as a clinical management strategy , patients with chronic disease such as diabetes , dyslipidaemia and renal failure require assessment of inflammation and subclinical cardiovascular complications . the laboratory indices include blood viscosity , which has been an established concept of three phenomena that ultimately lead to , and/or result from cardiovascular complications[13 ] . however , whole blood viscosity ( wbv ) is most often not performed even in the western world where there is capacity and facility to do so . in diabetes , it is known that hyperviscosity is strongly influenced by the excellence of glycaemic control[46 ] . in a previous study , hyperglycaemic index ( hba1c ) wbv levels in poorly controlled and excellently groups were compared using student 's t - test . the results showed that wbv is statistically significantly lower in the group with excellent glycaemic control compared to the group with poor glycaemic control . this report provided further evidence that wbv is worse in poorly controlled diabetes as well as demonstrated that extrapolation of wbv level from haematocrit and plasma protein values is a feasible and valid method to employ in diabetes management . however , the prevalence of abnormal blood viscosity in diabetes has yet to be established . in dyslipidaemia , one of the theories is that hypercholesterolemia contributes to atherosclerosis by increasing blood viscosity , which in turn complicates endothelial damage and thrombosis . further , oxidative stress is a factor in hypercholesterolaemia - induced atherogenesis whereby in tandem antioxidant defense protects against lipid peroxidation and atherosclerosis . for instance , there is evidence that severe hypercholesterolaemia may not be associated with development of atherosclerosis . there is also report that though hypercholesterolaemia is associated with blood viscosity , the effect of lipid - lowering therapy is inconsistent on blood viscosity . it has been depicted in patients with renal failure ( rf ) that oxidative stress is exacerbated during haemodialysis , as well as increase in wbv . this underlies one of modes of cardiovascular disease complications in rf , and the essence of aspirin therapy . it is also reported that preoperative aspirin therapy , by its antiplatelet effect , offers protective effect against postoperative renal injury and improving renal perfusion possibly by reducing blood viscosity but not without bleeding complications . all of these sum up to imply assessment of wbv in rf would benefit some patients . further , hypoalbuminaemia associated with rf is a cause of hyperviscosity by enhancing a reduction in erythrocyte deformability . there is the contrary belief in some quarters that anemia impacts low blood viscosity in people with rf , especially those at end stage . therefore , there are contrasting possibilities wbv associations with rf , which require a study to enable formulation of an opinion whether high or low blood viscosity is more prevalent in rf . thus , it is unknown whether increased wbv vis -  - vis hyperviscosity is significantly prevalent in conditions where there is laboratory evidence of dyslipidaemia , hyperglycemia and/or renal failure . further , whether such prevalence is significantly higher relative to where laboratory tests are negative would be worthy to establish . one of the interests of the series of  wbv issues  is to determine whether wbv is unduly highly sensitive and less specific . the hypothesis is that hyperviscosity would be highly prevalent in the sub - populations with higher levels of fasting blood sugar ( fbs ) , hypercholesterolaemia ( total cholesterol / high density lipoprotein ratio i.e. tc / hdl ratio ) and serum creatinine ( s. cr ) compared to apparently normal sub - populations . this hypothesis is founded on the premise that diabetes , dyslipidaemia and renal failure are pathologies strongly complicating cardiovascular disease , which involve changes in blood viscosity levels as a subclinical vasculopathy . diabetes , dyslipidaemia and renal failure are indicated fbs , tc / hdl ratio and s. cr respectively . the objective of this work is to investigate the prevalence of hyperviscosity in diabetes , dyslipidaemia and renal failure including ( i ) whether hyperviscosity is significantly more prevalent in sub - populations of fbs , tc / hdl ratio and s. cr positive results compared to the prevalence in negative results ; and ( ii ) whether fbs , tc / hdl ratio and s. cr levels are higher more associated with hyperviscosity group compared to hypo - to - normoviscosity group . this study is premised on the hypothesis that hyperviscosity should be more prevalent than hypoviscosity in chronic diseases . the findings from this study will lend credence to whether wbv test result showing increased level should be considered a complication worth managing in the chronic diseases . it is supported materially by the albury south west pathology  a unit of western pathology cluster of nsw health australia . the ethics committee of the area health service granted request through the operations manager for the use of de - identified data . ten years de - identified archived clinical pathology data for the period of january 1999 to december 2008 constitutes the database . 