[Correlation between capillary fasting glucose and HbA1c: study on 181 type 2 diabetics patients in Democratic Republic of the Congo].

OBJECTIVES: Due to lack of equipment, diabetic patients in Congolese hospitals are monitored only by capillary (CFG) or plasmatic fasting glucose. The purpose of this study was to estimate the correlation between the HbA1c and CFG in type 2 diabetic patients.
METHODS: From July 1st to October 30th, 2007, four CFG tests (one every two weeks) and one HbA1c test (immunoassay method) were performed in 181 type 2 diabetics managed at the University Hospital of Kinshasa. Correlation between the HbAlc test and each CFG test was determined by Pearson coefficient (r). Variation of HbA1c according to the average CFG was determined by simple linear regression.
RESULTS: Duration of diabetes varied between 1 and 32 years (median: 4 years). Patients had an average age of 56.4 +/- 11.2 years of age; a mean CFG of 9.38 +/- 3.62 mmol/L and HbA1c of 9.4 +/- 2.7%. HbA1c correlated better with average CFG (r = 0.753, p < 0.001) than with CFG performed 4 weeks earlier (r = 0.714, p < 0.001), 6 weeks earlier (r= 0.649, p < 0.001), 2 weeks earlier (r = 0.646, p < 0.001) and concomitantly (r = 0.636, p < 0.001). Extrapolation based on the linear regression equation showed that a delta of 1.925 mmol/L in average CFG = D 1% HbA1c.
CONCLUSION: In the type 2 diabetic patients in this study, average CFG of 4 tests carried out at 2-week intervals was well correlated to the HbAlc. Average CFG seems a good alternative for monitoring type 2 diabetes in environments not equipped for HbAlc testing.