Prevalence of Post-Glucose Challenge Hypoglycemia in Adult Patients With Cystic Fibrosis and Relevance to the Risk of Cystic Fibrosis-Related Diabetes.

OBJECTIVES: The clinical relevance of fasting and postprandial hypoglycemia in patients with cystic fibrosis (CF) is poorly characterized. Our aim in this study was to characterize the prevalence of hypoglycemia in adult patients during oral glucose tolerance test (OGTT) screening and determine its impact on the risk of developing CF-related diabetes (CFRD). METHODS: We analyzed 2 cohorts of pancreatic insufficient patients with CF exposed to comparable treatment recommendations in France (Lyon CF cohort [DIAMUCO]) and Canada (Montréal CF cohort [MCFC]). Patients were classified into 3 groups based on hypoglycemia absence or presence as well as its severity at baseline. We defined the groups as follows: level 2 hypoglycemia (L2H; plasma glucose [PG]<3.0 mmol/L), level 1 hypoglycemia (L1H; PG 3.0 to <4.0 mmol/L) and no hypoglycemia (NH) during an OGTT. RESULTS: A total of 153 MCFC and 114 DIAMUCO subjects were included in the study. In total, 22% of the patients experienced hypoglycemia, with 5% having it on 2 or more OGTTs. The L1H and L2H groups tended to have a lower 2-hour glucose and higher early-phase insulin secretion (insulin area under the curve at 0 to 30 minutes) compared with NH patients. In both cohorts, a greater proportion of men and patients with normal glucose tolerance had hypoglycemia. Over a 5-year period, there were no cases of CFRD in the L2H group, whereas 4 subjects in the L1H group and 36 in the NH group developed CFRD. CONCLUSIONS: Patients with hypoglycemia were at lower risk of developing CFRD, but at higher risk of early-phase insulin secretion and unsuppressed insulin secretion. This could potentially lead to further hypoglycemia after the 2-hour OGTT, suggesting high clinical relevance.

Template-operated MUP analysis is not accurate in the diagnosis of myopathic or neuropathic changes in the diaphragm.

OBJECTIVES: The aim of this study was to evaluate the quantitative motor unit potential (MUP) analysis in the diagnosis of myopathy and neuropathy of the diaphragm. METHODS: Diaphragm template-operated quantitative EMG were performed in 30 patients with myotonic dystrophy type 1 (DM1), 17 with myotonic dystrophy type 2 (DM2) and 40 with amyotrophic lateral sclerosis (ALS). RESULTS: Low MUP amplitude precluded MUP analysis in 21% of DM1 patients. Only a single DM1 patient had EMG findings consistent with myopathy. In this patient, and another 4 DM1 and 3 DM2 patients, findings were consistent with neuropathy. Neuropathic MUP changes were found in 92% of ALS patients, but due to motor neuron cell loss in only 60% MUPs analyses could be done. Phrenic nerve conduction studies correlated with respiratory function tests, whereas MUP parameters did not. CONCLUSION: Quantitative MUP analysis was not able to adequately sample diaphragm MUPs in patients with chronic myopathy or motor neuronopathy.

Low Vital Capacity Was Associated with Incident Diabetes in a Japanese Health Screening Population in Whom Obesity Was Not Prevalent.

