Quality of glycemic control according to hemoglobin versus fasting glycemia: Analysis in an urban and a rural population of Costa Rican diabetics

Abstract

Introduction:Glycosilated hemoglobin(HbA1c) is at pre-sent the best available test to reflect the metaboliccontrol ofdiabetic patients, however its useis not yet systematic in ournational health system.

Objective:To determinethequality of metabolic con-trolofCosta Rican diabetics by urbanization level, accordingto fasting blood glucose orHbA1c and tocompare their res-pective equivalent values.

Study design and methods:Retrospective study comparingthe twoparameters mentioned above, 237 diabetics contro-lled at 6 Primary Health Carecenters(EBAIS) of an ur-banHealth Area (Desamparados, one county of the San Joséprovince), and257 diabetics controlled in 3 Primary HealthCare Centers (EBAIS) of a rural Health Area, (Nicoya, onecounty of the province of Guanacaste), during the year2000.In the patients of Desamparados the blood glucose clo-sest to the month of July of2000 and its respective HbA1c,taken the same day, was registered.In those diabetics fromNicoya the averageblood glucose and HbA1cof the year2000 was used for the study.

Results:Fasting blood glucose in the urban diabeticswasmore frequently at higher levels: 35% >200 mg/dl, 20.5%between 141-180 mg/dl and only17.9% were within normalranges (60-110 mg/dl), thus exhibiting poor metabolic con-trol.Diabetics from the rural area had similar results,with27% over200mg/dl, 22.9% in the ranges of 141-180 and22.3% within normal ranges.

The HbA1c resultswere not adequate either, at the urban set-ting, 34.6% were overthe critical values of 9.5%, and only21.1% were lower than 6.5%, compared to 40.4% and 14.0%,respectively in the rural area.

When the equivalent ranges of fasting blood glucose werecompared with HbA1c, big differences were found; for nor-mal glycemic ranges (60-110mg/dl), only 58.5% of the urbandata, and 65.3% of the rurals, coincided with its equivalent ofHbA1c (< 6.5%); 30% of the urban patients and 37% ruralpatients had for this same values, HbA1c over 8%. When thevalues of blood glucose were over 200 mg/dl, the relationwith its HbA1c equivalent range (> 9.5%) was high:75.6%in urban area and 82.9 % in the rural area.

Conclusion:glycosilated hemoglobin is the best method toevaluate the quality of metabolic controlin diabetic patients,especially inthose that handle fasting levels <200 mg/dl. InCosta Rica glycosilated hemoglobin determination has notbeen generalized at primary health level and too many pa-tients are not receiving the benefit of an intensive therapy, be-cause they are being evaluated only with fasting blood gluco-se. The implementation of glycosilated hemoglobin is posi-ble for our national health system and it should be compul-sory in all Health Areas of Costa Rica.