Circadian Rythm of COPD symptoms in clinically based phenotypes. Results from Storico Italian observational Study

Background:Chronic Obstructive Pulmonary Disease (COPD) encompasses various phenotypes that severely limitthe applicability of precision respiratory medicine. The present investigation is aimed to assess the circadian rhythmof symptoms in pre-defined clinical COPD phenotypes and its association with health-related quality of life (HR-QoL), the quality of sleep and the level of depression/anxiety in each clinical phenotype.Methods:The STORICO (NCT03105999) Italian observational prospective cohort study enrolled COPD subjects. Aclinical diagnosis of either chronic bronchitis (CB), emphysema (EM) or mixed COPD-asthma (MCA) phenotype wasmade by clinicians at enrollment. Baseline early-morning, day-time and nocturnal symptoms (gathered via theNight-time, Morning and Day-time Symptoms of COPD questionnaire), HR-QoL (via theSt. George's RespiratoryQuestionnaire), anxiety and depression levels (via theHospital Anxiety and Depression Scale), quality of sleep (viaCOPD and Asthma Sleep Impact Scale), physical activity (via theInternational Physical Activity Questionnaire) as well aslung function were recorded.Results:606 COPD subjects (age 71.4 ± 8.2 years, male 75.1%) were studied. 57.9, 35.5 5.3 and 1.3% of the samplebelonged to the CB, EM, MCA and EM + CB phenotypes respectively. The vast majority of subjects reported early-morning and day-time symptoms (79.5 and 79.2% in the CB and 75.8 and 77.7% in the EM groups); the proportionsuffering from night-time symptoms was higher in the CB than in the EM group (53.6% vs. 39.5%,p= 0.0016). Inboth CB and EM, indiscriminately, the presence of symptoms during the 24-h day was associated with poorer HR-QoL, worse quality of sleep and higher levels of anxiety/depression.Conclusions:The findings highlight the primary classificatory role of nocturnal symptoms in COPD