Disease Course of Lower Respiratory Tract Infection With a Bacterial Cause

Jolien Teepe, MD, MSc; Berna D. L. Broekhuizen, MD, PhD; Katherine Loens, PhD; Christine Lammens, MSc; Margareta Ieven, PhD; Herman Goossens, MD, PhD; Paul Little, MD, PhD; Christopher C. Butler, MD, PhD; Samuel Coenen, MD, PhD; Maciek Godycki-Cwirko, MD, PhD; Theo Verheij, MD, PhD

Disclosures

Ann Fam Med. 2016;14(6):534-539. 

In This Article

Abstract and Introduction

Abstract

Purpose Bacterial pathogens are assumed to cause an illness course different from that of nonbacterial causes of acute cough, but evidence is lacking. We evaluated the disease course of lower respiratory tract infection (LRTI) with a bacterial cause in adults with acute cough.

Methods We conducted a secondary analysis of a multicenter European trial in which 2,061 adults with acute cough (28 days' duration or less) were recruited from primary care and randomized to amoxicillin or placebo. For this analysis only patients in the placebo group (n = 1,021) were included, reflecting the natural course of disease. Standardized microbiological and serological analyses were performed at baseline to define a bacterial cause. All patients recorded symptoms in a diary for 4 weeks. The disease course between those with and without a bacterial cause was compared by symptom severity in days 2 to 4, duration of symptoms rated moderately bad or worse, and a return consultation.

Results Of 1,021 eligible patients, 187 were excluded for missing diary records, leaving 834 patients, of whom 162 had bacterial LRTI. Patients with bacterial LRTI had worse symptoms at day 2 to 4 after the first office visit (P = .014) and returned more often for a second consultation, 27% vs 17%, than those without bacterial LRTI (P = .004). Resolution of symptoms rated moderately bad or worse did not differ (P = .375).

Conclusions Patients with acute bacterial LRTI have a slightly worse course of disease when compared with those without an identified bacterial cause, but the relevance of this difference is not meaningful.

Introduction

Lower respiratory tract infections (LRTIs) are among the most common reasons for consulting in primary care,[1] and physicians usually treat LRTI empirically based on clinical assessment without microbiological testing for the causal pathogen. Bacterial pathogens are often assumed to result in a different illness course than nonbacterial causes of acute cough, but knowledge of actual difference is lacking. In the few studies where potential pathogens have been systematically isolated from primary care patients with LRTI, a bacterial pathogen was identified in 19% to 43% of patients.[1–4] Difference in illness course, however, was not evaluated in these studies. Knowledge of actual illness course of bacterial LRTI compared with other LRTIs may be helpful in several ways. Physicians fear missing bacterial LRTI because they generally assume that disease course is more severe and prolonged in these patients and prescribe antibiotics as a defensive strategy.[5] As many of these antibiotics may not benefit patients, cause unwanted effects, and drive antimicrobial resistance,[6–9] insight into the illness course of bacterial LRTI untreated with antibiotics could help guide empirical antibiotic prescribing, support a strategy of initial observation (watchful waiting), and help set evidence-based expectations about the disease course for patients.

The aim of the present study was to describe the illness course of patients consulting in primary care with LRTI in whom a bacterial pathogen was isolated, and to compare their illness course with that of LRTI patients with no bacterial pathogen.

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