EFFECTS OF ANGIOTENSIN II BLOCKADE WITH IRBESARTAN ON INFLAMMATORY MARKERS IN HAEMODIALYSIS PATIENTS: A RANDOMISED DOUBLE BLIND PLACEBO CONTROLLED ONE-YEAR FOLLOW-UP TRIAL (SAFIR STUDY)

IntroductionHaemodialysis (HD) patients are exposed to various endogenous and exogenous factors, which in their sum contribute to a chronic inflammatory state evidenced by increased levels of pro-inflammatory cytokines. The renin-angiotensin-aldosterone system (RAAS) has important modulating activities in inflammation, and previous studies suggest an anti-inflammatory effect of angiotensin II receptor blocker (ARB) treatment. The aim of this study was to compare the effect of ARB versus placebo on plasma concentrations of inflammatory markers in HD patients. MethodsAdult HD patients were randomised for double-blind treatment with the ARB irbesartan 150 mg or placebo. After two weeks, daily dose was increased to 300 mg/day. Patients receiving RAAS-blocking agents at inclusion stopped this treatment one week before baseline. At baseline, 1 week, 3, 6, 9, and 12 months plasma high sensitivity C-reactive protein (hsCRP), interleukin (IL) 1β, IL-6, IL-8, IL-18, and transforming growth factor β (TGF-β) were measured using Luminex immunoassay technology. Data were analysed based on a multivariate repeated measurements model (xtmixed) with time and drug (placebo or irbesartan) and the interaction between them as factors using Stata/IC 12.1. ResultsEighty-two patients were randomised (placebo/irbesartan: 41/41) and 56 completed one year of treatment. The groups (placebo/irbesartan) were comparable at baseline (mean±SD): Males 26(63%)/30(73%); age 62±14/61±16 years; systolic blood pressure (BP) 145±19/148±21 mmHg; HD vintage 168±95/171±93 days; HD time 10±2/11±3 hr/week; urine output 1.3±0.7/1.5±0.8 L/24 h; glomerular filtration rate 4.8/5.7 mL/min/1.73m2. Predialysis systolic BP decreased to the same extent in the irbesartan (–10 mm Hg) and in the placebo arm (–8 mm Hg). Use of additional antihypertensive drugs, ultrafiltration volume and HD dosage were similar during follow-up. Baseline levels of inflammatory markers (median with range) were similar hsCRP 3.3(0.2-23.4)/2.7(0.2-29.6) μg/mL; IL-1β 1.1(0.0-45.9)/1.1(0.0-7.2) pg/mL; IL-6 10(1-90)/12(1-84) pg/mL; IL-8 31(9-134)/34(5-192) pg/mL; IL-18 364(188-1343)/377(213-832) pg/mL; TGF-β 3.2(0.8-13.9)/3.6(1.3-13.8) ng/mL. Overall, there was no significant difference in hsCRP, IL-6, IL-8, and TGF-β between patients receiving placebo, and irbesartan treated patients during the study period, and hsCRP, IL-6, IL-8, and TGF-β were relatively stable during the study period (P≥0.18 in all tests for parallel curves, equal levels, and constant levels). The IL-1β level was slightly different in the two groups over time, but not significantly (P=0.09 in test for parallel curves) and it was also relatively stable during the study period (P=0.71 in test for equal levels and P=0.49 in test for constant level). The IL-18 level, however, was not constant during the study period (P=0.001 in test for constant level), but there was no significant difference between placebo and irbesartan treated (P=0.58 in tests for parallel curves and P=0.51 in test for equal levels). ConclusionsNo significant short-term or long-term anti-inflammatory effect of irbesartan treatment was observed. Our findings suggest that in HD patients antihypertensive treatment with irbesartan (and most likely ARBs in general) does not have clinically relevant BP-independent effects that favourably impact on inflammation.