Patient-reported sleep quality was a significant and clinically meaningful predictor of multiple metrics of quality of life (QoL) in patients with chronic obstructive pulmonary disease (COPD), according to the results of the SPIROMICS cohort study (ClinicalTrials.gov Identifier: NCT01969344) published in Sleep.
Because sleep quality is known to be poor in patients with COPD and sleep disturbance is linked to low overall QoL in this population, the investigators sought to evaluate the effect of patient-reported sleep quality and the risk for obstructive sleep apnea (OSA) on disease-specific and overall QoL after accounting for demographics and disease severity.
Baseline data were collected from a total of 1341 participants; 892 were diagnosed with mild to moderate COPD (forced expiratory volume in 1 second [FEV1] ≥50% predicted) and 449 with severe COPD (FEV1 <50% predicted), in order to perform 3 nested regression models to predict QoL: Short Form-12 mental and physical components and St. George’s Respiratory Questionnaire. Dependent measures were used for the nested regressions: block 1: demographics and smoking history, block 2: disease severity (FEV1, 6-minute walk test), block 3: risk for OSA (Berlin Questionnaire), and block 4: sleep quality (Pittsburgh Sleep Quality Index).
Participants were aged 40 to 80 years, and those Patients with COPD had a smoking history of ≥20 pack-years. All participants were categorized into 4 strata: stratum 1: nonsmoker comparison participants, stratum 2: smokers without COPD, stratum 3: individuals with mild to moderate COPD, and stratum 4: individuals with severe or very severe COPD.
More than half of the participants with COPD reported poor sleep quality (mean Pittsburgh Sleep Quality Index, 6.4±3.9; 50% with a high-risk score on the Berlin Questionnaire). In all 3 of the nested regression models, sleep quality (block 4) was a significant predictor of poor QoL, over and above all of the variables in blocks 1 to 3 (P <.001).
The investigators concluded that poor sleep quality is a potentially modifiable risk factor for poor QoL in patients with COPD. Improvement in sleep quality in this population appears to be an important target for clinical interventions. Therefore, studies that combine optimal management of COPD symptoms with treatment of sleep disorders would help inform management of patients with COPD and potentially improve their QoL.
Zeidler MR, Martin JL, Kleerup EC, et al; SPIROMICS Research Group. Sleep disruption as a predictor of quality of life among patients in the Subpopulations and Intermediate Outcome Measures in COPD Study (SPIROMICS) [published online March 9, 2018]. Sleep. doi:10.1093/sleep/zsy044