Point-of-care CRP testing helps curb antibiotic use for COPD exacerbations
Using point-of-care testing (POCT) of C-reactive protein (CRP) to guide antibiotic prescribing in primary care clinics led to reduced antibiotic use for acute exacerbations of chronic obstructive pulmonary disease (COPD) without compromising clinical outcomes, the PACE* study finds.
“We were able to achieve a reduction in antibiotic use that is about twice the magnitude of that achieved by most other antimicrobial stewardship interventions, and demonstrate that this approach was safe,” said senior investigator Professor Nick Francis from Cardiff University's School of Medicine, Cardiff, UK.
As treatment failure for acute exacerbations of COPD can place patients at risk of serious complications such as respiratory decompensation and hospitalization, “clinicians are tempted to err on the side of doing more, which usually entails prescribing both oral glucocorticoids and antibiotics,” wrote Drs Allan Brett and Majdi Al‑Hasan from University of South Carolina School of Medicine, Columbia, South Carolina, US in an accompanying editorial. [N Engl J Med 2019;381:174-175]
“However, not all acute exacerbations are provoked by respiratory tract infection, and of those that are, it is difficult to distinguish whether viruses or bacteria are responsible,” they highlighted. “The dilemma is to identify patients who are most likely to benefit from antibiotics while avoiding unnecessary antibiotic use.”
To address the question of when to initiate antibiotic treatment, the PACE investigators randomized 653 patients (mean age 68.1 years, 51.6 percent male) with COPD (54.8 percent with moderate COPD [GOLD stage II]) who presented with acute exacerbations of COPD at primary care clinics in a 1:1 ratio to receive CRP-guided usual care or usual care alone. [N Engl J Med 2019;381:111-120]
CRP is an acute-phase biomarker previously shown to predict response to antibiotics. According to guidance given to clinicians in the study, antibiotics are unlikely to be beneficial if CRP falls <20 mg/L, likely to be beneficial if CRP exceeds 40 mg/L, and possibly beneficial if CRP levels is between these extremes coupled with presence of purulent sputum. However, clinicians were also advised that “antibiotic prescribing should be based on a comprehensive assessment of likely risks and benefits, given a patient’s underlying health status and clinical features,” rather than on CRP level alone.
Significantly fewer patients who underwent POCT for CRP reported antibiotic use during the first 4 weeks of follow-up than the usual-care group (57.0 percent vs 77.4 percent, adjusted odds ratio [OR], 0.31, 95 percent confidence interval [CI], 0.20 to 0.47).
There were also fewer patients in the CRP-guided arm who were prescribed antibiotics for acute COPD exacerbation at the initial visit (47.7 percent vs 69.7 percent, OR, 0.31, 95 percent CI, 0.21–0.45) and during the following 4 weeks (59.1 percent vs 79.7 percent, OR, 0.30, 95 percent CI, 0.20–0.46).
Furthermore, the coprimary endpoint of health status at 2 weeks, as assessed by the Clinical COPD Questionnaire, showed a difference of -0.19 (two-sided 90 percent CI, −0.33 to −0.05) in the total score between groups, in favour of CRP-guided care.
“[This] indicates that less antibiotic use and fewer prescriptions from clinicians did not compromise patient-reported disease-specific quality of life,” said the researchers.
“The findings from this study are compelling enough to support CRP testing as an adjunctive measure to guide antibiotic use in patients with acute exacerbations of COPD,” lauded Brett and Al‑Hasan.
“[Nonetheless,] it does not establish which patients (if any) truly benefit from antibiotic therapy or which antibiotics are most appropriate for COPD exacerbations,” they stated. “Additional clinical trials will be necessary to address these uncertainties.”