Manifestations And Pathology Of Renal Involvement In Ankylosing Spondylitisand And Its Risk Factors

Objective To fulfill retrospective analysis the clinical and laboratory characteristics of renal damage in Ankylosing spondylitis(AS)patients,to evaluate the risk factors and pathological features in kidney damage of AS patients,and to improve further understanding of renal involvement in AS.Methods We retrospectively reviewed the medical record of 1800 cases of ankylosing spondylitis who met the New York criteria from 2009.3 to 2015.3.Clinical and laboratory data of 1001 AS patients were analyzed about kidney damage(proteinuria,hematuria,eGFR decline and blood creatinine rise)of the basic characteristics,incidence,clinical manifestations,renal damage with gender,disease duration,smoke,pain correlation analysis site,drugs,HLA-B27,blood platelet and retinol binding protein;then further analysis of risk factors for kidney damage.Another selecting 503 patients further analyzed the urinary protein quadruplein,and it was significance to investigate earlier biomarkers;and finally selected 21 patients and all these patients were underwent percutaneous needle biopsy.We evaluated these patients with renal pathology and analyzed their baseline characteristics,clinical features,laboratory and urinalysis results,treatment protocols and treatment responses.Results 183 of 1001 AS patients had renal damages,accounting for 18.3%,Which,according to the simplified MDRD eGFR decreased patient obtained 12(1.2%)patients;89(8.9%)patients with proteinuria;99(9.9%)with hematuria;8(0.8%)patients had elevated creatinine;13 patients(1.3%)had both hematuria and proteinuria;acute renal failure patients in 3 patients(0.3%).The incidence of kidney damage in smoker was significantly higher than non-smokers,and the incidence of HLA-B27-positive patients with renal impairment were significantly higher than HLA-B27-negative patients.Binary variable Logistic regression analysis showed that male,the pain occurs simultaneously in axial and peripheral,smoking,NSAIDS medication history and retinol-binding protein were risk factors in the kidney damage of AS.There were 167(33.2%)patients of kidney damage in 503 patients.50(10.0%)patients had proteinuria;45(9.9%)patients had hematuria;elevated creatinine is 0 people,10(2.0%)had both proteinuria and hematuria;5(1.0%)patients had eGFR decreased;48(9.5%)patients had urinary transferrin increased;58(11.5%)patients had urinary ?1-microglobulin increased;70(13.9%)patients had urinary IgG immune globulin increased;32(6.4%)patients elevated microalbuminuria.Quadruple urine protein(urinary transferrin,?1 microglobulin in urine,urinary IgG,microalbuminuria)raised incidence of kidney damage of AS(P <0.05).Simple AS quadruple urinary protein levels compared with 24 hours proteinuria in AS patients finding that elevated erythrocyte sedimentation rate(P <0.05)and duration(P<0.05)were significantly different.IgA nephropathy had the highest incidence of renal involvement(8 of 21,38%),followed by mesangial-proliferative glomerulonephritis(7 of 21,33.3%),membranous nephropathy(2 patients,9.5%)and rarely minor-lesion glomerulonephritis(1 patient,4.8%),acute interstitial nephritis(1 patient,4.8%),sub-acute interstitial nephritis(1 patient,4.8%)and interstitial nephritis with mesangial-proliferative nephropathy(1 patient,4.8%).After treatment,the levels of serum creatinine,red blood cell and proteinuria in urine in the patients were improved or stabilized,but,the differences of these changes do not have statistical significance except IgA nephropathy patients in this study.Moreover,the renal function of 3 patients with interstitial nephritis improved significantly after therapy and discontinuation of the induced drugs.Conclusions The incidence of kidney damage in AS patients is not rare,and is more common in smokers and in patients with HLA-B27-positive.Male,the pain occurs simultaneously in axial and peripheral,smoking,NSAIDS medication history and retinol-binding protein is risk factors in kidney damage of AS patients.Urinary protein quadruple AS is early biological markers in renal involvement patients,and more significant in patients with a long duration and elevated erythrocyte sedimentation rate.Renal biopsy is highly recommended to determine prognosis and decide the treatment protocol in clinical practice of renal involvement in ankylosing spondylitis.