Evaluación de la función pulmonar en diabetes mellitus tipo 1 en la edad pediátrica

Resum

BACKGROUND. Chronic hyperglycemia of diabetes mellitus type 1 (DM1) involves multiple systems associated with continuing damage, dysfunction and failure of various organs. Complications of DM1 are mainly a consequence of microvascular damage. The diabetic retinopathy, nephropathy and neuropathy complications are well known. Certain studies had suggested that the lung is functionally involved in patient with DM1 in the course of the disease, but with contradictory results. The mechanism by which impaired glycemic control may lead a reduction in lung function is uncertain. The present study was designed to determine the lung function in children and adolescent with DM1 and to establish if there is any relationship with diabetic factors and complications. PATIENTS AND METHODS. A cross-sectional study design was undertaken in 100 diabetic patients and 77 match controls. Age of study population ranged 8 to 18 years (mean 12.8±2.6, 55.9% females) and none had evidence of lung, allergic, cardiac, neuromuscular, connective tissue or obesity disorders. All were nonsmokers. Age, sex, pubertal stage and anthropometric data were analyzed. Pulmonary function was studied by spirometry [forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1) and FEV1/FVC ratio], plethysmography [total lung capacity (TLC), residual volume (RV), RV/TLC ratio, airway resistance (Raw) and intrathoracic volume gas (ITGV)], diffusing capacity for carbon monoxide [total transfer of carbon monoxide (TLCO), alveolar ventilation (VA) and TLCO/VA ratio] and exhaled nitric oxide (NOe). Values were expressed as percentage of predicted value and SD-score corrected by height and pubertal stage, according with Rosenthal et al (1993). In diabetic patients, duration of diabetes, metabolic control [mean HbA1c (%) in the previous year], insulin dose, diabetic complications and biochemical data were analyzed. Data were analyzed using the Statistical Package for Social Sciences (SPSS) version 15.0. Statistical study included: bivariant analysis by χ 2 test (categoric variables) and t-student test (quantitative variables), ANOVA and correlation to assess difference. Significance level was p<0.05. The Ethical Committee of Clinic Investigation of Ramón y Cajal Hospital approved the study. All parents/tutors/patients completed and signed a consent form. CONCLUSIONS. This study suggests that the lung is functionally involved in children with DM1 early in the course of the disease and the role of the pubertal stage in the evaluation of lung function. On the other hand, this study emphasizes the importance of optimum glycemic control in order to prevent long-term diabetic complication. Performance of pulmonary function test must be followed up in time when reaching adulthood to establish long-term implications of what seem to be subtle initial alterations of pulmonary function in diabetic children.