Abstract
Background and Aims
We evaluated the natural history of chronic kidney disease with regard to progression to renal replacement therapy or death in a prospective cohort of patient. Few studies are published concerning patterns of kidney function decline before initiation of dialysis while decreasing glomerular filtration rate (GFR) trajectories can influence the outcomes of the following treatment.
Method
The analysis of Saint-Petersburg City nephrology center data among 5935 patients with GFR below 60 ml/min/1.73m with five and more follow-up visits. The outcomes data were collected from clinical and administrative databases.
Results
The most common causes of end stage renal failure were chronic glomerulonephritis (19%, decreasing over time 2009-2019), diabetes (16.9 %, stable), and hypertension (13.8 %, increasing). In 18.9% cases diagnosis was not established. 49% of patients show the rate in range 0-5 ml/min/1.73m per year; 33% had the rate more than 5 ml/min/1.73m per year; 17% of pts revealed slow but stable improvement of kidney function. Overall mean of the GFR change rates were -3.86±0.21 and -3.19±0.23 ml/min/1.73m per year for men and women; being significantly different for CKD stages: -1.23 (-1.93 ÷ - 0.61); -2.69 (-3.17 ÷ - 2.14); -4.91 (-5.55 ÷ - 4.47) and -6.42 (-7.52 ÷ - 5.63) for CKD 3A, 3B, 4 and 5. CKD progression rates differed between patients with various diagnoses and were associated with phosphate, calcium, anemia and iron deficiency, serum albumin and proteinuria levels. In women, total cholesterol levels out of normal range were linked with higher progression rates. In the multiple regression male gender was linked with higher GRF slope by 1.01 ml/min/1.73m per year. The reduced baseline GFR by 10 ml/min/1.73m per year; the reduced albumin - by 2 g/l, Hb - by 5 g/l, elevated phosphate - by 0.1 mmol/l, uric acid - by 0.2 mmol/l and proteinuria by 0.33 g/d were associated with similar increase of GFR slope (by about 10%). We found three different trajectories for GFR slope during three-year period before dialysis initiation: slow progression (-2.53, 95%CI -5.02÷-0.69 mL/min/1.73m per year) from CKD3B-CKD4 – 74% of patients, faster progression (-7.96, 95%CI -11.32÷-5.89) from CKD3 – 21% of patients, initially no progression (+0.24, 95%CI -1.54÷-2.05) with following acceleration of GFR slope (-19.2, 95%CI -29.7÷-10.8) from CKD3 – 5% of patients.
Dialysis was started at eGFR 7±3 ml/min/1.73m in “slow” group (31% - urgent start), 6±4 ml/min/1.73m in “fast” group (58% - urgent start) and 5±4 ml/min/1.73m in “accelerated” group (61% - urgent start).The rate of renal replacement therapy initiation over the 5-year observation period was 0.9%, 2.1%, 12.9% and 46.3%, respectively, for CKD stages 2, 3, 4, 5 while the mortality rate was 20.1%, 30.2%, 51.9 and 41.3% mainly for cardiovascular reasons. Thus, death was far more common than dialysis at all stages but CKD5, where it was comparable.
Conclusion
The identifying of the modifiable factors linked to CKD progression gives the opportunity to improve comprehensive renoprotective therapy. The efforts to decrease mortality in CKD3-4 cohort should be focused on prevention and treatment of coronary artery disease, congestive heart failure, diabetes mellitus, phosphatemia and anemia.
Intra-dialytic hypotension following the transition from continuous to intermittent renal replacement therapy