BackgroundPulmonary diseases are often complicated and have diverse etiologies. One common factor is the lack of therapeutics available for these diseases. The goal of this study was to investigate the impact of Renin-Angiotensin System (RAS)-modifying medications on incidence and time to pulmonary complications.MethodsA retrospective analysis was conducted using claims data from a US commercial insurance company (2007–2013). The study consisted of patients with an emerging hypertension (HTN) diagnosis. Cox analysis was used to look at the effect of angiotensin converting enzyme inhibitors (ACE-Is) and angiotensin receptor blockers (ARBs) in this population. The events included pneumonia and influenza (infectious), Chronic obstructive pulmonary disease (COPD) and allied conditions (inflammatory), and other diseases (structural).ResultsA total of 215,225 patients were followed in the study. These fell into three groups depending on the first prescribed anti-hypertension medication; ACE-Is (47.21%), ARBs (11.40%) and calcium channel blockers (CCBs)/Diuretics-Control (41.39%). The use of ACE-I as first treatment significantly reduced the incidence of infectious (Hazard Ratio (HR) 0.886, 95% Confidence Interval (95% CI) 0.859–0.886), inflammatory (HR 0.924, 95% CI 0.906–0.942) and structural outcomes (HR 0.865, 95% CI 0.847–0.885); it also increased the time (delayed) to diagnosis with prolonged treatment. Primary ARB use only significantly lowered the incidence of structural outcomes (HR 0.900, 95% CI 0.868–0.933); prolonged treatment did reduce incidence of all three diagnosis groups and significantly delayed disease onset.ConclusionsThere is an association between the use of ACE-Is and ARBs and a delay in the progression of pulmonary complications in vulnerable populations. Research into the RAS may identify future therapies for patients with potential chronic pulmonary conditions.