Sarcopenia and sleep in individuals with chronic obstructive pulmonary disease.

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

Methods: 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.

Results: Twenty-nine individuals with COPD were analyzed (16 women; 69 ± 7 years; BMI 27 ± 5 kg/m; FEV 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].

Conclusion: 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.