OBJECTIVES: There have been few studies regarding the relationship between respiratory function and incident diabetes in East Asian populations in whom obesity is not prevalent. METHODS: This is a 6-year follow-up study in a Japanese health-screening population that included 1874 men and 1093 women. Using Cox regression models, hazard ratios (HRs) of incident diabetes for percent vital capacity (%VC) and forced expiratory volume in 1 second divided by forced vital capacity (FEV1/FVC) were calculated. Diabetes was defined as simultaneous fasting plasma glucose (FPG) ≥7.0 mmol/L and glycated hemoglobin (A1C) ≥6.5% or use of antidiabetic medications. RESULTS: During the 6-year follow-up period (mean of 4.8 years), 71 men (3.8%) and 18 women (1.7%) developed diabetes. The HRs (95% confidence intervals [CIs]) of incident diabetes for each 1 SD increase in %VC and the lowest tertile of %VC compared with the highest tertile were 0.81 (0.66 to 1.00) (p=0.045) and 1.78 (1.01 to 3.16) (p=0.048), respectively, adjusted for sex, age, body mass index, antihypertensive drug use and A1C levels. After further adjustment for log high-sensitivity C-reactive protein, the HRs (95% CI) of incident diabetes for each 1 SD increase in %VC and the lowest tertile of %VC were 0.82 (0.67 to 1.01) (p=0.063) and 1.69 (0.95 to 3.01) (p=0.073), respectively. The association between FEV1/FVC and incident diabetes was not significant. CONCLUSIONS: %VC, but not FEV1/FVC, was significantly associated with incident diabetes in a Japanese health-screening population in whom obesity was not prevalent.

Early detection of changes in lung mechanics with oscillometry following bariatric surgery in severe obesity.

Obesity is associated with respiratory symptoms that are reported to improve with weight loss, but this is poorly reflected in spirometry, and few studies have measured respiratory mechanics with oscillometry. We investigated whether early changes in lung mechanics following weight loss are detectable with oscillometry. Furthermore, we investigated whether the changes in lung mechanics measured in the supine position following weight loss are associated with changes in sleep quality. Nineteen severely obese female subjects (mean body mass index, 47.2 ± 6.6 kg/m(2)) were evaluated using spirometry, oscillometry, plethysmography, and the Pittsburgh Sleep Quality Index before and 5 weeks after bariatric surgery. These tests were conducted in both the upright and the supine position, and pre- and postbronchodilation with 200 µg of salbutamol. Five weeks after surgery, weight loss of 11.5 ± 2.5 kg was not associated with changes in spirometry and plethysmography, with the exception of functional residual capacity. There were also no changes in upright respiratory system resistance (Rrs) or reactance following weight loss. Importantly, however, in the supine position, weight loss caused a substantial reduction in Rrs. In addition, sleep quality improved significantly and was highly correlated with the reduction in supine Rrs. Prior to weight loss, subjects did not respond to the bronchodilator when assessed in the upright position with either spirometry or oscillometry; however, with modest weight loss, bronchodilator responsiveness returned to the normal range. Improvements in lung mechanics occur very early after weight loss, mostly in the supine position, resulting in improved sleep quality. These improvements are detectable with oscillometry but not with spirometry.

Impact of varying physical activity levels on airway sensitivity and bronchodilation in healthy humans.

The purpose of this study was to determine if the amount of physical activity influences airway sensitivity and bronchodilation in healthy subjects across a range of physical activity levels. Thirty healthy subjects (age, 21.9 ± 2.6 years; 13 men/17 women) with normal pulmonary function reported to the laboratory on 2 separate occasions where they were randomized to breathe either hypertonic saline (HS) (nebulized hypertonic saline (25%) for 20 min) or HS followed by 5 deep inspirations (DIs), which has been reported to bronchodilate the airways. Pulmonary function tests (PFTs) were performed prior to both conditions and following the HS breathing or 5 DIs. Moderate to vigorous physical activity (MVPA) level was measured via accelerometer worn for 7 days. Following the HS breathing, forced expiratory volume in 1 s (FEV1) and forced vital capacity (FVC) significantly decreased from baseline by -11.8% ± 8.4% and -9.3% ± 6.7%, respectively. A 2-segment linear model determined significant relationships between MVPA and percent change in FEV1 (r = 0.50) and FVC (r = 0.55). MVPA above ∼497 and ∼500 min/week for FEV1 and FVC, respectively, resulted in minor additional improvements (p > 0.05) in PFTs following the HS breathing. Following the DIs, FEV1 and FVC decreased (p < 0.05) by -7.3% ± 8.6% and -5.7% ± 5.7%, respectively, from baseline, but were not related (p > 0.05) to MVPA. In conclusion, these data demonstrate that higher MVPA levels attenuated airway sensitivity but not bronchodilation in healthy subjects.