Circadian rhythms, insomnia and osteoarthritis pain: Comments on article titled "Circadian rest/activity rhythms in knee osteoarthritis with insomnia: A study of osteoarthritis patients and pain-free controls with insomnia or normal sleep". (21st October 2015) - Frange, Cristina; Hachul, Helena; Tufik, Sergio; Andersen, Monica Levy