document: rheumatoid arthritis ( ra ) is a progressive , autoimmune disease , characterized by chronic inflammation of synovial membrane and consistently degradation of articular cartilage and subchondral bone . 
   serum amyloid a ( saa ) is a highly conserved acute - phase protein , released in response to inflammation or infection . 
   production of acute - phase saa ( a - saa ) is stimulated by proinflammatory cytokines , such as interleukin-6 ( il-6 ) , il-1 , tumor necrosis factor ( tnf ) , interferon- , and transforming growth factor- ( tgf- ) . 
   the concentration of a - saa increases dramatically during acute inflammation and injury , reaching within 5 - 6 hours levels that are 1000-fold greater than normal [ 13 ] . as with other acute - phase reactants , 
   however , extrahepatic production of saa by several tissues and cell types has been described in patients with chronic diseases , for example , alzheimer 's disease , cancer , diabetes , obesity , insulin resistance , metabolic syndrome , and atherosclerosis [ 46 ] . 
   it has been even suggested that saa may play an important , pathogenic role in the proinflammatory cascade in the course of ra . 
   saa is not only an acute - phase protein but also a kind of apolipoprotein , relevant in cholesterol metabolism . 
   normally , saa circulates in low levels bound to high - density lipoprotein ( hdl ) , but during inflammation saa can contribute up to 80% of hdl apolipoprotein ( apo ) composition , exceeding apo - a1 in quantity and impairing the protective function of hdl . 
   saa may also increase the oxidation of low - density lipoprotein ( ldl ) and thus may be associated with cardiovascular ( cv ) disease ( cvd ) and atherogenesis [ 5 , 7 ] . 
   saa is also the precursor of amyloid a protein , a fibrillar , insoluble product deposited in major organs , which carries a risk of organ failure and premature death in the course of secondary amyloidosis . 
   aa amyloidosis is a late complication of ra , connected with active , long - standing , and disabling disease . 
   the prevalence of aa amyloidosis in ra reported in different studies is highly variable because the complication frequently remains undetected due to lack of clinical manifestations in many patients . 
   persistently high concentration of saa is a prerequisite for aa amyloidogenesis [ 1 , 3 ] . 
   high levels of saa correlate with the progression of amyloidosis and low levels are associated with its regression [ 2 , 9 ] . 
   it was reported that , in aa amyloidosis patients , serum saa concentration was the most important predictive parameter of the risk of death , associated with renal function . 
   the aim of the study was to assess the concentration of saa in ra patients with different disease activity , with reference to other inflammatory , metabolic parameters , as well as cv and renal disease risk factors . 
   the study group consisted of 140 ra patients admitted consecutively and treated in the department of rheumatology and connective tissue diseases , medical university of lublin . 
   the patients were qualified for the treatment in order to make a decision whether to maintain or modify the ongoing therapy , depending on an assessment of the disease activity . 
   the ethical committee of the medical university of lublin approved the design of the study . 
   demographic and clinical information was obtained through structured interview , review of medical records , self - report questionnaires , physical examination , laboratory tests , and high - resolution b - mode ultrasonography . 
   disease activity was measured using the disease activity score ( das ) based on evaluation of 28 joints ( das28 ) , calculated with the number of tender joint counts ( tjc ) and swollen joint counts ( sjc ) , erythrocyte sedimentation rate ( esr ) value , and patient 's global assessment ( pga ) of disease activity in visual analogue scale ( vas ) . 
   ability to perform daily activities was measured using the modified health assessment questionnaire ( m - haq ) with the range 03 ( a score 0 representing no impairment of function ) . 
   erosive form of ra was diagnosed in those patients , who presented erosions on joint surfaces of bones in radiograms of hands and/or feet , according to steinbrocker et al . 
   extra - articular symptoms were noted , which occurred during the whole course of the disease . 
   blood was collected after an overnight fasting to determine the complete blood cell count , erythrocyte sedimentation rate ( esr ) , serum concentration of crp , creatinine ( cr ) , total protein , albumin , fibrinogen , total cholesterol ( tc ) , hdl - cholesterol [ hdl - c ] , ldl - cholesterol [ ldl - c ] , and triglycerides ( tg ) at the university hospital central laboratory . 
   serum level of crp was measured by immunoturbidimetric assay , with the upper limit of the normal range at 5  mg / l . 
