Plasma connective tissue growth factor levels were elevated in patients with stable asthma, according to recent study results.

Researchers in Japan used the subtraction method to measure plasma connective tissue growth factor (CTGF) of 67 patients with stable asthma (mean age, 64.9 years; 37 women; median disease duration, 15 years) and 81 healthy volunteers (mean age, 48.7 years; 44 women). The correlations between plasma CTGF levels and clinical and physiologic parameters in patients with asthma were investigated.

Patients with asthma who had a percentage of predicted FEV1 less than 80% showed significantly greater levels of plasma CTGF than those with a percentage of predicted FEV1 of 80% or greater.

There was a significantly negative correlation between the plasma CTGF levels in patients with asthma and “forced vital capacity (FVC), FEV1, percentage of predicted FEV1, FEV1/FVC ratio, forced expiratory flow at 50% of the FVC (FEF 50%), percentage of predicted FEF 50%, forced expiratory flow at 75% of FVC (FEF 75%) and percentage of predicted FEF 75% parameters that reflect the degree of airway obstruction.”

Scores from the Asthma Control Test, a five-item questionnaire used to assess clinical control of asthma, had a negative correlation with plasma CTGF scores.

“Plasma N-terminal CTGF levels … were correlated with parameters of pulmonary function tests and asthma control,” the researchers concluded. “Plasma N-terminal CTGF levels detected using the novel subtraction method may be a useful surrogate marker for evaluation of persistent airway obstruction and disease control in asthma.”