Effect of insulin on airway responsiveness in patients with type 2 diabetes mellitus: A cohort study

BACKGROUND: The correlation between low insulin levels and a decreased sensitivity of the muscarinic receptor has been shown on induced-diabetes animal models. We designed a cohort study with the aim of evaluating the effects of insulin therapy on airway responsiveness (AR) in human patients with type 2 diabetes mellitus. METHODS: We enrolled 92 patients with type 2 diabetes who had switched from oral anti-diabetic therapy to treatment by insulin subcutaneous injection. Patients were administered the methacholine challenge test (MCT) at time 0 (pre-insulin therapy) and at intervals of 15, 30, 90, 180, and 360 days after insulin treatment. The decline of forced expiratory volume in 1 second (FEV(1))% from baseline (Delta FEV(1)) in response to inhaled methacholine (MCH) was determined to assess airway hyper-responsiveness (AHR). RESULTS: A total of 81 patients (18 women and 63 men) completed the study. Their mean age was 58 +/- 7 years and the mean duration of disease was 13.5 +/- 7.7 years. The mean decrease of FEV(1) at pre-insulin assessment was 2.96 +/- 2.6%. Compared with the pre-insulin value, a significant increase of Delta FEV(1) was observed at 15, 30, and 90 days after treatment (6.25%, CI 95% 5.4 to 7.2, p = 0.0005; 7.64%, CI 95% 6.6 to 8.1, p < 0.001; 6.45%, CI 95% 5.5 to 7.3, p = 0.0004, respectively), while after 180 and 360 days AR was similar to pre-insulin values (Delta FEV(1), 3.62%, CI 95% 2.7 to 3.5 and 3.11%, CI 95% 7.9 to 9.3, respectively). CONCLUSIONS: The finding of an increased AR in patients with type 2 diabetes during the first 3 months of insulin therapy may underline the importance of monitoring pulmonary function and respiratory symptoms in patients switching from oral anti-diabetic drugs to insulin therapy, especially in the subset of individuals with respiratory disorders

Comorbidity, Hospitalization, and Mortality in COPD: Results from a Longitudinal Study

We evaluated comorbidity, hospitalization, and mortality in chronic obstructive pulmonary disease (COPD), with special attention to risk factors for frequent hospitalizations (more than three during the follow-up period), and prognostic factors for death. Two hundred eighty-eight consecutive COPD patients admitted to respiratory medicine wards in four hospitals for acute exacerbation were enrolled from 1999 to 2000 in a prospective longitudinal study, and followed up until December 2007. The Charlson index without age was used to quantify comorbidity. Clinical and biochemical parameters and pulmonary function data were evaluated as potential predictive factors of mortality and hospitalization. FEV(1), RV, PaO(2), and PaCO(2) were used to develop an index of respiratory functional impairment (REFI index). Hypertension was the most common comorbidity (64.2%), followed by chronic renal failure (26.3%), diabetes mellitus (25.3%), and cardiac diseases (22.1%). Main causes of hospitalization were exacerbation of COPD (41.2%) and cardiovascular disease (34.4%). Most of the 56 deaths (19.4%) were due to cardiovascular disease (67.8%). Mortality risk depended on age, current smoking, FEV(1), PaO(2), the REFI index, the presence of cor pulmonale, ischemic heart disease, and lung cancer. Number and length of hospital admissions depended on the degree of dyspnea and REFI index. The correct management of respiratory disease and the implementation of aggressive strategies to prevent or treat comorbidities are necessary for better care of COPD patients