient than it was two decades ago and the results of transplants in India have improved considerably. These enable most patients at advanced stages to lead a healthy and productive life.