50,162-cases tested for fbs , lipid profile and s. cr from alternate years including 2000 , 2002 , 2004 , 2006 and 2008 were extracted . selection was limited to those that were concomitantly tested for all parameters as well as haematocrit and total proteins from the same phlebotomy collection time . wbv at high shear stress was determined from haematocrit and total proteins as previously published . results of wbv were categorized within the continuum into levels of 15.00 , 15.01 - 19.01 and 19.02 as indicative of low , normal and high wbv levels respectively . any tc / hdl value > 5.0 was considered dyslipidaemia / hypercholesterolaemia in this study . fbs results were categorized within the continuum into levels of 5.5 , 5.6 - 7.0 and 7.1 as indicative of normoglycaemia , prediabetic and diabetic levels respectively . the reference range for prediabetes in this study was based on the recommendation contained in the guideline of the diabetes australia . s. cr level of 120mol / l was taken as baseline for both genders in this study . a level 120mol / l was considered to indicate renal disease . first , all data were sorted in descending order by fbs , s. cr and tc / hdl ratio . following the protocol previously employed in this study series , the topmost ( n = 120 ) with all positive biochemistry ( co - pathologies + ) , and bottom ( n = 120 ) with all negative biochemistry ( co - pathologies - ) sub - populations were selected . it was considered to avoid errors due to unequal sample size such as exaggerating the effects of inequality of variance . the discretional criterion for selection of ( n = 120 ) representing each sub - population was to make the comparison be between the laboratory evidence - based co - morbidity vs. apparently normal biochemistry . comparison of actual wbv levels between sub - populations was performed by student 's t - test . univariate data sets of fbs , s. cr and tc / hdl ratio were sorted and separately sub - grouped into normo- and hyper- subpopulations . the prevalence of wbv categories in the subpopulations were evaluated by two - sample kolmogorov - smirnov test . in a reverse comparison , the levels of fbs , s cr and tc / hdl ratio associated with the wbv groups were determined . also following the same precaution against unequal sample size between groups as well as the protocol of comparing between highest - median - lowest wbv categories , ( n = 935 ) in the low wbv group was used as baseline to select the topmost and median data size from the high and normal wbv groups respectively . therefore , manova was performed on a data subset ( n = 2,805 ) comprising 935 in each group , using s - plus version 6.1 . table 1 shows the summary demographics of data ( table 1 ) . from the first analyses involving comparison of wbv levels in fbs , tc / hdl and s. cr sub - populations , it is observed that the mean wbv level associated with the ( all abnormal biochemistry ) subpopulation is statistically significantly higher compared with the ( all normal biochemistry ) subpopulation ( fig . 1 , p < 0.02 ) . summary of group statistics comparison of blood viscosity levels between negative and positive pathology . co - pathologies : combination of fasting blood sugar , serum creatinine and tc / hdl ratio ; wbv : whole blood viscosity ; ( - ) : normal biochemistry results ; ( + ) : positive biochemistry results . tables 24 show the cumulative prevalence of the different wbv categories associated with the subpopulations of hyper- and normo- creatinaemia , glycaemia and lipidaemia . univariate analyses show that normal wbv is statistically significantly more prevalent in all sub - populations of hyper- and normo- creatinaemia , glycaemia and lipidaemia in comparison with high and/or low wbv ( tables 24 ) . prevalence of wbv categories subpopulations of hyper- and normocreatinaemia prevalence of wbv categories subpopulations of hyper- and normolipidaemia prevalence of wbv categories subpopulations of hyper- and normoglycaemia though hyperviscosity and hypoviscosity are of very low prevalence , the following observations are noted . low viscosity is significantly higher in hypercreatinaemia , while normal wbv is significantly higher in normocreatinaemia ( fig . 2a)the prevalence of high wbv is more in hyperlipidaemia compared to normolipidaemia sub - population ( fig . this observation is consistent in all the years evaluated ( table 4 ) 
  the prevalence of high wbv is not different between hypercreatinaemia vs. normocreatinaemia . low viscosity is significantly higher in hypercreatinaemia , while normal wbv is significantly higher in normocreatinaemia ( fig . 2a ) the prevalence of high wbv is more in hyperlipidaemia compared to normolipidaemia sub - population ( fig . this observation is consistent in all the years evaluated ( table 4 ) comparative prevalence of wbv categories in different biochemistry subpopulations . dm : diabetic , fbs : fasting blood sugar , pre - dm : prediabetic ; s. cr : serum creatinine ; wbv : whole blood viscosity . in comparison of absolute fbs , tc / hdl and s. cr levels between the wbv groups , that is , hyperviscosity is associated with the worst hyperglycaemia ( p < 0.01 ) and hyperlipidaemia ( p = 0 ) . although lowest leve of s. cr is associated with the normoviscosity group , no directional association between wbv and s. cr levels were observed ( fig . comparison of creatinaemia , glycaemia and lipidaemia between wbv groups . * averaged standard deviation for tc / hdl : 1.5 , fbs : fasting blood sugar ( averaged standard deviation : 1.8 ) , hdl : high density lipoprotein , s. cr : serum creatinine ( averaged standard deviation : 4.7 , tc : total cholesterol , wbv : whole blood viscosity . this issue of the series has sought to compare as well as establish the prevalence of hyperviscosity and hypoviscosity in chronic diseases using laboratory - based evidence . the results show a low prevalence of hyperviscosity among people who have laboratory evidence of possible chronic diseases , as indicated by fbs , s. cr and/or tc / hdl ratio . however , the relatively low prevalence of hyperviscosity is statistically significantly greater when compared to the subpopulation that tested normal for any of the routine biochemistry markers . the cumulative prevalence of the different categories of wbv observed among subpopulations of hyper- and normal s. cr ( table 2 ) , as well as those of tc / hdl ratio ( table 3 ) and fbs ( table 4 ) affirm previous observations in this series that normal wbv level is consistently the most prevalent in general population . there is , however , a role for the measurement of other indices of subclinical vasculopathies vis -  - vis virchow 's triad that are implicated in chronic diseases . blood viscosity is one