Related Experiment Video
Updated: May 17, 2026
Alternative Therapy for Acute Exacerbation of Chronic Obstructive Pulmonary Disease: Moving Cupping Along Meridians
Published on: September 27, 2024
Number needed to treat in COPD: exacerbations versus pneumonias
1Centre for Clinical Epidemiology, Lady Davis Institute-Jewish General Hospital, Montreal,Quebec, Canada.
Background:
Several recent trials in chronic obstructive pulmonary disease (COPD) have assessed the effectiveness of the fluticasone-salmeterol combination inhaler in preventing COPD exacerbations, while finding an increased risk of pneumonia. The number needed to treat (NNT) is a simple measure to perform the comparative benefit-risk impact, but its calculation involving repeated outcome events such as COPD exacerbations has been incorrect. We describe the proper methods to calculate the NNT and, using data from published trials, apply them to evaluate the relative impact of fluticasone-salmeterol treatment on exacerbations and pneumonias in patients with COPD.
Methods:
We review the fundamental definition of NNT and quantify it for situations with varying follow-up times. We review the 'event-based' NNT, proposed and used for repeated event outcomes, show its inaccuracy, describe its proper use and provide an approximate formula for its application.
Results:
We show that a 1-year trial of the fluticasone-salmeterol combination versus salmeterol used the incorrect event-based approach to calculate the NNT as two patients that need to be treated for 1 year to prevent one COPD exacerbation, when the proper calculation results in a NNT of 14. In contrast, 20 patients need to be treated to induce one pneumonia case. For the TORCH trial, the NNT is 44 patients treated for 3 years with fluticasone-salmeterol versus salmeterol to prevent one exacerbation compared with 16 patients to induce one pneumonia case.
Conclusions:
The NNT is a useful measure of the effect of drugs, but its proper calculation is essential to prevent misleading clinical practice guidelines.
Related Concept Videos
01:28Pneumonia IV: Management
Bacterial Pneumonia Treatment
For bacterial pneumonia, antibiotics serve as the cornerstone of therapy. Initial treatment often begins with empirical antibiotics, tailored to the anticipated causative organism and adjusted based on culture results. Key antibiotic choices include:
01:26COPD: Management Using Bronchodilators and Corticosteroids
01:29Chronic Obstructive Pulmonary Disease-V: Management
Smoking Cessation
01:24Chronic Obstructive Pulmonary Disease
Smoking is a primary risk factor for COPD, with over 80% of patients having a history of it. Patients typically experience progressive dyspnea or labored breathing, frequent coughing, and recurrent pulmonary infections. Many eventually succumb to respiratory failure, characterized by...
01:30Pneumonia V: Nursing management and Prevention
The nurse must practice strict medical asepsis and adhere to infection control guidelines to minimize healthcare-associated infections.
Enhance airway patency
Position the patient correctly to facilitate drainage of the affected lung segments. Manual or mechanical percussion and vibration can also be employed.
01:20Chronic Obstructive Pulmonary Disease-I: Introduction