Latin News Agency for Medicine and Public Health
Diabetes is the most frequent cause of End Stage Renal Disease (ERT). More than 60% of dialysis patients are diabetic. For its part, dialysis is associated with malnutrition, dyslipidemia, inflammation and oxidative stress, which can increase the risk of cardiovascular or any-cause morbidity and mortality in these patients. Mortality in patients receiving dialysis of any type, significantly exceeds the rate observed in the general population. And the prognosis is also related to comorbidities that dialysis patients may present, such as type 2 diabetes mellitus or chronic hypertension. Studies show that the 5-year survival rate in non-diabetic dialyzed patients is 46%, compared to diabetic patients, which barely reaches 30%. Therefore, the diabetic patient with ERT constitutes a challenge for the nephrologist regarding the type of renal replacement therapy that must be offered to the patient and for the endocrinologist to control their glycemia.
End-stage renal disease (ERT) corresponds to stage 5, that is, the final stage of chronic kidney disease (CKD). When a person reaches this level of kidney damage, their kidneys are unable to carry out their functions, that is, they are unable to eliminate waste on their own and it is necessary to opt for renal replacement therapies to achieve this. The therapeutic option in question is called dialysis and is the process by which toxins and excess water are removed from the blood.
Currently, there are several types of dialysis, but there are two main types: hemodialysis (HD) and peritoneal dialysis (PD). Although both have their main objective in common, the mechanism used in each of them is different. In hemodialysis, the patient’s blood is completely withdrawn through a vascular access and brought to a dialyzer or double compartment filter. The blood circulates in one direction and the dialysis fluid circulates in the opposite direction, both separated by a semipermeable membrane that allows the exchange of water and solutes. On the other hand, peritoneal dialysis uses the peritoneal membrane as a semipermeable membrane to carry out the exchange. In this case, a sterile dialysis fluid is injected into the peritoneal cavity through a catheter and left there for a period of time for electrolyte and water exchange to occur. Subsequently, the liquid is removed. Generally, the process is repeated several times a day.
Now, among the causes of Chronic Kidney Disease, it is well known that Diabetes occupies the first place, followed by chronic arterial hypertension. The high blood glucose levels characteristic of this disease lead to the modification of corpuscular hemodynamics and stimulate processes of cellular proliferation and hypertrophy. In addition, it is responsible for activating different enzymatic reactions that increase oxidative stress and inflammation mechanisms in the kidney. And all this set of processes, finally lead to kidney damage, which, if not treated properly and on time, can be irreversible.
Comparison between Hemodialysis and Peritoneal Dialysis
Taking into account the above, diabetic patients with end-stage renal disease (ERT) constitute a great challenge for nephrologists, who are the professionals in charge of defining the way forward. It is clear that they are patients who require renal replacement therapy, however, it is necessary to evaluate the available options and individualize each patient.
When performing a review of the literature, the results obtained when comparing hemodialysis versus peritoneal dialysis are contradictory. Both options involve their own disadvantages, advantages and complications that must be taken into account when making a decision. In a recent study published by Klinger and Madziarska, data from the Canada and United States Peritoneal Dialysis Study Group (CANUSA), which demonstrated that hemodialysis and peritoneal dialysis, had similar survival rates during the study were taken into account. the first 2 years of treatment in diabetic patients. However, once the treatment lasted for more than 2 years, hemodialysis began to show greater benefits than peritoneal dialysis, since the latter was associated with higher mortality rates, as well as high rates of change in modality. : 57% of patients on peritoneal dialysis were switched to hemodialysis between months 24 and 36, compared to 6% in the case of patients on hemodialysis. Results that are similar to those obtained in other long-term observations that confirm that receiving an extension of hemodialysis treatment even longer than 2 years is associated with a greater survival in high-risk groups such as: the elderly, patients with cardiovascular disease and diabetics .
In another study carried out in Poland, 61 diabetic patients with kidney disease, older than 40 years, of which 35 were treated with hemodialysis and 26 received peritoneal dialysis were included. They were followed for 4 years and 21 of them survived at the end of the study (12 treated with HD and the other 9 treated with DP). Within this study, variables such as age, serum albumin and normalized urea clearance (Kt / V) were analyzed. According to the results, albumin was the only factor that was considered a predictor in this study. Patients who received PD versus those who were treated with HD had a significant decrease in serum albumin levels, which was associated with a negative impact on 4-year survival. The explanation is that the majority of diabetics treated with DP are not able to restore the loss of peritoneal albumin, which amounts to 6–8 gr per day, unlike HD patients who do not have this decrease. These patients usually have a strict medical follow-up and sometimes receive protein supplementation. For this reason, the researchers of this study concluded that the progressive decrease in serum albumin in the 3 months following the start of PD should be considered an alarm sign that suggests making the change to HD, in order to prevent protein energy expenditure in these patients and, therefore, improve their survival.
In other studies carried out, the body mass index has also been taken into account in order to analyze whether obesity may be a factor in consideration when recommending one of the two dialysis modalities in question. The ANZDATA study reported an increased risk of death in obese patients treated with PD versus HD when followed up for 2.5 to 3 years. The limitation of this study is that the majority of patients die less than 5 years after starting renal replacement therapy, therefore, the long-term effects of obesity -as a conventional risk factor- on future mortality, they could be overestimated by the short-term effects of malnutrition and / or inflammation present in these patients.
On the other hand, weight loss after starting dialysis has been repeatedly associated with increased risk of mortality, which has been particularly noted in patients treated with PD. However, these studies have not distinguished desired versus unwanted weight loss. Given the above, it is considered that obesity “per se” is not a contraindication for PD and that, in future research on these variables, other parameters additional to the body mass index should be taken into account since it does not distinguish the adipose tissue muscle.
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