   concentrations of tc , hdl - c , and tg were measured using the standard enzymatic technique ( biomaxima ) ; ldl - c was calculated according to the friedewald formula . 
   modification of diet in renal diseases ( mdrd ) was calculated for every patient to estimate the glomerular filtration rate ( gfr ) using serum cr concentration and demographic factors . 
   blood samples were also stored at 80c for further assessment of cystatin - c ( cys - c ) and saa . 
   cys - c is used as an endogenous marker for gfr , more precise than creatinine . 
   serum cys - c was measured using quantitative enhanced immunonephelometry method ( with commercially available assay developed by dade behring ) . 
   the producer recommended the normal range of cys - c between 0.53 and 0.95  mg / l independently of sex , age , and body mass . 
   serum concentration of saa was determined by a commercial enzyme - linked immunosorbent assay ( elisa ) , with detection limit 0.005  mg / l ( human saa ; biosource europe s.a . 
   igm - rheumatoid factor ( rf - igm ) was determined using the antirheumatoid factor elisa ( igm ) test ( euroimmun ) with the recommended upper limit of the normal range 20 units ( ru)/ml . 
   anticitrullinated protein antibodies ( acpa ) were determined using the quanta lite ccp3.1 igg / iga elisa assay ( inova diagnostics ) with negative results < 20  u / ml . height and weight were measured barefoot wearing light clothes . 
   body mass index ( bmi ) was calculated as the ratio of weight and squared height . during physical examination blood pressure ( bp ) 
   was performed in every patient , with assessment of corrected qt interval ( qtc ) . 
   the 10-year risk of fatal cvd using the systemic coronary risk evaluation ( score ) model according to the eular recommendations was estimated in every patient . 
   carotid intima - media thickness ( cimt ) was measured using high - resolution b - mode ultrasound ( logiq 7 ge ) . in every subject imt 
   was assessed bilaterally in the three regions : common carotid artery ( cca ) , carotid bulb ( bulb ) , and internal carotid artery ( ica ) . 
   the average of the maximal imt from all 6 carotid segments ( defined as mean cimt ) was used in the analyses . 
   it has been reported that cimt  0.6  mm is a marker of subclinical atherosclerosis . 
   plaques were defined as a distinct protrusion , greater than 1.5  mm into the vessel lumen . 
   results were expressed as mean ( standard deviation , sd ) or number ( % ) . 
   group differences were tested using student 's t - test and mann - whitney u test for normally and nonnormally distributed parameters , respectively . 
   spearman 's or pearson 's correlation test was used to determine the association between saa and clinical and laboratory variables . 
   multivariable analysis ( multiple linear regression ) was performed according to a forward selection procedure , introducing those variables that showed a statistically significant association with saa . 
   characteristics of patients with ra are presented in table 1 ; clinical and laboratory variables are presented in table 2 . 
   most patients were positive for rf - igm and acpa and had erosive form of ra , of low or moderate activity ( l / mda ) ( das28  5.1 ) at the time of assessment . 
   remission of ra according to das28 ( < 2.6 ) was observed in 8 patients ( 7 women and 1 men ) . 
   extra - articular symptoms during the course of ra were noted in 58 patients ( 41.4% ) and included rheumatoid nodules ( 40 patients ) , sicca syndrome ( 16 patients ) , interstitial lung disease ( 7 patients ) , amyloidosis ( 1 patient ) , and vasculitis ( 1 patient ) . at the time of examination disease modifying antirheumatic drugs ( dmards ) 
   were not used in 5 patients ( 3.6% ) . in the remaining 135 patients , treatment with at least 1 synthetic dmard 
   was administered : methotrexate ( mtx ) ( 58.6% of all patients ) , leflunomide , sulfasalazine , chloroquine , and cyclosporine . 
   biological dmards were used in 36 patients ( 25.7% ) ( adalimumab in 3 , etanercept in 15 , infliximab in 15 , and rituximab in 3 cases ) . 
   simultaneously , low - dose prednisone ( 10  mg / day ) was used in 108 patients ( 77.1% ) . 
   the mean saa concentration in the group of 140 patients was 327.0 ( 263.4 ) mg 
   positive , significant ( p < 0.05 ) correlations were found between saa and das28 , tjc , sjc , pga of the disease activity , morning stiffness , m - haq and esr value , concentration of crp , fibrinogen , and cys - c , as well as with white blood cell count ( wbc ) , platelet count ( plt ) , and score value . 
