| Background and objectives:Immunoglobulin A(IgA) nephropathy has the second highest detection rate following the membranous nephropathy in the elderly patients with renal biopsy. There were few studies on the elderly IgA nephropathy patients. Due to the limitation of these studies, the outcome of elderly patients was still controversial. The aim of this study is to explore the pathological features and prognosis characteristic of the elderly with IgA nephropathy, adjusting the main clinical features by the propensity score method.Methods:We enrolled 96 elderly (age?60) and 701 young (age between 18 and 40) patients diagnosed with primary IgA nephropathy from 1994 to 2014. (1) After 1:1 propensity score matching,79 elderly and 79 young patients were analyzed. There were no differences in gender, baseline estimated glomerular filtration rate (eGFR) and proteinuria between the groups. Referring to the Oxford classification, the pathological characteristics of each patients were scored. (1) We compared the clinicopathologic features, correlation and prognosis between the matched groups. The pathological factors influencing the baseline eGFR and proteinuria was analyzed by the univariate and multiple linear regression. (2) The associations between the Clinicopathological features and the rate of decline in renal function were determined by the univariate and multiple linear regression. The differences in the outcomes between two groups were assessed using the Kaplan-Meier analysis. The clinicopathologic variables effecting the prognosis of two groups were determined using the univariate and multivariate Cox regression analysis. All of the statistical analyses were performed using the SPSS 20.0.Results:1.(1) Compared to the control group, the elderly had higher serum glucose, higher systolic pressure, mean arterial pressure (MAP), pulse pressure and reduced serum uric acid, serum albumin. The prevalence of the diabetes and coronary heart disease were much higher in elderly. There were no differences between groups in the number of antihypertensive, the percentage of patients treated with RAS inhibitors and glucocorticoids. But the percentage of patients on immunosuppressant of the elderly was higher than the control.(2) Compared the pathological features in the matched control group, the elderly patients had increased in endocapillary proliferation (E), arteriosclerosis, arteriolar hyalinosis. and reduced in tubular atrophy/interstitial fibrosis (T), segmental glomerulosclerosis and/or adhesion. adhesion ratio, segmental and global sclerosis ratio.(3) In each matched group. the higher baseline proteinuria was related to the mesangial hypercellularity. while the worse baseline eGFR was accociated to the higher baselin uric acid, hemoglobin and tubular atrophy/interstitial fibrosis. Besides, the worse baseline eGFR in the elderly had a relationship with the higher global sclerosis ratio, mesangial hypercellularity. The baseline eGFR in the control was related to the higher MAP.2. (1) The rate of eGFR decline in the elderly group was more slowly than the matched control group (P=0.048). The elderly with intima thickened to more than the thickness of media (HR=-10.53,95% CI-20.86?-0.19) and higher radio of adhesion (HR=-0.72, 95%CI-1.21?-0.22) had a faster decline in eGFR. The matched patients in the control group with larger proteinuria (HR=-1.13,95% CI-2.06?-0.20), MAP (HR=-0.20,95% CI-0.34?-0.06) and segmental glomerulosclerosis and/or adhesion (HR=-8.30,95% CI-14.50?-2.10) had a faster decline in eGFR.(2) The mean follow-up period of the elderly group was 62.2±39.2 months, and 20 patients achieved 50% reduction in eGFR (or progressed to ESRD), the five-year and ten-year renal survival were 90.7% and 51.0%; 10 patients died, the five-year and ten-year survival were 89.0% and 61.3%.The mean follow-up period of the matched control group was 82.4±44.3 months, the follow-up eGFR of 31 patients declined over 50%(or progressed to ESRD), the five-year and ten-year renal survival were 72.0% and 26.7%,3 patients died, the five-year and ten-year survival were 94.7% and 94.7%. Kaplan-Meier analysis showed a reduced risk of decline in eGFR>50%(log rank P=0.062) and an increased all-cause mortality in elderly patients compared with the young (log rank P=0.007).(3) Cox regression analysis revealed that the baseline MAP (HR=0.84,95%CI 0.47? 1.50), segmental sclerosis ratio(HR=1.12,95%CI 1.02?1.22) were independent risk factors of decline in eGFR?50% in elderly patients, the baseline eGFR (HR=0.66,95%CI 0.49?0.90) and heavy proteinuria (HR=9.99,95%CI 1.11 ?90.27) were risk factors of death. While in the matched control group, the risk factors of decline in eGFR?50% were the baseline MAP (HR=1.40,95%CI 1.09? 1.81) and tubular atrophy/interstitial fibrosis (HR=25.77,95%CI 4.44?379.34). No clinicopathologic characteristic had been found that can predict the death in the control group.Conclusions:Compared to the young group with similar baseline clinical features, the elderly patients with IgA nephropathy have more severer endocapillary hypercellularity, arteriosclerosis and milder chronic pathologic lesions and tubular /interstitial lesion. The elderly patients have a better renal survival but increased all-cause mortality compared to the young when they shared the similar baseline clinical variables, which is different from the former studies. Segmental sclerosis ratio and baseline MAP are the independent risk factors in the elderly IgA nephropathy patients. |
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