Pos0086 a Transversal Study of 826 Untreated Gout Patients Shows That Echogenicity of the Renal Medulla Increases With Gout Duration/Severity and Steroid Use

Abstract

BackgroundDiffuse hyperechogenicity of the kidney pyramids, detected by kidney ultrasound (US) scan, has been reported as a frequent finding in severe, untreated, tophaceous gout. It seemed related to crystal deposition in the renal medulla and correlated with kidney function decrease, reviving the concept of gouty microcrystalline nephropathy [1].ObjectivesTo confirm this finding and to detect its progression with gout duration.MethodsPatients fulfilled the ACR/EULAR criteria, were not treated by urate-lowering drugs (ULD) at the time of examination; 44 % had received short courses of ULD in the past. They underwent kidney US scans by an experienced radiologist, who classified each kidney into 3 grades according to the presence and degree of hyperechogenicity of the renal pyramids, as compared to the renal cortex. Grade 0 was defined as no medulla hyperechogenicity; grade 1 by the observation of hyperechogenic spots in 1 or 2 renal pyramids; grade 3 as a diffuse hyperechogenicity of at least 3 pyramids (out of 5 scanned). Demographic variables, comorbidities, gout and biochemical features were retrieved from electronic files. US scans of the MTP joints allowed gradation of double contours from 0 to 3. Links between patients ‘features and renal medulla staging were assessed by Fisher exact or Kruskall and Wallis tests according to the type of variables. Multivariable analysis included all statistically significant features, with model selection on p.value using a proportional odds logistic regression model. All test were two-sided.Results826 consecutive new patients were included from August 1 to December 24, 2022. 88 % were males, median age was 49 years, median BMI 24.22 kg/m2, median gout duration 5 years, 70 % of patients had clinical tophi, median uricemia was 488,6 µmol/l, median creatininemia 83.5 mmol/l, median eGFR 93 ml/min. Both kidneys were classified at the same grade in every all patients. 65.5% of patients were at grade 0, 17.8 % at grade 1 and 16.7 % at grade 3. Table 1 shows links of the extent of medulla hyperechogenicity with patients ‘features. By multivariable analysis, positive correlation was found with male sex, hypertension, gout duration, tophi, double contours and uricemia; BMI, eGFR and cortilsolemia negatively correlated.ConclusionHyperechogenicity of the renal medullas progressively increased with gout duration, MSU deposition and steroid treatment, and associated with decrease of renal function and hypertension. These observations reinforce the early indication of ULDs in gouty patients.Reference[1]Bardin T et al. Kidney Intern 2021;99: 218–226Table 1.Main features of gouty patients by grades of medulla hyperechogenicityGrade 0n = 541Grade 1n = 147Grade 2n = 138p valuep.value MultiAge (y) median [IQR]47 [38, 56]51 [44, 59]54 [45, 62]<0.001Males n (%)441 (81.7)147 (100.0)138 (100)<0.001<0.001BMI (kg/m2) median [IQR]24.4 [22.5, 26.7]24.1 [22.5, 26.1]23.3 [21.2, 25.8]0.003<0.001Hypertension n (%)145 (26.8)54 (36.7)88 (63.8)<0.0010.006CHD n (%)6 (1.1)7 (4.8)7 (5.1)0.003Type 2 diabetes n (%)62 (11.5)17 (11.6)27 (19.6)0.04Gout duration (y) median [IQR]4 [2, 7]7 [4, 11]11 [8, 17]<0.001<0.001Tophi n (%)298 (55.1)14 (95.9)137 (99.3)<0.001<0.001Urinary stone n (%)23 (4.3)18 (12.2)13 (9.4)0.001SUA (umol/l) median [IQR]437 [322, 548]533 [432, 602]558 [493, 618]<0.001<0.001Creatininemia (mmol/l) median [IQR]81 [67, 92]87 [76, 106]93 [79, 107]<0.001eGFR > 60 ml/min n (%)506 (93.5)128 (87.1)112 (81.2)<0.001Maximum double contours<0.001<0.001 0 n (%)17 (34.1)0 (0.0)0 (0.0) Thin n (%)86 (20.7)8 (5.4)1 (0.7) Medium n (%)306 (73.6)114 (77.6)66 (47.8) Thick n (%)7 (1.7)25 (17.0)71 (51.4)8 am cortisol median [IQR]7.55 [3.58,10.33]6.60 [1.95,10.72]1.91 [0,59,8.06]<0.0010.005y: years; IQR: interquartile range; BMI: body mass index; CHD: coronary heart disease; eGFR estimated glomerular filtration rate (MDRD)Acknowledgements:NIL.Disclosure of InterestsNone Declared.