Table 6.
Summary of articles using generic sleep measures
| Outcome measure and authors | Study focus | COPD study sample | Measures of COPD severity | Outcome reported (mean ± SD) | Associations |
|---|---|---|---|---|---|
| Berlin Questionnaire Cavalcante et al35 | Occurrence and associations with RLS in a COPD population | 104 hospital outpatient attenders | mMRC 0 (4.8%); 1 and 2 (48.1%); 3 (34.6%); 4 (12.5%) | 30 (29%) of patients had a high probability of OSA | Risk of OSA not associated with RLS (P=0.25) |
| BNSQ Saaresranta et al41 | Sleep quality and excessive daytime sleepiness in ambulatory patients with moderate to severe COPD | 15 consecutive female clinic outpatients | FEV1 predicted <65% of daytime hypoxemia (PaO2 <10.0 kPa) and/or hypercapnia (PaCO2 >6.0 kPa); FEV1 % 36±12; FVC % 63±14; FEV1 (L) 0.73±0.45 (range 0.25–1.8); FVC (L) 1.3±0.45 | BNSQ 9.9±3.0 | BNSQ score higher than controls (9.9±3.0 versus 7.6±3.2; P=0.025) and correlated with insulin levels (r=0.59, P=0.027) and body movements (r=0.52, P=0.047) |
| IRLSG Lo Coco et al33 | Prevalence, severity, and associations with RLS in COPD patients | 87 COPD outpatients | GOLD stage II, 42.5%; stage III, 40.2%; stage IV, 17.3% | IRLSG score 32 (36.8%) | IRLSG score in COPD patients 20.5±2.8 versus 18.0±3.5 in controls (P=0.016); moderate correlation between ESS and IRLSG score (Spearman correlation 0.489, P=0.01) |
| SDQ Valipour et al42 | Differences in symptoms and polysomnographic parameters in COPD patients | 52 consecutive hospital outpatients | FEV1% predicted 60±10; FVC % predicted 93±12; FEV1/FVC 60±8 | SA 36.0±6.9 PLM 25.2±7.1 PSY 18.0±6.0 Narcolepsy 22.1±5.5 |
COPD patients had higher scores in PLM (25.2±7.1 versus 21.1±6.2, P=0.0003) and PSY (18.0±6.0 versus 15.3±5.0, P=0.035) Minimum SaO2 had an independent effect on SDQ subscale scores: SA (P=0.045), PLM (P=0.051), PSY (P=0.037), and narcolepsy (P=0.053) Mean overnight SaO2 was a significant predictor of PSY score (P=0.015) |
Abbreviations: BNSQ, Basic Nordic Sleep Questionnaire; COPD, chronic obstructive pulmonary disease; PLM, periodic limb movement; SDQ, Sleep Disorders Questionnaire; PSY, psychiatric sleep disorder; RLS, restless leg syndrome; IRLSG, International Restless Leg Study Group; SA, sleep apnea; FVC, forced vital capacity; FEV1, forced expiratory volume in 1 second; OSA, obstructive sleep apnea; mMRC, modified Medical Research Council Dyspnea scale; GOLD, Global initiative for chronic Obstructive Lung Disease; SaO2, arterial oxygen saturation; ESS, Epworth Sleepiness Scale; PaCO2, partial pressure of carbon dioxide; PaO2; hypercapnia PaCO.