Sarcopenia and sleep in individuals with chronic obstructive pulmonary disease

To verify the relationship between sarcopenia and sleep in individuals with chronic obstructive pulmonary disease (COPD).

Individuals with COPD were cross-sectionally assessed for lung function (spirometry), sleep (both subjectively [Pittsburgh Sleep Quality Index, PSQI] and objectively [Actiwatch sleep monitor]) and the presence of sarcopenia (handgrip strength by dynamometry). All tests were carried out in accordance with international standards.

Twenty-nine individuals with COPD were analyzed (16 women; 69 ± 7 years; BMI 27 ± 5 kg/m²; FEV₁ 59 ± 19% predicted). Upon division in groups according to the presence or absence of sarcopenia, individuals with sarcopenia (in comparison to those without sarcopenia) had shorter sleep time (81 [75-85] vs. 86 [81-90] %; p = 0.043), lower sleep efficiency (77 [69-83] vs. 85 [75-87] %; p = 0.038), longer time awake after sleep onset (92 [71-120] vs. 58 [47-83] minutes; p = 0.0012) and more marked sleep fragmentation, represented by a higher number of sleep blocks/night (46 [41-49] vs. 34 [26-48]; p = 0.018), higher number of awake blocks/night (45 [40-49] vs. 34 [26-48]; p = 0.018) and shorter duration of sleep blocks/night (9 [8-10] vs. 14 [8-58] minutes; p = 0.043). There was no statistical difference when comparing the PSQI variables between the groups. However, handgrip strength was negatively associated with PSQI components 2 [R= -0.51, p = 0.005] and 5 [R= -0.39, p = 0.037].

Individuals with COPD and sarcopenia (as measured by handgrip strength) have worse objectively measured sleep outcomes. This was not the case regarding a self-reported perception of worse sleep quality, although there was weak-to-moderate association between handgrip strength and subjective sleep.