Evaluation of the Effects of Glomerular Filtration Rate, Neutrophil-to-Lymphocyte Ratio, and Platelet-to-Lymphocyte Ratio on Mortality at the Initiation of Hemodialysis
This retrospective study of 1,136 hemodialysis patients found that while neutrophil-to-lymphocyte ratio and platelet-to-lymphocyte ratio showed no significant association with mortality, older age, diabetes, and a lower initial glomerular filtration rate were identified as independent predictors of increased death risk.
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When the kidneys fail, they lose the ability to filter waste and excess fluid from the blood, a condition that forces the body to rely on a machine to perform the work of these vital organs. This life-sustaining treatment, known as hemodialysis, is usually started when the kidneys' natural filtering capacity drops below a critical point. Doctors have long debated the perfect moment to begin this treatment: start too early, and the patient endures unnecessary medical procedures; start too late, and the buildup of toxins can become dangerous. To find the right balance, researchers often look at specific numbers in a patient's blood, hoping to find a clear signal that predicts who will survive and who might not. Two such signals that have gained attention are simple ratios calculated from a standard blood test. One compares the number of infection-fighting cells called neutrophils to immune cells called lymphocytes, while the other compares blood-clotting cells called platelets to those same lymphocytes. These numbers are cheap and easy to get, leading many to wonder if they could serve as early warning lights for death in patients starting dialysis.
A team of researchers in Turkey set out to test these ideas by looking back at the records of over a thousand patients who began hemodialysis in the Hatay province between 2010 and 2025. They focused on adults who had been on the treatment for at least three months, gathering data on their age, medical history, and the specific values of their blood tests at the very moment they started dialysis. The goal was to see if the levels of neutrophils, lymphocytes, and platelets, or the speed at which the kidneys were filtering blood, could predict who would pass away during their time on the machine. The researchers examined the data with great care, comparing the blood profiles of those who survived against those who did not, while also accounting for other factors like diabetes and high blood pressure.
The study involved 1,136 patients, with an average age of nearly 65 years. When the researchers first looked at the blood ratios, they found something surprising. Despite the hope that these inflammation markers would act as clear predictors, the numbers for the neutrophil-to-lymphocyte ratio and the platelet-to-lymphocyte ratio did not show a meaningful connection to whether a patient lived or died. Whether a patient had high or low levels of these ratios at the start of treatment did not significantly change their chances of survival. The same lack of connection was found when looking at the specific filtering rate of the kidneys, known as the glomerular filtration rate, when viewed as a single continuous number. In other words, the simple count of these blood cells did not tell the full story of a patient's fate.
However, when the researchers dug deeper into the broader picture, clear patterns emerged that pointed to different factors as the true drivers of mortality. The most significant predictors of death were the patient's age, whether they had diabetes, and how low their kidney function had dropped before treatment began. For every year a patient got older, their risk of death increased slightly but consistently. The presence of diabetes made the risk of death nearly twice as high compared to patients without the disease. Perhaps most notably, the timing of the treatment mattered significantly when viewed in specific ranges. Patients who started dialysis when their kidney filtering rate was below 7 milliliters per minute faced a much higher risk of death—more than two and a half times higher—compared to those who started when their rate was above 10. This suggests that waiting until kidney function is critically low before starting treatment may be more dangerous than starting slightly earlier.
The study also revealed that patients who passed away tended to be older, more likely to have diabetes or high blood pressure, and had lower levels of albumin, a protein that indicates good nutrition. They also had higher levels of ferritin, a marker often linked to inflammation. Yet, when the researchers used statistical methods to isolate the most powerful factors, age, diabetes, and the specific level of kidney function at the start of treatment remained the only independent causes of death. The blood cell ratios, while interesting, did not hold up as reliable predictors in this large group. The findings reinforce the idea that managing a patient's overall health, particularly their age and diabetes, and carefully timing the start of dialysis based on kidney function, are more critical than relying on simple blood cell ratios to predict survival. The research concludes that there is no single magic number for when to start dialysis, but rather a need for a personalized approach that weighs these specific, proven risks to give each patient the best chance at a longer life.
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