BackgroundPatients with primary antibody deficiency (PAD) frequently suffer from pulmonary complications, associated with severe morbidity and mortality. Hence, regular pulmonary screening by computed tomography (CT) scanning is advised. However, predictive risk factors for pulmonary morbidity are lacking. ObjectiveTo identify PAD patients at risk for pulmonary complications necessitating regular CT screening. MethodsA retrospective longitudinal cohort study of PAD patients (median follow-up 7.4 (2.3 – 14.8) years). CTs were scored using the modified Brody-II scoring system. Clinical and laboratory parameters were retrospectively collected. Potential risk factors were identified by univariate analysis when p<0.2 and confirmed by multivariable logistic regression when p<0.05. ResultsThe following independent risk factors for progression of airway disease (AD) were identified: 1) diagnosis of X-linked agammaglobulinemia (XLA), 2) recurrent airway infections (2.5/year), 3) presence of AD at baseline. Signs of AD progression were detected in 5/11 XLA patients and in 17/80 of the other PAD patients. Of the patients who progressed, 17/22 had preexistent AD scores ≥7.0%. Increased AD scores were related to poorer FEV1 values and chronic cough. CVID and increased CD4 effector/memory cells were risk factors for an interstitial lung disease (ILD) score ≥13.0%. ILD ≥13.0% occurred in 12/80 patients. Signs of ILD progression were detected in 8/80 patients and 4/8 patients showing progression had preexistent ILD scores ≥13.0%. ConclusionWe identified risk factors that distinguished PAD patients at risk for airway disease and interstitial lung disease presence and progression which could guide future screening frequency, however independent and preferably prospective validation is needed.