bariatric surgery has become an effective treatment for obesity , also reducing the onset of type 2 diabetes mellitus ( t2 dm )   as well as inducing remission   and reducing cardiovascular mortality and mortality in general [ 3 , 4 ] . obesity is a chronic condition characterized by elevated inflammatory markers [ 57 ] and is associated with nonalcoholic fatty liver disease ( nafld ) [ 8 , 9 ] . serum gamma - glutamyltransferase ( ggt ) and alanine aminotransferase ( alt ) are markers of nafld and of liver fat content [ 10 , 11 ] . increased platelet counts have been observed in conditions with chronic inflammation as well as in obesity , probably due to secondary thrombocytosis [ 1214 ] . in more advanced stages of nafld , with portal hypertension and splenomegaly , there is a linear association between decreased platelet counts and increased fibrosis in the histopathology of liver biopsies , which may indicate that platelet counts might be an important biomarker of the degree of fibrosis in nafld patients . platelet count is a simple , easy to perform , cost - effective , and accurate surrogate marker for predicting fibrosis severity in nafld patients . bariatric surgery improves steatosis and fibrosis in patients with morbid obesity nafld , and adjustable gastric banding in a previous study has been related to a nonsignificant trend of lowered platelet counts . regarding rygbp , one study reports a significant reduction in platelet counts 1 year after surgery . data after longer periods of followup , after rygbp as well as bpd - ds surgeries , are lacking . the aim of this study was to assess changes , if any , in morbidly obese patients treated with bpd - ds and rygbp , from baseline , that is , before surgery , to followups 1 year and 3 years after surgery , with regard to platelet counts and serum concentrations of ggt and alt . ten morbidly obese patients who had undergone bpd - ds surgery ( five men and five women ) , all caucasians , free from established diabetes , were recruited from the outpatient clinic of obesity care , uppsala university hospital , uppsala , sweden . data from the bpd - ds group were compared to that of a morbidly obese group ( n = 21 ; three men and eighteen women ) , all free from established diabetes and had undergone rygbp . patients were investigated preoperatively ( baseline ) and then 1 year ( 1st followup ) and 3 years ( 2nd followup ) after bpd - ds and rygbp , respectively . roux - en - y gastric bypass is a procedure that combines restriction and malabsorption . it is considered by many to be the gold standard because of its high level of effectiveness and its durability . more extreme malabsorption accompanies biliopancreatic diversion procedures , commonly performed with a duodenal switch in which a short , distal and common channel length of small intestine severely limits caloric absorption , which induces a greater weight loss than rygbp does . a very high bmi indicated that bpd - ds procedure was performed instead of rygbp at our clinic [ 19 , 20 ] . all participants underwent physical examination and blood tests for platelet count , ggt , and alt preoperatively ( baseline ) and at the 1st and 2nd followups . blood samples were collected from each patient ( following an overnight fast ) and were analyzed using routine tests at the department of clinical chemistry at uppsala university hospital [ 19 , 20 ] . weight ( kg ) and height ( m ) were measured on standardized calibrated scales , and bmi ( kg / m ) was calculated . tests were two tailed , and a p  value < 0.05 was considered significant . patient clinical characteristics at baseline , that is , before rygbp and bpd - ds surgeries , are shown in table 1 . there were no statistically significant intergroup differences in platelet counts or plasma concentrations of ggt and alt . mean weight and bmi were , as expected , higher in the bpd - ds group , selecting the patients for this procedure , and age was lower . bmi decreased by 43% in the bpd - ds group from 53.5  kg / m at baseline to 30.7  kg / m at 1st followup ( p < 0.001 ) and was unchanged between the 1st and 2nd followups ( 30.2  kg / m ,  p < 0.001 ) , as shown in figure 1(a ) . in the rygbp group , bmi was reduced by 30% from 42.3  kg / m at baseline to 29.7  kg / m at the 1st followup ( p < 0.001 ) but was 32.1  kg / m at the 2nd followup ( p < 0.001 ) , implying a 6% gain ( gain over the baseline bmi ) between the 1st and 2nd followups ( p < 0.001 ) . platelet counts were reduced by 22% in the bpd - ds group from 308  10/l at baseline to 240  10/l at the 1st followup ( p < 0.001 ) and were unchanged at the 2nd followup ( 244  10/l ,  p < 0.001 ) , as shown in figure 1(b ) . in the rygbp group , platelet counts were reduced by 10% from 297  10/l at baseline to 266  10/l at the 1st followup ( p = 0.012 ) but were 292  10/l at the 2nd followup ( p = 0.687 ) , implying a 9% increase between the 1st and 2nd followups ( p = 0.024 ) . katal / l at the 1st followup ( p = 0.01 ) and was 0.32 katal / l at the 2nd followup ( p < 0.001 ) , but this further decrease was not significant ( p = 0.867 ) , as shown in figure 1(c ) . in the rygbp group , ggt katal / l at the 1st followup ( p < 0.001 ) , with no further alteration at the 2nd followup ( 0.31 katal / l , p < 0.001 ) . katal / l at the 1st followup ( p = 0.004 ) and was unchanged at the 2nd followup ( 0.41  katal / l , p = 0.004 ) . in the rygbp group , katal / l at the 2nd followup ( p < 0.001 ) , implying a further decrease by 16% between the 1st and 2nd followups ( p = 0.02 ) . the main findings in this study were that liver enzymes , ggt and alt , markedly decreased over time after both rygbp and bpd - ds surgeries , but platelet counts only decreased significantly after bpd - ds . the alteration in platelet counts showed a somewhat different pattern after rygbp , with a reduction at the 1st followup but no significant change at the 2nd followup . it might be speculated that the sustained reduction in platelet counts may indicate a long - term improvement in the inflammation of the liver and a more pronounced decrease of liver - fat - content - related inflammation in obese patients treated by bpd - ds compared to rygbp . platelets vary daily and are depending on a variety of issues such as ethnicity , age , and gender . buckley et al . have showed in their analysis of serial platelet counts from 3,789 subjects that the repeatability of the platelet count is very high . obesity is an inflammatory condition [ 23 , 24 ] and a major risk factor for the development of nafld and liver disease . in obese patients , ultrasonographic examinations as well as liver biopsies have revealed that nafld is very common . as it is difficult to perform biopsies in all nafld patients , it has been reported that a lowered ggt may best predict improvements in inflammation and fibrosis in the hepatocytes in nafld , which are two major prognostic features in this condition , whereas changes in aminotransferase concentrations did not predict change in steatosis . furthermore , increased numbers of platelets are observed in conditions with low - grade inflammation , such as obesity , although the platelet counts are within normal ranges . overweight , obese , and morbidly obese females have significantly elevated platelet counts compared with normal - weight females and male subgroups . the gender difference in platelets might be due to the higher body fat mass in females . higher platelet counts are associated with more adverse clinical outcomes in patients with myocardial infarction and stroke . obesity is also associated with platelet dysfunction , increased adhesiveness , and activation [ 2628 ] . in more severe states of nafld with fibrosis , a consumption of thrombocytes are observed . in a recent study , yoneda et al . used liver biopsies to evaluate the clinical usefulness of measuring platelet counts for predicting the severity of liver fibrosis in 1,048 patients with nafld . our data show a sustained reduction in platelet counts over time after bpd - ds , probably induced by a more pronounced weight loss than after rygbp and possibly a more pronounced decrease of liver inflammation . one year after rygbp , a significant reduction in platelet counts was observed , which is in accordance with 1 year data from dallal et al . , but the reduction was not sustained at the 2nd followup , 3 years after surgery . there are several limitations in the present study such as the small number of patients and the lack of a morbidly obese control group followedup over 3 years . however , such patients can be logistically difficult to follow for long term followups . the bpd - ds group was significantly younger than the rygbp group , but no differences were observed between the two groups at baseline in platelet counts , ggt or alt . body fat content and liver fat content , measured by imaging techniques such as dual energy x - ray absorptiometry or ultrasonography , would have been warranted to investigate if and how different fat distribution might influence the variables analyzed in this study .   in conclusion , morbidly obese patients treated with rygbp and bpd - ds show a marked and sustained decrease in ggt and alt . a significant reduction in platelets , a marker for inflammation and fibrosis in nafld , was observed in both groups after 1 year but only in bpd - ds over time , which may indicate improvements in general inflammatory status and particularly steatohepatitis .
background . obesity is characterized by liver steatosis , chronic inflammation , and increased liver enzymes , that is , gamma - glutamyltransferase ( ggt ) and alanine aminotransferase ( alt ) , markers for nonalcoholic fatty liver disease ( nafld ) and liver fat content . increased platelet counts ( pcs ) 
 are associated with inflammatory conditions and are a valuable biomarker of the degree of fibrosis in nafld . 
 we investigated alterations in pc , ggt , and alt after biliopancreatic diversion with duodenal switch ( bpd - ds ) and roux - en - y gastric bypass ( rygbp ) . 
 methods . ten morbidly obese patients ( body mass index , bmi : 53.5  3.8  kg / m2 ) who underwent bpd - ds were evaluated preoperatively ( baseline ) and 1 year ( 1st followup ) and 3 years ( 2nd followup ) after surgery and compared with 21 morbidly obese patients ( bmi : 42.3  5.2  kg / m2 ) who underwent rygbp . results . over the 3 years of followup , changes in bpd - ds and rygbp patients ( bpd - ds / rygbp ) were as follows : 
 bmi ( 44%/24% ) , ggt ( 63%/52% ) , and alt ( 48%/62% ) . 
 pc decreased ( 21% ) statistically significantly only in bpd - ds patients . 
 conclusions . 
 morbidly obese patients treated by rygbp or bpd - ds show sustained reductions in bmi , alt , and ggt . 
 the decrease in pc and liver enzymes after bpd - ds may reflect a more pronounced decrease of liver - fat - content - related inflammation and , as a result , a lowered secondary thrombocytosis .