option as an index of stasis , which has the capacity to lead to cardiovascular complications . the issue here is that wbv is not being assessed routinely in patients who have chronic diseases such as diabetes , dyslipidaemia or kidney disease . although , data from this study indicate average hyperglycaemia across all wbv groups , the results indicate that the opposite hyperviscosity vs. hypoviscosity are associated with the equally opposite highest vs. lowest fasting blood glucose and tc / hdl ratio measures respectively ( fig . though , the report does not support the hypothesis in part with regards to kidney disease , the observations support the hypothesis in part that high wbv is relatively more prevalent , and hence sensitive to the potential subclinical vasculopathy , in hyperglycaemia and dyslipidaemia . at this juncture , first , many of the patients who have been assessed for these laboratory indices were apparently unhealthy and probably treated with drugs that include antiplatelet agents . the implication is that such medical therapies would have impacted reduction in wbv level , which in turn would have influenced observation of more prevalence of low wbv than high wbv . 54% haematocrit and 60  78g / l total proteins . when the practice of every clinical pathology laboratory should develop its own reference values applicable to their particular population is employed , it would be expected prevalence will differ in favor of greater prevalence of high wbv . for instance , those laboratories employing 46% haematocrit as upper limit will observe much more than the 4% reported prevalence of hyperviscosity , while those laboratories considering haematocrit level of 32% as normal will observe a much lower prevalence of hypoviscosity . the import point of emphasis is that the prevalence of hyperviscosity in chronic diseases is significant enough to assess as part of evidence - based intervention against cardiovascular complications . surely , if < 3% prevalence of prediabetes in overweight is worthy of note , it is thinkable that a possible > 4% prevalence of vasculopathy associated with abnormal clinical biochemistry should require attention . it has been recognized that while a reduction in the incidence of venous stasis syndrome can impact on sudden death , effective and safe use of prophylaxis antiplatelet when risk is unavoidable , as well as targeting only those persons who will benefit most from the therapeutic dose is an important factor . the previous issue in this series identified that low viscosity syndrome is synonymous with high international normalized ratio ( inr ) , which is a contraindication for anticoagulant and/or antiplatelet therapy . this issue identifies that low viscosity is < 2.5% prevalent in people evaluated for dyslipidaemia and hyperglycaemia . while the vast majority who has normoviscosity would benefit from prophylactic dosage , those with hyperviscosity really have stasis requiring antiplatelet therapeutic dose . however , aspirin as a non steroidal anti - inflammatory drug is often withdrawn from renal disease patients , because it is believed to impact negatively on renal functions and exacerbate cardiovascular complications . this study failed to observe consistent or unidirectional increase in wbv level associated with increasing serum creatinine . however , it highlights the need to assess wbv with a view to consider discrete and/or substitute antiplatelet therapy among individuals with kidney disease . it has been demonstrated in earlier issue of this series that hypoviscosity is synonymous to high international normalized ratio where anticoagulant / antiplatelet is likely to be associated with bleeding side - effect . this report indicates that up to 97.5% of cases investigated for chronic diseases do not have hypoviscosity , and therefore could benefit from either prophylaxis or therapeutic medication depending on whether wbv is normal or high respectively . the issue addressed here is that laboratory monitoring of stasis using wbv measures could provide evidence base for antiplatelet in patients who are being investigated for hypercreatinaemia , hyperglycaemia or hyperlipidaemia
background : diabetes and kidney failure are chronic diseases that are associated with cardiovascular complications , while dyslipidaemia is a strong risk factor . 
 hyperviscosity is believed to be associated and managed with antiplatelet , but not routinely assessed.aims:this work investigates the prevalence of hyperviscosity in diabetes , dyslipidaemia and renal failure with a view to determine the proportion of patients who may not require antiplatelet therapy.materials and methods : archived clinical pathology data for the period of 1999 to 2008 were utilized . 
 50,162-cases concomitantly tested for blood sugar , creatinine and lipid profile , as well as haematocrit and total proteins in five alternate years were extracted . 
 the prevalence of different viscosity ranges associated with positive results was evaluated.results:hyperviscosity is about 4% prevalent in hyperglycemia and hyperlipidaemia , less in hypercreatinaemia . 
 hypoviscosity has statistically significantly the least < 2.5% prevalent , while normoviscosity is most prevalent . 
 reverse analyses affirm that higher levels of hyperglycemia and hyperlipidaemia are statistically significant more associated with fourth compared to first quartile viscosity ( p < 0.01).conclusion : previous report demonstrated that hypoviscosity is synonymous to high international normalized ratio where anticoagulant / antiplatelet is not recommended . 
 this study demonstrates that up to 97.5% of cases investigated for chronic diseases could benefit from antiplatelet medication . 
 this report corroborates with previous reports that hyperviscosity may not be very frequent . 
 however , the level of stasis associated with laboratory evidence - based chronic disease affirms that the subclinical vasculopathy should be managed , and laboratory monitoring will provide clinical evidence base .