The Manchester Respiratory-related Sleep Symptoms scale for patients with COPD: development and validation

Abstract

Background

In COPD disturbed sleep is related to exacerbation frequency, poor quality of life, and early mortality. We developed the Manchester Respiratory-related Sleep Symptoms scale (MaRSS) to assess sleep-time symptoms in COPD.

Methods

Focus groups including COPD and age-matched controls were used to develop an item-list, which was then administered to COPD patients and age-matched controls in a cross-sectional study. Hierarchical and Rasch analysis informed item selection and scale unidimensionality. Construct validity was examined using Pearson’s correlation with the Sleep Problems Index, St George’s Respiratory Questionnaire (SGRQ), and FACIT-Fatigue scale. MaRSS change scores from baseline (stable) to exacerbation were assessed in a separate sub-study of COPD patients.

Results

Thirty-six COPD patients and nine age-matched controls produced an initial 26-item list. The cross-sectional study involved 203 COPD patients (male: 63%, mean age 64.7 years) and 50 age-matched controls (male: 56%, mean age 65.8 years). Eighteen items were removed to develop an eight-item unidimensional scale covering breathlessness, chest tightness, cough, sputum production, lack of sleep, and medication use. MaRSS scores significantly correlated with sleep problems, SGRQ Total, and FACIT-Fatigue (r=0.58–0.62) and demonstrated a good fit to the Rasch model (chi-squared=29.2; P=0.04). In the substudy, MaRSS scores demonstrated a moderate effect size from baseline to exacerbation visit in 27 patients with 32 exacerbation episodes (Cohen’s d=0.6).

Conclusion

The MaRSS is a reliable, valid, and clinically responsive measure of respiratory-related symptoms that disturb sleep. It is simple to use and score, making it suitable for research and clinical practice.

Keywords:

• COPD
• sleep
• dyspnea
• cough
• sputum
• outcome measure

Acknowledgments

This partnership received financial support from the Knowledge Transfer Partnerships programme (KTP). KTP is funded by the Technology Strategy Board along with the other government funding organizations (Grant number: KTP:8776). The project was also supported by the UK Medical Research Council.

Disclosure

The authors report no conflicts of interest in this work.

Supplementary materials

Study methods

At each stage, participants were recruited from a database of volunteers with and without COPD (COPD n≥800 and non-COPD n>2,000, respectively) at a respiratory clinical trials unit that works in collaboration with the University Hospital of South Manchester. Potential participants were contacted by telephone to ascertain their interest in taking part. If willing to participate an information pack and consent form were mailed to the patient and a study visit organized.

Inclusion criteria

Inclusion criteria were male and female patients aged 40 years or older diagnosed with COPD by a general practitioner or respiratory specialist using established criteria. These were FEV₁ <80% of predicted normal, FEV₁/FVC <0.70, and symptoms consistent with COPD. Airflow limitation was graded according to post-bronchodilator FEV₁ spirometry: GOLD was classified as FEV₁ ≥80% predicted: Grade 1 (mild); 50% ≤ FEV₁ <80% predicted: Grade 2 (moderate); 30% ≤ FEV₁ <50% predicted: Grade 3 (severe); FEV₁ <30% predicted: Grade 4 (very severe).

Past and current smokers (≥10 pack-year smoking history) were eligible to participate. Inclusion criteria were similar for the controls who may have had alternative long-term conditions, besides COPD. The reason for their inclusion was to eliminate sleep disturbance associated with age or other conditions so that, as far as possible, the final PROM focused on symptoms that were COPD-specific.

Exclusion criteria

Exclusion criteria included a chest infection in the previous 3 months; any other respiratory illness such as asthma, cystic fibrosis, and lung cancer; insufficient English skills to give informed consent and those regularly engaged in activities that could interrupt normal sleeping patterns (eg, night-shift workers).

Global rating of change questionnaire

Stage 4: To assess the test–retest reliability of the new measure. As part of the test–retest reliability of the MaRSS, participants were sent the item-list from Stage 3 and a global rating of change questionnaire. This assessed the stability of their health (much better; somewhat better; about the same; somewhat worse; much worse) since their first study visit. Participants returned the completed questionnaires within 1 week using the prepaid addressed envelope provided. Intraclass correlation coefficients examined test–retest reliability for participants who indicated their general health had remained “about the same” between visits.

Table S1 Symptom areas produced from focus group discussions

Table S2 Individual fit of the eight-item MaRSS to the Rasch unidimensional model

Table S3 Exacerbation-related change scores for MaRSS and CAT questionnaires