Low on salt: turning the spotlight on kidney organ donors

Kidney donors must be fully evaluated before donation. Age, blood group, and health are all factors. Minor ailments may not be a contraindication. Evaluation should favour donor. Follow-up is essential post-donation. Diet, exercise, and avoidance of drugs toxic to kidneys are key. Salt intake should be monitored as it can cause damage to single kidney. Early detection of CKD is essential to halt progression. Proteinuria is a sensitive marker. Drugs can reduce protein loss and halt damage. Control of BP is key to prevent end organ damage. Salt reduction globally is needed.

There is a great deal of attention paid to the recipient of a organ transplant, and rightly so, but the backbone of live kidney transplantation for transplant surgeons is also to make sure that donors do not face the same problem in the future.

Before donating the donor is fully evaluated to make sure the person is completely normal. Age-matched kidneys may be ideal but usually 18 to 60 years is accepted. Between 60- 70 years, an exceptional kidney function and health may permit donation. Blood group matching is usually required but O can donate to any group. Special centers can do blood group mismatched transplants with good results.

Minor ailments may not be a contraindication for donating .Diabetes or pre diabetes, obesity, hypertension, kidney stones, etc. require special attention Medical evaluation is always biased in the donor’s favour. Exemptions are sometimes made based on the full social and family setting in favour of the patient. For example, when the patient is the earning member in the family and his survival is essential for the whole family Diabetes in the donor is usually an absolute contraindication. Hypertension with easy control with a single tablet is permitted. It is also essential that the kidney function on special test is at least 75 ml per minute There should no protein leak. Metabolic workup in persons having small stone is a must. Those with multiple stones should be rejected. Normally the evaluation should favour the donor and the better working kidney should be left behind with the donor.

After the donation the person requires life long follow-up. Immediately after the surgery the kidney function drops by almost half and the single kidney starts working more to compensate the loss of the other. This is a process of hyperfiltration at the microscopic level and compensatory hypertrophy at the gross level. Donors require to periodically monitor blood pressure. Kidney function and protein loss should be checked at least once a year. Almost one third of donors would develop hypertension over several years but this almost the same incidence as in the general population. A small percentage would develop protein leak in the urine.

Fortunately even though the kidney function may be less than the normal population of the same age frank kidney failure is not common. So it is essential that the donors are instructed properly with regards to diet, exercise and avoidance of drugs toxic to the kidneys. DASH diet (dietary approaches to stop hypertension) would be ideal. Sufficient vegetables, fruits, whole grains, lean meat, moderate restriction of salt and sugar, and avoidance of transfats is essential.

The WHO and other medical associations caution on the importance of salt restriction to 5 gms per day in the general population. The 5 gms includes salt present in natural food, salt added during cooking and hidden salt present in preserved or packed food like bread and noodles. Restriction of salt reduces not only blood pressure but also strokes and kidney failure. The benefits of restriction is better if started early in life. Early this year the WHO said that only a few countries have a salt policy implemented legally. Although studies have not been done on the effects of salt intake in persons with a single kidney such as donors it would be correct to presume that the damage would be more. A recent study from MIOT international on the salt intake in renal donors has highlighted the importance of monitoring salt intake in kidney donors The study has been accepted for presentation at the Asian Transplant Week to be held at Seoul