Iohexol or Inuline clearance was realized in 21 adult CF patients, when they entered the lung transplant waiting list (n = 17) or when the patient was considered by the clinician at high risk for renal disease (n = 4). No patient was treated with aminoglycoside at the time of GFR measurement. BMI, history of diabetes mellitus and high blood pressure were recorded. Exposure to intravenous aminoglycoside within the 5 years before GFR measurement was calculated. Urines samples were collected to check for proteinuria and albuminuria.
Our population was predominantly male (57%). Mean age at GFR measurement was 31 years old. Mean BMI was 19 kg/m2. Only one patient had a history of high blood pressure, and 43% of patients were diabetic. Fourteen percent of patients had albuminuria of more than 30 mg/L and none of them had proteinuria. Mean days of exposure to IV aminoglycoside therapy within the 5 years before GFR evaluation was 169 days (Ranging from 60 to 280 days). Tobramycin was the most used aminoglycoside at the mean posology of 7.6 mg/kg/day. GFR was measured using iohexol for 15 patients and inuline was used for the remaining 6 patients. Mean measured GFR was 107 mL/min/1.73m2. Only 2 patients had a measured GFR <90 mL/min/1.73m2 for which GFR estimation using CKD EPI was unable to detect the moderate decline in kidney function (estimated GFR >90 mL/min/1.73m2).
Our sample was representative of the CF population. Despite prolonged exposition to high dose of aminoglycoside associated with a high prevalence of diabetes mellitus, no major decline in GFR is observed in our cohort.
There is no significant decrease in renal function in CF patients before lung transplantation.