   negative , significant ( p < 0.05 ) correlations were found between saa and concentration of albumin , hemoglobin , and qtc value . 
   all the above - mentioned variables were included in the multiple linear regression analysis , which confirmed significant associations for crp , wbc , and qtc ( table 3 ) . 
   the mean saa concentration was significantly higher in men than in women ( p = 0.01 ) ( table 4 ) . 
   the group of men , when compared with women , was characterized by higher inflammatory parameters [ crp 27.4 ( 23.3 ) versus 17.4 ( 21.9 )  mg / l , p = 0.005 ; fibrinogen 5.4 ( 1.2 ) versus 4.6 ( 1.3 )  g / l , p = 0.006 ] , unfavorable lipid parameters [ hdl 50.7 ( 11.6 ) versus 62.3 ( 15.0 )  mg / dl , p = 0.0001 ; tc / hdl index 3.8 ( 1.0 ) versus 3.4 ( 0.8 ) , p = 0.01 ] , higher cv risk markers [ cimt 0.86 ( 0.17 ) versus 0.77 ( 0.14 )  mm , p = 0.01 ; score 4.3 ( 3.9 ) versus 1.1 ( 1.5 ) , p < 0.0001 ] , and higher cys - c concentration [ 0.83 ( 0.24 ) versus 0.75 ( 0.21 )  mg / l , p = 0.04 ] . 
   significantly higher concentrations of saa were found in patients with high disease activity ( hda ) versus l / mda ( p < 0.0001 ) and in patients currently treated versus not treated with glucocorticoids ( gcs ) ( p = 0.002 ) ( table 4 ) . 
   significantly higher concentration of saa was also observed in patients with advanced atherosclerosis when compared with those without atherosclerotic plaques ( p = 0.04 ) and in patients with increased ( 1.0  mg / l ) versus normal cys - c level ( p = 0.004 ) ( table 4 ) . 
   the mean saa concentration was significantly lower in women currently treated with biological dmards ( p = 0.01 ) ( table 4 ) . 
   there was no such a correlation in men . among female patients treated with biological dmards , 
   anti - tnf inhibitors were used in 32 ( 94% ) and rituximab was used in 2 cases . the normal saa level ( < 10 
   mg / l ) was observed in 11 patients ( 7.9% ) , 10 women , and 1 man . 
   the mean concentration of saa in this group was 6.4 ( 4.4 )  mg / l ( range 09.9 ) . 
   patients with normal versus increased saa concentration were characterized by lower concentration of crp [ 11.4 ( 18.2 ) 
   mg / l versus 20.2 ( 22.7 ) , p = 0.03 ] and fibrinogen [ 4.1 ( 1.6 ) versus 4.8 ( 1.3 ) 
   g / l , p = 0.05 ] , lower wbc [ 6.0 ( 1.2 ) versus 8.1 ( 2.5 )  10/l , p = 0.003 ] , and higher qtc duration [ 373.8 ( 52.8 ) versus 332.2 ( 57.2 )  ms , p = 0.04 ] . 
   there were no significant differences in methods of treatment between the two groups of patients . 
   the major finding of the study was that serum saa concentration was high above normal in the vast majority of ra patients . 
   the normal saa level was found only in < 10% of patients , characterized by lower inflammatory burden and normal qtc duration . elevated above normal saa levels 
   were found not only in patients with hda , but also in those with l / mda assessed with das28 . 
   this observation suggests that in spite of favorable clinical assessment , sustained inflammation persists in most of ra patients and may be connected with the disease complications . in this study 
   , we demonstrated a direct relationship between saa and ra activity ( with both clinical and laboratory parameters of activity ) . 
   significantly higher saa was associated with the current treatment with gcs , which are commonly used in patients with hda . 
   women treated with biological dmards had significantly lower saa concentration than women treated only with synthetic dmards . 
   these results confirm better therapeutic effects of biological dmards in comparison to synthetic dmards resulting in lower disease activity . 
   the mean saa level was significantly higher in patients with plaques as a manifestation of advanced atherosclerosis . 
   significantly higher mean saa concentration was noticed in patients with increased cys - c level as an early marker of chronic kidney disease ( ckd ) . 
