Lung function in poorly controlled type 1 North African diabetic patients: A case-control study

Abstract

AimTo compare the lung function parameters of poorly controlled type-1-diabetes-mellitus (T1DM) patients with age-; height and sex-matched healthy-non-smokers (HNS). Population and methodsSubjects aged 35–60Yrs who have a poorly controlled T1DM (glycated-Haemoglobin level >7%) with a disease history of more than 10Yrs (n=14) and HNS subjects (n=14) were recruited. Clinical, anthropometric and fasting biological data were collected. Plethysmographic data (flows, volumes, estimated-lung-age (ELA), lung-capacity-to-transfer-carbon-monoxide (DLCO)) were measured. Large-airway-obstructive-ventilatory-defect (LAOVD) was defined as first–second-forced-expiratory-volume (FEV1)/forced-vital-capacity (FVC) below the lower-limit-of-normal (LLN). Restrictive-ventilatory-defect (RVD) was defined as total-lung-capacity (TLC)<LLN. Lung-hyperinflation was defined as residual-volume (RV)>upper-limit-of-normal. Student t-test and chi-2 test were used to compare plethysmographic data and profiles of the two groups. ResultsThe two groups were matched in chronological-lung-age (CLA) (respectively 47±7 vs. 50±8Yrs) and sex (7 males and 7 females in each group) and height. Compared to the HNS group, the T1DM one had significantly lower FEV1, FVC, slow-vital-capacity and maximal-mid-expiratory-flow (respectively 99±11% vs. 83±11%, 99±9% vs. 86±11%, 80±8% vs. 67±15% and 98±23% vs. 72±23%), had significantly higher TLC and RV (respectively, 105±20% vs. 123±24% and 108±22% vs. 131±24%) and had significantly higher percentage of subjects with lung-hyperinflation (7.1% vs. 43.0%). Both groups had similar percentages of LAOVD and RVD and similar corrected DLCO values. ELA of the T1DM group (57±10Yrs) was significantly higher than CLA. ConclusionPoorly controlled T1DM seems to alter ventilatory mechanics without effect on the alveolo-capillary-membrane. In addition, it accelerates the respiratory ageing.