A comparison between time to clinical stability in community-acquired aspiration pneumonia and community-acquired pneumonia

Antimicrobial therapy has been the main stay of therapy of community-acquired aspiration pneumonia (CAAP), but the duration of treatment has not been established. The objective of this study was to describe the time to reach clinical stability in patients with aspiration pneumonia compared to community-acquired pneumonia (CAP). A retrospective case control study at two university affiliated centers encompassing 329 consecutive patients admitted with CAAP and 329 consecutive patients with CAP was conducted between 2007 and 2011. While the median time to stability for patients with CAP was distributed around a median of 4 days, there was a bimodal distribution for time to clinical stability in patients with CAAP with dual peaks at days 2 and 5, respectively. CAAP patients who required more than 2 days to achieve clinical stability had a higher mortality rate compared to those with 2 days or less [odds ratio (OR) 5.95, 95% CI 2.85-12.4], and a longer hospital stay (6.6 ± 5.8 vs. 3.9 ± 1.2 days; p < 0.001). None of the CAAP patients who achieved clinical stability in 2 days or less was transferred to a higher level of care. In a multivariate analysis, time to clinical stability was found to be an independent predictor of outcome in patients with CAAP (OR 2.59, 95% CI 2.02-3.32). Normalization of vital signs in aspiration pneumonia follows a distinct pattern from that of patients with CAP. Time to achieve clinical stability may assist in identifying CAAP patients who are likely to require a shorter hospital stay and a shorter course of antimicrobial therapy.