GFR, ABI, High Blood Pressure Associated With Poor Prognosis in Patients With CKD

A 16-week exercise program demonstrated lower glomerular filtration rate (GFR), ankle-brachial index (ABI), and higher systolic blood pressure were associated with a poor prognosis in patients with chronic kidney disease (CKD), according to a study published in Reports in Public Health and conducted in Brazil. The aim of this study was to analyze the effects of the exercise intervention and cardiovascular disease risk factors on survival, quality of life, and CKD progression during follow-up.

The study was conducted during the 3-year post-trial observational follow-up of patients who underwent a 16-week exercise training program. The study was meant to assess how an exercise program would affect GFR, blood pressure, glucose and lipids, health-related quality of life (HRQOL), ABI, and the functional capacity of hypertensive adults with CKD.

Patients were included if they were non-diabetic aged 18 years and older who were diagnosed with high blood pressure and an estimated GFR (eGFR) between 15 and 59 mL/minute/1.73m². Patients with severe disability or amputated lower limbs without prosthesis, a history of acute myocardial infarction in the previous 6 months, and previous kidney transplants were excluded from the study.

There were 150 patients who were included in baseline measurements of the study. All outcome variables were measured 8 weeks after enrollment and at the end of the 16 weeks. All patients were followed for 3 years after the baseline assessment.

There were 128 patients who were located after 1028.79 (standard error [SE], 23.88) days from the trial inception with 23 who refused to reevaluate for GFR and HRQOL. Participants had a mean age of 65 years and were mostly White women, overweight or obese (mean BMI, 29.9; SE, 0.7/kg/m2), and with slightly reduced renal function (eGFR, 63.4; SE, 2.3mL/minute/1.73m2).

There were 13 patients who died after 3 years out of the 128 patients located. The patients died after a mean of 764.58 (SE, 11.1) days after randomization. No differences in death were found between the exercise and non-exercise groups.

In-trial eGFR (HR, 0.95; 95% CI, 0.92, 0.98) and in-trial ABI (HR, 0.03; 95% CI, 0.002, 0.43) were associated with survival in the univariate analysis. After adjusted analysis, both remained independent predictors of survival.

A univariate analysis for change in GFR demonstrated no influence of the exercise group but GFR was significantly associated with in-trial ABI (β, 0.25, coefficient, 10.44; 95% CI, 1.68, 19.20) and in-trial systolic blood pressure (β, –0.26, coefficient, –0.14; 95% CI, –0.25, 0.02). In the adjusted analysis, in-trial systolic blood pressure and in-trial ABI both remained as independent predictors of CKD progression.

There were some limits to this study, such as a lack of baseline quantitative measures of albuminuria, which is a known risk factor for CKD progression. Also, antiypertensive drug use was not recorded in the study. Approximately one-sixth of patients could not be located, and another one-sixth did not have their GFR estimated in the final assessment. The follow-up study could also be significantly underpowered.

The researchers concluded that short-term benefits of exercise on surrogate end points for patients with CKD do not imply long-term advantages in patient outcomes if infrastructure and life-course educational and motivational support are not provided.

Reference

Bohlke M, Barcellos FC, Santos IS, Mielke GI, Vargas MDM, Hallal PC. Effects of a 16-week physical training on clinical outcomes in patients with hypertension and chronic kidney disease: NEPHROS post-trial follow-up. Cad Saude Publica. 2022;38(5):e00061521. doi:10.1590/0102-311X00061521