Radiologic progression with minimal functional decline in cystic fibrosis: Insights from a prospective study

Timely identification and monitoring of lung disease progression are key components of effective management in patients with cystic fibrosis (CF). Pulmonary function tests (PFTs) and high-resolution computed tomography (HRCT) scans are commonly used to assess disease progression in these patients. Determining which modality provides the most sensitive and reliable assessment is crucial for establishing effective disease monitoring guidelines, particularly in India, where national guidelines are lacking.

To assess the progression of lung disease in patients with CF using a combination of HRCT and PFTs.

A total of 32 patients with CF were prospectively enrolled from the outpatient clinic and followed longitudinally. Clinical and physiological parameters, including age, spirometric indices, and HRCT based Bhalla scores, were evaluated at baseline and after one-year follow-up. Paired comparisons between baseline and follow-up HRCT scores, as well as baseline and follow-up PFT parameters, were performed using a two-tailed paired t-test to assess statistically significant changes over the follow-up period. Pearson correlation coefficient (r) was used to evaluate the relationship between HRCT scores and spirometric parameters at each individual time point (baseline and follow-up). A P value < 0.05 was considered statistically significant.

Of the 32 patients, 18 were female and 14 were male, with a mean age of 86.33 months (range: 48-192 months). The mean Bhalla score demonstrated a statistically significant increase from 5.50 at baseline to 8.25 at one-year follow-up (P < 0.001), representing an average percentage increase of 50%. In contrast, spirometric parameters, including forced expiratory volume in one second (FEV1), forced vital capacity (FVC), and FEV1/FVC showed a non-significant decline of 2.9%-5.2% over the study period (P > 0.05).

Despite significant radiological progression of structural lung damage detected by HRCT, pulmonary function parameters remained relatively stable. These findings suggest that PFTs may be less sensitive in detecting progressive structural deterioration in CF, underscoring the value of HRCT as a sensitive tool for disease monitoring and early detection of worsening lung disease.