Los criterios de la ADA infravaloran el impacto de la diabetes en la población española de más alto riesgo

Objetivos

Investigar la prevalencia de las alteraciones de la homeostasia glucidica en la poblacion de alto riesgo. Determinar la prevalencia de los factores clasicos de riesgo y comparar su rendimiento para el cribado de diabetes segun los criterios OMS y ADA.

Diseno y ambito

Estudio transversal, multicentrico, de deteccion selectiva de la poblacion asistida en 9 centros de atencion primaria y una unidad hospitalaria de diabetes (230.000 habitantes).

Pacientes

Mayores de 40 anos, no gestantes, con uno o mas factores de riesgo para la diabetes (IMC ≥ 30 kg/m², antecedentes familiares de diabetes, anomalia glucemica previa o ingesta de farmacos hiperglucemiantes).

Mediciones

Se informatizaron edad, sexo y factores de riesgo diabetologico. Se determino la glucemia basal (GB) y a las 2 horas (G2h) de una prueba de tolerancia oral (PTOG). Se calculo el valor predictivo positivo y la odds ratio para cada factor de riesgo. Por medio de curvas ROC (receiver operator characteristics) se identifico el valor de GB que maximiza la sensibilidad y especificidad de la G2h.

Resultados principales

Se evaluaron 580 individuos, 250 varones (43,1%), de edad media 58,1 ± 10,7 anos e IMC 31,2 ± 5,2 kg/m². Resultaron 132 (22,7%) diagnosticos de diabetes segun la OMS y 79 (13,6%) segun la ADA, pero solo en 53 (9,1%) coincidieron ambos criterios. La GB ≥ 126 mg/dl (7,0 mM), predijo una G2h ≥ 200 mg/dl (11,1 mM) con alta especificidad (94,2%) pero con muy baja sensibilidad (40,2%). Aplicando este nuevo punto de corte basal, el 50% de diabeticos (GB normal con G2h diabetica) no se hubiera diagnosticado. Los valores predictivos para los factores clasicos de riesgo segun los criterios OMS oscilaron entre el 23,4–29,1% y superaron siempre los obtenidos con los criterios ADA (11,6–18,3%; p < 0,01).

Conclusiones

La PTOG continua siendo clave en la deteccion de diabetes, puesto que la capacidad predictiva de la G2h supera ampliamente a la GB. Los criterios ADA infravaloran el impacto de la diabetes precisamente en la poblacion de mas alto riesgo.

Objective

The main aim was to investigate the prevalence of abnormal glucose homeostasis (impaired fasting glucose, impaired glucose tolerance and undiagnosed diabetes) on high-risk Spanish population. The second, to determine the prevalence and usefulness of classical risk factors for diabetes screening according WHO and ADA criteria and to evaluate the potential effect of different stepwise strategies.

Design and setting

Cross-sectional, multicentric, selective screening study carried out in primary health care which involved 9 health care centres and 1 diabetes unit (230000 inhabitants).

Patients

Individuals aged > 40 years, non pregnant with at least one major risk factor for diabetes: BMI ≥ 30 kg/m², a first degree relative with diabetes, previous abnormality of glucose tolerance or the use of oral hyperglycaemic drugs for a long time.

Measurements

Database including sex, age and risk factors. Diagnoses were based on measurement of fasting plasma glucose (FPG) followed by a 2h-plasma glucose (2hPG) using a 75 gr. oral glucose tolerance test (OGTT). Positive predictive value (PPV) and odds ratio were calculated for each risk factor. The FPG concentration which maximised the sensitivity and specificity with respect to the 2hPG was established by means of the ROC-curves (receiver operator characteristics).

Main results

580 individuals were evaluated, 250 males (43.1%), mean age 58.1 ± 10.7 years and BMI 31.2 ± 5.2 kg/m². A total of 132 (22.7%) individuals presented diabetes according the WHO criteria, 79 (13.6%) according ADA and only 53 (9.1%) according both sets of criteria. FPG ≥ 126 mg/dl (7 mM) predicted a diabetic 2hPG with high specificity (94.2%) but a very low sensitivity (40.2%). If that cut-point was used alone for early screening half the diabetics with normal FPG but with a diabetic 2hPG would not have been diagnosed. According the WHO criteria PPV for classical risk factors oscillated between 23.4–29.1% and were significantly higher than those obtained according ADA criteria (11.6–18.3%; p < 0.01).

Conclusions

The OGTT is still the cornerstone for diabetes screening thus the FPG predictive value greatly decreases the FPG predictive value. ADA criteria undervalues the diabetes impact mainly on high-risk population.