Correlation analysis of anemia and renal function decline in patients with IgA nephropathy by using generalized additive mixed model / 中华肾脏病杂志

ABSTRACT

Objective:To investigate the relationship between anemia and renal function prognosis in IgA nephropathy (IgAN) patients.Methods:Patients diagnosed with IgAN by renal biopsy in Shenzhen Second People′s Hospital (The First Affiliated Hospital of Shenzhen University) from January 1, 2010 to December 31, 2018 were retrospectively analyzed. Patients who lacked baseline estimated glomerular filtration rate (eGFR), or patients with the baseline eGFR<15 ml·min -1·(1.73 m 2) -1, or patients who lacked baseline hemoglobin data were excluded. Clinical data, laboratory data, pathological data and follow-up data of renal function were collected. Patients were divided into anemic group (hemoglobin level<120 g/L in males and<110 g/L in females) and non-anemic group. A generalized additive mixed model (GAMM) was used to analyze the relationship between anemia at baseline and decreased renal function (eGFR) in follow-up. Results:A total of 821 IgAN patients were enrolled in this study, including 666 non-anemia patients and 155 anemia patients. There were 397 males (48.36%), aged (34.91±9.46) years. The median baseline eGFR was 72.00(15.00, 167.46) ml·min -1·(1.73 m 2) -1, and the median baseline urinary protein quantification was 1.00(0.01, 15.82) g/24 h. The median follow-up time was 176(0, 3 770) days. A total of 2 352 repeated measurements were performed of which 1 268 (53.91%) repeated measurements were from males. Compared with those in non-anemia group, patients in anemia group had lower levels of baseline eGFR, body mass index (BMI) and serum albumin, higher proportion of females, and higher pathologic manifestations of glomerular segmental sclerosis (S1), tubulointerstitial atrophy/fibrosis (T1 and T2), and crescent (C1 and C2) (all P<0.05). Using the single-factor GAMM, the eGFR decreased by 4.778 ml·min -1·(1.73 m 2) -1 (95% CI 2.727-6.830, P<0.001) more per year in the anemia group than that in the non-anemia group. After adjusting for age, gender, BMI, blood uric acid, mean arterial pressure, serum albumin, blood cholesterol, 24 h urinary protein, glomerular mesangial cell proliferation (M), capillary cell proliferation (E), glomerular segmental sclerosis (S), tubulointerstitial atrophy/fibrosis (T), and crescent formation (C), each additional year of time, eGFR decreased by 6.817 ml·min -1·(1.73 m 2) -1 (95% CI 4.245-9.388, P<0.001) more in the anemia group than that in the non-anemia group. Conclusions:Anemia is correlated with renal function decline in IgAN patiens. IgAN patients with anemia have accelerated deterioration of progress. Early intervention of anemia might delay renal function progression.