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
104 kidney donors were studied. The average follow up was 4 years with a maximum follow-up of 27 years. None of the donors developed kidney failure. The average drop of kidney function from pre-donation state was 21% by calculated GFR . What was alarming was that only 13% of donors were following restricted salt intake. The average salt intake measured by the 24 hours sodium excretion in the urine was 9.2 gms with a maximum of 14gms per day. This is more than the general population’s intake of salt as reported by the ICMR. This is the first time that donors’ intake of salt is being reported. Further studies are required and estimation of urinary sodium as a measure of salt intake should be included in kidney donors follow up so suitable advice can be given.
Chronic Kidney disease(CKD) affects almost 10% of the worlds population. Even if a small percentage of those patients progress to end stage kidney disease requiring dialysis or transplantation the burden on the health resources and economy would be enormous .So it is essential to detect CKD early and intervene to halt the disease. Proteinuria or protein leak and blood creatinine are the commonest markers used to detect kidney disease.
Creatinine is produced by muscles in the body and excreted by the the kidneys. Since normally only kidneys remove the creatinine ,its measurement in blood reflects kidney function .Mathematical formulae adjusting for age, weight and sex are used to calculate kidney function and express as eGFR(Glomerular function rate)Although the test is sensitive, there is a problem of lack of standardisation in laboratories. Protenuria or protein leak is a more sensitive test and 85% of the kidney diseases are detected earlier than creatinine estimation. Protein has a large molecular weight and does not appear in the urine unless the microscopic vessel (glomerulus)in the kidney is damaged or it is secreted by tubules. The quantity of protein loss in the urine reflects the kidney damage and is used as a measure to see the response for treatment.
Proteinuria can be measured both qualitatively and quantitatively. Strips are used in the laboratory in routine urine examination to detect proteinuria/albuminuria. This is only a screening test. For more precise information a spot sample can be estimated quantitatively for protein/albumin and creatinine. The result is expressed as a ratio of protein to creatinine. The gold standard is the measurement of protein in a 24 hour urine sample. Proteinurea unlike creatinine is not only a marker of kidney disease but also a cause for progression of kidney disease. This understanding has led to the development of several group of drugs which would lower protein loss to reduce damage to the kidneys. They include the anti renin system (ACE and ARB) group of drugs, the SGLT2 inhibitors, anti aldosterone drugs etc.
Of course a specific treatment where possible would reverse the kidney disease like immunosuppresions in allergic disorders and, withdrawal of drugs likely to damage kidneys. This may include native and other herbal medications which may contain heavy metals .Of couse a good control of blood pressure makes a big difference in all kidney disorders It is not surprising from the recent studies of ICMR and WHO to know that 35 to 40 % of adult population in the world have high blood pressure often undiagnosed presenting with an end organ damage. Even in those in who have been diagnosed the control is poor .It is sad that even now youngsters have presented for the first time with reduced vision due to condition called malignant hypertension(often systolic 200 and diastolic 120).
In a study conducted by Sapiens Health foundation a NGO from Chennai amongst college students 5% had hypertension 20% were obese and 6% had abnormal protein excretion in urine. More than 80% did not know the recommendation of salt intake per day. A project undertaken by the Kidney Trust run by M. K. Mani covered villages in and around Chennai. The Blood pressure and diabetes were detected doorstep and simple low cost drugs were administered to control BP and sugar with a .remarkable reduction in kidney failure in contrast to comparable villages where there was no intervention. A recent study from China showed that a simple measure of using salt substitutes reduced strokes considerably.
It is hightime we realise the importance of this, and implement salt reduction globally.
(Dr. Rajan Ravichandran is director, MIOT Institute of Nephrology, and chairman, Sapiens Health Foundation. ravidoc55@yahoo.co.in)