   the results of our study indicate that , in ra patients , saa could be considered as a biomarker associated with both the current inflammatory disease activity and chronic complications , the risk of cv and renal involvement in the course of ra . 
   persistently elevated saa concentration increases the risk of amyloidosis development due to deposition of amyloid proteins in different tissues and organs . 
   our results are consistent with data in literature , which reported a strong correlation between saa and ra activity . the saa level correlated with clinical disease activity ( 28-joint sjc ) and 
   it has been demonstrated that saa may be also produced by rheumatoid synovial tissue ( but not in normal synovial membrane ) , inducing cell growth , angiogenesis , invasion and migration of cells , secretion of proinflammatory cytokines ( tnf , il-1 , il-6 , and il-8 ) , chemokines , reactive oxygen species , and matrix metalloproteinases ( mmp ) [ 2 , 6 , 20 , 21 ] . 
   therefore , saa may play a pathogenic role locally in joint destruction and cartilage damage [ 2022 ] . the correlation between saa level and wbc 
   may be associated with the reported function of saa as a priming agent , rendering neutrophils more responsive to opsonized particles , as well as inducing chemotaxis and adhesion to endothelial cells and cellular migration [ 23 , 24 ] . 
   significantly higher saa levels were found in patients currently treated with gcs , which seems to be a paradoxical effect . 
   however , gcs are commonly used in patients with hda , presenting increased inflammatory parameters . on the other hand , 
   it was reported that gcs induce extrahepatic saa expression , which has been shown in tissue cultures   and confirmed in patients with chronic obstructive pulmonary disease . 
   further prospective determinations of saa are necessary to define an accurate answer . according to our knowledge , 
   we also found significantly higher saa concentration in women not treated with biological dmards , which indicates more active disease in these cases . 
   however , patients in our group received therapy with different biological dmards ( one of the three tnf inhibitors or rituximab ) , which hinders a reliable assessment of relationship between saa and biological treatment . in literature , there is no data on the association between saa and rituximab . 
   there are few reports on the effect of anti - tnf [ 2731 ] and anti - il-6 [ 31 , 32 ] treatment on saa concentration , dealing mostly with patients with amyloidosis , secondary to ra . 
   the blockade of tnf prevents high systemic saa concentrations that are largely driven by tnf . 
   the effective and early dmards treatment works as the primary prevention of amyloidosis , as well as the secondary prevention in a subclinical phase of this complication . 
   however , even during anti - tnf therapy , excessive , extrahepatic expression of saa , mediated by il-6 and gcs , could probably be maintained in rheumatoid synovial tissue . in this case , saa may upregulate tnf itself and may be a potent upstream mediator of tnf , influencing response to existing anti - tnf therapy . 
   high level of saa during anti - tnf treatment might serve as a biomarker of persistent synovial inflammation , resistant to the therapy currently used . in our patients , 
   the mean saa concentration was significantly higher in men than in women , which may be related to significantly higher parameters of inflammation and unfavorable cv risk factors in men . according to literature , women have higher saa levels than men , for various reasons , due to hormonal status , interaction with leptin , or different body composition [ 33 , 34 ] . 
   men have larger intra - abdominal fat deposits , which produce significant amounts of cytokines ( tnf , il-6 ) , even in larger quantity than subcutaneous adipose tissue . 
   we observed significantly higher saa levels in patients with atherosclerotic plaques and increased cys - c serum concentration , which indicates the risk of cv and renal complications . 
   it has been demonstrated that cells within human atherosclerotic lesions ( foam and endothelial cells , smooth muscles ) could express saa and release to circulation at the site of plaque rapture [ 35 , 36 ] . 
   no independent effect of saa on cimt value was observed in one study . in literature , saa 
   is reported as a predictor of coronary artery disease and further coronary events , as well as biomarker of cerebrovascular disease [ 38 , 39 ] . 
   cys - c has been reported as a prognostic marker of risk for death , cv , and kidney outcomes in elderly patients , with and without ckd . in the whole group of our patients , 
   the mean qtc duration was below 350  ms and was inversely correlated with saa concentration . 
   intriguingly , in patients with normal saa level , the mean qtc duration was normal . according to our knowledge , 
   this is the first report on the association between saa and short qtc , which should be taken into account , considering a risk of life - threating arrhythmias , especially in patients with high saa concentration . 
