Early versus later response to treatment in patients with community-acquired pneumonia: analysis of the REACH study

BACKGROUND: Key goals in the treatment of CAP include early response to treatment and achievement of clinical stability. The US FDA recommends early response endpoints (72 hours after initiation of treatment) in clinical trials for the treatment of community-acquired bacterial pneumonia. REACH (REtrospective Study to Assess the Clinical Management of Patients With Moderate-to-Severe Complicated Skin and Soft Tissue Infections [cSSTI] or CAP in the Hospital Setting) was a retrospective observational study, providing current data on the clinical management and resource burden of CAP in real-life settings in European hospitals. This analysis reviews the characteristics and outcomes of patients showing early positive response to treatment (time to clinical stability [TCS] ≤4 days, as assessed by Halm's criteria) compared with patients with later positive response (TCS >4 days). METHODS: Patients were adults, hospitalized with CAP (2010-2011) and requiring in-hospital treatment with intravenous antibiotics. RESULTS: Of the 2039 patients included in REACH, 585 (28.7%) had TCS assessed by Halm's criteria: 332 (56.8%) showed early response (median 3.0 days), and 253 (43.2%) showed later response to treatment (median 7.0 days). Use of Halm's criteria varied across participating countries, ranging from 0% (Belgium) to 49.1% (UK). Patient characteristics and relevant medical history were similar between the two groups. There were no notable differences in initial antibiotic therapy between groups, except that more early responders had been treated with amoxicillin-clavulanate and amoxicillin monotherapy (22.6%; 7.5%, respectively) than later responders (5.9%; 1.2%, respectively). Initial treatment modification and re-infection or recurrences were less frequent in early responders compared with later responders (14.2% and 3.3% vs. 34.8% and 5.9%, respectively). Early responders had a shorter duration of hospitalization (mean 9.4 ± SD 7.0; median 8.0 days vs. mean 15.6 ± SD 10.5; median 12.0 days, respectively), lower rate of ICU admission (3.3% vs. 21.3%) and shorter duration of ICU stay (mean 6.2 ± SD 5.7; median 4.0 days vs. mean 10.4 ± SD 10.1; median 8.0 days, respectively) compared with later responders. Mortality was low in both groups. CONCLUSIONS: Achieving early clinical stabilization in CAP (≤4 days) is associated with improved outcomes, lower requirement for initial treatment modification or readmission and lower resource use, compared with a later response.