Table 4– A comparison of time to decline in FVC in relation to technetium-99m-labelled DTPA clearance in ILD of SSc and IPF patients
DTPA clearance variableTime to decline in FVC
SSc-ILDIPF
HR (95% CI)p-valueHR (95% CI)p-value
Increasing rapid total clearance# min1.02 (1.01–1.03)0.0010.99 (0.97–1.00)0.11
Patients with an abnormal clearance# min2.10 (1.25–3.53)0.0050.59 (0.28–1.26)0.18
Increasing rapid fast clearance min1.15 (1.04–1.28)<0.010.98 (0.92–1.04)0.47
Increasing %FC1.02 (1.00–1.04)0.020.99 (0.97–1.01)0.39
Increasing delayed slow clearance min0.99 (0.98–1.01)0.361.01 (1.00–1.02)<0.01
  • FVC: forced vital capacity; DTPA: diethylene triamine pentacetate; ILD: interstitial lung disease; SSc: systemic sclerosis; IPF: idiopathic pulmonary fibrosis; HR: hazard ratio; %FC: % DTPA cleared by the fast component. #: 168 SSc-ILD patients and 97 IPF patients; : 126 SSc-ILD patients and 81 IPF patients.