Background The diagnosis and treatment of patients hospitalised with community-acquired pneumonia (CAP) is predicated on an acutely abnormal chest radiograph.¹ Little is known about patients who present with infective respiratory symptoms with no consolidation, who have clinically significant non-pneumonic lower respiratory tract infection (LRTI).

Methods A prospective observational cohort study of consecutive patients admitted to hospital with infective respiratory symptoms and treated for suspected CAP over winter 2013/14. Management was at the discretion of the admitting team.

Results Of 628 patients admitted to hospital during the study, 304 (48.4%) did not have acute consolidation on chest radiograph; 166 were reported as clear, and 138 as either longstanding abnormality or not acute infection. Patients with LRTI had lower admission C-reactive protein levels (median 49 mg/l vs. 85 mg/l; p < 0.01), were older (median 80.0 years vs. 76.3 years; p = 0.005), and were more likely to be managed on a non-respiratory ward (174/304 (57.2%) vs. 127/324 (39.1%); p < 0.001). A higher proportion of patients with LRTI were care home residents, although this did not reach statistical significance (56/304 (18.4%) vs. 45/324 (13.9%); p = 0.12). A microbiological diagnosis was made in only 9/304 (3.0%) patients with LRTI compared with 45/324 (13.9%) with CAP (p < 0.0001). CAP patients had a discharge clinical code of CAP (J12–18) in 247/324 (76.2%) cases; 121/304 (39.8%) patients with LRTI were miscoded as CAP. Thirty-day mortality was similar in both groups (48/324 (14.8%) vs. 43/304 (14.1%) p = 0.82), but median length of hospital stay was longer for patients with CAP (7.0 days vs. 5.6 days; p = 0.002).

Conclusion Almost half patients treated for CAP were misdiagnosed and over-treated with broad spectrum antibiotics. Patients with non-pneumonic LRTI were older, with lower C-reactive protein levels, but similar 30-day mortality. Acute respiratory illness in this group may therefore be driven by decompensated comorbidity rather than an underlying inflammatory condition; broad spectrum antibiotics may not be useful. No national guidance currently exists on the optimal management of this group, and further study is required.

Reference

1. Lim WS et al. BTS guidelines for the management of community acquired pneumonia in adults: update 2009. Thorax 2009,64 Suppl 3,iii1-ii55