Abstract:

Objective To investigate the relationship between the skin micro-circulation changes and disease duration in type 2 diabetic patients.Methods Micro-circulation of lower extremity in 50 type 2 diabetic patients whose disease durations were less than 5 years(n=24) and more than 15 years(n=26),and age-sex-matched control subjects(n=30) were measured with laser doppler flowmeter(LDF) and by the method of post occlusive reactive hyperemia(PORH).The first step was to measure rest flux of the skin of the left foot(PORH_rest),then the lower extremity flow was occluded at higher than 20 mmHg suprasystolic pressure higher than for 2 min.Skin blood flux was measured during and after occlusion using LDF continuously.PORH parameters were rest flux of the skin(PORH_rest),maximum increase in hyperemia perfusion(PORH_max),time-to-peak(T_p),amplitude of peak perfusion(PORH_peak),PORH_max=PORH_peak-PORH_rest and PORH_max/T_p=(PORH_peak-PORH_rest)/T_p.All diabetic patients were given tests for fasting plasma glucose(FPG),serum creatinine,blood routine,glomerular filtration rate(GFR),urinary albumin excretion rate(UAER),left lower extremity blood pressure,calculated body mess index(BMI) and waist-to-hip ratio(WHR).Results 1) The longer diabetic duration,the lower the PORH_peak of skin micro-blood-flow in diabetes and less than controls(controls 21.67±3.15,diabetic duration less than 5 years group 16.61±6.67,diabetic duration more than 15 years group 10.54±3.22,P<0.01).2) PORH_max of skin micro-blood-flow in diabetes at lower extremity skin was significantly reduced in Type 2 diabetic patients compared with the controls(controls 12.87±3.68,diabetic duration less than 5 years group 9.76±5.89,diabetic duration more than 15 years group 5.08±3.14,P<0.01).3) Bivariate correlations analysis showed and that the correlation factors of PORH_peak from big to small were: diabetic duration(r=-0.538,P<0.01),log urinary albumin excretion rate(UAER)(r=-0.447,P<0.01),glomerular filtration rate(GFR)(r=0.368,P<0.05),age(r=-0.365,P<0.05).The correlation factors of PORH_max from big to small were: diabetic duration(r=-0.497,P<0.01),log urinary albumin excretion rate(UAER)(r=-0.480,P<0.01),glomerular filtration rate(GFR)(r=0.318,P<0.05),FPG(r=-0.301,P<0.05).Linear regression analyze showed that the relationship of PORH_peak and diabetic duration was the most intimate(the standardized coefficients of diabetic duration was-0.575,P< 0.01);The relationship of PORH_max and diabetic duration was also the most intimate(the standardized coefficients of diabetic duration was-0.533,P<0.01).4) Regrouping the type 2 diabetic patients(n=50) by HbA1c(HbA1c<10%,n=26;HbA1c ≥10%,n=24),age,sex,logUAER of two groups were not statistically significant(P>0.05),PORH_peak and PORH_max of two groups were also not statistically significant(P>0.05).Conclusion The longer the diabetic duration,the worse skin micro-circulation of lower extremity in type 2 diabetes.

Key words: type 2 diabetes mellitus, duration, micro-circulation, laser doppler flowmeter