Lung function didnot decrease significantly during the prodromal period, but byDay 0, PEFR had fallen from baseline by a median 8.6 (IQR 0to 22.9) L/min, FEV1 by 24.0 (IQR 216.1 to 84.3) ml, and FVCby 76.0 (IQR 240.4 to 216.4) ml. The declines in lung func-tion, whether measured by PEFR, FEV1, or FVC, were allhighly significant (p , 0.001). Significantly greater decreasesin PEFR were seen when the exacerbation was associated withsymptoms of increased dyspnea (r 5 20.12 [n 5 449]; p 50.014), colds (r 5 20.09 [n 5 449]; p 5 0.047), or increasedwheeze (r 5 20.12 [n 5 449]; p 5 0.009), but not with othersymptoms.

Before onset of exacerbation there was deterioration inthe symptoms of dyspnea, sore throat, cough, and symptoms of acommon cold (all p , 0.05), but not lung function.

Combined initial COPD assessment

It should be noted that the use of a fixed FEV1/FVC ratio (< 0.7) to define airflowobstruction may result in over-diagnosis of COPD in the elderly,(30,31) and under-diagnosis in young adults,(31

Case

There have now been several large population studies (8–10)showing that the number and severity of exacerbations are lowerin patients with mild to moderate COPD (FEV1  50% pre-dicted), whereas in severe disease the rate of COPD exacerba-tions may increase to 1.5 to 2.5/patient/yr.

Recently, Williams et al. sug-gested that the incremental shuttle walking test (ISWT)could be substituted for the 6MWT as an alternativemeasure of exercise capacity within the index and intro-duced the i-BODE (4). As field exercise tests, the ISWTand 6MWT are closely related (5, 6), though ISWT isconsidered to be closer to a maximal exercise test (7),whereas the 6MWT reflects a more functional exerciseperformance

Subjects were followed-up at 3 months, 6 months, and every 6 monthsthereafter for a maximum of 3 years. All patients had their vital statusconfirmed 3 years after recruitment.Information on COPD exacerbations was collected at scheduled visitsby investigators using the case report forms and based on either sub-jects’ recall of exacerbation events or available medical records for exac-erbation events, supplemented by monthly phone calls. For the purposeof the current analysis, we focused on those exacerbation episodes thatrequired hospital admission (hospitalized exacerbation).

Multicomponent scales have been developed toimprove prognosis prediction in COPD, and they haveproved to be better predictors of survival than anyisolated variable.

This newly proposed CODEX index is essentially anevolution of the BODE and BODEX indexes, retain-ing their cutoffs for dyspnea, obstruction, and previousexacerbations, but replacing BMI with comorbiditymeasured using the original Charlson index modifiedby age.

BODE2 (body mass index [BMI], airflow obstruction, dyspnea, andexercise capacity), BODEX3 (BMI, airflow obstruction, dyspnea, and previous severeexacerbations), ADO4 (age, dyspnea, and airflow obstruction), and DOSE5 (dyspnea,airflow obstruction, smoking status, and exacerbation frequency

We were not able to include all potential predictorsavailable from the literature, such as exercise capacity, theSt George’s Respiratory Questionnaire, oxygen therapy,and gastroesophageal reflux

(EXACT)

such as bloodeosinophil count, chronic bronchitis, gastroesophagealreflux, socioeconomic status, and insurance coverageimprove risk prediction remains to be investigated.

Second, ACCEPT does not advance ourunderstanding of how various risk factors operatein combination. Many variables appear to be simplymarkers of severity rather than biological predictors ofreal risk. The authors address one of these: contrary toestablished literature, current smoking confers reducedrisk of exacerbation, probably because patients withsevere disease and high frequency of exacerbations aremore likely to have quit smoking.

Finally, preventionof severe exacerbations is needed before they occur,and performance of this risk tool in individuals whohave never had an exacerbation is not clear and needsto be tested.

HOME OR OFFICE MANAGEMENT OF COPD EXACERBATIONS

More than 80percent of exacerbations of COPD can be managed on an outpatient basis, sometimes afterinitial treatment in the office or emergency department.

ADVICE RELATED TO COVID-19

Vitamin D supplementation — Adhering to current guidelines regarding vitamin Dsupplementation in patients with a 25-hydroxyvitamin D level <20 or 30 ng/mL (50 or 75nmol/L) reduces COPD exacerbations in addition to benefits in reducing falls and fractures

Noninvasive ventilation — For patients who require noninvasive ventilation (NIV) during ahospitalization for a COPD exacerbations and who remain hypercapnic, nocturnal NIV athome significantly reduces the risk of rehospitalization

Prophylactic azithromycin

PREVENTION

Pulmonary rehabilitation

Smoking cessation (see "Overview of smoking cessation management in adults")•Proper use of medications (including inhaler technique) ( table 5 and table 6and table 7 and table 8) (see "The use of inhaler devices in adults")•Vaccination against seasonal influenza (see "Seasonal influenza vaccination inadults")•Vaccination against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)(see "COVID-19: Vaccines")•Pneumococcal vaccination ( figure 1) (see "Pneumococcal vaccination in adults")