Evaluation of factors affecting progression in diabetic chronic kidney patients

Introduction: Chronic kidney disease (CKD) is the chronic, progressive, and irreversible loss of the functional capacity of the kidneys, developed due to various reasons. CKD is a widespread and increasingly prevalent public health issue. Due to its often silent course, awareness and early diagnosis of CKD are low, especially in the early stages.Currently, diabetes mellitus is the leading cause of CKD in adults. Diabetic nephropathy, characterized by abnormal amounts of protein in the urine, is a factor indicating the progression of CKD. Cardiovascular diseases in diabetic CKD are considered as comorbidities of diabetes. This study aimed to investigate the factors influencing the progression of the disease in diabetic CKD patients. Identifying factors affecting the decline in glomerular filtration rate (GFR) and the initiation of renal replacement therapy (RRT), especially those that can be prevented, aimed to reduce the need for renal replacement therapy. Factors affecting cardiovascular disease and mortality were also explored. Materials and Methods: A retrospective study was designed by examining the files and hospital database of diabetic CKD patients followed between January 2014 and March 2023 at the Nephrology Clinic of Akdeniz University Hospital. Demographic characteristics, comorbidities (cardiovascular disease, etc.), medications, clinical and laboratory data (GFR, serum albumin, proteinuria, PTH, ferritin, calcium, phosphorus, HbA1c) of the included patients were retrospectively analyzed. Factors affecting the decline in GFR and the initiation of renal replacement therapy were evaluated. Factors affecting cardiovascular disease and mortality were also investigated Results: The average age of the 192 included patients was 65.29±10.72 years, with 135 males and 57 females. The most common comorbidity in patients with chronic kidney disease under follow-up and all diabetic was hypertension (98.4%). This was followed by hyperlipidemia (84.4%), coronary artery disease (54.7%), peripheral artery disease (19.8%), and stroke (17.2%). Additionally, 76% of the patients were found to be receiving ACE inhibitors or ARB treatment. During the follow-up period, progressive GFR decline was observed in 81.8% of the patients, while GFR was preserved in 18.2% of them. RRT was initiated in 131 patients due to a decrease in GFR, and 43.2% of the patients died during the follow-up. Among those who started RRT, hemodialysis (78.6%) was the preferred treatment option, followed by transplantation (13%) and peritoneal dialysis (8.4%). The average time until the initiation of RRT was determined to be 25.41±22.94 months. Factors influencing the decrease in GFR were found to be statistically significant for ferritin (p=0.007), albumin value (p=0.017), proteinuria (p<0.001), and initial GFR value (p=0.001). Variables such as initial PTH (p=0.007), average PTH (p=0.037), 2nd measurement of ferritin (p=0.040), age (p=0.005), initial GFR (p=0.008), and gender (p<0.001) significantly differed according to the presence of coronary artery disease. In patients with peripheral artery disease, ferritin value [291.5 (128-514)] was significantly higher compared to those without peripheral artery disease [165 (97-371)] (p=0.032). Other variables did not show significant differences between patients with and without peripheral artery disease (p>0.05). Variables showing significant differences according to the presence of stroke were HbA1c Initial (p=0.033), HbA1c Average (p=0.003), and age (p=0.013). The average age was statistically significantly higher in deceased patients [67 (61-75) years] compared to surviving patients [64 (58-71) years] (p=0.003). No statistically significant differences were detected in other parameters (p>0.05). Correlation analysis results between the time until the initiation of RRT and some parameters were presented. The correlation coefficient "r" mentioned in the analysis results is the correlation coefficient. The correlation coefficient takes a value between -1 and +1. Here, +1 indicates a positive perfect relationship, while -1 indicates a negative perfect relationship. r=0.00 is interpreted as "no relationship", r=0.01-0.29 as "low-level relationship", r=0.30-0.70 as "moderatelevel relationship", r=0.71-0.99 as "high-level relationship", and r=1.00 as a "perfect relationship". Low-level relationships were observed for all variables with significant relationships with the time until the initiation of RRT. A 1-unit increase in the 2nd measurement of ferritin variable increased the probability of GFR change by 1.006 times (OR: 1.006; 95% CI: (1.002-1.010); p=0.003), and a 1-unit increase in the initial GFR variable increased it by 1.086 times (OR: 1.086; 95% CI: (1.032-1.144); p=0.002). However, the probability of GFR change was 3.464 times higher in females than in males (OR: 3.464; 95% CI: (1,026-11,695); p=0.045) and 4.104 times higher in non-ACE inhibitors/ARB users than in users (OR: 4.104; 95% CI: (1,028-16,380); p=0.046). Conclusion: In our study, high levels of proteinuria, low serum albumin levels, and an increase in ferritin levels were found to be significant for a decrease in glomerular filtration rate and disease progression. In addition to the decrease in glomerular filtration rate, the effect of these factors on the duration of RRT was also found to be significant. Initial GFR level, increase in ferritin, PTH, advanced age, and male gender were found to significantly affect hypertension, which is one of the macrovascular complications of chronic kidney disease and the most important cause of mortality in chronic kidney disease. Among these factors, advanced age was associated with increased mortality. Key Words: Chronic Kidney Disease, Diabetes, Glomerular Filtration Rate, Progression , Cardiovascular Disease , Mortality