Conference: 2010 International PHA Conference and Scientific Sessions
Release Date: 06.22.2010
Presentation Type: Scientific Sessions
Pugh M, Robbins I, Rice T, Newman J, Hemnes A.
Vanderbilt University Medical Center, Nashville, TN, USA
BACKGROUND. Diabetes mellitus is a well-established risk factor for systemic vascular disease, but the relationship of glucose intolerance and diabetes mellitus with pulmonary vascular disease is not known.
Previous studies have suggested insulin resistance is common in pulmonary arterial hypertension (PAH); and the metabolic syndrome, which includes insulin resistance, is common in pulmonary venous hypertension. Glycosylated hemoglobin (HbA1c) is emerging as a preferred test for the diagnosis of diabetes mellitus (DM). We have found that elevations in HbA1c are common in PAH; however the relationship of elevated HbA1c with PAH severity and functional assessment is unknown. We hypothesized that glucose intolerance evidenced by a HbA1c ≥ 6.0% is common in PAH and is associated with more severe disease.
METHODS. We prospectively measured HbA1c in patients with PAH diagnosed by right heart catheterization who were seen over a six-month period at our Pulmonary Vascular Center. Detailed demographic, functional, and hemodynamic data were collected at enrollment and subsequent visits and recorded in a database. Data are presented as mean ± standard deviation.
RESULTS. 51 patients with PAH were evaluated, 10 patients had known DM. 41 patients without history of diabetes had HbA1c collected (mean age 52 ± 14, female = 31, IPAH = 26). The mean HbA1c was 6.0 ± 0.6%. 23 PAH patients (56%) had unrecognized glucose intolerance (HbA1c ≥ 6.0%) denoting high risk for DM, 6 (15%) had unrecognized DM (HbA1c ≥ 6.5%). Age and body mass index (BMI) were not different in PAH patients with glucose intolerance or DM and those with normal HbA1c (age 55 ± 10 vs 49 ± 18 yrs, p = 0.24; BMI 29.9 ± 9 vs 28.5 ± 7 kg/m2, p = 0.6). Right heart catheterization data, C-reactive protein, and brain natriuretic peptide levels were not different between groups. Glucose intolerance was common in patients with NYHA Class III heart failure (n=13/18). Mean six-minute walk distance (6MWD) for PAH patients with HbA1c > 6.0% was significantly lower (figure).
CONCLUSIONS. Unrecognized glucose intolerance and diabetes mellitus are common in PAH patients and higher HbA1c correlates with worse six-minute walk distance. Further studies are needed to discern if dysregulated glucose or insulin resistance play a role in PAH pathogenesis or are a feature of more severe disease.