   cardiovascular mortality is significantly increased in ra , with a risk of sudden death about twofold higher than in non - ra subjects [ 41 , 42 ] . 
   it has been suggested that this phenomenon may be associated with serious arrhythmias as a result of nonstructural cardiac alterations , such as reduced heart rate variability ( hrv ) or qt interval abnormalities . 
   shortening of qtc , recognized with the value < 350  ms , is associated with increased risk of atrial fibrillation with rapid ventricular tachycardia . 
   the study in patients with inflammatory arthritis demonstrated that high sensitivity crp ( hscrp ) was inversely correlated with hrv and directly correlated with qtc duration . 
   the study population consisted mostly of patients with spondyloarthropathies and only 25% of ra patients of unknown disease activity . 
   it is suggested that systemic inflammation may affect cardiac nervous system , irrespectively of other cv risk factors . 
   it seems that a short qt interval does not by itself predict risk of life - threating arrhythmias but rather should be taken in context of each individual patient . 
   the strengths are as follows : ( 1 ) relatively large sample of consecutive patients with ra , treated in our department , ( 2 ) the detailed characteristics of patients , who have been considered in all aspects of ra pathology including several inflammatory , cv , metabolic parameters , and assessment of renal function , ( 3 ) the design of the study which was based on clinical practice , and ( 4 ) according to our knowledge being the first study which evaluates the potential association of high saa level with qtc shortening , increasing the risk of serious arrhythmias and sudden death . 
   there are also some limitations including the following : ( 1 ) our patients were treated with different biological dmards ; that is why it is difficult to determine the exact association between saa and effect of therapy ; ( 2 ) ecg recording was performed routinely in every patient and qtc duration was assessed automatically , with no special procedure , and hrv was not assessed ; and ( 3 ) we did not collect detailed information about the ongoing treatment , which may influence heart rate . as a consequence , further investigation is needed to confirm the observed relationship , in relation to concurrent treatment . in our study , in patients with ra , 
   serum saa levels strongly correlated with the activity of the disease and were significantly higher in patients with high disease activity . 
   however , high saa concentrations were observed also in patients with low or moderate disease activity , in spite of clinical improvement . concurrent treatment with gcs was associated with higher saa and therapy with biological dmards was associated with lower saa concentration . 
   the mean saa level was inversely associated with qtc duration and markedly higher in patients with atherosclerotic plaques , emphasizing increased cv risk resulting from chronic inflammatory process . 
   we also found significantly higher saa levels in patients with increased cys - c as a marker of ckd , emphasizing increased risk of renal disease . 
   high saa concentration was strongly connected with the activity of the disease and the risk of cv and renal involvement in ra patients . 
   prospectively , repeated assessment of saa may facilitate searching ra patients with persistent inflammation and increased risk of extra - articular complications , as well as amyloidosis development .
summary: objectives . 
   rheumatoid arthritis ( ra ) is a systemic , inflammatory disease . 
   serum amyloid a ( saa ) is an acute - phase protein , involved in pathogenesis of atherosclerosis . 
   the aim of the study was to assess serum concentration of saa in ra patients , with reference to other inflammatory parameters and markers of extra - articular involvement . 
   methods . 
   the study population consisted of 140 ra patients , low / moderate disease activity ( l / mda ) in 98 ( 70% ) patients and high disease activity ( hda ) in 42 ( 30% ) . 
   comprehensive clinical and laboratory assessment was performed with evaluation of electrocardiogram and carotid intima - media thickness . 
   results . the mean saa concentration [ 327.0 ( 263.4 ) 
   mg / l ] was increased highly above the normal value , even in patients with l / mda . 
   simultaneously , saa was significantly higher in patients with hda versus l / mda . 
   the mean saa concentration was significantly higher in patients treated with glucocorticoids , was inversely associated with qtc duration , and was markedly higher in patients with atherosclerotic plaques , emphasizing increased cv risk . 
   saa was significantly higher in patients with increased cystatin - c level . 
   conclusions . in ra patients , 
   high serum saa concentration was strongly associated with activity of the disease and risk of cv and renal involvement . 
   recurrent assessment of saa may facilitate searching patients with persistent inflammation and risk of extra - articular complications .