High resolution computerized tomography of the chest and pulmonary function testing in evaluating the effect of tobramycin solution for inhalation in cystic fibrosis patients.
Study design (if review, criteria of inclusion for studies)
randomized, double-blind, placebo-controlled pilot study
Participants
32 subjects >/=6 years old with mild to moderate CF lung disease
Interventions
tobramycin solution for inhalation (TSI) for 28 days
Outcome measures
FEV1, FEF 25-75, HRCT scores
Main results
31 subjects completed the study.HRCT scores decreased 4.06 +/- 3.20 (mean +/- SD) for TSI and decreased 0.17 +/- 1.78 for placebo subjects (P = 0.13). Mean forced expiratory flow during middle half of forced vital capacity (FEF(25%-75%)) predicted increased 6.08 +/- 4.86 for TSI and decreased 0.60 +/- 2.34 for placebo (P = 0.23). Percentage forced expiratory volume in 1 s (FEV(1)) predicted increased slightly for both TSI and placebo (1.29 +/- 3.33 for TSI and 1.17 +/- 1.4 for placebo) (P = 0.97). Two of eight HRCT component scores (atelectasis and inhomogeneity) were observed to be highly discordant with observed HRCT global total score and other HRCT component scores. A modified total score was calculated by dropping them from the global total score. The modified HRCT total scores decreased 6.68 +/- 3.09 for TSI subjects and increased 0.02 +/- 2.0 for the placebo subjects (P = 0.07). Sample sizes were calculated to show statistical significance by differences in modified total HRCT scores, global total HRCT scores, FEF(25%-75%) predicted or FEV(1) % predicted. A total of 60, 100, 200, and over 800 patients would be necessary respectively.
Authors' conclusions
HRCT can be a useful measure of change in CF pulmonary disease, requiring a smaller sample size than that required to show treatment effect by pulmonary function testing (PFT) alone.